биота российских вод японского моря - Materials of Alexey Shipunov

BIOTA OF THE RUSSIAN WATERS OF THE SEA OF JAPANVolume 1CRUSTACEA(CLADOCERA, LEPTOSTRACA, MYSIDACEA,EUPHAUSIACEA)AND PYCNOGONIDAPart 2Edited byA.V. AdrianovVLADIVOSTOKDALNAUKA2007

БИОТА РОССИЙСКИХ ВОД ЯПОНСКОГО МОРЯТом 1РАКООБРАЗНЫЕ(ВЕТВИСТОУСЫЕ, ТОНКОПАНЦИРНЫЕ, МИЗИДЫ,ЭВФАУЗИИДЫ)И МОРСКИЕ ПАУКИЧасть 2Под редакциейакадемика А.В. АдриановаВЛАДИВОСТОКДАЛЬНАУКА2007

УДК 595 (571.6)Биота российских вод Японского моря. Т. 1, ч. 2.Ракообразные (ветвистоусые, тонкопанцирные, мизиды, эвфаузииды) и морские пауки /В.В. Петряшев, Е.П. Турпаева, И.К. Ривьер, Л.С. Школдина, А.Г. Погодин, Б.M. Борисов; под ред.А.В. Адрианова. Владивосток: Дальнаука, 2007. 161 с.ISBN 978-5-8044-0736-8В англоязычной версии первого тома определителя (русскоязычная версия вышла в 2004 г.)рассматриваются два отряда класса жаброногих ракообразных (Ctenopoda и Onychopoda), три отрядакласса высших раков (Leptostraca, Mysidacea и Euphausiacea) и класс морские пауки. Всего в книгеописано 11 семейств, 37 родов и 81 вид и подвид, известные в российских водах Японского моря исопредельных акваторий. Для каждой группы даны краткая морфологическая характеристика, сведенияпо биологии и определительные таблицы семейств, родов и видов. Для видов приведены синонимия,описания, сведения о распространении и биологии.Книга предназначена для морских биологов, зоологов, преподавателей и студентов-биологов.Ил. 52 табл.-рис., 2 карты; библ. 218.Biota of the Russian Waters of the Sea of Japan. Vol. 1, part 2.Ed.-in-Chief A.V. AdrianovCrustacea (Cladocera, Leptostraca, Mysidacea, Euphausiacea) and Pycnogonida / V.V. Petryashov,E.P. Turpaeva, I.K. Rivyer, L.S. Shkoldina, A.G. Pogodin, B.M. Borisov;Ed. by. A.V. Adrianov. Vladivostok: Dalnauka, 2007. 161 p.ISBN 978-5-8044-0736-8The English version of the first volume of the Key (the Russian one was published in 2004) includestwo orders of the class Branchiopoda (Ctenopoda and Onychopoda), three orders of the classMalacostraca (Leptostraca, Mysidacea and Euphausiacea) and the class Pycnogonida. Totally 11 families,37 genera and 81 species and subspecies from the Russian waters of the Sea of Japan and adjacent watersare treated in the book. Morphological and biological data, keys to families, genera and species for eachgroup are given. Description of the species is supplemented with synonyms, distribution and biologicaldata.The book is intended for marine biologists, zoologists, and lecturers and students of the biologicaldepartments.The book is illustrated by 52 plates of figures and 2 maps; bibl. 218.Редакционная коллегия серии:А.В. Адрианов (главный редактор), Г.В. Коновалова, В.В. Михайлов,С.Е. Поздняков, Б.И. Сиренко, С.Д. Степаньянц, В.Г. Чавтур,А.В. Чернышев (отв. секретарь)E-mail: inmarbio@mail.primorye.ruРедакционная коллегия тома:А.В. Адрианов (отв. редактор), А.В. Чернышев, В.Г. ЧавтурРецензент В.А. КудряшовISBN 978-5-8044-0736-8 (т. 1, ч. 2) © Колл. авторов, 2007ISBN 5-8044-0408-3 © Институт биологии моря ДВО РАН, 2007© Дальнаука, 2007

FOREWORDIn memory of Oleg Grigorievich Kussakinand Vladimir Leonidovich KasyanovThe Russian version of the present volume published in 2004 was the first in a seriesof identification keys Biota of the Russian Waters of the Sea of Japan. The need topublish such kind of books has been pressing for a long time, as it is on the coast of theSea of Japan that many scientific institutions and universities, which conduct complexresearch of animals, plants, fungi, and microorganisms of the Russian Far East, arelocated. Sixty-seven scientists from nine cities of the Russian Federation and Ukrainetake part in this unique project. Five volumes, devoted to several groups of crustaceans,sea spiders, prokaryotes, phoronids, and brachiopods have been already publishedby now.The keys will comprise all known species of free-living and symbiotic organismsfound in the Russian waters of the Sea of Japan (figs. 1, 2): from the mouth of the Tumen(Tumannaya) River in the south to the northern boundary of the Tatar Strait,going along the line between Tyk Cape (51°45′ N, 141°41′ E) and Yuzhny Cape(51°41′ N, 141°06′ E), and to the western boundary of the La Perouse (Soya) Strait,going along the line between Kuznetsov Cape (46°03′ N, 141°55′ E) and NoshappuCape (45°27′ N, 141°39′ E). In cases of poorly studied groups of organisms, speciesfrom the adjacent water areas of the Sea of Japan and Sea of Okhotsk will be included.The first volume of the key Biota of the Russian Waters of the Sea of Japan isdevoted to the sea spiders and to four groups of crustaceans (Cladocera, Mysidacea,Leptostraca, and Euphausiacea). The chapter on the Cladocera was written by Irina K.Rivier (I.D. Papanin Institute for Biology of Inland Waters, Russian Academy ofSciences (RAS), Borok Village) and Larissa S. Shkoldina (Institute of Marine Biology,Far Eastern Branch of the RAS, Vladivostok), the chapters on the Leptostraca andMysidacea, by Viktor V. Petryashov (Zoological Institute, RAS, St.-Petersburg), thechapter on the Euphasiacea, by Viktor V. Petryashov, Artur G. Pogodin (Institute ofMarine Biology, Vladivostok), and Boris M. Borisov (Far Eastern Regional HydrometeorologicalResearch Institute, Vladovostok), and the chapter on the Pycnogonida, byElena P. Turpaeva (P.P. Shirshov Institute of Oceanology, RAS, Moscow).The Russian version was edited by Oleg G. Kussakin, Vladimir L. Kasyanov,Vladimir G. Chavtur, and Alexey V. Chernyshev. The preparation for publication beganunder the supervision of Oleg G. Kussakin, who, before his death, checked all themanuscripts and began to write a chapter on isopods. On the initiative of Vladimir L.Kasyanov, Director of the IMB, Biota… is published in two languages, Russian andEnglish, and only the first volume was not translated. It took two years to prepare theEnglish version, which was also slightly updated by the authors.Translation into English was performed by N.V. Miroshnikova. The dummylayout was made by E.S. Moroz. The Far Eastern Branch of the Russian Academy ofSciences provided technical support and helped with publication (basic research program"Biodiversity" of the Presidium of the Russian Academy of Sciences, grantN 06-I-P11-037).Editorial board7

Fig. 1. Map of the northern part of the Sea of JapanFig. 2. Map of Peter the Great Bay8

SUBPHYLUM CRUSTACEACLASS BRANCHIOPODA Latreille, 1817Superorder CLADOCERAMilne-Edwards, 1840 sensu Negrea et al., 1999Irina K. Rivier 1 , Larissa S. Shkoldina 2General characteristics 3Cladocerans (superorder Cladocera) is a peculiar group of very small (usuallysmaller than 1 mm, rarer up to 4 mm) planktonic crustaceans of freshwater origin.They inhabit various continental and marine waters, where they are abundant and oftendominate.The body of most cladocerans is enclosed in a thin transparent shell, the dorsalpart of which (brood pouch) bears embryos, while the lateral parts (valves) protectthoracic limbs in filter-feeding cladocerans; in predatory cladocerans the valves arenot developed. Marine forms (Penilia and Podonidae) have the enclosed brood pouchcovered by shell, which isolates embryos from the external environment. In the Podonidaethe shell containing the brood pouch is enlarged; it grows together with embryosand has a hydrostatic function as well.The body of cladocerans is divided into a head, a thorax, a usually reduced abdomen,and a postabdomen (cauda). There is a compound eye and an ocellus (“naupliuseye”), which is reduced in some taxa. The first pair of antennae (antennules)represents sense organs provided with papillae (aestetascs) and short sensory setae,obviously performing a tactile function. In males the antennules are usually movableand longer than in females. Antennae 2 are locomotory organs. The mouth parts(mandibles, maxillulae and maxillae) are situated posteriorly. They are used to manipulateand push food particles into the gut. The body is indistinctly segmented andprovided with four to six pairs of thoracic limbs, being filtering organs in most cladoceransand grasping organs in predators. The postabdomen is situated posteriorly andusually provided with claws and “swimming” setae (setae natatoriae).The distinctive feature of the cladocerans’ life cycle is direct development (excludingthe genus Leptodora, which has the stage of a metanauplius larva; the Leptodoridaeare presently separated in the superorder Leptodorida) and the alternation ofgamogenetic and parthenogenetic reproduction, including the stage of a resting (latent)egg. Hatching newborn cladocerans (the first generation) from resting eggs give rise toseveral parthenogenetic generations. In most cladocerans parthenogenetic eggs devel-1 I.K. Rivier is the author of the systematic part of the chapter “Podonidae” and of the figuresof Podonidae (excluding figs. 1–3, 5 in pl. VIII).2 L.S. Shkoldina is the author of the chapter “Sididae” and figures 1–4 in plate I (Penilia avirostris).3 The chapter “General description” and the parts concerning distribution, biology, and ecologyare written by the authors in collaboration.9

oping in the brood pouch have a full reserve of nutrients for embryos. But in membersof the genus Penilia and the Onychopoda (Polyphemoidea) parthenogenetic eggs donot have the same reserve and get nutrients from the inner hypodermic wall of thebrood pouch. Eggs develop in the brood pouch into tiny young cladocerans, whichhatch out and grow into adults, going through several ecdyses. The young of the Polyphemoidaehatch out by the destruction of female’s brood pouch; these young are bornsexually mature.The appearance of males in populations depends on unfavourable conditions. Afterfertilization the ovicell begins to accumulate yolk in the ovary. After the period oftrophoplasmatic growth in the ovary, resting eggs having only an elastic membraneflow to the brood pouch where dense chitinous membranes are formed. In the podonidsat complete ripening of the eggs the death of a female follows, and the restingeggs sink to the bottom (Swammerdam, 1685). Unlike the Cercopagidae, amongwhich particular gamogenetic females appear, in the Podonidae the resting eggs aredeveloped in parthenogenetic females after fertilization. The resting egg, covered withthick chitinous membranes protecting it from unfavourable environment conditions,rests on oozy sediments.The present work is based on the taxonomic system, by which the superorderCladocera includes three orders: Ctenopoda (two families), Anomopoda (ten families),and Onychopoda (three families) (Dumont & Negrea, 2002). The superorder Cladoceracontains more than 450 species belonging to 52 genera. Most cladocerans (95%) arefound in freshwater habitats, 3% (about 30 species) – in brackish water habitats (includinglandlocked seas, e.g. the Caspian and the Aral), and only eight species occurin marine environments (Bowman & Abele, 1982). One of these species belongs to thefamily Sididae (Penilia avirostris Dana, 1849), and other seven to the family Podonidae.All eight species occur in the Sea of Japan, and seven of them, excluding Podonintermedius Lilljeborg, 1853, are found in its northwestern part (Peter the Great Bay).Most cladocerans, including Sididae, are filter feeders; they feed on algae, bacteria,and detritus. Species of the order Onychopoda (Polyphemoidea) are mostly predators,feeding on larger organisms (small crustaceans, rotifers, protozoans, and algae).Cladocerans represent the important trophic part of plankton communities, being consumersof organic matter and food for other organisms, particularly for fishes.Cladocerans are typical neritic species of the Sea of Japan. The coastal zone inhabitedby various neritic animals is 3–5 miles wide in the northern part of the Sea ofJapan, narrowing southward to a width of 0.5–1 mile within the Korea Strait and expandingto 7–10 miles in the eastern part of the sea near the Korea Strait (Kun &Meshcheryakova, 1954; Kun, 1975). Currents may bring cladocerans to the open sea(Brodsky, 1955; Meshcheryakova, 1960; Miklukhina, 1967). Some species of the superorder(Pseudevadne tergestina, Podon leuckarti, Pleopis polyphemoides, and Peniliaavirostris) are indicators of coastal surface water conditions (Biryulin et al., 1970).In summer cladocerans may be abundant in the neritic zone. They are common andoften dominate and subdominate in the plankton of Peter the Great Bay.Specimens for drawing some missing biological stages of four species of the podonids(Podon leuckarti, Pleopis polyphemoides, Evadne nordmanni, and Pseudevadnetergestina) were picked out from the plankton samples collected in 1996–2002in Vostok Bay (Peter the Great Bay) and in the south-western part of Peter the GreatBay.10

Main references: Manuilova, 1964; Mordukhai-Boltovskoi & Rivier, 1987;Rivier, 1998; Dumont, Negrea, 2002.Systematic partKEY TO MARINE FAMILIES OF THE CLADOCERA1(2). Shell oblong, with well-developed valves, not fused ventrally, covering 6 pairs ofthoracic leaf-shaped limbs ....................................... I. Sididae Baird, 1850 (p. 11)2(1). Shell conical or oval, without valves, not covering 4 pairs of cylindrical thoraciclimbs .................................... II. Podonidae Mordukhai-Boltovskoi, 1968 (p. 14)Order CTENOPODA Sars, 1865I. Family SIDIDAE Baird, 1850Shell oblong, elongated, oval; valves cover body with all appendages. Head relativelylarge, distinctly separated from body. Antennules movable, with 9 (Sidinae) or 6(Peniliinae) estetascs, short in females, long and provided with long flagellum inmales. Swimming antennae well developed, long, robust, biramous; exopod with numerous(not less than 8) plumose setae, situated at apex, as well as on sides of segments.Body provided with 6 pairs of leaf-shaped thoracic limbs of similar arrangement;endopods of 5 anterior pairs armed with rows of long filtratory setae. Postabdomenelongated, smooth, or armed with spines or setae.Cladocerans of this family are filter feeders, eating microscopic algae, fine detritus,and bacteria. The family consists of two subfamilies. Members of one genus of thesubfamily Peniliinae Dana, 1849 inhabit marine waters.Subfamily Peniliinae Dana, 1849Female head ventrally with two rostral outgrowths. Antennule with 6 aestetascs.Adults with big dorsal organ. Both branches of swimming antenna 2-segmented.Brood pouch closed; parthenogenetic eggs with little yolk; maxillary glands rounded,without long bending nephridial canals. Rudimentary epipodites present only on thoraciclimbs 3 and 4. Postabdominal claws much longer than postabdomen itself.Genus Penilia Dana, 1849Type species: Penilia avirostris Dana, 1849.The diagnosis of the genus coincides with the diagnosis of the subfamily.The genus presumably consists of one species. Korovchinsky (2004) notes that P.avirostris has not yet been studied in detail over its wide geographical range and thereforeshould be regarded as a problematic taxon.11

Biology and ecology. P. avirostris is a typical neritic warm-water species and acommon member of plankton communities in the coastal waters of the subtropical andtropical zones of the ocean. It is most abundant near river estuaries (Goswami & Devassy,1991) and may come to river mouths, too (Egborge et al., 1994). In subtropicaland tropical regions P. avirostris occurs at a depth of 30 m or near the bottom anddoes not make daily migrations (Mullin & Onbe, 1992; Onbe & Ikeda, 1995). In Peterthe Great Bay in the regions 30–70 m deep the species was collected only from warmupper layer, not deeper than 20 m.The species is most abundant usually in the middle of summer. In the Inland Seaof Japan it appears as early as late May, and the density is highest in mid-July (up to10–60 thousand sp./m 3 ); in September-October cladocerans disappear from the plankton(Onbe, 1974; Onbe & Ikeda, 1995). The temperature and salinity ranges of thespecies are wide: in the coastal waters of China, namely near Hong Kong, it was foundat a temperature of 16–32˚C and a salinity of 7.3–37.2‰ (Tang et al., 1995). In thenorth-western part of the Sea of Japan peaks of P. avirostris density have been recordedfor later periods. In the southern part of Amursky Bay (Alekseev Bight of PopovIsland, in 1973) P. avirostris appeared in July at a temperature of 17.9˚C; it was one ofthe most abundant (2245 sp./m 3 ) plankters in August at 21.1˚C; in September at17.9˚C its density was 388 sp./m 3 ; in October its numbers drastically decreased to disappearby the end of the month (Mikulich & Biryulina, 1977). The species was notfound in Peter the Great Bay during the “cold” years of 1962–1967 (Kos, 1969, 1974,1976, 1977). In the south-western part of Peter the Great Bay P. avirostris appearssporadically in mid-July at a temperature of 14–17°C and attains maximum density(up to 560 sp./m 3 ) in late August at 20–22°C. In the eastern part of Peter the Great Baythe species is recorded for periods shorter than in the western part. In Vostok Bay it isusually found when the water is warmest (21.8–22.4°C), in late August and in September,reaching a density of 500 sp./m 3 P. avirostris occurs in Peter the Great Bay tillthe end of September or to October (Shkoldina, 2001).Subitaneous (summer) eggs of P. avirostris are alecithal, they are nourishedthrough the brood pouch. Every female bears from two to nine parthenogenetic embryos,Onbe (1974) recorded the highest (seven-nine) number of such embryos forJune. The process of embryonic development divides into 12 stages (Della Croce &Bettanin, 1965). Generally the eggs develop in the brood pouch for three-four days,but sometimes the period shortens to just 30 hours; during 36–40 days the parthenogeneticfemale produces six generations (Onbe, 1978a). Females with resting eggs appearin the population when its density is highest (for the Inland Sea of Japan – in lateJuly), making 1–2% of the whole number of specimens. Gamogenesis intensifies, andthe number of the females with the resting eggs increases towards the end of warmseason, reaching up to 50% of the population (Onbe, 1974, 1978a). Usually the femaleof P. avirostris has one, rarer two resting eggs, which develop going through nine successivestages (Onbe, 1978a). The further formation of the egg’s membrane, its maturation,and the hatching out of a young cladoceran takes place in the oozy sediments.The length of the resting egg ranges from 0.21 to 0.29 mm (usually 0.25); the width,from 0.14 to 0.20 mm (usually 0.18 mm); the membrane is 0.10 mm thick, and thenewborn cladoceran length is about 0.4 mm (Onbe, 1973, 1985; An illustratedguide…, 1997). The resting eggs are found in the sediments the year round; their maximumquantity is recorded for September (Onbe, 1978a).13

In Peter the Great Bay in August and September mainly juveniles and parthenogeneticfemales are found. Great number of males and few gamogenetic females wererecorded in Vostok Bay in late September at a surface temperature of 16.4–17°C.P. avirostris feeds on microflagellates consuming bacteria (Turner et al., 1988).Order ONYCHOPODA Sars, 1865II. Family PODONIDAE Mordukhai-Boltovskoi, 1968Body oval, more or less elongated. Shell not covering thoracic limbs, rudimentary,not separated into valves. It performs hydrostatic function and serves as place fordevelopment of embryos. Shell contains brood pouch growing together with embryosto fill up whole inside of it. Head large, formed of one strongly pigmented compoundeye. Antennules small, immovable, fused with head. Antennae relatively small; upperbranch (4-segmented) has 7 setae; lower branch (3-segmented) has 6 setae. Body has 4pairs of thoracic limbs without filtratory setae, with well developed exopods on 3 anteriorpairs and with maxillary processes. Endopod armed with 7–10 setae; exopod with1–4 setae. Abdomen and cauda very short, so that cauda situated just behind limbs 4.Cauda in shape of rounded or pointed process, or with well developed claws of variousshapes and sizes. Caudal (“swimming”) setae well developed, situated on tubercleor on small cylindrical outgrowth. Male slightly smaller than female, with larger headand eye; testes well developed, projecting into valve cavity; limbs 1 with hooks; peneswell developed, situated behind limbs 4.Members of this family are viviparous; embryos are protected by the closedbrood pouch and chitinous shell. Podonids are predators, with special limbs modifiedto catch various organisms ranging from 100 to 200 µm (dinoflagellates, centric diatoms,rotifers, and the like).KEY TO THE GENERA OF THE FAMILY PODONIDAE1(4). Exopods of limbs 2 and 3 with 3–4 setae.2(3). Exopods of limbs 1 with 3–4 setae. Shell rounded ......................1. Pleopis (p. 14)3(2). Exopods of limbs 1 with 2 setae. Shell elongated .............. 2. Pseudevadne (p. 17)4(1). Exopods of limbs 2 and 3 with 1–2 setae.5(6). Exopods of limbs 2 with 1 seta. Shell semispherical, rounded at apex ........................................................................................................................... 3. Podon (p. 19)6(5). Exopods of limbs 2 with 2 setae. Shell elongated, tapering towards apex orpointed at its tip .......................................................................... 4. Evadne (p. 21)1. Genus Pleopis Dana 1853Type species: Pleopis polyphemoides (Leuckart, 1859).Shell rounded, globular in females with numerous embryos, in males triangular,with rounded apex. Depression between head and shell clearly visible. Branches ofantennae with shortened distal segments, twice as short as other antennal segments.This character differs Pleopis spp. from Podon spp. Four-segmented branch with 714

setae; 3-segmented branch with 6 setae. Exopods of thoracic limbs 1–3 with 3–4 setae.Cauda formed of 2 triangular pointed outgrowths. Caudal setae situated on small tubercle.KEY TO THE SPECIES OF THE GENUS PLEOPIS1 (2). Exopod of limbs 1–3 with 4 setae, cauda with caudal claws covered with spinules................................................................................. 1. P. schmackeri (p. 15)2 (1). Exopod of limbs 1–3 with 3 setae, cauda in shape of pointed conical tubercles................................................................................... 2. P. polyphemoides (p. 16)1. Pleopis schmackeri (Poppe, 1889)(Pl. II, figs. 1–6)Poppe, 1889: 293–300; Yamazi, 1966: 192, pl. 88, fig. 3 (Podon schmackeri); Mordukhai-Boltovskoi,1978: 523–529, figs. 2, 3; Mordukhai-Boltovskoi & Rivier, 1987: 109–110,fig. 59; Rivier, 1998: 121–122, figs. 42–47 (Pleopis schmackeri).Description. Parthenogenetic female. Body rounded; head separated frombody by depression. Shell, containing brood pouch, semispherical. Swimming antennaeshort; terminal segment on each of 2 branches twice shorter than penultimate one;penultimate segment twice shorter than preceding one. Each exopod of limbs 1, 2, and3 bears 4 setae; that of limb 4 with only 2 setae. Fourth seta on exopod of limbs 1–3present among podonids only in P. schmackeri. Setal formula 4.4.4.2. Endopodsarmed with numerous setae, too. First segment of endopod of limb 1 with 7 setae oninner side; second segment with 2 short setae, twice shorter than apical ones. Maxillaryprocesses especially developed on limbs 2 and 3, with long pointed spines. Caudalclaws straight, thin, covered with clearly noticeable spinules. Caudal setae situatedon tubercle, together with small denticles.Height of parthenogenetic female from 0.45–0.65 mm to 0.87 mm (Kim & Onbe,1989a). Same authors present sizes of 2 almost rounded males: height 0.43 and0.46 mm, length 0.42 and 0.43 mm.Distribution. P. schmackeri has the narrowest geographical range among themarine podonids. It is distributed along the Asian coast from the south-eastern shoresof Indochina Peninsula (13°N) to the eastern coast of Korea (38°30′N). It is abundantin the bays north of Hong Kong, 22°30′N (Tang et al., 1995), inhabits the whole areaof the Korea Strait, and comes into the southern regions of the Sea of Japan (Kim &Onbe, 1989b). The species also migrates north along the Japan Islands to 40°N and tothe Pacific Ocean to 155°E (Kim & Onbe, 1989b).The species is rarely found in Peter the Great Bay; it was recorded only sporadicallyin the south-western part of the bay in July and August (Shkoldina & Pogodin,2001; Shkoldina et al., 2002).Biology and ecology. The development begins in April in the southernmostpoints of the distributional range. The species is most abundant in August; in Septemberand October only isolated specimens were found in the plankton. The most abundantpopulations (up to 100 sp./m 3 ) were recorded in the Korea Strait in August, andless numerous ones off the southern shores of Honshu Island and near Kii Peninsula15

(Japan). P. schmackeri matures at a temperature of 19.7–30.4°C and a salinity of29.37–34.27‰, while the optimal values for this species are 24° and 33.7‰ respectively(Kim & Onbe, 1989b). In various bays near Hong Kong it has been recorded ata temperature of 17–29°C and a salinity of 31–37‰ (Tang et al., 1995). P. schmackeriis not abundant in comparison with other marine podonid species. The maximum densityhas been recorded off the coasts of Korea (30–80 sp./m 3 ); near the southern coastsof Japan the highest density has been 6.4 sp./m 3 .According to Kim and Onbe (1989a), the mean fecundity of this species is 2.3–7.1 embryos, and the individual fecundity is one to 9 embryos. Other authors mentionup to 19 embryos per a female (Tang et al., 1995). The largest specimens (0.45–0.65mm) occur in the north of the range, about 45% of animals in the population being0.5–0.55 mm long, bearing five-six embryos each (Kim & Onbe, 1989b).The reproduction is so abundant owing to pedogenesis inherent in this species.Well-developed embryos being still in the brood pouch of the parthenogenetic femalealready have miniature rounded embryos in their own brood pouches (Kim & Onbe,1989a).Remarks. P. schmackeri differs from the other Podonidae in the presence of foursetae on the exopods of limbs 1–3 and denticles on the caudal claws.2. Pleopis polyphemoides (Leuckart, 1859)(Pl. III, figs. 1–9; VIII, fig. 5)Leuckart, 1859: 262–265, tabl. 7, fig. 5 (Evadne polyphemoides); Lilljeborg, 1900: 633–636, tabl, 85, figs. 7–11; Rammner, 1930: 4, figs. 5–6; Manuilova, 1964: 303, fig. 173; Yamazi,1966: 191, pl. 88, fig. 2; Flössner, 1972: 395–397, abb. 186 (Podon polyphemoides); Negrea,1983: 346–348, fig. 143; Mordukhai-Boltovskoi & Rivier, 1987: 110–112, fig. 60; Rivier,1998: 123–124, fig. 48–56 (Pleopis polyphemoides).Description. Parthenogenetic female. Shell rounded, inflated at great numberof embryos. Head elongated, separated from body by pronounced depression.Swimming antenna, as in P. schmackeri, with small, weak as if undeveloped apicalsegment. Each exopod of thoracic limbs 1–3 with 3 setae; exopod of limb 4 with 2setae. Formula of setae 3.3.3.2. Setae of exopod, as in P. schmackeri, short, not reachingapical setae of endopod. Cauda in shape of 2 conical outgrowths. Length0.5–0.6 mm; height 0.55–0.65 mm.Gamogenetic female. In the young female the brood pouch is empty, and agamogenetic egg grows in the ovary, accumulating nutrients. When the egg is fullynourished, it moves into the brood pouch to form its membranes.Size of resting egg 150–210 µm (mean size 180 µm) (Onbe, 1985).Male. Shell small, far smaller than head, rounded at top. Testes on sides of intestine;penes well pronounced behind limbs 4. Apical segment on endopod of limbs 1with hook on inner side. Male smaller than female (height up to 0.6 mm), but its headlarger.Distribution. P. polyphemoides has the widest geographical range, extendingeven farther every year. It is exceptionally neritic species, occurring in relatively warmwaters with wide range of salinity, from 1.05 to 35.23‰ (Negrea, 1983). It is distributedin the coastal waters of Europe, the North and South America, Africa, Southeastand East Asia. In the Russian waters of the Far Eastern seas it is common in Peter the16

Great Bay, but no one specimen has been recorded from the Sea of Okhotsk and theBering Sea.Biology and ecology. P. polyphemoides is an exceptionally neritic species in theFar East seas. It prefers surface waters, but may occur to a depth of about 100 m. InPeter the Great Bay of the Sea of Japan it is found at a temperature from 6 to 26°C andfrom low (several ‰) to normal seawater salinity (Kos, 1977). Maximum density hasbeen recorded for autumn. In the southwestern part of Peter the Great Bay the specieshas two peaks of density, in July and in September. Thus, in Sivuchya Bay its densityreached 500 sp./m 3 in July, then in August at a surface water temperature of 20–22°Cthe population declined, and in September (at a temperature of 17–19°C) it reached1047 sp./m 3 (18.3% of the total density of zooplankton) (Shkoldina & Shevchenko,2001). In the western part of Peter the Great Bay P. polyphemoides appears in July at18°C temperature and 33–34‰ salinity. Maximum density, 616 sp./m 3 , was recordedfor mid-October at 14.1°C, and specimens were found singly until January, when temperaturefell below zero (Mikulich & Biryulina, 1977). In Vostok Bay the species isusually found during a period from June till October. Substantial desalination of theinner part of the bay stimulates its mass development (Shkoldina, 2001). It appears insmall numbers in June at a temperature of 13.4–13.8°C (Shkoldina, 2002) and attainspeak density (over 7.6 thousand sp./m 3 ) twice: in August at 21.3°C and in October at14.3°C.P. polyphemoides is abundant in the coastal waters of Korea in the Sea of Japan.Its density reaches 10% of the total density of the zooplankton in July. In Novemberand December males and gamogenetic females comprise 30–40% of the total densityof the population (Yoo & Kim, 1990). The species occurs in the coastal waters of Koreaall the year round excluding February (Yoo & Kim, 1987). The seasonal dynamicsand ecology of the species were most thoroughly studied for the Inland Sea of Japan(Onbe, 1974). P. polyphemoides is found there in the plankton from April-May untilearly August. Its density widely varies from year to year; it is highest (2–38 thousandsp./m 3 ) from late May till early July, at a temperature of 12–26.8°C. The species disappearsat a temperature between 22.8 and 26.8°C, depending on a mean temperatureof a year. It inhabits the upper 20 m deep layer of water, being most abundant to 10 m.The fecundity of P. polyphemoides is two to ten embryos per female; it is maximalin April (four–ten); in late June the number of embryos decreases to two–six.Small amounts of males and females with resting eggs occur in mid-June. The newlyhatched specimen of P. polyphemoides has well developed eye and limbs, and weaklydeveloped brood pouch (Onbe, 1974).Observations of P. polyphemoides in the ports of the Mediterranean Sea andChesapeake Bay show that it is relatively tolerant to pollution; under conditions ofeutrophication it even increases in numbers (Mordukhai-Boltovskoi & Rivier, 1987;Rivier, 1998).2. Genus Pseudevadne Claus, 1877Type species: Pseudevadne tergestina Claus, 1877.Body oval or triangular, with rounded apex. Shell narrowing to apex or inflated,depending on size of embryos and their number, as in members of genus Evadne.Shell with strongly pronounced crests of fornix, and with pigment cells of hypodermis17

placed in 5–8 parallel rows. Exopod of limb 1 with 2 setae, exopods of limbs 2–3 with3 setae. Setal formula 2.3.3.1. Cauda in shape of triangular outgrowths.Pseudevadne tergestina Claus, 1877(Pl. IV, figs. 1–10; VIII, figs. 1–4)Claus, 1877: 142, tabl. 5, figs. 15, 16 (Pseudevadne tergestina); Cheng & Chen, 1966:174, pl. 3; Yamazi, 1966: 193, pl. 88, fig. 6 (Evadne tergestina); Mordukhai-Boltovskoi, 1969:21, pl. 2, fig. 3 (Pleopis tergestina); 1978: 523–528, fig. 2; Negrea; 1983: 348–351, fig. 144;Mordukhai-Boltovskoi & Rivier, 1987: 112–114, fig. 62; Rivier, 1998: 123–126, figs. 57–65(Pseudevadne tergestina).Description. Parthenogenetic female. Shell oval, inflated if embryos matureand even more inflated if embryos numerous. Nuchal depression poorly pronounced,in adult female with large shell almost not pronounced at all. With young cladoceranshatching and new eggs entering brood pouch, the latter gets smaller and becomes triangular(pl. IV, fig. 10). Shell provided with fornix at level of basipodites of thoraciclimbs, partially covering basipodites. Five to eight rows of hypodermic cells seen asdark spots situated along shell, clearly visible when embryos small, but poorly expressedwhen embryos or resting eggs reach maturity.Antennae small; 3-segmented branch with 1 short and 5 long setae; 4-segmentedbranch with 1 short and 6 long setae. Exopods well expressed on limbs 1–3 only; theirsetae longer than apical setae of exopods. Exopod of limb 4 in form of small tuberclewith 1 seta. Setal formula of exopods 2.3.3.1. Maxillary processes well developed onlimbs 2 and 3. Caudal claws triangular. Height 0.8–1.2 mm. Size of shell depends onnumber of embryos.Gamogenetic female can be clearly identified only after fertilization. Restingegg seen as small dark spot near limbs 3 and intestine. It grows in ovary until fullynourished, then moves into brood pouch, where hard chitinous membranes form (pl.IV, fig. 2; VIII, fig. 4).Lower surface of shell has opening and funnel-shaped indentation (vagina) withcanal leading to brood pouch (Onbe, 1978b). Similar arrangement for reproductionpresent in all podonids (Rivier, 1968). Gamogenetic female often has two eggs, one ineach ovary. Size of resting egg 190–240 µm (usually 200 µm) (Onbe, 1985).Male has relatively large head and eye. Hook (transformed terminal seta) onlimb 1 regularly rounded, situated at end of enlarged apical segment. Other apical setaein male thicker than in female. Testes somewhat protruding into empty transparentshell cavity; penes behind limbs 4. Height to 0.85 mm.Distribution. P. tergestina inhabits the neritic zones of subtropical and tropicalregions. Warm currents may transport it to the temperate zones of the Atlantic andPacific oceans.The species is common in the plankton of Peter the Great Bay in warm seasons.In the 1930s P. tergestina was abundant in Possjet Bay and south of it at a temperatureof 25–26°C (Brodsky, 1981); in the 1960s it was not found in Possjet Bay (Kos, 1976,1977). In some years the species can be brought far north by Tsushima Current, up tothe South Sakhalin and the South Kuril Islands (Brodsky, 1959). It does not commonlyoccur near the middle and northern Primorye (from Olga Bay to Vladimir Bay); butin the summers of warm years (for example, in 1974) P. tergestina was distributed as18

far as the Tatar Strait (Bokhan, 1984). The species is also transported by the warmKuroshio Current to the north-eastern tip of Hokkaido Island and to the South KurilIslands (Onbe et al., 1996).Biology and ecology. P. tergestina is a warm-water species of the Peter theGreat Bay fauna, appearing in the middle of summer hydrological season. In 1973 itappeared in Alekseev Bight in August at a temperature of 21.1°C and in September (at17.9°C) reached maximum density (59 sp./m 3 ). As water got colder, the density of thespecies sharply decreased, but it still occurred sporadically until December (Mikulich& Biryulina, 1977).In the south-western part of Peter the Great Bay small numbers of P. tergestinaappear in late August, its density growing in September up to 141 sp./m 3 (Shkoldina &Shevchenko, 2001). In September of 1996 gamogenetic females with one-two developingresting eggs each were recorded in some regions of the bay at a surface watertemperature of 17–19°C.In Vostok Bay P. tergestina usually appears in mid-August when the water iswarmest (22.4°C), reaching a density of 186 sp./m 3 , which decreases to 3.3 sp./m 3 inSeptember (Shkoldina, 2001). It occurs singly until late October, when water temperatureis 13–14°C. At this period gamogenetic females with resting eggs are found, too.The species’ biology and ecology was intensively studied for the Inland Sea ofJapan. Onbe’s records (1974) show that this species appears among the plankton inlatitude about 34°20′N in May or June, reaching maximum abundance in July-Augustand staying in the sea until September-October. Maximum density (8.7–9.4 thousandsp./m 3 ) is registered at a temperature of 22.3–23°C, but in September assemblages upto 30 thousand sp./m 3 were recorded. The bulk of the cladocerans inhabit the upperlayer of water (10–15 m), concentrating at a depth of 3 m in July and nearer to the surfacein August. At night the number of females with mature embryos is maximal, andbefore dawn the young hatch. The same patterns of reproduction were observed in theCaspian Evadne (Rivier, 1969). During a period of gamogenetic reproduction a populationincludes from 2.2 to 12.5% of males and up to 12.4% of females with restingeggs. Females with resting eggs are among the largest specimens in a population(Onbe, 1978b). Japanese scientists observed the hatching of a young P. tergestinafrom a resting egg (pl. VIII, fig. 1). The process begins, like in all the Polyphemoidea,when a rounded egg breaks up into 2 unequal halves; an embryo at this stage alreadyhas a well-pigmented eye. The size of a resting egg varies from 190 to 240 µm (averagesize is 200 µm). Resting eggs are found in sediments all the year round, theirnumber is maximal (7.7 thousand eggs/m 2 ) in July, with the peak density of the cladoceransin the plankton about 3 thousand sp./m 3 (Onbe, 1985).Among the contents of the foregut of P. tergestina large centric diatoms werefound (Kim et al., 1989).3. Genus Podon Lilljeborg, 1853Type species: Podon leuckarti (Sars, 1862).Shell in females rounded, in males small, having irregular shape. Head elongated,anteriorly globular, separated from shell by clearly seen depression. Antennalbranches with well-developed apical segments; number of setae on 4-segmented and3-segmented branches identical (6 setae). Exopods of thoracic limbs weakly devel-19

oped, small, armed with 1–2 setae. Endopods relatively weakly armed. First segmentof limb 1 bears 5 small setae, second, 4: two long apical ones and two short ones.Cauda in shape of two thin, long, tapering appendages, not pointed at ends, with rowsof small setules.Podon leuckarti (Sars, 1862)(Pl. V, figs. 1–11)Sars, 1862: 293 (Pleopis leuckarti); Lilljeborg, 1900: 636–639, tabl. 85, fig. 12, tabl. 86,figs. 1–3; Rammner, 1930: 4, figs. 7–8; Manuilova, 1964: 305, fig. 174; Yamazi, 1966: 191, pl.88, fig. 1; Mordukhai-Boltovskoi, 1969: 22, pl. 3, fig. 1; Flössner, 1972: 392, abb. 184; Negrea,1983: 344–345, fig. 142; Mordukhai-Boltovskoi & Rivier, 1987: 115–116, fig. 64; Rivier,1998: 127–128, figs. 66–74 (Podon leuckarti).Description. Parthenogenetic female. Depression between head and shellclearly expressed. Head relatively large; nuchal organ situated nearer to depression.Shell semispherical; if embryos numerous, shell inflated, globular. Swimming antennaewell developed, segments have normal size. Each branch with 6 setae, attachedidentically on outer and inner branches. Thoracic limbs relatively weakly armed. Eachexopod of limbs 1–3 with 1 seta; exopod of limb 4 with 2 setae. Setae of exopodsthick, straight, and covered with spinules. Setal formula 1.1.1.2. First segment of endopodof limb 1 with 4 long curved setae; each endopod of limbs 2–4 with 4 apicalsetae, 2 of them thick and relatively short. Maxillary processes on limbs 2 and 3 robust,with sensory setae and 2–3 large spines. Mandible bears 1 large tooth with 2 lateraldenticles and strongly ramified process, placed perpendicular to main plane ofmandible. Cauda in shape of 2 long thickening outgrowths with rows of small denticlesand setae. Length up to 0.9 mm, height up to 0.8 mm.Gamogenetic female. Shell globular if brood pouch filled with eggs. Egg hassomewhat irregular shape. During membrane forming hypodermic cells clearly visible.Length of body up to 0.75 mm, height up to 0.8 mm. Diameter of resting egg 210–230 µm (Onbe, 1985).Male. Shell smaller than head. Eye larger than in female. Penes small, testes almostnot protruding into shell cavity. Apical segment of limb 1 enlarged, providedwith well-developed hook. Length up to 0.9 mm, height up to 0.8 mm.Distribution. P. leuckarti is one of the most widely dispersed marine species ofthe Podonidae. It is distributed from the coasts of Greenland to the southern tip ofAmerica, from the Spitsbergen and Wrangel Islands to the Mediterranean and SouthChina seas. In the Russian waters of the Far East it occurs in the coastal zone of thenorthern tip of Chukchi Peninsula up to the Gulf of Anadyr, and penetrates in thewarmest belt along the Koryak coast to Olyutorsky Bay and to the south along thecoast of Kamchatka and the Commander Islands (Vinogradov, 1956). It is distributedin the western part of the Bering Sea (Geinrich, 1961) and the northern part of the Seaof Japan (Kun, 1975); it is common in Peter the Great Bay (Kos, 1976, 1977; Brodsky,1981; Mikulich & Biryulina, 1977). However, it is the least abundant species of thepodonids in the Inland Sea of Japan (Onbe, 1985).Biology and ecology. P. leuckarti is a temperate-cold water species. It appears inthe northern part of its geographical range when water is warmest (the end of summerto autumn), and the farther south along the range the earlier it appears. It occurs in the20

plankton of the north-western part of the Sea of Japan and the Inland Sea of Japanfrom early spring till early summer. Records from the Chukchi, Bering and Japan seastestify that P. leuckarti is a neritic, eurythermal, and euryhaline species with a temperaturerange from 4 to 21˚C and a salinity range from 4 to 34‰ (average seawater salinity)(Kos, 1977).In the western part of Peter the Great Bay (Alekseev Bight of Amursky Bay) thefirst appearance of P. leuckarti was recorded for April, when temperature rose abovezero; in June the density was maximal, and in August, when water temperaturereached 21˚C, the species disappeared (Mikulich & Biryulina, 1977).In the south-western part of Peter the Great Bay P. leuckarti is also found onlytill August. In mid-July, when water temperature varied from 14 to 17˚C, the speciesgenerally occurred in bights and adjacent areas, with a mean density of 500 sp./m 3(Shkoldina & Shevchenko, 2001). Sporadic occurrences were recorded from the openpart of the Bay, and only for the cold near-bottom water layer.In Vostok Bay P. leuckarti appears in early June at a water temperature of 12–13˚C, but by the end of June and later, at a temperature above 20˚C, it is not found(Shkoldina, 2001, 2002).Seasonal dynamics of P. leuckarti is studied thoroughly for the Inland Sea of Japan(Onbe, 1974). The species appears there in early May, reaches maximum densityin late June, and disappears in August. Other evidence (1974–1977) point out that thespecies is present in the plankton from February-March till June (Onbe, 1985), and itsabundance is not more than 0.6–0.7 thousand sp./m 3 .Near the eastern coast of Hokkaido Island (43˚N, south of Sakhalin Island) P.leuckarti dominated among the podonids in mid-October. Parthenogenetic femalescomprised from 36 to 52.4% of all females in the population; gamogenetic femalescomprised from 39.8 to 52.8%. Most females had one resting egg; only one femalehad two eggs. Observations showed that in the daytime these cladocerans near the bottomor the surface may gather into assemblages, dissipating at night. Females withresting eggs mostly accumulate near the bottom and don’t rise up to the surface, thusprotecting themselves from predators (Saito & Hattori, 2000).Among the contents of the intestine of P. leuckarti mostly centric diatoms includingSkeletonema costatum were found (Kim et al., 1989).4. Genus Evadne Loven, 1836Type species: Evadne nordmanni Loven, 1836.Shell elongated, with pointed apex. Head not clearly separated from shell. Nuchalorgan situated on top of head. Branches of swimming antennae with 6 setae. Thoraciclimbs biramous, with relatively long exopods. Each exopod of limbs 1–2 bears twosetae; each exopod of limbs 3–4 bears one seta. Exopod of limb 1 equal in length tofirst segment of endopod. Cauda in shape of 2 conical pointed outgrowths.KEY TO THE SPECIES OF THE GENUS EVADNE1 (2). Exopod of limb 3 has 2 setae. Apex of shell produced into pointed peak .......................................................................................................... 1. E. spinifera (p. 22)21

2 (1). Exopod of limb 3 with one seta. Apex of shell pointed, but without peak ....................................................................................................... 2. E. nordmanni (p. 23)Evadne spinifera P.E. Müller, 1867(Pl. VI, figs. 1–8)Müller, 1867: 225, tabl. 6, figs. 11–12; Claus, 1877, tabl. 6, fig. 21; Lilljeborg, 1900:647–649, tabl. 86, fig. 18; tabl, 87, figs. 1–3; Rammner, 1930: 5, figs. 11, 12; Dolgopolskaya,1958: 51–56, figs. 18–21; Manuilova, 1964: 308, fig. 177; Yamazi, 1966: 192, pl. 88, fig. 4;Flössner, 1972: 400–401, abb. 188; Negrea, 1983: 353, fig. 146; Mordukhai-Boltovskoi &Rivier, 1987: 122, fig. 71; Rivier, 1998: 135, figs. 93–100 (Evadne spinifera).Description. Parthenogenetic female. Body ovoid; no nuchal depression;head fused with shell, produced into pointed peak. Swimming antennae weakly developed;segments almost square. Apical segments on both branches more than twiceshorter and thinner than preceding segments; each branch with 6 long, soft, plumosesetae. Exopods of limbs 1–3 with 2 setae; setal formula 2.2.2.1. Mandible with onelarge tooth and 2 horn-shaped processes. Maxillary processes well developed on limbs2 and 3. Length 0.6–0.8 mm, height 1.3–1.4 mm.Male somewhat smaller than female, with large eye, characteristic for podonids,with narrower than in female shell having long pointed peak. Penes not protrudingpast limb 4; testes clearly visible in empty shell cavity. Apical segment of limb 1 withlarge, well-developed hook. Height 1.05–1.3 mm.Distribution. E. spinifera is distributed in all the oceans, excluding polar seas,also in inland seas like the Baltic, the Mediterranean, and the Black. It rarer occurs inequatorial waters compared to temperate waters. E. spinifera does not penetrate theOkhotsk and Bering seas and is not common for the Sea of Japan, where it is the leastabundant form among all the podonids of the Far East seas. Numerous works of Japanesescientists do not register this species for the Inland Sea of Japan.Kos (1976, 1977) and Brodsky (1981), who made detailed research of the zooplanktonof Possjet Bay, do not mention E. spinifera for this region, but it was found in1989–1990 in the south-western part of Peter the Great Bay (Shkoldina & Pogodin,1999, Shkoldina et al., 2004). The species occurs south of the Kuril Islands (40°N),where the warm Kuroshio Current flows (Brodsky, 1955). It is one of the subtropicalspecies of Peter the Great Bay, the subtropical and tropical groups of species beingtwo most important zoogeographical groups of the bay. E. spinifera does not occur inthe neritic zones of the middle and northern coastal waters of Primorye (Kos, 1960).The occurrence of warm-water species of the podonids, including E. spinifera,depends on the effect of warm waters moved by the considerably meandering KuroshioCurrent. When the current veers from the coast, warm-water species disappearfrom Possjet and Peter the Great bays (Kos, 1969). The Kuroshio can transport E. spiniferaas far as the north-eastern coast of Honshu Island (Onbe et al., 1996).Biology and ecology. E. spinifera is a relatively poorly studied species. In thesouthern part of the Sea of Japan (Toyama Bay), where investigations were conductedfrom February 1990 to January 1991, maximum density of E. spinifera was recordedfor July. In September these cladocerans were distributed vertically to a depth of 30 mat night and in the daytime migrated to the surface (Onbe & Ikeda, 1995).22

Evadne nordmanni Loven, 1836(Pl. VII, figs. 1–10)Loven, 1836: 1, tabl. 1–2, figs. 1–16; Müller, 1867: 222, tabl. 6, figs. 8–10; Lilljeborg,1900: 647, tabl. 86, figs. 4–17; Rammner, 1930: 5, figs. 9, 10; Dolgopolskaya, 1958: 46–50,figs. 14–16; Manuilova, 1964: 307–308, fig. 176; Cheng & Chen, 1966: 174, pl. 2; Yamazi,1966: 192–193, pl. 88, fig. 5; Mordukhai-Boltovskoi, 1969: 23, pl. III, fig. 4; Flössner, 1972:398–400, abb. 187; Onbe, 1974: 90–92, fig. 6, A; Negrea, 1983: 351–355, fig. 146; Mordukhai-Boltovskoi& Rivier, 1987: 123–125, fig. 78; Rivier, 1998: 135–136, figs. 101–109(Evadne nordmanni).Description. Parthenogenetic female. Shell elongated, with pointed apex, inold specimens with many embryos, oval, with rounded outline. Swimming antennaesmall, with decreased apical segments. Head not separated from shell. Exopod of limb1 almost equal in length to second segment of endopod; exopods of limbs 2–3 small.Each exopod of limbs 1–2 with two setae, each exopod of limbs 3 with one seta; setalformula 2.2.1.1. Maxillary process well developed on limbs 2 and 3. Apical setae onendopod of limb 1 long, on endopod of limbs 2 and 3 short and claw-like. Cauda inshape of 2 conical pointed outgrowths. Length 0.6–0.7 mm, height up to 1.2–1.4 mm.Gamogenetic female generally has one resting egg. Females with restingeggs almost largest specimens in population.Male. Shell almost triangular. Testes protruded into shell cavity, clearly visible.Hooks on limb 1 thin, not pointed. Length 0.5–0.65 mm, height 0.7–0.8 mm.Distribution. E. nordmanni is distributed in cold and temperate waters. It occursin the open seas of the Arctic, Pacific, and the Atlantic oceans (excluding the tropicalzones of the Pacific and the Atlantic); in the inland seas, namely the White, Baltic,Mediterranean, Black seas, and the Inland Sea of Japan (Rivier, 1998); as well as inthe Far East seas (Kun, 1975).In the north-western Pacific, the northernmost record of E. nordmanni is from thesouth of the Bering Sea, near Africa Cape (Vinogradov, 1956), whereas Podon leuckartiis distributed farther north. In the western part of the Bering Sea E. nordmannioccurs in the plankton at the beginning of autumn (September and October), when thewater is warmest (Geinrich, 1961). In the Sea of Okhotsk the species can breed in thecoastal zone around the whole periphery of the sea (Lubny-Gertsyk, 1959). Near thesouthern tip of Sakhalin Island E. nordmanni inhabits Aniva Bay and penetrates intothe Sea of Japan via the La Perouse Strait (Ponomareva, 1961). It is a common speciesfor the north-western part of the Sea of Japan, occurring in all bights and bays, includingPeter the Great Bay (Kos, 1960; Shkoldina, 2001, 2002).Cold currents bring E. nordmanni to the southern part of the Sea of Japan, alongthe coast of Korea. The farther south, the earlier (mid-spring to early spring) E. nordmanniappears in the plankton (Kim, 1985; Yoo & Kim, 1987; Onbe et al., 1996). Thespecies also occurs near China (Jian Dong, 1991).Biology and ecology. E. nordmanni is a temperate-cold water species. Its rangeis extended in north-south direction, and the periods of occurrence of this species inthe plankton depend on the latitude and are regulated by the same mechanisms as inPodon leuckarti. In the Sea of Okhotsk and the Bering Sea E. nordmanni appears inlate summer or in autumn (Vinogradov, 1956). In the Tatar Strait (49°–51°30′N) theappearance of all the podonid species depends on the extent of the warming up of the23

water from year to year. For example, in cold years (1975) only E. nordmanni and Podonleuckarti were found in this area (Bokhan, 1984).In the southernmost part of the Russian Far East waters (Peter the Great Bay) E.nordmanni appears in spring and reaches maximum density in early summer and inautumn. Thus, in Amursky Bay (Alekseev Bight of Popov Island) the species occurredin the plankton May through January and had two peaks of density, from mid-June tomid-July and from mid-October to mid-November. First specimens were recorded inMay at a water temperature of 5°C, in June at an average temperature of 13.2°C thedensity was 230 sp./m 3 , and in autumn, when temperature ranged from 9 to 3°C, apopulation maximum of 162 sp./m 3 was recorded (Mikulich & Biryulina, 1977).Chuchukalo et al. (1980) show that E. nordmanni appeared in Amursky Bay(near Reineke Island) in early June at a water temperature of 11–13°C, and in July (at21°C) the density already attained 7 thousand sp./m 3 . Temperature rising to 21–22.3°CJuly through late August, E. nordmanni decreased in numbers to 0.5 thousand sp./m 3 .In late autumn (November) at a temperature of 7.1°C the abundance of the speciesslightly enhanced (Chuchukalo et al., 1980).In the south-western part of Peter the Great Bay E. nordmanni is vertically distributedfrom 0 to 50 m. Its peak density was recorded for July (in Kalevala Bight, 3.5thousand sp./m 3 ); in August, when temperature was the warmest (21°C), the densitysharply decreased; and in September rose again (Shkoldina & Shevchenko, 2001).Kos’ records (1976) display that in mid-summer (late June–early July) the density ofE. nordmanni was low (5–25 sp./m 3 ) in Possjet Bay at a temperature of 17–20°C. Inthis bay the species was found at a temperature of 6.6–21°C and a salinity of 26.31–33.17‰. A maximum density of E. nordmanni (260 sp./m 3 ) was registered at offshorestations (Kos, 1977).In the south-western part of Peter the Great Bay gamogenetic females with latenteggs were recorded for July and September, and were not found in August. It may indicatethat E. nordmanni has two reproduction cycles in the southern part of its distributionalrange. In 2002 in Vostok Bay E. nordmanni occurred in the plankton untillate October, at a temperature of 12–13°C, and females with well-developed restingeggs constituted the bulk of the population.The biology and ecology of E. nordmanni are most extensively studied for the InlandSea of Japan (34°N). In this area the species appears in March-April and disappearsin June; it attains a maximum density of 2.7–3.4 thousand sp./m 3 at 15–16°C. E.nordmanni appears in the plankton at a temperature from 8 to 11°C and disappears at atemperature from 21.4 to 23.8°C (Onbe, 1974). In March and April females have thelargest size (length up to 0.55–0.6 mm) and highest fecundity (up to 10–12 embryos).Males and gamogenetic females appear in the population in mid-June, and by the endof the month parthenogenetic females almost disappear (Onbe, 1974). Resting eggsare light brown and have a size of about 200 µm (Onbe, 1985).The analysis of the intestine’s content showed that E. nordmanni feeds on largecentric diatoms, particularly Skeletonema costatum. On other evidence, the podonidsmay also consume dinoflagellates (Kim et al., 1989).24

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Mordukhai-Boltovskoi, F.D. 1968. On the taxonomy of the Polyphemoidae // Crustaceana.Leiden. V. 14, pt 2. P. 197–209.Mordukhai-Boltovskoi, F.D. 1969. Order Cladocera // Opredelitel Fauny Chernogo iAzovskogo Morei. Kiev. P. 8–31. (In Russian).Mordukhai-Boltovskoi, F.D. 1978. A contribution to the taxonomy of marine Podonidae(Cladocera) // Zool. Zhurnal. V. 57, N 4. P. 523–529. (In Russian).Mordukhai-Boltovskoi, F.D. & I.K. Rivier. 1987. Predatory Cladocera of the worldfauna. Leningrad: Nauka. 182 p. (In Russian).Müller, P.E. 1867. Danmark Cladocera // Schiödtes Naturhist. Tidskr. Bd 3, N 5.S. 53–240.Mullin, M.M. & T. Onbe. 1992. Diel reproduction and vertical distributions of the marinecladocerans, Evadne tergestina and Penilia avirostris, in contrasting coastalenvironments // J. Plankton Res. V. 14, N 1. P. 41–59.Negrea, S. 1983. Fauna Republicii socialiste România. Crustacea. V. 4, Fasc. 12. Cladocera.Bucurest. P. 90–92, 341–355.Onbe, T. 1973. Preliminary notes on the biology of the resting eggs of marine cladocerans// Bull. Plankton Soc. Japan. V. 20, N 1. P. 74–77.Onbe, T. 1974. Studies on the ecology of marine Cladocerans // J. Fac. Fisch. Anim.Husb. Fukuyama Univ. V. 13, N 1. P. 84–179.Onbe, T. 1978a. The life cycle of marine cladocerans // Bull. Plankton Soc. Japan.V. 25, N 1. P. 41–54.Onbe, T. 1978b. Gamogenetic forms of Evadne tergestina Claus (Branchiopoda, Cladocera)of the Inland Sea of Japan // J. Fish. Husb. Hirosima Univ. V. 17,N 1. P. 43–52.Onbe, T. 1983. Preliminary observations on the marine cladoceran Pleopis (“Podon”)schmackeri (Poppe) // J. Fac. Appl. Biol. Sci. V. 22, N 1. P. 55–64.Onbe, T. 1985. Seasonal fluctuations in the abundance of populations of marine cladoceransand their resting eggs in the Inland Sea of Japan // Mar. Biol. V. 87. P. 83–88.Onbe, T. 1991. Some aspects of biology of resting eggs of marine cladocerans // Crustaceanegg production. Crust. Iss. V. 7. P. 41–56.Onbe, T. & T. Ikeda. 1995. Marine cladocerans in Toyama Bay, southern Japan Sea:seasonal occurrence and day-night vertical distributions // J. Plankton Res. V. 17,N 3. P. 595–609.Onbe, T., Terazaki, M. & S. Nagasawa. 1996. Summer distribution of marine cladoceransin Otsuchi Bay, northeastern Honshu, Japan // Bull. Plankton Soc. Japan.V. 43, N 2. P. 121–131.Ponomareva, L.A. 1961. Zooplankton of Aniva Bay // Trudy Instituta Okeanologii.V. 51. P. 103–111. (In Russian).Poppe, S.A. 1889. Ein neuer Podon aus China nebst Bemerkungen zur Synonymie derbekannten podon // Arten. Adhandl. Naturwis. Vereinsin Bremen. Bd 10. S. 295–300.Rammner, W. 1930. Phyllopoda. Tierwelt der Nord-u-Ostsee. Leipzig. Tiel. 10. S. 1–31.Rivier, I.K. 1968. On reproduction of the Polyphemoidae (Podonidae) of the CaspianSea // Biologiya i Troficheskiye Svyazi Presnovodnykh Bespozvonochnykh iRyb. N 17 (20). P. 58–69. (In Russian).Rivier, I.K. 1969. Diel rhythms in reproduction of the Polyphemoidae of the CaspianSea // Fiziologiya Vodnykh Organizmov i Ih Rol v Krugovorote OrganicheskogoVeschestva. N 19 (22). P. 128–136. (In Russian).27

Rivier, I.K. 1998. The predatory Cladocera (Onychopoda: Podonidae, Polyphemidae,Cercopagidae) and Leptodoridae of the world. Leiden. 214 p.Saito, H. & H. Hattori. 2000. Diel vertical migration of the marine Cladoceran Podonleuckarti: variations with reproductive stage // J. Oceanol. V. 56. P. 153–160.Sars, G.O. 1862. Hr. studios. medic. G.O. Sars fortsatte sit foredrag over de af ham iomegnen af Christiania iagttagne Crustacea, Cladocera // Forhandl. Vidensk.-Selsk. Christiania (1861). P. 250–302.Shkoldina, L.S. 2001. On the zooplankton of the Zaliv Vostok marine refuge // V DalnevostochnayaKonferentsiya po Zapovednomu Delu, Posvyaschennaya 80–letiyu so Dnya Rozhdeniya Akademika RAN A.V. Zhirmunskogo. Vladivostok,October 12–15, 2001: Materialy Konferentsii. Vladivostok: Dalnauka. P. 317–318. (In Russian).Shkoldina, L.S. 2002. Description of zooplankton of the bights of the Vostok Bay westcoast (Peter the Great Bay, Sea of Japan) at the beginning of summer // Ekologicheskie,Gumanitarnye I Sportivnye Aspekty Podvodnoi Deyatelnosti. MaterialyNaychno-Prakticheskoi Konferentsii / Eds. V.I. Suslyaev, V.I. Goncharov.Tomsk: Izd-vo Tomskogo Universiteta. P. 123–134. (In Russian).Shkoldina, L.S. & A.G. Pogodin. 1999. Composition of plankton and bioindication ofwaters in the south-western Peter the Great Bay, Sea of Japan // BiologiyaMorya. V. 25, N 2. P. 178–180. (In Russian).Shkoldina, L.S. & A.G. Pogodin. 2001. On the inventory of the zooplankton of the FarEastern State Marine Reserve // V Dalnevostochnaya Konferentsiya po ZapovednomuDelu, Posvyaschennaya 80-letiyu so Dnya Rozhdeniya Akademika RANA.V. Zhirmunskogo. Vladivostok, October 12–15, 2001: Materialy Konferentsii.Vladivostok: Dalnauka. P. 319–320. (In Russian).Shkoldina, L.S., Pogodin, A.G. & V.I. Lapshina. 2004. Plankton. Composition ofzooplankton // Dalnevostochny Morskoy Biosfernyi Zapovednik. V. 2. Biota /Ed. A.N. Tyurin. Vladivostok: Dalnauka. P. 637–648. (In Russian)Shkoldina, L.S. & O.G. Shevchenko. 2001. The summer plankton of Sivuchya and KalevalaBights (Peter the Great Bay, Sea of Japan) // Oceanography of the JapanSea: Proc. CREAMS’ 2000 Internat. Symp. Vladivostok: Dalnauka. P. 245–254.Swammerdam, J. 1685. Histoire générale des Insectes. Ou l'on expose clairement lamanière lente & presqu'insensible de l'accroissement de leurs membres, & ou l'ondécouvre évidemment l'erreur ou l'on tombe d'ordinaire au sujet de leur prétenduetransformation. Utrecht, Jean Ribbius. pet. in-4, (8), 215, (1 bl), (2) p., 1 tabl., 13 pl.Tang, K.W., Chen, Q.C. & C.K. Wong. 1995. Distribution and biology of marine cladoceransin the coastal waters of southern China // Hydrobiologia. V. 307,N 1–3. P. 99–107.Turner, J.T., Tester, P.A. & R.L. Ferguson. 1988. The marine cladoceran Penilia avirostrisand the “microbial loop” of pelagic food webs // Limnol. Oceanogr.V. 33. P. 245–255.Vinogradov, M.E. 1956. Distribution of zooplankton in the western part of the BeringSea // Trudy Vsesoyuznogo Gidrobiologicheskogo Obschestva. V. 7. P. 173–203.(In Russian).Yamazi, I. 1966. Illustrations of marine plankton of Japan. Osaka: Hoikusha. 369 p.Yoo, K. & S. Kim. 1987. Seasonal distribution of marine cladocerans of Chinhae Bay,Korea // J. Oceanol. Soc. Korea. V. 22, N 2. P. 80–86.Yoo, K. & S. Kim. 1990. Seasonal change in the reproductive pattern of the marinecladoceran Podon polyphemoides in Korean waters // Bull. Korean Fish. Soc.V. 23, N 2. P. 141–144.28

Plate I. Penilia avirostris (1–4 – original figs.; 7, 8 – from Negrea, 1983; 5, 6, 9,10 – from An illustrated guide…, 1997): 1 – parthenogenetic female, lateralview; 2 – postabdomen, lateral view; 3 – female: posterior lower corner of valve;4 – female: antenna; 5 – female: antennule; 6 – female: head, frontal view;7 – male: hook on thoracic limb (P1); 8 – male: antenna; 9 – male, lateral view;10 – thoracic limb29

Plate II. Pleopis schmackeri: 1 – parthenogenetic female; 2 – antenna (AII);3–5 – thoracic limbs (P1–P3); 6 – postabdomen; caudal claws (CC) and setae natatoriae;ex – exopod, en – endopod, mx – maxillary process30

Plate III. Pleopis polyphemoides: 1 – parthenogenetic female; 2 – male; 3–6 – thoraciclimbs; 7 – limb 1 of male; 8 – antenna; 9 – mandible. Abbreviations like inplate II31

Plate IV. Pseudevadne tergestina: 1 – parthenogenetic female; 2 – gamogenetic femalewith mature resting eggs; 3 – female, dorsal view; 4–7 – thoracic limbs;8 – male; 9 – limb 1 of male; 10 – parthenogenetic female just after molting andbreeding (brood pouch contains new eggs); f – fornix. Other abbreviations like inplate II32

Plate V. Podon leuckarti: 1 – parthenogenetic female; 1–5 – thoracic limbs with maxillaryprocesses; 6 – limb 1 of male; 7 – postabdomen with setae natatoriae;8 – mandible; 9 – male; 10 – gamogenetic female with resting egg; 11 – parthenogeneticfemale just after molting and breeding (brood pouch contains neweggs). Abbreviations like in plate II33

Plate VI. Evadne spinifera: 1 – parthenogenetic female; 2 – male; 3–6 – thoraciclimbs; 7 – antenna; 8 – mandible. Abbreviations like in plate II34

Plate VII. Evadne nordmanni: 1 – parthenogenetic female; 2 – male; 3–6 – thoraciclimbs; 7 – postabdomen; 8 – limb 1 of male; 9 – mandible; 10 – young parthenogeneticfemale35

Plate VIII. Pseudevadne tergestina (1–4): 1 – embryo developing in a resting egg; 2,3 – newly hatched parthenogenetic females (from Onbe, 1974); 4 – postabdomenand limbs (P3–P4) of gamogenetic female; resting egg growing in ovary (ov) andvagina (v).Pleopis polyphemoides: 5 – young cladoceran, just hatched out of resting egg(from Onbe, 1974)36

CLASS MALACOSTRACA Latreille, 1802Order LEPTOSTRACA Claus, 1880Viktor V. PetryashovGeneral characteristicsThe leptostracans (order Leptostraca) are higher crustaceans belonging to thesubclass Phyllocarida of the class Malacostraca. The body of a leptostracan is dividedinto two tagmata: the cephalothorax and the pleon. The body consists of five cephalic,eight thoracic, seven pleon segments, and a telson, ending with a furca, formed by twoflat rami (pl. I, figs. 1, 2). The eyes are stalked, faceted, but in some deep-water speciesthe eyes lack pigment and not faceted. The cephalon, thorax, and sometimes mostpart of the pleon are covered dorsally, laterally, and in some cases ventrally with acephalothoracic shield, or carapace, fused to the dorsum of the protocephalon. Thecarapace is composed of two valves, fastened together by a muscle-retractor. The frontalmargin of the carapace is provided in the middle with a plate-like movable rostrum.The leptostracans have a pair of antennules, a pair of antennas, eight pairs of thoracicappendages (thoracopods), and six pairs of abdominal appendages (pleopods). Theantennule (antenna I) consists of a four-articulate peduncle (protopod) and a multiarticulateflagellum; the outer side of the antennule is provided with a flat antennularscale. The antenna (antenna II) is uniramous; it consists of a three-, rarer fourarticulatepeduncle and a multiarticulate flagellum-like endopod; an exopod is lacking.The thoracopods are leaf-shaped; each one is composed of a protopod, epipod, exopod,and an endopod, the latter may be one- or many-segmented. The articulations ofthe thoracopod parts may be fused. The first four pairs of the pleopods are well developed;each first to fourth pleopod consists of a two-segmented protopod, flat onesegmentedexopod, and a flat two-segmented endopod. The fifth and sixth pairs of thepleopods are rudimentary small uniramous plates. The seventh pleonal segment iswithout any appendages.The leptostracans are marine crustaceans; they occur in depths from the high sublittoralto the bathypelagial zone. There are twenty-five species of them known presently.They are found in all the world oceans, except for the arctic waters. The leptostracansare deposit-feeders, and pelagic species are apparently filter-feeders.In the females of the families Nebaliidae and Paranebaliidae setae of the thoracopodsform a brood chamber, in which full maturation of embryos takes place. In Nebaliopsidaeeggs are probably laid directly into the water, and organisms developthrough metamorphosis.The leptostracans can be collected using epibenthic sledges, horizontal and verticalplankton nets, as well as trawls and scoop nets. Fixation should be made in 75%ethanol and in 4% formaldehyde.The order is composed of three families, one of which, Nebaliidae, was recordedin the Sea of Japan.Main references: Dahl, 1985, 1996; Martin et al., 1996.37

Systematic partFamily NEBALIIDAE Baird, 1850Carapace without sculpture, with postero-dorsal cleft; mandible with welldevelopedmandibular palps and incisor processes; first maxilla with long whipshapedpalp; exopods of second-fourth pleopods not blade-shaped, elongate, slender,more than 4 times as long as broad.The species of only one genus Nebalia of the seven genera of this family werefound in the Sea of Japan.Genus Nebalia Leach, 1814Type species: Nebalia herbstii Leach, 1814.Rostrum without subterminal spine; eye with dark pigment; eye-stalk with papilla;carapace without setae on posterior margin; posterior margins of 5th and 6th pleonalsegments serrate; exopod of 1st pleopod with row of spinules placed medially onouter margin.Two species of the genus Nebalia were recorded in the northern half of the Seaof Japan. The armature of the 5th and 6th pleopods is described as a character distinguishingthem from other closely related species and for the purpose of showing therange of variations of this character in both species (other authors mention the smallernumber of spines).KEY TO THE SPECIES OF THE GENUS NEBALIA1 (2). Spine-like denticles on posterior margins of pleonal segments broadly roundeddistally (pl. II, fig. 1). Furcal rami approximately 1.5 times as long as telson(pl. II, fig. 5) ............................................................................. 1. N. bipes (p. 38)2 (1). Spine-like denticles on posterior margins of pleonal segments acutely pointed(pl. II, fig. 6). Furcal rami approximately twice as long as telson (pl. II, fig. 10) .................................................................................................. 2. N. hessleri (p. 39)1. Nebalia bipes (Fabricius, 1780)(Pl. I, figs. 1–7; II, figs. 1–5)Fabricius, 1780: 246 (Cancer bipes); Kroyer, 1847: 436-446 (Nebalia bipes); Jankowski,1976: 46–47, figs. 78, 80 (Nebalia nemurensis).Description. Posterior margins of pleonal segments with denticles having broadlyrounded tips. Dorsal terminal seta on peduncle of first pleopod reaches basal 1/3 to1/2 of row of small setae on exopod. Fifth pleopod bears 4–10 distolateral spines.Sixth pleopod bears from 4 (in juveniles) to 5–7 distolateral spines. Furcal rami 1.4–1.7 times as long as telson. Length of body up to 13.5 mm.Distribution. N. bipes is an amphiboreal species. It is distributed in the Atlanticand the Arctic Oceans from the North America, Iceland, and Trondheim Fjord (Nor-38

way) to Greenland, the Spitsbergen, the White Sea, and the Novaya Zemlya (72°23′N,52°41′E); in the Pacific Ocean from the Inland Sea of Japan to the Chukchi Sea(67°44.9′N, 172°47.9′W). In the Sea of Japan it occurs in Peter the Great Bay, off thenorthern coast of Primorye, and in the Tatar Strait.Habitat and breeding. N. bipes is found in depths from 0 to 200–820 m, mostlyto 50 m, on sandy, silty, less commonly on stony and rocky grounds, often among algaeand sea grasses. Females with embryos were recorded in the Sea of Japan Maythrough early September.2. Nebalia hessleri Martin, Vetter & Cash-Clark, 1996(Pl. II, figs. 6–10)Martin et al., 1996: 347–372.Description. Posterior margins of pleonal segments with acutely poined denticles.Dorsal terminal seta on peduncle of first pleopod reaches basal 1/3 of row ofsmall setae on exopod. Fifth and sixth pleopods with 6–8 distolateral spines. Furcalrami 2–2.2 times as long as telson. Length of body up to 15 mm.Distribution. Until recently, this species was known only from the type locality:32°52.5′N, 117°15.5′W (La Jolla, South California). Four specimens of N. hessleriwere collected on July 18, 1975 near the Asian coast, viz.: off the southern coast ofPrimorye, between Zeleny and Bugristy Capes (northeast of Povorotny Cape, about42°50′N, 133°30′E).Habitat. N. hessleri occurs in the high sublittoral zone between 10 and 20 m(type locality at 19 m).Remarks. The specimens found in the Sea of Japan differ from the type specimensin the larger number of distolateral spines on fifth and sixth pleopods (7–8spines in the Sea of Japan specimens versus 6 spines in the type specimens).ReferencesCannon, H.G. 1960. Leptostraca. Klassen und Ordnungen des Tierreichs. Bd 5, Abt. 1,Buch 4, Tl. 1. 81 S.Dahl, E. 1985. Crustacea Leptostraca, principles of taxonomy and a revision of Europeanshelf species // Sarsia. V. 70, N 2–3. P. 135–166.Dahl, E. 1996. Phyllocarides // Traite de Zoologie. Crustaces. Anatomie, systematique,biologie. T. 7, fas. 2. P. 865–896.Fabriсius, O. 1780. Fauna Groenlandica. (Hafniae et Lipsiae: I. G. Rothe). 452 p.Jankowski, A.V. 1976. Family Nebaliidae // Zhivotnyie i Rasteniya Zaliva Petra Velikogo.Leningrad: Nauka. P. 46–47. (In Russian).Kroyer, H. 1847. Karcinologiske Bidrag. Naturhistorisk Tidskrift. T. II. 2, Raekka.453 p.Martin, J.W., Vetter, E.W. & C.E. Cash-Clark. 1996. Description, external morphology,and natural history observations of Nebalia hessleri, new species (Phyllocarida:Leptostraca) from southern California, with a key to the extant families andgenera of the Leptostraca // Crustacean Biology. V. 16, N 2. P. 347–372.Yashnov, V.A. 1948. Order Leptostraca // Opredelitel Fauny i Flory Severnykh MoreiSSSR. Moscow: Sovetskaya Nauka. P. 223. (In Russian).39

Plate I. Nebalia bipes: 1 – female (from Yashnov, 1948); 2 – male (from Yashnov,1948); 3 – rostrum; 4 – eye; 5 – antennule; 6 – antenna; 7 – 3rd thoracopod40

Plate II. Nebalia bipes: 1 – distal margin of 4th pleonal segment; 2 – first pleopod; 3 –5th pleopod; 4 – 6th pleopod; 5 – telson with furca.Nebalia hessleri: 6 – distal margin of 6th pleonal segment; 7 – first pleopod; 8 –5th pleopod; 9 – 6th pleopod; 10 – telson with furca41

Order MYSIDACEA Boas, 1883Viktor V. PetryashovGeneral characteristicsThe order Mysidacea is a subdivision of the superorder Peracarida. Mysids areshrimplike higher crustaceans (pl. I, fig. 1). Their body is divided into two tagmata:the cephalothorax and the abdomen. The body consists of six-seven segments of thehead (five segments of the protocephalon and one to two segments of the maxilliped),six-seven thoracic segments, six abdominal ones, and the telson. The eyes are facetedand borne on movable stalks; visual elements sometimes more or less reduced, oftenresulting in the reduction of the eyes. Most part of the head and the thorax is coveredwith a well-developed head shield, or carapace, fused to the dorsum of three to four(rarer) anterior thoracic segments. The antennules (antennae 1) are well developed;they consist of a three-segmented peduncle and two many-segmented flagella. Thethird segment of the peduncle in males may bear a setaceous appendix masculina atthe distal margin. The antennae (antennae 2) are also well developed; they consist of athree-segmented protopod, a scaled exopod (antennal scale, or scaphocerite), and anendopod. The endopod of the antenna is composed of a three- to four-segmented basalpart and many-segmented flagellum. The mysids have eight pairs of thoracic limbs(thoracopods), one or two anterior pairs of which are transformed into maxillipeds. Allthoracopods are biramous; they are composed of an exopod and an endopod, attachedto a common base – protopod. Three constituent segments of the protopod are a precoxa(basal one), a coxa, and a basis (distal one). The coxa in several anterior thoracopodsis provided with a process (epipod). The segments of the endopod, from the baseto the apex, are a preischium, ischium, merus, carpus, propodus, and a dactylus. Theend of the dactylus is often armed with a claw-like spine. There is often a knee-likeprominence between the merus and the carpus. The mysids belonging to the tribeErythropini and to the genus Inusitatomysis of the tribe Mysini have the carpus and thepropodus joined obliquely, and the knee-like prominence is the feature inherent mainlyto these groups. Members of the above-mentioned groups from the Sea of Japan,plus the species of the subfamily Gastrosaccinae may have the propodus further dividedinto subjoints, usually two in number. In many species the carpus and the propodusare fused and have secondary division into several small subjoints (this is characteristicof the most species of the tribe Mysini from the northern half of the Sea ofJapan). The Sea of Japan species lack branchiae (podobranchs). Posterior two, or, rarer,three or seven pairs of the thoracopods in females are provided with welldevelopedplates (oostegites) on their inner sides. The oostegites form the marsupium,in which embryos develop; the development is full and direct. The mysids have fivepairs of abdominal limbs (pleopods). The pleopods may be uniramous or biramous.They are often reduced or absent in females and better developed in males. In manyspecies the fourth or, rarer, the third pair of the pleopods in males is elongate andmodified, as it is used in copulation. One pair of flat biramous uropods and the telsonform a tailfan. The species from the Sea of Japan are provided with the statocyst onthe basal part of the endopods of the uropods.42

The mysids inhabit marine, brackish, and fresh waters; they are distributed verticallyin depths from 0 to 8500 m. There are nekto-benthic (hyperbenthic), pelagic, andepibenthic forms among the mysids; several species are the commensals of sponges.Nekto-benthic and epibenthic species occur over and on various types of substrates.At present about 1000 species belonging to 152 genera of mysids are known.They inhabit all the oceans, most abundant in tropical and subtropical waters, thenumber of species decreasing towards polar regions. The mysids are omnivorous;most species are filter-feeders or carnivores.Mysidacea of the Sea of Japan belong to five biogeographical groups, namely:amphiboreal-arctic (2 species), Pacific subtropical-boreal (2 species), West Pacificsubtropical-boreal (2 species), Pacific widespread boreal (4 species), and West Pacificwidespread boreal (7 species). It means that the widespread boreal species predominatein the fauna of this region (11 species). The subtropical-boreal species (4 in number)should not be considered to occur in warm waters, as they are found in the northernareas of the Bering Sea, and most of them also in the Chukchi Sea. Two amphiboreal-arcticspecies must be really cold-water ones, and are therefore in the Sea of Japanrecorded only from the Tatar Strait. The analysis of the sublittoral mysid fauna refersthe studied region to the Manchurian-Kamchatkan district of the Far Eastern biogeographicalsuperprovince, while the analysis of very poor meso-bathypelagic fauna refersit to the Sea of Japan district of the Japanese – Far Eastern province (Petryashov,2005).Mysids should be collected using horizontal plankton nets and epibenthicsledges. Mysids are rather numerous in vertical samples taken by large plankton nets;they may also be collected by benthopelagic samplers attached to the trawls, pelagicand bottom trawls, and scoop nets. They are rarely found among the material taken bydredgers. The mysids should be fixed in 75% - ethanol or in 4% - formaldehyde.The present keys are based on the Murano’s classification (Murano, 1999) withsome additions and modifications from Tchindonova (1981) and Nouvel et al. (1999):suborder Lophogastridafamily Gnathophausiidaefamily Lophogastridaefamily Eucopiidaesuborder Stygiomysinafamily Lepidomysidaefamily Stygiomysidaesuborder Petalophthalminafamily Petalophthalmidaesuborder Mysidafamily Boreomysidaefamily Mysidaesubfamily Thalassomysinaesubfamily Siriellinaesubfamily Rhopalophthalminaesubfamily Gastrosaccinaesubfamily Mysinaesubfamily Mysidellinae43

It should be noted that there is no yet consensus on the system of the order. Manyresearchers establish only two suborders within the order Mysidacea, viz. Lophogastridaand Mysida, including the other two suborders into the suborder Mysida. Otherauthors erect the suborder Lophogastrida as a separate order (Martin & Davis, 2001).Some biologists don’t accept the independence of the families Gnathophausiidae andBoreomysidae. There is no general agreement among authors as to the number of tribesin the subfamily Mysinae. Some workers separate only four tribes (Erythropini,Leptomysini, Mysini, and Heteromysini) and attribute the rest to the tribe Erythropiniand one genus to the tribe Leptomysini.Members of the suborder Mysida and the family Mysidae have been found in theRussian waters of the Sea of Japan.Systematic partSuborder Mysida Boas, 1883Branchiae on thoracopods absent. Basal part of endopod of uropod provided withstatocyst.I. Family MYSIDAE Dana, 1850Female marsupium consists of two, rarer three pairs of well-developed oostegites(in some genera rudimentary pairs of oostegites also present). (Species inhabiting theRussian waters of the Sea of Japan have one-segmented exopod of uropod; no rudimentarysuture; outer margin covered with numerous (more than 10) spines, but withoutsetae, or covered with numerous setae, but without spines).Only two subfamilies of six occur in the northern part of the Sea of Japan.KEY TO THE SUBFAMILIES OF THE FAMILY MYSIDAE1(2). Female marsupium consists of two pairs of oostegites and one pair of lateral (epimeral)lamellae of first abdominal segment (pl. II, fig. 6). Outer margin of exopodof uropod without setae, with 1, 2, or more spines (pl. II, fig. 3) ........................................................................................................... I. Gastrosaccinae (p. 44)2(1). Female marsupium consists of 2, rarer 3 pairs of oostegites, lateral (epimeral)lamellae on first abdominal segment absent (pl. IV, fig. 6; XIV, fig. 2). Outermargin of exopod of uropod without spines, with numerous setae (pl. III, fig. 6) .................................................................................................... II. Mysinae (p. 46)I. Subfamily Gastrosaccinae Norman, 1892Female marsupium consists of two pairs of oostegites and one pair of epimerallamellae of first abdominal segment. Exopod of uropod one-segmented, outer marginwith one, two, or more spines, without setae from distal spine to base of exopod.Only one genus (Archaeomysis) of eight ones constituting the subfamily Gastrosaccinaeis found in the Russian waters of the Sea of Japan.44

1. Genus Archaeomysis Czerniavsky, 1882Type species: Archaeomysis grebnitzkii Czerniavsky, 1882.Male pleopods biramous. Exopod of pleopod 3 very much elongate, consists ofmore than 5 segments; stick-shaped seta situated on apex; endopod consists of 1–7segments (pl. II, fig. 2). Pleopods 1–5 of female biramous. Outer margin of exopod ofuropod bears more than 10 spines gradually increasing in length towards apex (pl. II,fig. 3).1. Archaeomysis grebnitzkii Czerniavsky, 1882(Pl. II, figs. 1–7)Czerniavsky, 1882a: 73 (Archaeomysis grebnitzkii); Holmes, 1894: 563 (Callomysis maculata);Zimmer, 1927: 635 (Archaeomysis maculata); Hanamura, 1997: 688–697 (Archaeomysisarticulata).Description. Relatively deep slit situated on each side of dorsodistal depressionof carapace, in most specimens covered by fold of integument. Antennal scale almostrectangular; outer margin smooth, without setae, with one distal spine projectingbeyond its apex; antennal scale 2.25–4.0 times as long as broad. Pleopod 3 in maleslongest; exopod of pleopod 3 extends to middle of fifth segment of abdomen, or evento basal part of telson; ratio of length of basal segment of exopod to length of protopod(sympod) is 0.6–1.0; other segments of this exopod small, numbering from 1–3 (inimmature males) to 4–8. Endopod of this pleopod relatively short, number of segmentsranges from 1–3 (in immature males) to 3–7 (in adult males). Distal 2/3–3/4 of outermargin of exopod of uropod bears 10 to 25 spines (juveniles have not less than 4spines). Telson elongate, trapezoid, with V-shaped cleft on apex, 1.8–3.3 times as longas broad at base; lateral margins bear 5–7 pairs of spines in juveniles, and up to 7–11pairs in adult specimens. Maximum length of male 19.0 mm; maximum length of female23.1 mm.Distribution. A. grebnitzkii is a widespread Pacific boreal species (if A. japonicais accepted as a variety of A. grebnitzkii, then it is a subtropical-boreal species). It isdistributed from the Island of St. Paul (the eastern Bering Sea) and Ugolnaya Bight(the south-eastern part of the Gulf of Anadyr) in the north, to the south of California(La Jolla), Hokkaido Island and Peter the Great Bay (A. japonica is distributed as farsouth as Nagasaki).Habitat and breeding. In the Sea of Japan, as well as everywhere within its areaof distribution, A. grebnitzkii is found from the upper level of the littoral zone (duringhigh tides) to depths of 34–40 m. It occurs on various substrates, from rocks to sandymud, though it prefers sand or other substrates mixed with sand, or with patches ofsand. It is a eurythermal (from -1.8° to +26°C) and euryhaline (18.0–34.3‰) species.Females with embryos were recorded in the Sea of Japan from July to September,number of embryos varied between 11 and 75.Remarks. The species A. articulata Hanamura, 1997 is a geographical variety ofA. grebnitzkii. All the characters described in the differential diagnosis give an indicationthat there are transitional forms between tipica and articulata. These transitionalforms are most numerous in the north-eastern part of Peter the Great Bay.45

II. Subfamily Mysinae Hansen, 1910Female marsupiums consist of 2–3 pairs of oostegites; epimeral lamellae absenton first abdominal segment. Outer margin of exopod of uropod bears setae, no spines.The subfamily Mysinae comprises six tribes; the species of two of them inhabitthe northern part of the Sea of Japan.KEY TO THE TRIBES OF THE SUBFAMILY MYSINAE1(2). Carpus and propodus of each endopod of thoracopods 3–8 with obliquely articulated(pl. III, fig. 4). Outer margin of antennal scale (or at least its basal third)smooth, unarmed, often with distal spine (pl. III, fig. 2; pl. IV, fig. 1–5); sometimesantennal scale absent or reduced to spine. Male pleopods 2–5 well developed,biramous, natatory .................................................... 1. Erythropini (p. 46)2(1). Carpus and propodus of each endopod of thoracopods 3–8 fused, with secondarydivision into subjoints; no oblique articulation (pl. VI, fig. 5; XVI, fig. 4) (exceptfor genus Inusitatomysis (pl. V, fig. 5). Forms of antennal scale and telson greatlyvary: mysids from Russian waters of Sea of Japan have outer margin of antennalscale setose, without spines (pl. VI, fig. 3; VII, fig. 3), or saw-toothed,without setae (pl. V, fig. 3). In males at least second pleopod rudimentary anduniramous. Exopod of fourth pleopod in males elongate and modified (pl. VI,fig. 4; VII, fig. 5), except for genus Inusitatomysis: endopod elongate and exopodrudimentary (pl. V, fig. 6) ................................................ 2. Mysini (p. 49)1. Tribe Erythropini Hansen, 1910Stalked eyes well developed, have ordinary shape or visual elements of eyes dividedinto two distinct regions. Antennal gland not hypertrophied. Outer margin ofantennal scale, or at least its basal third, smooth, unarmed (armed with setae only ingenus Nipponerythrops). Sometimes antennal scale absent or reduced to spine. Carpusand propodus of each endopod of thoracopods 3–8 obliquely articulated (except forgenus Arachnomysis). Male pelopods 2–5 well developed, biramous, natatory. Telsonentire, without cleft.Two of twenty-nine genera of this tribe (under the classification by Tchindonova(1981)) are found in the Sea of Japan.KEY TO THE GENERA OF THE TRIBE ERYTHROPINI1(2). Lateral margins of distal half of telson armed with spines (pl. III, fig. 7) (Endopodof male pleopod 4 elongate and with strong seta on apex [pl. III, fig. 5]) ...................................................................................................... 1. Holmesiella (p. 47)2(1). Lateral margins of telson smooth, unarmed (pl. IV, fig. 4–7). (Male pleopod 1with normally developed, many-segmented exopod and unsegmented endopod(pl. IV, fig. 2), other male pleopods well developed and have normal shape[pl. IV, fig. 3]) ................................................................... 2. Meterythrops (p. 47)46

1. Genus Holmesiella Ortmann, 1908Type species: H. anomala Ortmann, 1908.Eyes large, spherical. Antennal scale long, straight, extends beyond distal marginof antennular peduncle. Endopod of male pleopod 4 longer than exopod, with long andstrong seta on apex. Telson elongate, triangular; apex narrowly truncate, with one pairof plumose setae and two pairs of spines; inner pair of spines noticeably shorter thanouter pair; distal 1/2–2/3 of lateral margin of telson with spines gradually increasing inlength towards apex of telson.The genus consists of two species, one of which is found in the Sea of Japan.Ortmann, 1908: 6–7.1. Holmesiella anomala Ortmann, 1908(Pl. III, figs. 1–7)Description. Second and third segments of antennular peduncle have ordinaryarticulation: margin of third segment does not cover dorsally distal part of secondsegment. Antennal scale lanceolate, 3–5.5 times as long as broad; distal spine-likedenticle on its outer margin does not reach its apex. Endopod of male pleopod 4 verymuch elongate, 2.7–3.4 times longer than exopod. Telson 1.5–2.0 times as long asbroad at base; lateral margins armed with 11 to 22 spines. Maximum length of males39.3 mm, maximum length of females 45.8 mm.Distribution. H. anomala is a widespread Pacific boreal species, distributedfrom the Sea of Japan coast of Korea (36°19′N, 129°47′E), Sagami Bay, and the southof California to the Bering Sea (the crosspiece of Olyutorsky Cape). The species hasbeen recorded in the Sea of Japan only once.Habitat and breeding. H. anomala is a sublittoral-upper bathyal species, verticallydistributed from 10–25 m to a depth of 1320 m. It is mainly found in the upperbathyal zone and moves to the sublittoral and epipelagic zones apparently in course ofdaily vertical migrations. It is found in waters with a temperature of -1.7° to +4°C anda salinity of 29.5–34.35‰. H. anomala occurs predominantly over silty and sandy bottoms.There are no records for the breeding of this species in the Sea of Japan.2. Genus Meterythrops Smith, 1879Type species: M. robusta Smith, 1879.Eyes spherical. Antennal scale elongate and lanceolate, or diamond-shaped; extendsto distal margin of antennular peduncle. Anterior margin of carapace producedinto triangular rostral plate with broadly rounded apex. Endopod of male pleopod 1one-segmented, exopod many-segmented. Telson elongate, triangular, with slightlytruncated apex; lateral margins smooth, unarmed; apex with two pairs of spines andone pair of median plumose setae.This genus consists of five species, two of which inhabit the Sea of Japan.47

KEY TO THE SPECIES OF THE GENUS METERYTHROPS1(2). Eyes large, twice as long as first segment of antennular peduncle, extend beyondlateral margins of carapace in dorsal view (pl. IV, fig. 1) ...... 1. M. robusta (p. 48)2(1). Eyes small, almost equal in length to first segment of antennular peduncle, donot extend beyond lateral margins of carapace in dorsal view (pl. IV, fig. 5) ........................................................................................... 2. M. microphthalma (p. 48)1. Meterythrops robusta Smith, 1879(Pl. IV, figs. 1–4)Smith, 1879: 93 (Meterythrops robusta); G.O. Sars, 1879: 98 (Parerythrops robusta).Description. Eyes large, spherical, 2 times as long as first segment of antennularpeduncle; extend beyond lateral margins of carapace in dorsal view. Antennal scaleusually lanceolate, rarer diamond-shaped, 1.8–4 times as long as broad (usually 2–3times). Distal part of scale, extending beyond base of spine on outer margin, comprises0.28 to 0.5 of whole length of antennal scale (usually about 1/3). Maximum lengthof females 21.0 mm, maximum length of males 24.0 mm (in the Tatar Strait – correspondingly10.2 mm and 13.6 mm).Distribution. M. robusta is an amphiboreal-arctic species. In the Atlantic Oceanand in the Arctic it is known from the eastern coast of the USA (40° N) and southernNorway to Greenland (69° N near the western coast), the eastern Murman Coast, andalong the continental slope of the Arctic basin to the East Siberian Sea (78°06.3′N,154°15.7′E). In the Pacific Ocean it is distributed from the Strait of Juan de Fuca, thesouth-western coast of Sakhalin Island and the eastern coast of Iturup Island (Kurils)to the Bering Sea (60° N).In the Sea of Japan it has been recorded only in the Tatar Strait off the southwesterncoast of Sakhalin, near the villages of Kalinino and Antonovo.Habitat and breeding. M. robusta occurs in the sublittoral and upper bathyalzones, between 17 and 620 m of depth: it is common in the Pacific in depths from 100to 200 m, and in the Tatar Strait it is found in depths from 60 to 125 m. It occurs inwaters with a temperature from -1.8° to +15°C and a salinity of 29.5–35‰, usuallyover sandy and silty bottoms, sometimes mixed with stones. There are no records forthe breeding of this species in the Sea of Japan.2. Meterythrops microphthalma Tattersall, 1951(Pl. IV, figs. 5–7)Tattersall, 1951: 113–116 (Meterythrops microphthalma); Taniguchi, 1969: 47–48 (Meterythropsrobusta).Description. Eyes relatively small, almost equal in length to first segment of antennularpeduncle, do not extend beyond lateral margins of carapace in dorsal view.Antennal scale diamond-shaped, 2.1–3.8 times as long as broad. Distal part of scale,extending beyond base of robust spine on outer margin, comprises 1/3–1/2 of wholelength of antennal scale (usually about 2/5). Maximum body length all over area ofdistribution, as well as in Sea of Japan: of females 23.5 mm, of males 24.6 mm.48

Distribution. M. microphthalma is a West Pacific widespread boreal species. Itis distributed from Sagami Bay (the eastern coast of Honshu Island) and the southernSea of Japan to the northern Bering Sea (60° N, near Olyutorsky Cape).Habitat and breeding. M. microphthalma inhabits the mesopelagic and bathypelagiczones; during vertical migrations it can also penetrate the epipelagic zone. It isfound from 10–26 m to a depth of 2800 m; at night it usually occurs at 800–200 m, inthe daytime – at 1100–600 m. It is found in waters with a temperature from +0.2° to+5°C and a salinity of 33–34.4‰. Females with embryos were recorded in the Sea ofJapan from January till February and from August till October. The number of embryosin each female varies between 8 and 24. M. microphthalma is a most abundantmeso-bathypelagic mysid species in the Sea of Japan and Sea of Okhotsk.2. Tribe Mysini Hansen, 1910Carpus and propodus of thoracopods 3–8 fused, with secondary division into subjoints,without oblique articulation (except for genus Inusitatomysis). Forms of antennalscale and telson greatly vary: in genera from Russian waters of Sea of Japan outermargin of antennal scale setose and without spines, or (in genus Inusitatomysis) sawtoothedand without setae; telson entire, not cleft on apex, cleft only in genus Inusitatomysis.In males at least pleopod 2 rudimentary and uniramous. Exopod of malepleopod 4 elongate and modified, except for species of genus Inusitatomysis, whichhave endopod elongate and exopod rudimentary.The tribe Mysini is comprised of 48 genera, and the mysids of nine genera occurin the northern part of the Sea of Japan, namely: Inusitatomysis, Xenacanthomysis,Stilomysis, Disacanthomysis, Neomysis, Boreoacanthomysis, Hemiacanthomysis, Exacanthomysis,and Paracanthomysis.KEY TO THE GENERA OF THE TRIBE MYSINI1(2). Outer margin of antennal scale saw-toothed, without setae (pl. V, fig. 3). Telsonwith V-shaped cleft on apex (pl. V, fig. 8) ....................... 1. Inusitatomysis (p. 50)2(1). Outer margin of antennal scale with setae along its full length, lacks spines(pl. VI, fig. 3; VII, fig. 3; IX, fig. 1). Telson entire, not cleft (pl. VI, fig. 7; IX,fig. 7; XII, figs. 5, 6; XIV, fig. 5).3(4). Second and third segments of antennular peduncle in males with spiny knob-likeprocesses; inner flagellum of antennule with row of striated shell-like processes(pl. VI, fig. 2). Exopod of male pleopod 4 relatively robust, strongly curved atbase, one- to three-segmented, usually one-segmented with one or two indicationsof suture (pl. VI, fig. 4). (Eyes cylindrical [pl. VI, fig. 1]. Telson elongate,linguiform; its apex with row of subequal spines, shorter or equal in length tolarge spines of lateral margin of telson, usually much shorter [pl. VI, fig. 7]) ........................................................................................... 2. Xenacanthomysis (p. 51)4(3). Male antennule has ordinary shape: without spiny knob-like processes on secondand third segments of peduncle and without striated shell-like processes on innerflagellum (pl. VII, fig. 2; XVI, fig. 2). Exopod of male pleopod 4 relatively thin,slender, always straight at base, 1–5-segmented (pl. VII, fig. 5; VIII, fig. 2; IX,fig. 5; XVI, fig. 5).49

5(6). Female marsupium consists of 3 pairs of well-developed oostegites. Exopod offourth pleopod of male 4–5-segmented (pl. VII, fig. 5). (Male pleopod 3 biramous;exopod 4-segmented; endopod unsegmented, but relatively long: it comprises1/2–2/3 of exopod length (pl. VII, fig. 4). Telson elongate, linguiform, withbroadly rounded apex, bearing 2 pairs of spines; outer pair much longer than innerone [pl. VII, fig. 7]) .......................................................... 3. Stilomysis (p. 52)6(5). Female marsupium consists of 2 pairs of well-developed oostegites. Exopod offourth pleopod of male 2- to 3-segmented, or unsegmented (pl. VIII, fig. 2; IX,fig. 5; XVI, fig. 5).7(8). Exopod of fourth pleopod of male 3-segmented: third distal segment very small,ratio of length of first (basal) segment of exopod to lengths of second and third(distal) segments is 23:5:1 (pl. VIII, fig. 2). (Antennal scale elongate, withrounded apex, 5.4–10 times as long as broad (pl. VIII, fig. 1). Tergites of distalthoracic segment and all abdominal segments smooth, without transverse furrows.Telson elongate, longuiform, with rounded apex, bearing 2 pairs of spines;outer pair twice as long as inner one; spines on distal third of telson gathered in5–10 groups [pl. VIII, fig. 4]) ..................................... 4. Disacanthomysis (p. 53)8(7). Exopod of fourth pleopod of male 2-segmented or unsegmented (pl. IX, fig. 5;XVI, fig. 5).9(10). Antennal scale with pointed apex (pl. IX, fig. 1). (Exopod of fourth pleopod ofmale 2-segmented [pl. IX, fig. 5]) ........................................ 5. Neomysis (p. 54)10(9). Antennal scale with rounded apex (pl. XIII, figs. 1, 5; XVI, fig. 3).11(16). Exopod of fourth pleopod of male 2-segmented (pl. XIII, figs. 2–6; XIV, fig. 3).12(15). Tergites of distal thoracic segment and all abdominal segments smooth, withouttransverse furrows (pl. IX, fig. 4).13(14). Telson elongate, triangular, with truncated apex (pl. XIII, fig. 4). (Antennalscale 3.4–5.8 times as long as broad (pl. XIII, fig. 1); 6–38 spines situated onventral side of endopod of uropods, near statocyst (pl. XIII, fig. 3); spinesgrouped on distal 2/3 of lateral margin of telson) ......................................................................................................................... 6. Boreoacanthomysis (p. 58)14(13). Telson elongate, linguiform, with rounded apex (pl. XIII, figs. 8–9). (Antennalscale 3.4–5.4 times as long as broad (pl. XIII, fig. 5); ventral side of endopodof uropods armed with 14–31 spines situated along major part of inner marginfrom statocyst to apex; spines on lateral margin of telson gradually increase inlength towards apex, not grouped) ..................... 7. Hemiacanthomysis (p. 59)15(12). Tergites of distal thoracic segment and of all abdominal segments with transversefurrows (pl. XIV, fig. 2; XV, fig. 2) ............... 8. Exacanthomysis (p. 60)16(11). Exopod of fourth pleopods of male unsegmented (pl. XVI, fig. 5) ................................................................................................... 9. Paracanthomysis (p. 61)1. Genus Inusitatomysis Ii, 1940Type species: Inusitatomysis insolita Ii, 1940.Eye flattened; cornea bud-shaped, situated along outer margin (Pl. V, fig. 1). Labrumwithout anterior process (Pl. V, fig. 4). Antennal scale lanceolate; outer marginsaw-toothed, without setae. Carpus and propodus of thoracopods 3–8 joined obliquely.Female marsupium consists of 3 pairs of oostegites. Male pleopods 1–3 and 5, as well50

as all female pleopods, rudimentary, in shape of narrow undivided plates. Exopod ofmale pleopod 4 rudimentary, in shape of very small lobe fused full length with endopod;endopod very much elongate, consists of 8–11 segments (Pl. V, fig. 6). Telsontrapezoid, with V-shaped cleft on apex, at bottom of which 2 plumose setae situated;lateral margins of cleft saw-toothed; telson bears spines over entire length of lateralmargins.There is only one species in the genus.1. Inusitatomysis insolita Ii, 1940(Pl. V, figs. 1–8)Ii, 1940: 163–167 (Inusitatomysis insolita); Banner, 1948: 67 (Inusitatomysis sp.); Tattersall,1951: 160–162 (Inusitatomysis serrata); Bacescu & Gleye, 1979: 131–133 (Inusitatomysiscalifornica).Description. Antennal scale 3–4.5 times as long as broad; outer margin armedwith 4–9 spines; distal spine far from reaching apex of scale. Endopod of male pleopod4 long, extends to basal part of telson; first segment longest of all others takentogether with terminal setae. Inner margin of endopod of uropod provided with 1 spinenear statocyst. Telson 1.6–2.4 times as long as broad at base; spines on lateral marginsubequal, except for distal pair, being about twice longer than others; cleft depth comprises0.1–0.2 of telson length. Maximum length of females 22.6 mm, maximumlength of males 21.3 mm.Distribution. I. insolita is a widespread Pacific boreal species. It is distributedfrom the Korea Strait, Shikotan Island (Kurils), and the south of California (33°21'N)to Bering Island. The records from the Sea of Okhotsk have only been off the KurilIslands and in Terpeniya Bay. In the Russian waters of the Sea of Japan it is found inPeter the Great Bay and in the Tatar Strait near the coast of Sakhalin.Habitat and breeding. I. insolita is a sublittoral species. It occurs in depths from25 to 260 m, predominantly between 50 and 160 m, in the Sea of Japan in depths from25 to 125 m. It is found in waters with a temperature from -1.7° to +10°C and a salinityof 30–34.8‰. The species occurs mainly over sand and muddy sand, sometimesmixed with stones. There are no records for breeding.2. Genus Xenacanthomysis Holmquist, 1980Type species: Neomysis pseudomacropsis Tattersall, 1933.Eye with relatively long stalk, cylindrical. Anterior margin of carapace evenlyrounded (Pl. VI, 8). Second and third segments of male antennular peduncle providedwith spiny knob-like processes; inner flagellum with row of striated shell-likeprocesses. Antennal scale lanceolate, with rounded apex, armed only with setae alongwhole length of its margin. Labrum elongate, heart-shaped with short acute anteriorprocess. Female marsupium consists of 2 pairs of ordinary oostegites. All femalepleopods and all pleopods, except for pleopods 4, of males rudimentary, plate-shaped,and unsegmented. Exopod of male pleopod 4 robust, strongly curved at base, 1- to 3-segmented, articulations often rudimentary, partial; outer margin armed with 5–7 longsetae; two terminal setae plumose, long, strong, curved; endopod short, unsegmented.51

Telson elongate, linguiform; apex broadly rounded, bears row of subequal spines, aslong as or often noticeably shorter than large spines on lateral margin.The genus consists of only one species.1. Xenacanthomysis pseudomacropsis (Tattersall, 1933)(Pl. VI, figs. 1–8)Tattersall, 1933: 194–197 (Neomysis pseydomacropsis); Ii, 1936: 589 (Acanthomysispseudomacropsis); Holmqiust, 1980: 501–510 (Xenacanthomysis pseudomacropsis).Description. Eyes widely spaced; cornea spherical. Antennal scale 8.3 times (injuveniles) to 4.5 times as long as broad. Carpo-propodus of endopod of thoracopods3–8 consists of 5 (in juveniles) to 6–9 subjoints. Exopod of male fourth pleopod 4 to6.7 times longer than endopod. Endopod of uropod armed with one, or sometimes twospines situated near statocyst. Telson 2.6–3.3 times as long as broad at base. Its lateralmargins bear 32 (in juveniles) to 60 spines, which on distal 1/2–3/4 of lateral margins(excluding apical part) gathered in 4–8 indistinct groups (one or several small spinesfollowed by larger spine). Maximum length of females 20.2 mm, of males 18.2 mm.Distribution. X. pseudomacropsis is a widespread Pacific boreal species. It isdistributed from the coast of the North Korea, the central part of the coast of Honshuon the Sea of Japan side, from Shikotan Island (Kurils) and the Strait of Juan de Fucato Point Barrow (northern part of Alaska). In the Russian waters of the Sea of Japan itis found in Peter the Great Bay and in the Tatar Strait.Habitat and breeding. X. pseudomacropsis is a sublittoral species. It is found atdepths from 0 to 104 m, usually to 50–70 m, in the Sea of Japan recorded at 0–80 m. Itoccurs at a temperature from -1.5° to +18°C and a salinity of 28–34.3‰, predominantlyover sand, rarer over muddy sand or silt, occasionally mixed with rocks. Femaleswith embryos were recorded in the Sea of Japan in May (embryos at stages I–II) andin July (stages II–III), the number of embryos ranging from 21 to 35.3. Genus Stilomysis Norman, 1892.Type species: Mysis grandis Goes, 1864.Eye large, with trapezoid stalk. Cornea almost spherical, slightly flattened dorsoventrally(pl. VII, fig. 1). Antennal scale elongate, lanceolate, with rounded apex, 2-segmented; margins covered only with setae (pl. VII, fig. 3). Marsupium consists of 3pairs of oostegites. All female pleopods and male pleopods 1, 2 and 5 reduced to plate.Male pleopods 3 and 4 biramous; endopod one-segmented; exopod of pleopod 3 short,consists of 4–5 segments; exopod of pleopod 4 long, consists of 4–5 segments, relativelythin, basal segment longest, straight. Telson elongate, linguiform, with roundedapex, not cleft.The genus comprises three species. Only one species was recorded in the northernpart of the Sea of Japan.1. Stilomysis grandis (Goes, 1864)(Pl. VII, figs. 1–7)Goes, 1864: 176 (Mysis grandis); G.O. Sars, 1879: 106 (Mysideis grandis); Norman,1892: 148 (Stilomysis grandis).52

Description. Antennal scale 4.3–9.4 times as long as broad. Carpo-propodus ofthoracopods 2–8 consists of 3 to 5 subjoints (in northwestern Pacific mysids, usuallyof 3 segments). Exopod of pleopod 3 of male 1.5–2.3 times longer than endopod. Exopodof pleopod 4 of male 3.7–7.8 times longer than endopod; basal segment slightlylonger than all other segments of exopod together with terminal seta. Inner margin ofendopod of uropod bears row of 20 to 56 spines, extending from statocyst almost toapex. Telson with relatively broadly rounded apex, 2.0–2.75 times as long as broad atbase. Lateral margin of telson covered with numerous (38–73) spines, gradually increasingin length towards apex, or gathered in indistinct groups. Apex of telsonarmed with 2 pairs of spines, outer one 1.5–3 times longer than inner one. Maximumlength of females 39.9 mm, of males 41.2 mm.Distribution. S. grandis is an amphiboreal-arctic species. It is found in the PacificOcean and the adjacent Arctic regions from British Columbia, the Tatar Strait andIturup Island of the Kurils (crosspiece of Kasatka Bay) to the Chukchi Sea (67°20.9′N,164°58.4′W). In the North Atlantic and in the Arctic it occurs from Labrador Peninsulaand northern Norway to the western coast of the Novaya Zemlya Archipelago andthe border between the Krasnaya Armiya Strait (Severnaya Zemlya Archipelago) andthe Laptev Sea. The species is found in the Sea of Japan in the Tatar Strait: from MoneronIsland (46°08.2′N) to 49°40′N.Habitat and breeding. S. grandis is a sublittoral-upper bathyal species. Its depthrange is from 0 to 402 m, predominantly from 25 to 200 m; in the Sea of Japan recordedat depths from 89 to 175 m. It occurs in waters with a temperature from -1.8° to+8.1°C and a salinity of 30 to 35‰ over sandy or silty bottoms, rarer over stony bottoms.There are no records for the breeding of this species in the Sea of Japan.Remarks. Stilomysis major Tattersall, 1951 from the southern part of the Sea ofJapan is closely related to S. grandis, differing from it in the more elongate antennalscale (10 times as long as broad) having very narrowly rounded apex, and in the morenarrowly rounded apex of the telson: the ratio of the telson width at the apex to thesame at the base is 1/30–1/20 (in S. grandis 1/6–1/10); the lateral margin of the telsonis armed with up to 84 spines. There is one more related species, S. camtschatica Marukawa,1928, but it is likely to be a dwarf form of S. grandis.4. Genus Disacanthomysis Holmquist, 1981Type species: Orientomysis dybowskii Derjavin, 1913.Eye large, stalk trapezoid. Antennal scale elongate, 2-segmented, with setae allalong margin. Labrum with long, sharp anterior process. Female marsupiums composedof 2 pairs of well-developed oostegites. All male pleopods except for pair 4 andall female pleopods rudimentary, plate-shaped, relatively short, except for pleopods 5in males. Male pleopod 5 elongate, slightly shorter than pleopod 4, with row of lateralsetae and strong, long terminal seta. Male pleopod 4 biramous with one-segmentedendopod, about as long as 1/2 of 3-segmented exopod; basal segment of exopod longest;distal segment very small: approximate ratio of lengths of segments 23:5:1. Eachsegment of exopod armed with 1–2 simple distal setae; distal segment additionallywith two strong plumose setae. Endopod of uropod with row of spines on small lobe atinner ventral margin near statocyst. Telson linguiform; lateral spines situated on itsdistal third, gathered in distinct groups; rounded apex bears 2 pairs of spines.There is one species in the genus.53

3(4). Truncated apex of telson less than 1/7 as broad as base of telson (pl. IX, fig. 7).Rostral plate rectangular, with rounded distal corners (pl. IX, fig. 3) ........ ................................................................................................................. 1. N. rayii (p. 55)4(3). Truncated apex of telson more than 1/7 as broad as base of telson (pl. X, fig. 6).Rostral plate triangular, with rounded or, rarer, pointed apex (pl. X, figs. 2, 3) ........................................................................................... 2. N. awatschensis (p. 56)5(2). Spines on distal third of lateral margin of telson longer than distances betweentheir bases, thereby seeming appressed to each other (pl. XI, fig. 6). Tergites ofdistal segment of thorax and segments 1–5 of abdomen with 2–3 shallow transversefurrows (pl. XI, fig. 3). (Apex of telson with two pairs of spines; outer pairtwice as long as inner one ............................................... 3. N. czerniawskii (p. 56)6(1). Apex of telson rounded (pl. XII, figs. 5, 6). (Spines on distal third of lateral marginof telson longer than distances between them, thereby seeming appressed toeach other. Apex of telson with 2–3 pairs of equal spines. Tergites of distal segmentof thorax and all abdominal segments smooth, without furrows) ................................................................................................................ 4. N. mirabilis (p. 57)1. Neomysis rayii (Murdoch, 1885)(Pl. I, figs. 1, 2; IX, figs. 1–7)Murdoch, 1885: 519 (Mysis rayii); Holmes, 1900: 223 (Neomysis franciscorum); Zimmer,1904: 470 (Neomysis rayii); Derjavin, 1913: 198 (Neomysis toion); Schmitt, 1919: 6(Neomysis franciscana).Description. Antennal scale long, 9.5–13.6 times as long as broad. Anterior marginof carapace with rectangular rostral plate, having rounded distolateral corners.Carpo-propodus of each of thoracopods 5–8 consists of 7–10 (in juveniles) to 19–21subjoints. Exopod of male fourth pleopods 1.5–2.7 times as long as endopod; basal(proximal) segment of exopod 3.7–8.5 times longer than distal one. Small lobe situatedon ventral side of endopod of uropod between statocyst and inner margin,armed with 17–22 (in juveniles) to 56 spines. Telson triangular, with narrow truncatedapex: apex width 7.5–12 times less than base width; telson 2.6–3.3 times as long asbroad at base; lengths of spines on distal third of lateral margin less than distances betweenthem; apex armed with 2 pairs of spines: inner spines 3–5 times shorter thanouter ones, the latter usually longer than longest spines on lateral margin. Maximumlength of females 42.1 mm, of males 39.0 mm.Distribution. N. rayii is a Pacific subtropical-boreal species. It is distributedfrom San-Francisco (California) and Tianjin (Gulf of Pohai) to Beechey Point (northerncoast of Alaska) and the Long Strait. In the Sea of Japan it is found in the TatarStrait and in Possjet Bay.Habitat and breeding. N. rayii is a sublittoral species, with a depth range from 0to 79 m, mostly to 50 m, in the Sea of Japan from 2 to 78 m. It is found in waters witha temperature from -1.7° to +25°C and a salinity from 15 to 34.3‰, over sand andmuddy sand, rarer over boulders, pebbles, or silt. There are no records for the breedingof this species in the Sea of Japan.55

2. Neomysis awatschensis (Brandt, 1851)(Pl. X, figs. 1–6)Brandt, 1851: 126 (Mysis awatschensis); Czerniavsky, 1882b: 30 (Heteromysis intermedia);Zimmer, 1904: 468 (Neomysis awatschensis); 1904: 469 (Neomysis intermedia); Nakazawa,1910: 248 (Neomysis nigra); Marukawa, 1928: 6 (Neomysis isaza).Description. Antennal scale 5–9.4 times as long as broad. Anterior margin of carapaceproduced into small triangular plate with rounded or pointed apex. Carpopropodusof each of thoracopods 5–8 consists of 3–6 (in juveniles) to 6–9 subjoints.Exopod of pleopod 4 of male 3 to 6.7 times longer than endopod; basal (proximal)segment of exopod 1.6–5.6 times longer than distal one. Ventral side of endopod ofuropod with lobe between statocyst and inner margin, bearing from 10–16 (in juveniles)to 15–30 spines. Telson triangular with broad truncated apex: width of telson atapex 2.3–5.8 times less than width of telson at base; telson 1.75–4.0 times as long asbroad at base; its lateral margin armed with 12–18 spines, as long as or shorter thandistances between them; apex with 2 pairs of spines: outer ones 3 times as long as innerones and about 1.5 times as long as longest spines on lateral margin. Maximumlength of female body 18.1 mm, of male body 14.3 mm.Distribution. N. awatschensis is a West Pacific subtropical-boreal species. It isdistributed from the mouth of the Yangtze River (China), the northern coast of theSouth China Sea (China), and Shikoku Island (Japan) to Anadyr and Bristol bays andthe north-western coast of Alaska (Chukchi Sea – 68˚24′N), also in the boreal faunarefugia in the Arctic: the lower course of the Chaun River (western part of ChukchiPeninsula) and in the Makkenzie River delta (north-western Canada); often occurs inthe lower course of rivers: in the Amur River to the mouth of the Ussuri River. Therecords for the Sea of Japan are from De-Kastri Bay, Sovetskaya Gavan Bay (KonstantinovskayaBight), Olga (in the river mouth) and Possjet bays (Ekspeditsiya andNovgorodskaya Bights, the lower course of the Gladkaya River).Habitat and breeding. N. awatschensis is an estuarine-freshwater and high sublittoralspecies. Its depth range is 0–11 m, in the Sea of Japan from 0 to 3 m. It isfound in waters with a temperature from -1° to +26°C and a salinity range of 0–27‰,mostly over sandy bottoms, rarer over other types of bottoms (from boulders and gravelto silt). Females with stage I–III embryos were recorded in Possjet Bay from Julytill September. The number of embryos varies from 6 to 29.3. Neomysis czerniawskii Derjavin, 1913(Pl. XI, figs. 1–6)Derjavin, 1913: 199 (Neomysis czerniawskii); Schmitt, 1919: 6 (in part) (Neomysis andersoni).Description. Antennal scale 9–15 times as long as broad. Anterior margin of carapacewith rostral plate; apex broadly rounded. Carpo-propodus of each of thoracopods5–8 consists of 5–6 (in juveniles) to 7–12 subjoints. Tergites of distal thoracicsegment and first to fifth abdominal segments with 2–3 shallow transverse furrows.Exopod of pleopod 4 of male 2.1–4 times as long as endopod; basal (proximal) segmentof exopod 4.5–6 times as long as distal one. Ventral side of endopod of uropods56

provided with lobe between statocyst and inner margin, armed with 13 to 41 spines.Telson elongate, triangular, with slightly truncated apex; telson 2.5–3.3 times as longas broad at base; lateral margin with 27 to 44 spines, gathered in 6–11 groups on distalhalf; 2 pairs of spines situated on apex; outer pair twice longer than inner one, almostas long as longest spines on lateral margin. Maximum length of female body 20.4 mm,of male body 19.1 mm.Distribution. N. czerniawskii is a West Pacific subtropical-boreal species. It isdistributed from the coast of Shandong Peninsula and the south of Hokkaido Island(Japan) to Alaska Peninsula and Kotzebue Bay (north-western Alaska). In the Sea ofJapan it has been recorded in Peter the Great Bay (Possjet Bay, 42°37′N, 131°06′E)and in De-Kastri Bay (Observatoriya Island).Habitat and breeding. N. czerniawskii is a high sublittoral species, found indepths from 0 to 31 m, throughout its area of distribution, as well as in the Sea of Japan.It occurs in waters with a temperature from -1° to +26°C and a salinity of 19.67–30‰, over sandy bottoms. There are no records for the breeding of this species in theSea of Japan.4. Neomysis mirabilis (Czerniavsky, 1882)(Pl. XII, figs. 1–6)Czerniavsky, 1882b: 33 (Heteromysis mirabilis); Zimmer, 1904: 468 (Neomysis mirabilis);Schmitt, 1919: 6 (in part) (Neomysis andersoni); Ii, 1936: 581 (Neomysis nakazawai).Description. Antennal scale 8.7–15 times as long as broad. Anterior margin ofcarapace evenly rounded or with small triangular rostral plate having rounded apex.Carpo-propodus of endopod of thoracopods 5–8 consists of 7–8 (in juveniles) to 15subjoints. Exopod of pleopod 4 of male 2.3–3.2 times as long as endopod; basal (proximal)segment 2.6–6 times as long as distal one. Ventral side of endopod of uropodwith lobe between statocyst and inner margin, armed with 29–69 spines. Telson elongate,triangular, with rounded apex, sharply tapers in distal half or third, 2.4–3.5 timesas long as broad at base. Lateral margins of telson with 33 to 50 spines, almost evenlyincreasing towards apex or gathered in 6–9 distinct groups (these two varieties alsohave transitional forms). Apex of telson armed with 2 to 3 pairs of equal spines. Maximumlength of female body 35.5 mm, of male body 37.5 mm.Distribution. N. mirabilis is a West Pacific widely dispersed boreal species,found from Wŏnsan (Korea) and the northern Japan (40°N) to the Bering Sea coast ofAlaska (65°N) and the north-eastern coast of Kamchatka (61°30′N). It seems to beubiquitous in the northern Sea of Japan: recorded from various parts of Peter the GreatBay, the Tatar Strait, and Vladimir Bay.Habitat and breeding. N. mirabilis is a sublittoral species. In the area of its distribution,as well as in the Sea of Japan it occurs at depths from 0 to 140 m, mostly to30 m, at a temperature from -1.6° to +24°C and a salinity of 15–34.3‰, predominantlyover sand or muddy sand, rarer over boulders and pebbles, or over silt. Femaleswith 6 to 76 embryos in the marsupiums were registered in the Sea of Japan Marchthrough September. N. mirabilis is one of the most abundant species in the coastal watersof the Sea of Japan.57

6. Genus Boreoacanthomysis Fukuoka et Murano, 2004Type species: Mysis schrencki Czerniavsky, 1882.Carapace produced anteriorly into relatively short triangular rostral plate withalmost pointed or narrowly rounded apex. Eyes well developed, trapezoid, slightlydepressed dorsoventrally. Labrum with short anterior spiniform process. Antennalscale lanceolate, with rounded apex, armed with setae all along its outer and innermargins; subapical suture present. Marsupium composed of 2 pairs of well-developedoostegites. Tergites of free thoracic segments and all abdominal segments smooth,without transverse furrows or any transverse rows of spines and setae. First to thirdand fifth pleopods of male and all pleopods of female uniramous, reduced to unsegmentedplate, increasing in length from first to fifth; fifth pleopod of male not reachingmiddle of last abdominal segment. Fourth pleopod of male biramous; endopodreduced to unsegmented lobe; exopod long, almost straight, 2-segmented, proximalsegment long, armed on each distal corner with seta (occasionally without one or bothsetae); distal segment short, armed with 2 long, strong, subequal terminal setae andshort setae on distal corners (occasionally without one or both of these setae). Endopodof uropod armed with numerous, densely set spines on ventral surface near innermargin in statocyst region. Telson elongate, linguiform or triangular, with narrowapex; lateral margins armed on anterior 1/3–1/2 with almost equal spines set rathersparsely and on posterior 2/3–1/2 with grouped spines set densely, each group consistingof one large spine and one-three smaller ones; apex with 2 pairs of spines, outerspines much longer than inner ones.The genus comprises one species.1. Boreoacanthomysis schrencki (Czerniavsky, 1882)(Pl. XIII, figs. 1–4)Czerniavsky, 1882b: 20 (Mysis schrencki); Derjavin, 1913: 198 (Orientomysis schrencki);Ii, 1936: 589 (Acanthomysis schrencki); Holmquist, 1981b: 408 (Pacifacanthomysisschrencki); Fukuoka, Murano, 2004: 2137–2143 (Boreoacanthomysis schrencki).Description. Antennal scale 3.4–5.8 times as long as broad. Carpo-propodus ofendopod of thoracopods 5–8 consists of 3 (in juveniles) to 4–6 subjoints. Exopod offourth pleopod of male (with terminal setae) 3.0–4.0 times as long as endopod; basal(proximal) segment 3–6 times as long as distal one. Endopod of uropod armed with 6–8 (in juveniles) to 38 spines on ventral lobe placed near statocyst. Telson with slightlytruncated apex, 2.1–3.5 times as long as broad at base; inner spines on its apex 2–3times as short as outer ones. Maximum length of female body 18.5 mm, of male body14.6 mm.Distribution. B. schrencki is a West Pacific widespread boreal species. It is distributedfrom Possjet Bay (Sea of Japan) and the eastern coast of Hokkaido Island toParamushir Island (Kurils) and the northern coast of the Sea of Okhotsk. In the Sea ofJapan it occurs in Peter the Great Bay and in the Tatar Strait.Habitat and breeding. This is a sublittoral species, vertically distributed from 0to 80 m, mostly to 25 m. It occurs in waters with a temperature from -1.2° to +21.4°Cand a salinity between 29.5 and 34.3‰, predominantly over rocks and boulders orsandy silt, rarer over gravel with pebbles or silt. Females bearing embryos were rec-58

orded in the Sea of Japan for May and August-September. The number of embryosvaries between 17 and 68.7. Genus Hemiacanthomysis Fukuoka et Murano, 2002Type species: Acanthomysis dimorpha Ii, 1936.Carapace anteriorly produced to relatively short triangular rostral plate. Eyes welldeveloped, trapezoid, slightly depressed dorsoventrally. Labrum with comparativelylong anterior spiniform process. Antennal scale lanceolate, with rounded apex, setoseall along length of inner and outer margins; subapical suture present. Marsupium consistsof 2 pairs of well-developed oostegites. Tergites of free thoracic segments and ofall abdominal segments smooth, without transverse furrows or transverse rows ofspines or setae. First to third and fifth male pleopods and all female pleopods uniramous,reduced to unsegmented plate, increasing in length from first to fifth. Fourthpleopod of male biramous; endopod reduced to unsegmented lobe; exopod long, almoststraight, 2-segmented; proximal segment long, armed on each distal corner withseta (occasionally without one or both setae), distal segment short, armed with twolong, strong subequal terminal setae and one short seta on distal corner, or without thisseta. Endopod or uropod armed with spines throughout length of inner margin fromstatocyst almost to apex. Telson elongate, triangular, with narrowly rounded apex orlinguiform, with lateral margins bearing subequal spines.The genus comprises one species.1. Hemiacanthomysis dimorpha (Ii, 1936)(Pl. XIII, figs. 5–9).Ii, 1936: 593 (Acanthomysis dimorpha); Fukuoka & Murano, 2002: 210–214 (Hemiacanthomysisdimorpha).Description. Antennal scale 3.4–5.4 times as long as broad. Carpo-propodus ofendopod of thoracopods 5–8 consists of 3–5 (in juveniles) to 4–7 subjoints. Exopod offourth pleopod of male 3 (in immature males) to 1.3 times as long as endopod; basal(proximal) segment of exopod 4–7 times as long as distal one. Inner margin of endopodof uropod armed with row of 14 (in juveniles) to 31 spines extending from statocystalmost to apex. Telson 1.4–2.7 times as long as broad at base; apex armed with 3–4 pairs of equal spines in females, with 2 pairs of spines in males; outer pair twicelonger than inner one or than lateral spines. Maximum length of females 25.7 mm, ofmales 17.6 mm.Distribution. H. dimorpha is a West Pacific widespread boreal species. It is distributedfrom the Korea Strait to the northern Bering Sea: Tkachen Bay (64°25′N;172°48′W). It has been recorded from the Sea of Japan near the Korea Strait and in theTatar Strait.Habitat and breeding. The species is sublittoral, vertically distributed from 10to 140 m, in the Sea of Japan from 10 to 104 m. It occurs in waters with a temperaturerange between -1.7° and +19°C and a salinity range between 28.44 and 34.5‰, oversand, silt, gravel with pebbles, rarer over clay. Females with embryos were registeredin the Sea of Japan July through August. The number of embryos ranges from 13 to49.59

8. Genus Exacanthomysis Holmquist, 1981Type species: Acanthomysis davisi Banner, 1948.Carapace anteriorly produced into pointed triangular rostral plate. Labrum withrelatively long anterior spiniform process. Antennal scale lanceolate, with roundedapex, setose all along length of margins; subapical suture present. Marsupium composedof 2 pairs of well-developed oostegites. Tergites of free thoracic segments andof all abdominal segments with 2–3, occasionally with 4 transverse dorsolateral furrows,in some specimens breaking dorsally. First to third and fifth male pleopods andall female pleopods uniramous, reduced to unsegmented plate. Fourth pleopod of malebiramous, relatively short; endopod at least half as long as exopod; exopod 2-segmented; proximal segment straight, with one small and one large simple setae ondistal corners or sometimes without them; distal segment with one very small seta orwithout it and with two strong subequal terminal setae. Endopod of uropod with relativelyshort row of spines on ventral surface between inner margin and statocyst. Telsonelongate, triangular; lateral margins with numerous spines, grouped on distal 1/2–2/3 of these margins: each large spine followed by one or several smaller spines.Remarks. Making morphological analysis of the species belonging formerly tothe genus Acanthomysis, Holmquist (1981a, b) did not manage to define a genus for A.stelleri and A. borealis due to the poor condition of available specimens. Besides, thespecimens, which she had in her disposal, identified by Derjavin as A. stelleri, provedto be A. borealis. It has been determined now based on rather sizeable collections (20samples, 268 specimens of A. stelleri and 35 samples, 662 specimens of A. borealis)that these species agree with the diagnosis of the genus Exacanthomysis and may beincluded in it. The only different character in A. borealis is the apex of the telson,which is not narrowly truncated as in the other related species, but narrowly rounded.However, it may be considered as a distinguishing character at a species level.KEY TO THE SPECIES OF THE GENUS EXACANTHOMYSIS1(2). Telson elongate, triangular, with slightly truncated apex (pl. XIV, fig. 5) ................................................................................................................. E. stelleri (p. 60)2(1). Telson elongate, triangular, with rounded apex (pl. XV, fig. 5) ............................................................................................................................... E. borealis (p. 61)1. Exacanthomysis stelleri (Derjavin, 1913)(Pl. XIV, figs. 1–5).Derjavin, 1913: 202 (Orientomysis stelleri); Ii, 1936: 589 (Acanthomysis stelleri); Holmquist,1981a: 260 (Exacanthomysis arctopacifica); Murano, 1991: 81–86 (Exacanthomysis japonica).Description. Antennal scale straight, 4–5.7 (in juveniles up to 8.6) times as longas broad. Carpo-propodus of endopod of thoracopods 5–8 with 4–7 subjoints. Exopodof pleopod 4 of male 1.3–3.3 times as long as endopod; basal (proximal) segment ofexopod 3–6 times as long as distal one. Endopod of uropod armed with 4–5 (in juveniles)to 5–11 spines on ventral surface close to statocyst. Telson elongate, triangular,60

with slightly truncated apex, abruptly tapering in distal 1/3, spines on distal 1/2–2/3 oflateral margin gathered in 8–14 distinct groups; apex with 2 pairs of spines; outertwice as long as inner and equal to, usually shorter than large spines on lateral margin.Maximum length of females 24.4 mm, of males 25.2 mm .Distribution. E. stelleri is a West Pacific widespread boreal species. It is distributedfrom Possjet Bay (Sea of Japan) and Hokkaido Island to Kodiak Island and thesouthern part of the Chukchi Sea, excluding the northern and western areas of the Seaof Okhotsk. It is found in the Sea of Japan in Peter the Great Bay and in the TatarStrait.Habitat and breeding. The species is sublittoral, vertically distributed from 0 to104 m, mostly to 25 m. It occurs in waters with a temperature range from –1.5° to+21.2°С and a salinity range from 27 to 34.5‰, over sandy, rarer over silty bottoms.There are no records for the breeding of this species in the Sea of Japan.2. Exacanthomysis borealis (Banner, 1954)(Pl. XV, figs. 1–7).Banner, 1954: 135 (Acanthomysis borealis); Holmquist, 1981a: 251–256 (Acanthomysisstelleri).Description. Antennal scale slightly S-shaped, 5.4–9.3 times as long as broad.Carpo-propodus of endopod of thoracopods 5–8 consists of 5–8 subjoints. Exopod ofpleopod 4 of male 2–3 times as long as endopod; basal (proximal) segment of exopod4.6–6 times as long as distal one. Number of spines on ventral side of endopod of uropodnear statocyst varies from 3 (in juveniles) to 6. Telson elongate, triangular, withnarrowly rounded apex, abruptly tapering in distal third; spines on distal half of lateralmargin gathered in 8–12 groups; apex with 2 pairs of spines: outer spines almost equalin length to adjacent lateral ones and slightly (in females) or twice (in males) longerthan inner ones. Maximum length of males and females 18.5 mm.Distribution. E. borealis is a West Pacific widespread boreal species, distributedfrom Possjet Bay (Sea of Japan), Zeleny Island (Malaya Kurilskaya Gryada = SmallKurile Islands) to Kodiak Island, Bristol Bay and the eastern coast of Kamchatka(61°N). In the Sea of Japan it is found in Peter the Great Bay and in the Tatar Strait.Habitat and breeding. E. borealis is a sublittoral species; its depth range is from0 to 104 m, mostly from 25 to 100 m, in the Sea of Japan from 9 to 104 m. It occurs inwaters with a temperature from -1° to +18°C and a salinity of 28–34.5‰, over rocks,boulders, sand and silt. Females with embryos were recorded in the Sea of Japan inAugust. The number of embryos varies from 20 to 65.9. Genus Paracanthomysis Ii, 1936Type species: Paracanthomysis hispida Ii, 1936.Eyes large, spherical. Antennal scale lanceolate, with rounded apex, 2-segmented, bears only setae on margins. Female marsupium consists of 2 pairs of oostegites.All pleopods, except for fourth pleopods of male rudimentary, one-segmented,plate-like. Fourth pleopod of male biramous, with short one-segmented endopod andlong one-segmented exopod, bearing 2 long serrate terminal setae; distal 1/3–1/4 of61

exopod with one simple lateral seta. Telson entire, linguiform; or elongate, triangular,with rounded apex.One of three species of this genus is known from the northern part of the Sea ofJapan.1. Paracanthomysis shikhotaniensis Petryashov, 1983(Pl. XVI, figs. 1–7)Petryashov, 1983: 125–128 (Paracanthomysis shikhotaniensis); Takahashi & Murano,1986: 61–65 (Paracanthomysis spadix).Description. In male, outer flagellum of antennule 2 times as broad as inner one,curved horn-like at base; inner flagellum has ordinary form. In females inner flagellumof antennule lanceolate, 2.5 times as broad as outer one, and about 2–2.5 times aslong as peduncle; outer flagellum has ordinary form. Antennal scale 7–12 times aslong as broad (in juveniles 10–12 times as long as broad). Carpo-propodus of endopodof thoracopods 3–8 consists of 4 (in juveniles) to 5–7 subjoints. Tergites of distal thoracicsegment and all abdominal segments smooth, without furrows or spines. Exopodof pleopod 4 of male 2.8 (in young males) to 8.6 times as long as endopod. Ventralside of endopod of uropod, near statocyst, bears 3 (in juveniles) to 4–7 spines. Telsonelongate, linguiform, 2–3.3 times as long as broad at base; spines on distal half of lateralmargin, excluding its apical part, gathered in 3–10 distinct groups; spines on apicalpart of lateral margin almost equal; apex with 2 pairs of spines: inner pair slightlyshorter than outer one, outer spines almost as long as adjacent lateral spines. Maximumlength of females 27.1 mm, of males 22.6 mm.Distribution. P. shikhotaniensis is a West Pacific widespread boreal species, distributedfrom the north-eastern Japan and Possjet Bay (Sea of Japan) to Korf Bay(Bering Sea); no one specimen has been recorded off the northern and western coast ofthe Sea of Okhotsk. In the Sea of Japan it is found in Peter the Great Bay and in theTatar Strait.Habitat and breeding. P. shikhotaniensis is a high sublittoral species; its depthrange is from 0 to 21.5 m. It occurs in waters with a temperature from -1.5° to+22.6°C and a salinity of 30–34‰, over rocks, rarer over boulders and gravel, sand, ormuddy sand. It is most abundant near rocks and capes with strong surf. Females withembryos were recorded in the Sea of Japan for May, July, and August. The number ofembryos ranges from 8 to 54.ReferencesBacescu, M. & L.G. Gleye. 1979. New Mysidacea from the Californian waters // Trav.Mus. Hist. Nat. Grigore Antipa. V. 20. P. 131–141.Banner, A.H. 1948. A taxonomic study of the Mysidacea and Euphausiacea (Crustacea)of the northeastern Pacific. Part II. Mysidacea, from tribe Mysini throughsubfamily Mysidellinae // Trans. Roy. Can. Inst. V. 27. P. 65–124.Banner, A.H. 1954. New records of Mysidacea and Euphausiacea from the northeasternPacific and adjacent areas // Pacif. Sci. V. 8. P. 125–139.Brandt, F. 1851. Th. Middendorffs Riese in den aussersten Norden und Osten Sibiriens// Zoologie. Bd 2, N 1. S. 79–148.62

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Mauchline, J. 1980. The biology of mysids and euphausiids // Adv. Mar. Biol. V. 18.677 p.Murano, M. 1991. Two new species of the tribe Mysini (Crustacea, Mysidacea) and anew record of Acanthomysis quadrispinosa from Japan // Bull. Nat. Sci. Mus.,Tokyo. V. 17, N 2. P. 81–91.Murano, M. 1999. Mysidacea // South Atlantic Zooplankton. Leiden: Backhuys Publishers.P. 1099–1140.Murdoch, J. 1885. Description of seven new species of Crustacea and one worm fromArctic Alaska // Proc. U. S. Natl. Mus. V. 7. P. 518–522.Nakazawa, K. 1910. Notes of Japanese Schizopoda // Annot. Zool. Japan. V. 7.P. 247–261.Norman, A.M. 1892. On British Mysidae, a family of Crustacea Schizopoda // Ann.Mag. Nat. Hist. Ser. 6. V. 10. P. 143–166.Nouvel, H., Casanova, J.-P. & J.-P. Lagardere. 1999. Ordre des Mysidaces(Mysidacea Boas 1883) // Traite de Zoologie. T. III, fas. IIIA. Crustaces Peracarides.Memor. Inst. Oceanograph. N 19. P. 39–86.Ortmann, A.E. 1908. Schizopod crustaceans in the U. S. National Museum. Schizopodsfrom Alaska // Proc. U. S. Natl. Mus. V. 34. P. 1–10.Petryashov, V.V. 1983. Paracanthomysis shikhotaniensis sp.n. (Crustacea, Mysidacea)from the coast of Shikotan Island // Zool. Zhurnal. V. 62, N 1. P. 125–128. (InRussian).Petryashov, V.V. 2005. Biogeographical division of the North Pacific sublittoral andupper bathyal zones by the fauna of Mysidacea and Anomura (Crustacea) // BiologiyaMorya. V. 31, N 4. P. 233–250. (In Russian).Sars, G.O. 1879. Carcinologische Bidrag till Norges Fauna. 1. Monographic over deved Norges Kyster forekommende Mysider. Part 3. Christiania. 131 p.Schmitt, W.L. 1919. Schizopod crustaceans // Report of the Canadian Arctic expedition1913–18. Ottawa. V. 7. Crustacea. Part B. P. 1–8.Smith, S.I. 1879. The stalk-eyed crustaceans of the Atlantic coast of North Americanorth of Cape Cod // Trans. Connecticut Acad. Arts. Sci. V. 5. P. 27–136.Takahashi, K. & M. Murano. 1986. A new species of the genus Paracanthomysis(Crustacea, Mysidacea) from northeastern Japan // Bull. Nat. Sci. Mus., Tokyo.V. 12, N 2. P. 61–66.Taniguchi, A. 1969. Mysidacca and Euphausiacea collected in the south-east of Hokkaido,Japan // Bull. Fac. Fish. Hokkaido Univ. V. 20. P. 43–59.Tattersall, W.M. 1933. Euphausiacea and Mysidacea from western Canada // Contrib.Canadian Biol. Fish. New Ser. V. 8, N 15. P. 183–205.Tattersall, W.M. 1951. A review of the Mysidacea of the United States National Museum// Bull. U. S. Nat. Mus. N 201. 292 p.Tchindonova, J.G. 1981. New data on systematic position of some deep-sea mysids(Mysidacea, Crustacea) and their distribution in the World Ocean // Biology ofthe Pacific Ocean depths: Proceedings of the XIV Pacific Science Congress(Khabarovsk, August 1979). Section “Marine Biology”. Issue 1. Vladivostok.P. 24–33.Zimmer, C. 1904. Die Arctischen Schizopoden // Fauna Arctica. Bd 3, N 3. S. 415–492.Zimmer, С. 1927. Mysidacea // Handbuch der Zoologie. Berlin; Leipzig. Bd 3. S. 607–650.64

Plate I. Full-length view of Neomysis rayii, female (1) and male (2), general morphology:1 – antennules (antennae I); 2 – antennae (antennae II); 3 – eyes; 4 – carapace;5 – thoracopods; 6 – marsupium; 7 – pleopods 1–3; 8 – male pleopods 4;9 – uropods; 10 – telson65

Plate II. Archaeomysis grebnitzkii (1–4 – specimens collected off the coast of BeringIsland, 5–7 – specimens collected off the coast of Peter the Great Bay): 1 – antenna;2 – male pleopod 3; 3 – uropod, ventral view; 4 – telson; 5 – carapace,dorsal view; 6 – female marsupium, composed of oostegites and epimeral lamellaeof first abdominal segment; 7 – telson66

Plate III. Holmesiella anomala: 1 – male antennules; 2 – antennae; 3 – eye; 4 – thoracopod6 (oa – oblique articulation); 5 – male pleopod 4; 6 – uropod, ventral view;7 – telson67

Plate IV. Meterythrops robusta (1–4): 1 – male cephalon and anterior margin of carapace;2 – male pleopod 1; 3 – male pleopod 2; 4 – telson; Meterythrops microphthalma(5–7): 5 – male cephalon and anterior margin of carapace; 6 – femalemarsupium, composed only of oostegites; 7 – telson68

Plate V. Inusitatomysis insolita: 1 – eye; 2 – male antennule; 3 – antenna; 4 – labrum;5 – thoracopod 3 (oa – oblique articulation); 6 – male pleopod 4; 7 – uropod,ventral view; 8 – telson69

Plate VI. Xenacanthomysis pseudomacropsis: 1 – eye; 2 – male antennule; 3 – antenna;4 – male pleopod 4; 5 – thoracopod 5; 6 – uropod, ventral view; 7 – telson; 8– anterior margin of carapace70

Plate VII. Stilomysis grandis: 1 – eye; 2 – male antennule; 3 – antenna; 4 – malepleopod 3; 5 – male pleopod 4; 6 – uropod, ventral view; 7 – telson71

Plate VIII. Disacanthomysis dybowskii: 1 – antenna; 2 – male pleopod 4; 3 – uropod,ventral view; 4 – telson72

Plate IX. Neomysis rayii: 1 – antenna; 2 – eye; 3 – anterior margin of carapace; 4 –distal segment of thorax and all abdominal segments; 5 – male pleopod 4; 6 –uropod, ventral view; 7 – telson73

Plate X. Neomysis awatschensis: 1 – antenna; 2 – anterior margin of carapace (f. typica);3 – anterior margin of carapace (f. intermedia); 4 – male pleopod 4; 5 – uropod,ventral view; 6 – telson74

Plate XI. Neomysis czerniawskii: 1 – antenna; 2 – anterior margin of carapace; 3 –distal segment of thorax and all abdominal segments; 4 – male pleopod 4; 5 –uropod, ventral view; 6 – telson75

Plate XII. Neomysis mirabilis: 1 – antenna; 2 – anterior margin of carapace; 3 – malepleopod 4; 4 – uropod, ventral view; 5 – telson (f. typica); 6 – telson (f. nakazawai)76

Plate XIII. Boreoacanthomysis schrencki (1–4): 1 – antenna; 2 – male pleopod 4;3 – uropod, ventral view; 4 – telson. Hemiacanthomysis dimorpha (5–9): 5 – antenna;6 – male pleopod 4; 7 – uropod, ventral view; 8 – female telson; 9 – maletelson77

Plate XIV. Exacanthomysis stelleri: 1 – antenna; 2 – distal segment of thorax and allabdominal segments; 3 – male pleopod 4; 4 – uropod, ventral view; 5 – telson78

Plate XV. Exacanthomysis borealis: 1 – antenna; 2 – distal segment of thorax and allabdominal segments; 3 – male pleopod 4; 4 – uropod, ventral view; 5 – male telson;6 – apex of male telson; 7 – apex of female telson79

Plate XVI. Paracanthomysis shikhotaniensis: 1 – female antennule; 2 – male antennule;3 – antenna; 4 – thoracopod 7; 5 – male pleopod 4; 6 – uropod, ventralview; 7 – telson80

Order EUPHAUSIACEA Dana, 1883Viktor V. Petryashov, Artur G. Porodin, Boris M. BorisovGeneral characteristicsEuphausiids are shrimplike higher crustaceans of the superorder Eucarida. Theyare also known as krill. The body is divided into two tagmata (cephalothorax and abdomen)and is composed of five segments of the head, eight thoracic, six abdominalsegments, and the telson (pl. I, figs. 1–4). The eyes are stalked, faceted, usually welldeveloped, with the cornea in some species divided into two lobes. Most part of thehead and thorax, except for the bases of the thoracopods with the gills, is covered by acarapace, dorsally fused with the thoracic segments. Each antennule (antenna 1) consistsof a three-segmented peduncle and two many-segmented flagella. In many generathe antennular peduncle, beside setae, may bear tubercles, spines, and lappets. Eachantenna (antenna 2) consists of a one-segmented (as a result of the fusion of threesegments) protopod, an exopod (antennal scale, or squama), and an endopod with athree-segmented peduncle and many-segmented flagellum. There are eight pairs of thethoracopods. They are biramous (exo- and endopod), relatively similar in arrangement,and not transformed into maxillipeds. One or two distal pairs are shortened(family Bentheuphausiidae) or reduced (family Euphausiidae). In the forms with bilobedeyes the second and/or third pairs of the thoracopods are transformed into elongatedgrasping organs. The coxapodites of the thoracopods bear epipods, forming gillson their outer side, and small blade-shaped endites, best developed on the first thoracopods,on their inner side. There are five pairs of pleopods on the abdomen. They arewell-developed both in males and females, natatory, biramous, with similar arrangement.Pleopods 1 and 2 in males are provided with a copulatory organ (petasma). Thesixth abdominal segment has a pair of flattened biramous (both rami are onesegmented)uropods. The uropods in combination with the telson form a tailfan. Thespecies of the family Euphausiidae have light-emitting organs (photophores). Thereare usually ten of them, two on the lower parts of the eye-stalks, four on the bases ofthe thoracopods 2 and 7, and four on the first to fourth abdominal segments betweenthe pleopods. The species of the genus Stylocheiron are provided with only five photophores:one on each eye-stalk and on the bases of the thoracopods 7, and one on thefirst abdominal segment.Euphausiids are exclusively marine crustaceans living in the pelagic zone, indepths from 0 to 5000 m, sometimes going down to the bottom. At present two familiesof euphausiids are known (Euphausiidae and Bentheuphausiidae), which include11 genera and 86 species. Euphausiids occur in all the oceans, with the species diversitybeing widest in tropical and subtropical waters. Only one family, Euphausiidae, isrepresented in the Sea of Japan.Biology. Euphausiids are usually omnivorous, main types of feeding are predationand filtration. Their ontogenetic development is commonly divided into four periods,viz.: embryonic, larval, juvenile, and adult. Euphausiids have internal fertilization;round eggs are laid in portions; the process of reproduction takes place in the pelagiczone. Nauplii (stages I–III) (pl. III, fig. 1), like the next stage, metanauplii81

(pl. III, figs. 2, 7–9), do not feed. Feeding begins not earlier than the stage of calyptopisI (pl. III, fig. 3). The calyptopis phase (C) is divided into three stages (CI, CII [pl.III, figs. 4, 10], and CIII). Calyptopis 3 after molting transforms into a furcilia (F0), astage without the pleopods (pl. III, figs. 5, 11). Endo and Komaki (1979) proposed aformula describing the development of a furcilia at successive stages.F(0): larva without pleopods; F(n): larva with 4 or less pairs of pleopods; F(5N):larva with 5 pairs of glabrous pleopods (pl. III, fig. 6); F(sn): larva with less than 5pairs of glabrous and feathery pleopods; F(SN): larva with 5 pairs of glabrous and featherypleopods; F(6Tsp) or F(7Tsp): larva with 5 pairs of feathery pleopods and 6 or 7terminal spines at telson’s end; F(4Tsp) or F(5Tsp): terminal spines in larva reducefrom 6–7 to 4–5; F(2Tsp) or F(3Tsp): terminal spines in larva reduce from 6–7 to 2–3;F(1Tsp): larva with only one terminal spine.The adult form is distinguished by the appearance of outer sexual characters. Wehave determined that the genital system in E. pacifica appears at a size of 6–7 mm,and in the species of the genus Thysanoessa at 7–10 mm. After breeding, the gonadsof males and females reduce to their juvenile form, and in males some elements of thepetasma also partially reduce. The oocytes which have not been laid are resorbed (Pogodin& Saprykina, 1981a, b).Role in ecosystems. In spite of relatively small number of species, euphausiidsinhabit all the oceans of the world. Though the species diversity is wider in tropicaland subtropical waters, huge abundance and high biomass of euphausiids are particularfor temperate and cold waters, providing food source for baleen whales, birds, andalmost all commercially valuable pelagic fish. Euphausiids constitute from 22.2% (inwinter) to 8.4% (in autumn) of the whole zooplankton biomass in the epipelagic zoneof the northwestern Sea of Japan (Dolganova, 2000). More than ten thousand tons onlyof the krill Euphausia pacifica have been annually caught in the coastal zone of Japansince 1950–1960s (Komaki, 1967). It is used in that country for making foodproducts, for bait, as a main component of mixed fodder, and as food for culturedtrout, carp, and shrimps.Methods of catching and fixation. Euphausiids are caught with large horizontalor vertical plankton nets and pelagic trawls. They can be fixed in 75% ethanol or in 4–6% formalin, the latter being preferable.Unpublished data collected by B. Borisov were used for characterizing the biologyand ecology of the Sea of Japan euphausiids. Data on species composition and distributionof euphausiids in the central and southern parts of the Sea of Japan were takenfrom Dr. M. Araki’s manuscript of dissertation (1971), which was sent to A.G. Pogodinby Dr. T. Ikeda.Main references: Boden et al., 1955; Ponomarjeva, 1963; Lomakina, 1978;Mauchline, 1980; Baker et al., 1990.Systematic partFamily EUPHAUSIIDAE Holt & Tattersall, 1905Eyes well developed. Thoracopods 8 and sometimes 7 more or less reduced;pleopods 1 and 2 in males with petasma.82

The family Euphausiidae comprises ten genera. Ten species of five genera (Euphausia,Thysanoessa, Pseudeuphausia, Nematoscelis, and Stylocheiron) occur in theSea of Japan (Ponomarjeva, 1963; Araki, 1971; Lomakina, 1978; Pogodin, 1981).Four species belonging to two genera were found in the Russian waters of the Sea ofJapan, namely: Euphausia pacifica, Thysanoessa inermis, T. raschii, and T. longipes.Finds of two more species, Euphausia similis and Thysanoessa inspinata (Adrianov &Kussakin, 1998) have not been proved by our data.KEY TO THE GENERA OF THE FAMILY EUPHAUSIIDAE1(2). Exopod of thoracopod 7 well developed, but short. (Frontal plate of rostrum welldeveloped) ......................................................................... 1. Thysanoessa (p. 83)2(1). Exopod of thoracopod 7 rudimentary, in shape of small one-segmented setaceousplate. (Frontal plate of rostrum absent) ................................ 2. Euphausia (p. 86)Genus Thysanoessa Brandt, 1851Type species: Thysanoessa longipes Brandt, 1851.Frontal plate of rostrum long, narrow, sharply pointed. Carapace with keel runningfrom its middle to anterior region. Eyes with (bilobed) or without constriction,rounded; bilobed eyes pyriform; upper lobe narrower than lower one. Thoracopods 1–6 with full complement of normally developed segments. Species with bilobed eyeshave long inflated endopods of thoracopods 2, thus modifying this pair of limbs intograsping organs. Thoracopod 7 with normally developed, but short exopod; endopodof this thoracopod consists of 1–2 segments in females and absent in males. Thoracopod8 rudimentary, consisting only of small, thin 1–2 segmented exopod.Three species of ten comprising this genus occur in the Sea of Japan.KEY TO THE SPECIES OF THE GENUS THYSANOESSA1(4). Tergites of abdomen smooth, without sharp keels. (Posterior margin of one ortwo terminal segments of abdomen occasionally with small spine).2(3). Lower margin of carapace without spine. Posterior margin of tergite of abdominalsegment 6 and sometimes also segment 5 with small spine. Eyes without constriction,in juveniles usually with constriction in upper anterior part ................................................................................................................... 1. T. inermis (p. 84)3(2). Lower margin of carapace with anterior spine. Tergites of all abdominal segmentssmooth, without spines. Faceted part of eye round, without constriction................................................................................................. 2. T. raschii (p. 85)4(1). Tergites of abdominal segments 3–5 with keels ending in spines. (Eyes bilobed,pyriform, constriction transverse, upper lobe narrower than lower one. Posteriormargin of each abdominal segment 3–5 with spine. Lower part of carapace withmedian spine) ....................................................................... 3. T. longipes (p. 85)83

1. Thysanoessa inermis (Kroyer, 1846)(Pl. I, fig. 1; II, fig. 1)Kroyer, 1846: pl. 7, figs. 2,3 (Thysanopoda inermis, T. neglecta); G.O. Sars, 1883: 51–52(Euphausia inermis, Thysanoessa borealis); Hansen, 1911: 8; Lomakina, 1978: 183–185, figs.112, 113; Baker et al., 1990: p. 74, fig. 9b (Thysanoessa inermis).Description. Frontal plate of rostrum long, reaching end of first segment of antennularpeduncle, lanceolate, with pointed tip. Eyes without (forma inermis) or withconstriction; upper lobe narrower (f. neglecta). Carapace without lateral spine. Thoracopodsidentical in arrangement (f. inermis), or thoracopods 2 modified into graspingorgans (f. neglecta) due to elongated segments 4 and 5 and inflated basal segments.Distal 6th abdominal segment shorter than 2 penultimate segments (4 and 5) takentogether; its posterior end with small mid-dorsal spine pointed backward. Fifth abdominalsegment often with similar spine.Length of body in euphausiids from northern part of Sea of Japan up to 34 mm.Remarks. The studies of the North Atlantic euphausiid fauna showed that formaneglecta is a stage of T. inermis, represented by late larval stages and juveniles. Adultspecimens of f. neglecta are very rare and have not been recorded in the Northern Pacific,particularly in the Sea of Japan (Lomakina, 1978).Nemoto (1966) discovered a phenomenon of wedgewise change of the rate ofspecimens with spines at the end of fifth and sixth abdominal segments. The percentageof specimens with two spines decreases westward, from 75% in Alaska Bay to16% in the Sea of Okhotsk. He also reports single finds of specimens with spines onabdominal segments 6, 5, and 4.Distribution. T. inermis is a widespread boreal-arctic species. In the northwesternpart of the Pacific Ocean it has not been recorded south of 37˚ N in the Sea of Japanand the Pacific side of the South Kuril Islands. In the northeastern part of the PacificOcean the species has not been recorded south of 52˚ N. In the Atlantic Ocean itis found north of 39˚ N near the American coasts, in the La Manche and Skagerrakstraits. In the Arctic T. inermis is possibly circumpolar, found in all seas of Russia, inthe Beaufort Sea, in the east of the Canadian part of the Arctic, and around Greenland.In the Sea of Japan the southern boundary of the distributional range of this specieslies north of 37˚ N near the continent and 39˚ N near the Japan coast. In the TatarStrait it occurs to 51˚ N. The densest swarms of this species were observed in the easternhalf of the sea near the northern Hokkaido and the South Sakhalin in spring.Habitat and breeding. T. inermis is an epi- to mesopelagic species, in the Sea ofJapan found to depths around 1000 m (Vinogradov, 1968). Spring pre-breeding andbreeding assemblages begin to accumulate near the northern Hokkaido in the secondhalf of March, with maximum concentration in the near-surface layer. Then assemblagesmove northward, to the coastal zone of the southwestern Sakhalin up toIliynsky shoal (about 48˚ N). Phenological wave passes over the eastern part of the seanorthward from Hokkaido to 50˚ N from March to late May-early June. In Peter theGreat Bay mass breeding of T. inermis begins in the second to third decade of April.Diameter of egg capsules 600–925 µm, perivitelline space well developed (80–86% ofthe whole egg volume).Euphausiids of this species feed on meso- and microzooplankton, phytoplankton,and if food is scarce, on detritus and other euphausiids.84

2. Thysanoessa raschii (M. Sars, 1864)(Pl. I, fig. 2; II, figs. 2, 5)M. Sars, 1864: 83 (Thysanopoda raschii), G.O. Sars, 1883: 51 (Euphausia raschii);Hansen, 1911: 42; Lomakina, 1978: 185–187, fig. 114; Baker et al., 1990: p. 72, fig. 8a(Thysanoessa raschii).Description. Frontal plate of rostrum broad, slightly shorter than basal segmentof antennular peduncle; tip slightly blunt in males, pointed in females. Eyes round,without constriction. Lateral margin of carapace with small anterior spine. All thoracopodsidentical in arrangement. Abdominal segments smooth, without spines anddorsal keels.Euphausiids from northern part of Sea of Japan with maximum length of body29 mm (Pogodin, Gorbatenko, 1984).Distribution. T. raschii is a widespread boreal-arctic species. In the PacificOcean it occurs north of 40˚ N near the coasts of Asia and north of 45˚ N near theBritish Columbia. In the Atlantic Ocean it was found north of 40˚ N off the coasts ofAmerica and the northern coast of Great Britain. In the Arctic it is possibly circumpolar,found near the western coast of Greenland and from the Spitsbergen and the NorwegianSea eastward to the Beaufort Sea. In the Sea of Japan the species has not beenrecorded south of 43˚ N. In spring the population penetrates as far as the most northernpart of shallow-water area of the Tatar Strait.Habitat and breeding. T. raschii is a neritic, epipelagic species. It usually occursin depths to 200 m, more deep-water finds are rare. These euphausiids mainlyfeed on meso- and microzooplankton; in spring and autumn on phytoplankton; and, iffood is scarce, on detritus. In the population of the northern Tatar Strait the breedingprocess begins in April and proceeds till late July or even early August, depending onmean temperature of a year. Diameter of eggs 350–500 µm, perivitelline space narrow.3. Thysanoessa longipes Brandt, 1851(Pl. I, fig. 3; II, fig. 3; III, figs. 7–11)Brandt, 1851: 128; Lomakina, 1978: 176–178, fig. 106, 107; Baker et al., 1990: p. 68, fig.3b (Thysanoessa longipes); Marukawa, 1928: 4 (T. armata).Description. Frontal plate of rostrum long, narrow, with pointed tip and mediankeel, stretching to anterior region of carapace. Eyes with transverse constriction, upperlobe noticeably smaller. Lateral margin of carapace with spine placed slightly past itsmidpoint. Endopod of thoracopod 2 elongated, almost equal to antennule; its segment6 with lateral setae on both sides; segment 7 short and broad, with 4 strong setae. Eachtergite of abdominal segments 3–5 with well-expressed dorsal keel; keel on segment 3ends in robust spine; keels on other tergites with smaller spines. Tergite of abdominalsegment 6 without keel, its distal margin sometimes with small spine. Euphausiidsfrom northern part of Sea of Japan with maximum length of body 34 mm.Distribution. T. longipes is a Pacific widespread boreal species. It is distributednorth of 34°N near the Asian coast and north of 38°24′N near the American coast upto Point Barrow (Chukchi Sea). In the Sea of Japan the southern boundary of the distributionalarea stretches from the Korean coast (36–37°N) to Wakasa Bay (around85

35°45′N) of Honshu Island. In the Tatar Strait this relatively deep-water species appearsat 50°N in spring, and moves slightly southward in summer.Habitat and breeding. T. longipes is an epi- to mesopelagic species, which inhabitsthe Sea of Japan to depths of about 2000 m. In the cold-water part of the sea itoccurs from 100 to 2000 m of depth in the daytime and from the surface to 1700 m atnight. Breeding in the Sea of Japan have not been studied, in the southern part of theSea of Okhotsk this species breeds from March till June (Afanasiev, 1985). Endo andKomaki (1979) described the larval stages of T. longipes, beginning from calyptopis Iand to the last instar of a furcilia, as well as a postlarval larva. The material used forthese studies was collected from a water layer of 0 to 150 m depth. The samples examinedcontained neither eggs, nor nauplii or metanauplii which could belong to T.longipes. Due to this fact the conclusion was made that the species breeds in depthsmore than 150 m. One of the authors (B.M. Borisov) managed to identify a metanaupliusof T. longipes from the central part of the Sea of Japan (pl. III, figs. 7–11 ).Euphausiids of this species mostly feed on meso- and macrozooplankton (copepods,chaetognaths, and euphausiids), but occasionally eat phytoplankton and protozoa.2. Genus Euphausia Dana, 1852Type species:Euphausia superba Dana, 1852.Frontal plate of rostrum usually well developed, triangular, with acute tip; rarershort, rudimentary, sometimes absent. Eyes round, without constriction. Thoracopods7 and 8 rudimentary, only with exopod in shape of small one-segmented setaceousplate; endopod absolutely reduced. Other thoracopods have normal arrangement, similarwith each other.The genus comprises 32 species. Three species occur in the Sea of Japan, thoughin the Russian waters of this sea only one species, E. pacifica, has been found.23b.1. Euphausia pacifica Hansen, 1911(Pl. I, fig. 4; II, figs. 4, 6, 7; III, figs. 1–6)Hansen, 1911: 28; Lomakina, 1978: 129–130, fig. 70; Baker et al., 1990: p. 64, fig. 22a,Description. Rostrum without frontal plate, anterior margin of carapace in shapeof obtuse angle, sometimes with slightly rounded end. Carapace without keel, lateralmargin with median spine. Eyes without constriction, like in T. raschii, of normal sizeand almost round in shape. Basal segment of antennule with small flat tubercle, sharplypointed and directed obliquely upward; upper part of segment slightly flattened andbears row of short setae with tips curved forward. Dorsal side of abdominal segmentswithout keels and spines. Length of body up to 25 mm.Distribution. E. pacifica is a Pacific widespread boreal species, also penetratingnorthern subtropical regions. It is distributed north of 33–34°N near the Asian coasts,of 38–40°N in high seas, and of 26°N near the American coast. In the Sea of Okhotskit has been recorded only in the southern half and in the Bering Sea only in the southwesternhalf. In the Sea of Japan the species is ubiquitous, distributed from the TsushimaStrait to the most northern shallow-water region of the Tatar Strait.86

Habitat and breeding. E. pacifica is an epi- to mesopelagic species, in the Seaof Japan inhabiting depths to 1000 m (Vinogradov, 1968). Diurnal vertical migrationsare observed in euphausiids 8 mm long and larger. In the cold-water regions of the seaassemblages are densest at depths of 200–300 m in the daytime and from the surfaceto 150 m at night. In the warm-water regions assemblages are densest at depths from300 to 400 m in the daytime. Considerable density of assemblages is registered todepths of 600–650 m. Young euphausiids with body length up to 7–8 mm remain inthe upper 100-m layer day and night.From February to April E. pacifica breeds, and the phenological wave of nearsurfaceassemblages of pre-breeding and breeding krill moves from the southwesternpart of Honshu Island northward to Hokkaido. Euphausiids gather in assemblages at anear-surface temperature of 6–7 °C and disseminate when temperature reaches 16 °C(Komaki, 1967). This is the main period of intensive inshore krill fishery in Japan. Inthe eastern region of the sea the phenological wave starts in February and moves fromsouth to north. Breeding begins in the northern half of the Tatar Strait only in July,when water warms up to 13–14 °C, it is most intensive in August-September and endsin mid-October (Pogodin, 1981, 1990). There are almost no data on E. pacifica breedingin the coastal waters of Primorye. One of the authors (B.M. Borisov) found theeggs of E. pacifica in Amursky Bay (Peter the Great Bay) on November 17, 2004. Accordingto A.G. Pogodin’s data (1982) the diameter of E. pacifica egg capsules rangefrom 425 to 625 µm, and according to B.M. Borisov’s unpublished data the diameteris 370 to 530 µm (at the diameter of egg capsules equal to 530 µm, the diameter of anembryo was 340 µm).The diet of these euphausiids includes wide range of objects; their preference isfor meso- and microzooplankton, whereas phytoplankton and detritus are consumedrarer.ReferencesAdrianov, A.V. & O.G. Kussakin. 1998. A chek-list of the biota of Peter the Great Bayof the Sea of Japan. Vladivostok: Dalnauka. 350 p. (In Russian).Afanasiev, N.N. 1985. Macroplankton of the northern Sea of Okhotsk: Avtoref. Diss…Kand. Biol. Nauk. Moscow: IOAN SSSR. 25 p. (In Russian).Araki, M. 1971. [Ecology of the Euphausiid distribution in the Sea of Japan and SurugaBay. The manuscript of dissertation (In Japanese). 66 p., 55 figs.]Baker, A. de C., Brinton, B.P., & E. Brinton. 1990. A practical guide to the Euphausiidsof the world. London: British natural history museum. 96 p.Boden, B.P., Johnson, M.W., & E. Brinton. 1955. The Euphausiacea (Crustacea) of theNorth Pacific // Bull. Scripps Inst. Oceanogr. V. 6(8). P. 287–400.Brandt, F. 1851. Krebse // Middendorff A.Th.v., Reise in den äussersten Norden undOsten Sibiriens während der Jahre 1843 und 1844. V. 2, Zool. (1). S. 79–148.Dolganova, N.T. 2000. The composition, seasonal and interannual dynamics of theplankton of the northwestern Sea of Japan: Avtoref. Diss… Kand. Biol. Nauk.Vladivostok: TINRO-tsentr. 23 p.Endo, Y. & Y. Komaki. 1979. Larval stages of euphausiids with descriptions of thoseof Thysanoessa longipes Brandt // Bull. Jap. Sea reg. Fish. Res. Lab. V. 30.P. 97–110.87

Hansen, H.J. 1911. The genera and species of the order Euphausiacea, with account ofremarkable variation // Bull. Inst. Oceanogr. Monaco. N 210. P. 1–54.Komaki, Y. 1967. On the surface swarming of euphausiid crustacean // Pacif. Sci.V. 21. P. 433–448.Kroyer, H. 1846. Atlas des Crustacés. Voyage de la Commission scientifique du Norden Scandinavie, en Laponie, au Spitzberg et aux Feröe pendant les anneés 1838–1840, sur la corvette La Recherche commandée par M. Fabvre. Publ. par ordre duRoi sous la direction de M.M. Paul Gaimard.Lomakina, N.B. 1978. Euphausiids of the world (Euphausiacea). Opredeliteli po FauneSSSR. Izd. ZIN AN SSSR. V. 118. 223 p. (In Russian).Marukawa, H. 1928. Über neue 5 Arten der Schizopoden // Annot. Oceanogr. Res.,Tokyo. V. 2. P. 1–6.Mauchline, J. 1980. The biology of mysids and euphausiids //Adv. Mar. Biol. V. 18.677 p.Nemoto, T. 1966. Thysanoessa euphausiids, comparative morphology, allomorphosisand ecology // Sci. Rep. Whales. Res. Inst., Tokio. N 20. P. 109–155.Pogodin, A.G. 1981. Breeding of euphausiids (Euphausiacea, Crustacea) in the northernpart of the Tatar Strait // Genetika i Razmnozhenie Morskikh Zhivotnykh.(Materialy XIV Kongressa TNA, Khabarovsk, 1979). Vladivostok: Izd. DVNTsAN SSSR. P. 196–203. (In Russian).Pogodin, A.G. 1982. Some stages of Euphausia pacifica development // BiologiyaMorya. N 2. P. 72–75. (In Russian).Pogodin, A.G. 1990. Speed of growth of Euphausia pacifica in the northern Sea ofJapan // Biologia Morskogo Planktona. Vladivostok: Izd. DVO AN SSSR. P. 92–101. (In Russian).Pogodin, A.G. & K.M. Gorbatenko. 1984. Species composition, distribution, sexualand size & age structure of euphausiids in the northern Tatar Strait. Vladivostok:TINRO. 16 p. Dep. TsNIITEIRKh 21 05. 1984. N 589 rkh-84. 16 p. (In Russian).Pogodin, A.G. & M.I. Saprykina. 1981a. On the Euphausiid reproduction in the watersof the northern Tatar Strait in June–September 1973 // Izv. TINRO. V. 105.P. 33–41. (In Russian).Pogodin, A.G. & M.I. Saprykina. 1981b. On the life cycle of euphausiids in the northernTatar Strait // Tezisy Dokladov 4-go Siezda VBGO. Kiev: Naukova Dumka,Ch. 1. P. 88–90. (In Russian).Ponomarjeva, L.A. 1955. The euphausiids of the Kurile-Kamchatka Trench // TrudyIOAN SSSR. V. 12. P. 288–297. (In Russian).Ponomarjeva, L.A. 1963. Euphausiids of the Northern Pacific, their distribution andabundant species ecology. Moscow. 142 p. (In Russian).Sars, G.O. 1883. Oversigt of Norges Crustaceer med forelobige Bemaerkninger overde nye eller mindre bekjendt Arter I (Podophthalmata - Cumacea - Isopoda -Amphipoda) // Forhandl. Vidensk. Selsk. Forh., Christiania. N 18. P. 1–124.Sars, M.Hr. 1864. Sars gav nogle tillaeg till sine i et foregaaende Møde meddeeltelagttagelser over de maerkvaedige, paa Bugsiden af Thysanopoda beliggendeSandseredskaber, or anmeldte ved samme Leilighed Opdagelsen af to nye norskeArter af denne Krebs–dyrsia egt. // Forh. Vidensk Selsk. Krišt. P. 79–84.Vinogradov, M.E. 1968. Vertical distribution of oceanic zooplankton. Moscow: Nauka.320 p. (In Russian).88

Plate I. Full-length lateral view: 1 – Thysanoessa inermis; 2 – T. raschii; 3 – T. longipes;4 – Euphausia pacifica89

Plate II. Dorsal view of anterior part of body (1–4), thoracopods 7 (5, 6), palp ofmandible (7): 1 – Thysanoessa inermis; 2, 5 – T. raschii; 3 – T. longipes; 4, 6, 7 –Euphausia pacifica90

Plate III. Larval stages of Euphausia pacifica (1–6) and Thysanoessa longipes (7–11):1 – nauplius (N1); 2, 7–9 – metanauplius (7 – abdomen, dorsal view, 8 – antenna,9 – lateral view); 3 – calyptopis I; 4, 10 – calyptopis II; 5, 11 – furcilia (F0);6 – furcilia (5N)91

SUBPHYLUM CHELICERATA HEYMONS, 1901 1CLASS PYCNOGONIDA Brunnich, 1764Elena P. TurpaevaGeneral characteristicsThe class Pycnogonida (the later accepted names are Pantopoda, or Podosomata)includes peculiar, exclusively marine animals which combine morphological featuresof the Crustacea and the Chelicerata. Owing to some exterior resemblance toterrestrial spiders they got the name “sea spiders”. In the pycnogonids some featuresof primitive organization are preserved, and this class represents an independentgroup, like the Chelicerata or the Mandibulata (Dunlop & Arango, 2004).The bodies of the pycnogonids, living in the Sea of Japan, consist of a foursegmentedtrunk, proboscis, small abdomen, and seven pairs of appendages (pl. I, fig.1). Some species have segmented trunks, in others, segments of trunks are fused.Every segment has a pair of lateral processes with which the legs articulate. The first(cephalic or ocular) segment has in addition small processes for the first, second, andthird pairs of appendages, as well as a protruding proboscis. There is an oculartubercle on the dorsal side of the cephalic segment, bearing four eyes – a pair ofanterior and a pair of posterior ones. Segment 4 bears a protruding abdomen with ananal opening on its end.The pycnogonids’ appendages consist of segments. The first pair of appendages(chelifori) of the Sea of Japan pycnogonids usually consist of two segments: thestraight cylindrical first segment (scape) and the second segment (chela) consisting ofa broadened proximal part (palm) with two fingers – movable and immovable (pl. I,fig. 2). Appendages of such a type serve for grasping and holding of prey, but in somespecies these appendages are reduced. The second pair of appendages (palpi) is tactileorgans; the number of segments of this pair ranges from one to ten (the species of thegenus Nymphonella have up to 20 segments). The third pair of appendages (ovigers) inmales is assigned to bear progeny, and both male and female ovigers also serve forcleaning the body of sessile organisms living on it (hydroids, alcionarii, bryozoans andothers). The oviger consists of five-ten segments, the seventh to tenth ones are armedwith thin flat compound spines with toothed or smooth edges, and the tenth one ofmany species has a small claw on its end.The next four pairs of appendages are legs. The legs of all pycnogonids consist ofeight segments, every one of which have its own name or named by its number (first,second, third, etc.). The first three segments, usually short, are called coxae. The nextthree segments are long: the fourth segment is a femur, the fifth and sixth segmentsform a tibia (they are called tibia 1 and tibia 2 correspondingly). Relatively shortseventh and eighth segments form a tarsus; the seventh segment (called the tarsus1 In the last decade specialists oppose the class Pycnogonida to the rest of the chelicerates (Euchelicerata)or regard it as a sister group to all other modern arthropods (Euarthropoda) –Editorial note.92

proper) may be straight or calyciform; the eighth segment (propodus) may be straightor slightly curved; it bears a main, or terminal claw and a pair of auxiliary claws on itsend. There are several basal spines on the sole of the eighth segment's ventral side.Some species have a small protrusion (heel) with large spines at the proximal part ofthe sole.The digestive system of the pycnogonids consists of a pharynx (foregut), midintestine,and a hind-intestine. The pharynx is situated inside the proboscis that has atriangular mouth, provided with three cutting plates ("lips"), on its end. There is a socalled "filter" at the proximal part of the pharynx. The "filter" is a net of chitinousthreads, densely interlaced with one another, which holds back large particles comingthrough the mouth. The mid-intestine is situated in the trunk; it is quite short, but hasmany branches (diverticula), supplying nutrients to legs. The hind-intestine is veryshort and has no outgrowths. It extends through the abdomen and opens through theanus.There is no blood-vascular system, but there are lacunae through which liquidcirculates, transporting nutrients from the diverticula of the intestine to the muscles.The nervous system of the pycnogonids consists of two anterior ganglia(suprapharyngeal and subpharyngeal) innervating the eyes and the first to third pairsof appendages and of a chain of four ganglia innervating every segment of the trunk;nerves extending to the legs also originate from these ganglia.The reproductive system of the most pycnogonid species consists of a U-shapedtube, lateral outgrowths of which extend inside the first, second, third and fourthsegments of the legs, where germ-cells mature. Pycnogonids are dioecious animals.Sexual pores are situated on the second coxae of the legs on their ventral sides,females having such pores on all legs, males – on the third and fourth legs.Usually females are larger than males; their trunks are more robust. The males inmost species have thinner trunks, relatively more elongated and having strongerarmature of spines and setae. Males of the families Nymphonidae, Ammotheidae,Callipallenidae have longer ovigers than females, the fifth segments (the longestsegments of these appendages) are noticeably curved. As for the familiesPhoxichilidiidae and Pycnogonidae, only males have ovigers.During the period of breeding males wind mucous cords with eggs round theirovigers. The eggs stick together by the secretion of the male's cement glands situatedon the dorsal sides of the femurs. Growing larvae stay on the male's body for quite along time and seemingly feed on the organisms living on its surface. Larvae of themost species parasitize on hydroids.Adult pycnogonids are free-living animals, some species are ectoparasites. Theyfeed on soft tissues of hydroids, sea anemones, jelly-fishes, sponges, corals and, moreseldom, on mollusks, starfishes, and sea urchins; they also feed on benthic protistans(Komokiacea).The sea spiders are benthic animals that sometimes are able to swim. They can becaught by bottom trawls, dredges, sometimes they got into benthic traps; they mayrarely be taken by plankton nets and other pelagic fishing gear. The pycnogonidsshould be preserved in 70% alcohol, or at least in neutralized formalin. Preparation insome cases is necessary for the identification of a species. During this processappendages should be separated as whole units or divided into segments, withoutdestruction of the adjoining segments, because the correlation between the lengths ofsegments may be important for identification.93

The class Pycnogonida is currently divided into no larger taxa than families. Thesection on sea spiders is based on the taxonomic system proposed by Schimkewitsch(1929) with minor later additions and changes (Hilton, 1942a,b; Hedgpeth, 1948;Pushkin, 1993). Ten families are established within the class, namely: Ammotheidae,Nymphonidae, Callipallenidae, Phoxichiliidae, Austrodecidae, Colossendeidae,Decolopodidae, Rhynchothoracidae, Endeidae, and Pycnogonidae.At present there are 50 species of the pycnogonids registered for the Sea ofJapan, belonging to 17 genera and 6 families, of which 21 species of 7 genera and 4families occur in the Russian waters of the Sea of Japan. The taxa which have not yetbeen found in this region are marked with an asterisk (*).Systematic partKEY TO THE FAMILIES OF THE CLASS PYCNOGONIDA1(8). Adults have chelifores; in some species chelifores reduced to small buds.2(5). Both sexes have palps, consisting of 5 to 10, or 20 segments.3(4). Chelifore strong, longer than proboscis, with 2 segments; fingers of chela haveteeth or tubercles on inner margin; palp consists of 4–7 segments .................................................................................................................. I. Nymphonidae (p. 94)4(3). Chelifore feeble, shorter than proboscis, with 1–3 segments; fingers of chelareduced, or not reduced, but without teeth on inner margin; palp of both sexesconsists of 8–10, or 20 segments ................................. II. Ammotheidae (p. 105)5(2). Palp absent, or consists of 1–4 segments.6(7). Both sexes have ovigers composed of 9–10 segments, with compound spines on4 distal segments ..................................................... *III. Callipallenidae (p. 119)7(6). Only males have ovigers composed of 5–6 segments ...... ....................................................................................................................... IV. Phoxichilidiidae (p. 122)8(1). Adults without chelifores.9(10). Palp consists of 8–9 segments; oviger of both sexes consists of 10 segments,with claw and several rows of compound spines ............ .......................................................................................................................... *V. Colossendeidae (p. 127)10(9). Palps absent; ovigers absent or present only in males, with 7–9 segments .............................................................................................. VI. Pycnogonidae (p. 129)I. Family NYMPHONIDAE Wilson, 1878Trunk elongated and divided into segments (excluding the genus Paranymphon);segment 1 with broad anterior part and narrow middle one, forming neck. Cheliforelong, 2-segmented, with well-developed chela. Palp longer than proboscis, consists of4–7 segments. Oviger of both sexes consists of 10 segments, segments 7 to 10 havecompound spines placed in single row. 4–6 pairs of legs present.Only one genus of this family is represented in the Sea of Japan.94

1. Genus Nymphon Fabricius, 1794Type species: Pycnogonum grossipes Fabricius, 1780.Trunk elongated, cylindrical, smooth, appendages usually covered with setae;segment 1 long, moderately broadened anteriorly, neck well-expressed; lateralprocesses separated by intervals. Ocular tubercle situated on posterior part of neck.Abdomen cylindrical. Chelifore covered with setae; scape slender, cylindrical, longerthan proboscis; chela broader than scape, fingers shorter or longer than palm, usuallywith teeth on inner margin. Palp consists of 5 segments, segments 2 and 3 usuallylong, segments 4 and 5 shorter, with thick setae. Oviger 10-segmented, segments 4and 5 longest, 4 distal segments short, with row of compound spines, terminal clawwith teeth on inner margin. Legs several times longer than trunk, femur and both tibialongest of all segments, tarsus varies in length, propodus longer or shorter than tarsus,propodus armed with short spines and setae and in most species also has longer basalspines on proximal, medial, or distal part of sole or along entire sole surface. Mainclaw well-developed, auxiliary claws vary in length, absent in some species.There are 13 known species of Nymphon in the Sea of Japan, 8 of which occur inthe Russian waters.KEY TO THE SPECIES OF THE GENUS NYMPHON1(26). Auxiliary claws present.2(13). Compound spines of oviger serrate, with one pair of lateral teeth.3(6). Propodal sole armed with large, strong spines, less or equal to propodal diameterin length, situated proximally or distributed over entire sole.4(5). Proboscis slightly shorter than cephalic segment of trunk; segment 2 of palpshorter than segment 3; ocular tubercle tall, with pointed top ............................................................................................................................. 1. N. grossipes (p. 96)5(4). Proboscis much shorter than cephalic segment; segment 2 of palp equal tosegment 3 or longer; ocular tubercle low, with pointed or flat top and smalllateral tubercles ............................................................... 2. N. brevirostre (p. 97)6(3). Large spines on propodal sole poorly developed or absent.7(12). Neck slender, long, more than half length of cephalic segment; segments 4 and5 of palp almost equal in length; spines on propodus hardly noticeable, placedmedially, in groups of 2–3 spines.8(9). 2 tall tubercles in shape of truncated cones situated on cephalic segment nearchelifores’ bases .................................................................. 3. N. striatum (p. 98)9(8). Anterior part of cephalic segment without tubercles ............. ............................................................................................................................ 4. N. longitarse (p. 99)10(11). Ocular tubercle with rounded top, auxiliary claws very small ............................................................................................................... N. longitarse longitarse11(10). Ocular tubercle cylindrical, with conical pointed apex; auxiliary claws reachmiddle of main claw ................................... * N. longitarse elongatum (p. 99)12(7). Neck relatively short and thick; segment 4 of palp much shorter than segment 5;no large spines on propodal sole .................. * N. longitarse brevicollis (p. 100)13(2). Compound spines with 1, 2, or more pairs of lateral teeth, no serration.95

14(15). Compound spines with 1 pair of large lateral teeth; propodus armed with 6–7spines distributed over entire sole ............................. 5. N. bisseratum (p. 100)15(14). Compound spines with 2 or more pairs of lateral teeth.16(19). Fingers of chela longer than palm, almost straight, only tips curved.17(18). Processes of ovigers situated on proximal part of neck, just in front of lateralprocesses of 1st legs ..................................................... *N. japonicum (p. 101)18(17). Processes of ovigers situated on anterior part of neck at place where cephalicsegment expands ......................................................... *N. micropedes (p. 101)19(16). Fingers of chela falciform.20(23). Fingers of chela thin, equal in length to palm.21(22). Propodal sole armed with small spinules of equal size ............ ..................................................................................................................... *N. kodanii (p. 101)22(21). Propodal sole armed with spinules and several (3–6) large spines, situatedmedially and distally .................................................... 6. N. hodgsoni (p. 102)23(20). Fingers of chela shorter than palm.24(25). Trunk and appendages covered with peculiar bifurcate setae; neck long,processes of ovigers situated on sides of neck, at small distance from lateralprocesses of 1st legs; 12–15 large spines along length of propodal sole ......................................................................................................... *N. stocki (p. 102)25(24). Trunk with long simple setae on lateral processes and leg segments; neckshort, thick; processes of ovigers in contact with 1st legs lateral processes;fingers of chela in adults with small tubercles on inner margin, no teeth, injuveniles fingers of chela with dense short blunt teeth; propodal sole armedwith row of spinules and 4–6 large spines, situated medially and distally ....................................................................................... 7. N. braschnikowi (p. 103)26(1). Auxiliary claws absent.27(28). Palp 3 times longer than proboscis, with segments 4 and 5 equal in length;compound spines serrate, with one pair of lateral teeth; tarsus longer thanpropodus, main claw shorter than propodus .............. ................................................................................................................ 8. N. uniunguiculatum (p. 104)28(27). Palp 2 times longer than proboscis; its segment 4 shorter or occasionallyalmost equal to segment 5; compound spines with several large lateral teeth;tarsus and propodus almost equal; main claw equal to propodus or longer .............................................................................................. *N. albatrossi (p. 104)1. Nymphon grossipes (Fabricius, 1780)(Pl. II, figs. 1–6)Schimkewitsch, 1930: 400–415, figs. 101–106; Losina-Losinsky, 1961: 69–70; Utinomi,1971: 318, Turpaeva, 2004a: 1087–1088, figs. 1, 1–4.Description. Trunk slender, smooth; segment 1 almost as long as all othersegments combined, greatly expanded anteriorly; neck thin. Lateral processes long,separated by more than their diameters. Ocular tubercle tall, cylindrical, with conicalpointed apex; eyes large, pigmented. Proboscis cylindrical, as long as segment 1 oftrunk. Abdomen straight, slightly longer than 4th lateral processes. Chelifore strong;scape longer than proboscis; chela as long as scape, with short setae; fingers short,96

thick, in some specimens 2 times shorter than palm, with equal teeth on inner margin.Palp almost 1.5 times longer than proboscis; its segment 2 shorter than segment 3;segment 4 almost twice shorter than segment 5; distal segments densely covered withsetae. Oviger long (male oviger 1.5 times longer than trunk), thin; segments 4 and 5longest, slightly broadened distally; segments 6–10 combined shorter than segment 5;compound spines thin, denticulate, with one pair of large lateral teeth. Legs 4 timeslonger than trunk; coxae short; femur slightly longer than tibia 1; tibia 2 1/3 longerthan femur; tarsus usually longer than propodus, but may also be shorter (especially injuveniles); propodus slightly curved, with one row of spinules and 4–8 large spinesproximally and often also medially on sole; main claw strong, curved, slightly longerthan half of propodus; auxiliary claws as long as half of main one. Body length 6 mm,width – 54 mm.Geographical distribution. N. grossipes is a circumpolar arctic-boreal species.In the Pacific Ocean it inhabits the Bering Sea, Sea of Okhotsk and the northern partof the Sea of Japan (near the South Sakhalin). It also occurs on the Pacific side of theshelf zones of the Kuril and Japan islands.Vertical distribution. N. grossipes is found in depths from 4 to 1466 m. In theseas of the Russian Far East it has been found between 20 and 592 m of depth.Remarks. The species varies greatly, especially towards the borders of itsgeographical range. Thus, for example, in the Pacific Ocean, east of Honshu Island, N.heterospinum was found (Hedgpeth, 1949), which Losina-Losinsky (1961) and laterHedgpeth (1963), assigned to N. grossipes. Hedgpeth also considers N. nigrognatumHilton, 1942, found off Vancouver Island, and N. oculospinum Hilton, 1942, found inthe Gulf of California, to be the forms of N. grossipes. Losina-Losinsky, in his studiesof the specimens from Far Eastern seas (1961), notes that there are transitional formsbetween N. grossipes and N. mixtum Kroyer.2. Nymphon brevirostre Hodge, 1863(Pl. II, figs. 7–13)Schimkewitsch, 1930: 392–400, figs. 98, 99; Losina-Losinsky, 1961: 51 (pl. 1), 67–69;Hedgpeth, 1949: 235 (tabl. 1), 242 (tabl. 2), 246, 248; Turpaeva, 2004a: 1086.Description. Trunk small, but robust, cylindrical, almost smooth; segment 1equal to segments 2 and 3, anterior part rather broadened, neck short. Ocular tuberclelow, in shape of truncated cone, with two lateral bumps (“shoulders”). Probosciscylindrical, rounded on top, shorter than segment 1 of trunk. Abdomen straight, short.Chelifore strong, with sparse setae; scape and chela equal in length, as long asproboscis or slightly shorter; fingers shorter than palm, both armed similarly. Palpthin, short, slightly longer than scape of chelifore; segment 2 as long as segment 3 orslightly longer; segment 4 shorter than segment 5. Oviger has normal length,compound spines lanceolate, serrate, with one pair of lateral teeth. Legs slightly morethan 3 times longer than trunk, with sparse short setae; 2nd coxa 1.5 times longer thaneach of 2 others; femur and tibia 1 almost equal; tibia 2 longest; tarsus shorter thanpropodus, propodus gently curved, with several large spines proximally and mediallyon sole; main claw as long as 1/3 to 1/2 of propodus, strong; auxiliary claws equal tohalf of main claw or shorter. Body length about 5 mm.97

Geographical distribution. N. brevirostre is a circumpolar arctic-boreal species.It is greatly variable; 9 subspecies were found in the Arctic region (Losina-Losinsky,1935; Turpaeva, 2004a). In the Far Eastern seas of Russia it occurs in the Bering Sea,Sea of Okhotsk, and the northern part of the Sea of Japan, where it was recorded nearthe western coast of the South Sakhalin and in the Tatar Strait. A subspecies N.brevirostre kurilensis Losina-Losinsky, 1961 occurs in the Pacific Ocean on the shelfsurrounding the Kuril Islands. In the Sea of Okhotsk, near the Yamskie Islands N.brevirostre ochoticum Turpaeva, 2004 has been recently described. On the North-American shelf two forms were found, described as N. microcollis Hilton, 1942 and N.gracile Hilton, 1942, but Hedgpeth (1949) considers them forms of N. brevirostre.Vertical distribution. The species is distributed from the littoral zone to a depthof 677 m.3. Nymphon striatum Losina-Losinsky, 1929(Pl. III, figs. 7–12)Losina-Losinsky, 1929: 538–340, fig. 1; 1933: 64–67, fig. 13; 1961: 59; Nesis, 1967:248; 1976: 77, fig. 178; Hong, Kim, 1987: 139, 160–161; Nakamura & Child, 1991: 61–62;Nakamura, 1994: 15; Turpaeva, 2004a: 1092–1093.Description. Trunk elongated, slender; lateral processes separated by twice theirown diameters. Cephalic segment equal in length to rest part of trunk; neck very long,thin, in large specimens reaches half length of cephalic segment; neck of juvenilesslightly shorter. Anterior part of segment 1 broadened; 2 tall tubercles in shape oftruncated cone situated near frontal margin. Proboscis cylindrical, 1.5 to 2 timesshorter than segment 1. Abdomen short, slightly expanded medially, erected almostvertically. Chelifore moderately long; scape longer than proboscis; chela slightlyshorter than scape; fingers with curved tips, slightly shorter than palm. Palp thin; itssegment 2 slightly longer than segment 3, segments 4 and 5 equal in length, orsegment 5 slightly longer. Male oviger 1.5 times longer than trunk; female ovigerslightly shorter than trunk; segment 4 longest; compound spines serrate, with one pairof lateral teeth. Legs 3.5 to 5 times longer than trunk, thin, with sparse long setae;femur slightly shorter than tibia 1; tibia 1 shorter than tibia 2; length of tarsus varies:large specimens’ tarsus twice longer than propodus, juveniles' tarsus almost equal topropodus; propodal sole armed with one row of spinules, among which 2–3, rarer 5,large spines situated medially, sometimes large spines absent. Main claw heavy,slightly curved distally, shorter than half of propodus; auxiliary claws slightly shorterthan half of main one. Body length about 8 mm.Geographical distribution. N. striatum is known only from the Far Eastern seas.It occurs off the north-eastern coast of the Korea Peninsular, near Hokkaido Island, theeastern coast of Japan and in Toyama Bay; it is also found near the Pacific Oceansides of Shikotan and Kunashir islands (the Kurils) and in the south of the Sea ofOkhotsk. In the Sea of Japan it was recorded near the coast of Primorsky Region (fromPossjet Bay to De-Kastri Bay) and the south-western coast of Sakhalin Island.Vertical distribution. The species is sublittoral; it occurs at depths of 1–180 m.98

4. Nymphon longitarse longitarse Kroyer, 1844–1845(Pl. IV, figs. 1–5)Schimkewitsch, 1930: 434–451, figs. 118–120; Losina-Losinsky, 1935: 15, 30–31; 1961:65; Hedgpeth, 1949: 247–248; 1963: 1330–1331; Utinomi, 1971: 318–319 (Nymphonlongitarse).Description. Trunk thin, smooth; cephalic segment longer than three otherscombined, slightly expanded anteriorly; neck very long and thin; lateral processesrather long, divided by broad intervals. Proboscis cylindrical, almost 1.5 times shorterthan cephalic segment. Ocular tubercle cylindrical with conical rounded top; eyeslarge, pigmented. Abdomen short, straight. Chelifore thin; scape longer thanproboscis; chela slightly shorter than scape; fingers almost equal in length to palm,tips curved. Palp longer than proboscis; segments 2 and 3 equal; segment 4 slightlyshorter than segment 5; segment 5 lanceolate, only slightly shorter than segment 3.Male oviger more than 1/5 longer than trunk; segments 4 and 5 equal in length;compound spines small, lanceolate, denticulate, with one pair of lateral teeth. Legsvery thin and long, with short sparse setae; 2nd coxa almost equal in length to 1st and3rd coxae combined; femur in females slightly swollen; tibia 1 longer than femur andshorter than thin and very long tibia 2; tarsus almost twice longer than propodus;propodal sole with row of thin short spinules, usually 2–3 larger spines situatedmedially among them. Losina-Losinsky (1935) noticed, that such "large" spines oftenbarely different from others, or even specimen may have these spines on some legsand do not have them on others. Main claw twice shorter than propodus, almoststraight, gently curved distally; auxiliary claws very small. Adult body length about7 mm, width about 60 mm.Geographical distribution. Nymphon longitarse longitarse is a widespreadcircumpolar boreal arctic subspecies. It is distributed in the Barents, White,Norwegian and Greenland seas, Baffin Bay and the Davis Strait, in the north-westernpart of the Atlantic Ocean near the eastern coast of the North America up to latitude40˚ N, also in the Bering Sea, Sea of Okhotsk, Sea of Japan (Peter the Great Bay, OlgaBay, the western coast of Sakhalin), and near the Kuril Islands. It mostly inhabits thesublittoral zone.*Nymphon longitarse elongatum Hilton, 1942(Pl. IV, figs. 12–15)Hilton, 1942a: 5; Hedgpeth, 1949: 251–252, fig. 22; Hong, Kim, 1987: 158, fig. 15(Nymphon elongatum).Description. This subspecies differs from nominative species in tall oculartubercle with conical top and lateral tubercles, in shorter fingers of chela, and longertarsus of leg (2.5 as long as propodus).Geographical distribution. N. longitarse elongatum occurs in the north-westernpart of the Pacific Ocean, in the eastern part of the Sea of Japan (Toyama Bay), nearthe north-western coast of the Korea Peninsula and in the East China Sea at depthsfrom 16 to 1600 m.99

*Nymphon longitarse brevicollis Losina-Losinsky, 1929(Pl. IV, figs. 6–11)Losina-Losinsky, 1933: 68–69; 1935: 30–34, fig. 4; 1961: 65–66; Hedgpeth, 1949: 248;1963: 1331 (Nymphon longitarse brevicollis).Description. This subspecies differs from nominative species in more compacttrunk. Neck shorter and thicker, shorter than half of cephalic segment; ocular tuberclelow, with flat top; proboscis only 1.5 times as short as cephalic segment of trunk. Legsnot as thin as in N. longitarse longitarse, but of same length; tarsus only 1.5 timeslonger than propodus; usually propodal sole lacks larger spines; auxiliary clawsnoticeably longer and reach 1/3 of main claw. Palp rather long; its segment 4noticeably, sometimes even twice, shorter than segment 5, but in some specimensthese segments may be almost equal, like those in N. longitarse longitarse.Geographical distribution. This subspecies is mainly high arctic, but alsooccurs near Sakhalin Island (at the Terpenyia Bay entrance) and on the Pacific Oceanside of the South Kuril Islands. In some regions N. longitarse brevicollis is foundalong with N. longitarse longitarse.5. Nymphon bisseratum Losina-Losinsky, 1961(Pl. III, figs. 1–6)Losina-Losinsky, 1961: 66, fig. 4.Description. Trunk robust, smooth; lateral processes separated by less than theirown diameters, longer than trunk width, slightly expanded distally; each with severallong setae dorsally on distal margins. Cephalic segment equal to or longer thananother part of trunk, slightly broadened anteriorly; neck elongated. Ocular tuberclelow, with rounded top, situated near base of neck, opposite oviger implantation; eyeslarge, pigmented. Proboscis cylindrical, noticeably shorter than cephalic segment.Abdomen long, reaches as far as distal edge of 1st coxae of 4th legs. Chelifore feeble;scape equal to proboscis and to chela, fingers equal to palm in length, gently curved,bearing small teeth. Palp 1.5 times longer than proboscis; its segments 2 and 3 equal;segment 4 twice shorter than segment 5; both distal segments covered with short setae.Compound spines of oviger with rounded tips and with only one pair of lateral teeth.Strong legs covered with setae; 2nd coxa longer than 1st and 3rd combined; tibia 1longer than femur; tibia 2 much longer than tibia 1; tarsus slightly shorter thanpropodus. Main claw almost 3 times shorter than propodus; auxiliary claws longerthan half of main claw. Propodal sole bears 6–7 large spines medially and distally andseveral spinules between them. Measurements of only one specimen available: trunklength 7.25 mm, proboscis 1.5 mm, palp 2.2 mm, leg 21.4 mm.Geographical distribution. The only specimen was caught in the Sea of Japannear the western coast of the South Sakhalin, near the town of Nevelsk, at a depth of101 m.100

*Nymphon japonicum Ortmann, 1891(Pl. VI, figs. 1–8)Ortmann, 1891: 158–159, pl. 24, fig. 1; Hedgpeth, 1949: 249, fig. 20; Hong & Kim,1987: 158–160, fig. 16; Nakamura, 1987: 5–6, fig. 3.Description. Trunk elongated, segmented; lateral processes 1.5 times longer thantheir diameters, separated by almost as long as their lengths. Neck 3 times as long asbroad, anterior part of segment 1 only twice broader than neck width. Ovigerimplantations in contact with 1st lateral processes. Ocular tubercle low, with roundedtop, situated near neck base; eyes pigmented. Proboscis cylindrical, 1.5 times shorterthan cephalic segment. Abdomen straight, reaches beyond distal margins of 4th lateralprocesses, protrudes obliquely upward. Chelifore strong; scape cylindrical, longer thanproboscis, evenly armed with sparse setae and row of setae on distal margin; chelashorter than scape; fingers longer than palm, almost straight, with curved tips. Largespecimens have 30 large teeth on immovable finger and 35 smaller teeth on movableone. In juveniles immovable finger armed with 19–32, movable finger, with 27–40teeth. Palp thin; segment 2 longest; segment 3 longer than segment 5; segment 5greatly longer than segment 4. Oviger: 5th segment longest, 1.5 times longer than 4thone; both segments armed with short setae; segment 6 three times shorter thansegment 5, evenly covered with setae; compound spines bear 3 pairs of lateral teeth;terminal claw only slightly shorter than terminal segment, armed with 7 teeth on innermargin. Legs long; 2nd coxa longer than 1st and 3rd combined; femur shorter thantibia 1, whereas tibia 1 noticeably (almost 1.5 times) shorter than tibia 2; tarsus andpropodus subequal; large spines sparsely distributed over propodal sole. Main clawless than half of propodus; auxiliary claws longer than half of main one.Geographical distribution. N. japonicum is distributed along the eastern andwestern coasts of Japan, in the western part of the Tsugaru Strait, off the south-easterncoast of the Korea Peninsula and in the Korea Strait. Distribution pattern of N.japonicum suggests that the species penetrates as far as the north-eastern part of theSea of Japan.Vertical distribution. It occurs at depths of 30–439 m.*Nymphon micropedes Hedgpeth, 1949(Pl. VII, figs. 1–5)Hedgpeth, 1949: 254–256, fig. 24.N. micropedes is known from the Pacific shelf of the northern part of HonshuIsland, from Suruga Bay to the Tsugaru Strait. The known bathymetric range is 85–923 m.*Nymphon kodanii Hedgpeth, 1949(Pl. VII, figs. 6–10)Hedgpeth, 1949: 252–254, fig. 23; Turpaeva, 2004b: 1230–1231, figs. 1, 9–12.N. kodanii is distributed near the western coasts of Honshu and Kyushu islands(south of 40°N) and in the eastern part of the Sea of Japan at depths from 140 to 1200 m.101

6. Nymphon hodgsoni Schimkewitsch, 1913(Pl. V, figs. 1–6)Schimkewitsch, 1913: 244–248, figs. 15–25; 1930: 512–517, figs. 155a, 156a, 158, 160–166; Losina-Losinsky, 1933: 71; 1961: 63; Hedgpeth, 1949: 250–251, fig. 21; Turpaeva,2004b: 1234–1235, fig. 4.Description. Trunk robust, elongated, smooth; only distal margins of lateralprocesses armed with short setae. Lateral processes approximately 1.2–1.4 times aslong as broad, separated by not more than half their own diameters. Cephalic segmentlonger than another part of trunk; anterior part twice broader than neck, with smallprocesses of chelifores, palps and ovigers; neck short; oviger processes in contact withlateral processes of 1st legs. Ocular tubercle low, with rounded top, slightly bentbackwards; eyes large; posterior pair larger than anterior one. Proboscis straight,cylindrical, equal in length to cephalic segment. Abdomen straight, longer than fourthlateral processes, protruded obliquely upward. Chelifore slightly shorter than trunk;scape shorter than proboscis, expanded mid-distally; chela longer than scape; fingersbearing long teeth placed at angle to palm, gently curved, their thin tips cross; lengthof fingers as a whole equal to length of palm, but immovable finger much shorter thanmovable one. Palp rather thin; its segment 2 slightly longer than segment 3; ovalsegment 4 about 1.5 times as long as broad; segment 5 straight, lanceolate, 2.5 timeslonger than segment 4. Oviger more than twice longer than trunk; its segment 4 almoststraight, equal to segments 1 to 3 combined; in males segment 5 longest, expandeddistally and curved proximally; 4 distal segments subequal; claw twice shorter thanterminal segment, thin, with 9 long teeth on inner margin. Compound spines bear 3–4pairs of lateral teeth. Legs strong, 6 or more times longer than trunk; coxa 2 slightlyexpanded distally, equal in length to coxae 1 and 3 combined; femur longer than allcoxae combined; tibia 1 slightly longer than femur; tibia 2 one and half times longerthan tibia 1. Distal segments of legs noticeably thinner than other segments; tarsusslightly shorter than propodus; propodal sole provided with row of small spines andseveral larger spines on distal half. Main claw thin, curved, slightly shorter than halfof propodus; auxiliary claws 3.5 times shorter than main one. All appendages coveredwith setae, longest setae on legs. Measurements of male: trunk 8.55 mm; proboscis4.6 mm; chelifore 8.2 mm; palp 7.3 mm; oviger 19.3 mm; third leg 53.5 mm.Measurements of female: trunk 3.55 mm; proboscis 1.45 mm; chelifore 3.55 mm; palp2.8 mm; oviger 5.05 mm; third leg 15.25 mm.Geographical distribution. The species inhabits the Sea of Okhotsk, also foundin the Pacific Ocean near the Kuril Islands and in the northern part of the Sea of Japan(near the western coast of Sakhalin and Plastun Bight). It has not been recorded southof latitude 43°N.Vertical distribution. It occurs at depths from 42 to 1530 m.*Nymphon stocki Utinomi, 1956(Pl. VIII, figs. 1–5)Utinomi, 1955: 10–13, figs. 6, 7; 1971: 321.The species was found near the western coast of Japan, near Goto Island(Toyama Bay), at a depth of 324 m and north of Noto Island at a depth of 123 m.102

7. Nymphon braschnikowi (Schimkewitsch, 1906)(Pl. V, figs. 7–14)Schimkewitsch, 1906: 248–251, pl. I, figs. 2b, 3b, 4b, 5a, 6a; Hedgpeth, 1949: 250, fig.21a, c; Losina-Losinsky, 1961: 62; Turpaeva, 2001: 77–79, fig. 2; 2004b: 1232–1234, fig. 3.Description. Trunk robust, elongated, completely segmented. Lateral processesbroad, slightly more long than broad; separated by 3–4 times less than their owndiameters. Cephalic segment greatly expanded anteriorly; neck well developed, bearssmall processes of chelifores. Processes of ovigers in close contact with 1st legs lateralprocesses, almost as long in diameter as 3/4 length of neck. Ocular tubercle morebroad than tall, with flat top and large poorly pigmented eyes. Segments II and III oftrunk subequal in length, segment IV half shorter than each of them. Proboscis robust,cylindrical, slightly shorter than cephalic segment, protruded obliquely downward.Chelifore strong; scape slightly swollen distally, shorter than proboscis; chela longerthan scape; palm almost straight, thicker than scape and equal to it in length. Fingersheavy, far shorter than palm; immovable finger short, straight, wedge-shaped;movable finger longer than immovable one, curved proximally; both fingers bear veryshort, blunt, closely set teeth on inner margins. Palp 1.5 times shorter than chelifore;segment 2 longest; distal segments broad, rounded, their combined length slightly lessthan segment 3 length; segment 5 one and half times longer than its width. Ovigertwice longer than trunk; segments 4 and 5 equal in length and longest of all others; 3distal segments equal to one another. Compound spines curved, bear 3–4 pairs oflateral teeth. Terminal claw twice shorter than segment 10, straight, with very denselyset small blunt denticles on inner margin. Legs robust, seven times longer than trunk;coxae short; coxa 2 strongly expanded distally, asymmetrical; coxa 3 equal to coxa 1,also asymmetrical; femur and tibia 1 equal; tibia 2 one and half times longer than eachof them; tarsus and propodus short; tarsus twice as long as broad, propodus 1.5 timeslonger than tarsus, almost straight; propodal sole bears row of short setae and 5–6spines, equal in length to half of propodus width or less, situated medially and distally.Main claw almost straight, shorter than half of propodus; auxiliary claws small,shorter than 1/4 of main claw. Females differ from males in secondary characters: theyhave large genital pores on all legs and poorer armature, but bear short tough setae onfrontal margin of trunk, distally on lateral processes, and on all appendages.Measurements of female: trunk 7.2 mm, proboscis 3.5 mm, abdomen 1.8 mm,chelifore 7.7 mm, palp 4.8 mm, oviger 15.1 mm, 3rd leg 50.9 mm.As for juveniles, their chelae also bear short wedge-shaped fingers. Distalsegments of palp shorter than segment 3. Auxiliary claws on legs hardly noticeable.2nd coxa in male juveniles almost 3 times longer than 1st coxa, while tarsus more thantwice shorter than propodus.Geographical distribution. N. braschnikowi occurs in the Sea of Okhotsk, onthe shelf zone of the Kuril Islands; it has also been recorded in the Sea of Japan nearSakhalin Island. The finding of this species near the southern coast of HokkaidoIsland, reported by Hedgpeth, is doubtless. Judging by its appearance (Hedgpeth,1949, fig. 21), the specimen found must be identified as N. hodgsoni.Vertical distribution. The distribution range is between 26 and 120 m.103

8. Nymphon uniunguiculatum Losina-Losinsky, 1933(Pl. VI, figs. 9–16)Losina-Losinsky, 1933: 62–64, fig. 12; 1961: 72; Hedgpeth, 1949: 263, fig. 29; Kim,1984: 534, fig. 3a–f; Hong & Kim, 1987: 161; Turpaeva, 2004a: 1096.Description. Trunk smooth; cephalic segment longer than three other segmentscombined; anterior part of it greatly expanded; neck slender, tapering toward base.Lateral processes long, twice as long as broad; intervals between them equal or longerthan their own diameters. Proboscis cylindrical, considerably shorter than cephalicsegment. Ocular tubercle low, cylindrical, with flat top and two bumps on sides; eyeslarge. Abdomen short, pointed obliquely upward. Chelifore almost 3 times longer thanproboscis; scape much longer than proboscis, thin; chela thin, too, slightly shorter thanscape; palm almost cylindrical; fingers slightly shorter than palm, thin, bearingnumerous densely placed teeth on inner margins. Palp very thin, 3 times longer thanproboscis, like chelifore; segment 2 longest; segment 3 slightly shorter; equalsegments 4 and 5 slightly shorter than segment 3. Oviger in males twice longer thantrunk; segment 5 longest, segments 7 to 10 almost equal in length, bearing welldevelopeddensely set lanceolate, serrate compound spines, having two lateral teetheach. Compound spines on distal ends of segments often without lateral teeth.Terminal claw with small denticles. Legs thin, male legs 7 times longer than trunk,bearing few setae; 1st coxa shortest; 2nd coxa 4 times longer than 1st one, havingdistal projection with genital pore; 3rd coxa more than 1.5 times longer than 1st one;femur much shorter than tibia 1; female femur expanded; tibia 1 shorter than tibia 2;tarsus in males almost 4 times (in females – 3 times) shorter than tibia 2; propodus 1.5times shorter than tarsus; tarsus and propodus both thin and straight. Propodal solecovered with minute setules, devoid of even small spines. Main claw slightly longerthan half of propodus, no auxiliary claws. Measurements of male (holotype): trunk5.3 mm, proboscis 1.75 mm, chelifore 5.05 mm, palp 5.15 mm, 3rd leg 37.5 mm.Female (paratype) larger than male: trunk 6.15 mm, chelifore 5.95 mm, palp 6.3 mm,3rd leg 51.05 mm.Geographical distribution. In the Russian waters of the Sea of Japan N.uniunguiculatum is found in Peter the Great Bay. It also occurs near the coasts ofHokkaido and Honshu islands, the north-western coast of Korea, and off the SouthKurils.Vertical distribution. The species has been recorded at depths of 150–770 m.*Nymphon albatrossi Hedgpeth, 1949(Pl. VIII, figs. 6–10)Hedgpeth, 1949: 263–266, fig. 30.N. albatrossi occurs in the south-eastern part of the Sea of Japan near the westerncoast of Honshu Island, from Toyama Bay to the Korea Strait, also south and west ofKyushu Island in depths from 150 to 800 m.104

II. Family AMMOTHEIDAE Dohrn, 1881The family combines rather different forms of sea spiders, having compact orelongated trunk, segmented or unsegmented. Chelifore consists of 1, 2, or 3 segments,poorly developed and usually shorter than proboscis, with feeble or reduced fingers,completely absent in some species. Palp often longer than proboscis, consisting of 6–10 (even 20) segments. Both males and females have 10-segmented oviger, with orwithout terminal claw, with compound spines, placed in rows or irregularly, or withcommon flat spines. Four pairs of legs present. Males have genital pores on 3rd and4th legs, females on all legs.KEY TO THE GENERA OF THE FAMILY AMMOTHEIDAE1(4). Trunk compact, disk-shaped, unsegmented or not completely segmented (insome specimens segmentation may be complete); lateral processes placed incontact or radiate out from trunk like rays.2(3). Chelifore 2-segmented; palp 8–9 segmented; coxa 1 of leg bears one tall dorsodistaltubercle ........................................................................ 1. Achelia (p. 105)3(2). Chelifore usually in shape of rudimentary buds; palp consists of 4–7 segments;coxa 1 of leg lacks dorso-distal tubercle ............................*Tanystylum (p. 114)4(1). Trunk elongated, segmented; lateral processes separated by broad intervals.5(6). Chelifore consists of one segment, very small; segment 7 of oviger curved, withtuft of setae on convex side; segment 8 implanted on side of segment 7 ............................................................................................. 2. Lecythorhynchus (p. 115)6(5). Chelifore consists of 2–3 segments; segment 7 of oviger not curved; segment 8implanted on it distally.7(8). Palp consists of 18–20 segments, distal part of it looking like whip; distal ends of1st legs also whip-shaped ............................................... *Nymphonella (p. 116)8(7). Palp consists of 9–10 segments; all legs identical, without whip-shaped ends.9(10). Anterior part of cephalic segment covers implantations of chelifores hood-like;segment 2 of oviger longest; proboscis oval .................... 3. Cilunculus (p. 117)10(9). Anterior part of cephalic segment does not cover implantations of chelifores;segment 2 of oviger much shorter than segment 4; proboscis with one or twoconstrictions, separating its medial oviform part from proximal and distalconical parts .................................................................. *Ascorhynchus (p. 118)1. Genus Achelia Hodge, 1864Type species: Achelia ehinata Hodge, 1864Trunk short, shield-shaped, unsegmented, partially segmented, or, very rarely,completely segmented. Anterior part of cephalic segment has two lateral angles;lateral processes in contact or separated by small intervals, having different width inmales and females. Ocular tubercle situated on anterior part of cephalic segment; eyeswell-developed. Proboscis heavy, often oval, spindle-shaped, sometimes cylindrical.Abdomen fused with distal segment of trunk, usually long. Chelifore short, consists of105

2 segments; adults have vestigial chelae with reduced fingers or without them. Palpconsists of 6–8 segments, usually longer than proboscis. Oviger consists of 10segments, male oviger longer than female one, bearing few compound spines placedirregularly, or bearing simple spines placed similarly. Legs short, covered withtubercles and spines; femur distally bears conical process, larger in males, havingopening of cement gland on top in males; tarsus small, caliciform; propodus more orless curved; in most species propodal sole provided with large spines proximally andsmall spines medially and distally. Main claw usually large, curved; auxiliary clawsusually smaller than main one. Males have genital pores on special process (genitalspur), situated on coxa 2 of legs 3 and 4.KEY TO THE SPECIES OF THE GENUS ACHELIA1(14). Trunk unsegmented, without articulation lines.2(3). Propodal sole lacks isolated large spines; lateral processes in males long, thin,separated by intervals, expanding distally; no compound spines on oviger .................................................................................................... 1. A. borealis (p. 107)3(2). Propodal sole bears large spines.4(5). Dorsal side of trunk has two tubercles, placed one after another, with spines ontops; in adults abdomen base rises over trunk surface, making it saddle-shaped................................................................................. 2. A. bituberculata (p. 108)5(4). Dorsal side of trunk smooth and even, without any tubercles.6(7). Proboscis twice shorter than trunk, almost cylindrical, with rounded tip....................................................................................... *A. brevirostris (p. 108)7(6). Proboscis robust, almost equal to trunk in length, oval, spindle-shaped, orpyriform.8(9). Ocular tubercle cylindrical, tall, with conical top bearing small eyes; chelifores,palps and legs bear long spines, covered with short thin setae .......................................................................................................................... *A. latifrons (p. 109)9(8). Ocular tubercle low, conical; eyes situated in its middle part; all appendages bearlong spines without setae.10(11). Two small tubercles with apical spines on frontal margin of trunk and at distalangles of lateral processes; proboscis oval; chelifore longer than half ofproboscis; scape bears medial tubercle with spine on top ...................................................................................................................... 3. A. kurilensis (p. 109)11(10). Frontal margin of trunk smooth; each lateral process in adults bears one smalltubercle without spines (juveniles may lack such tubercles, or may have 2tubercles with apical spines on each lateral process); proboscis has anothershape; chelifore much shorter than half of proboscis.12(13). Proboscis spindle-shaped; propodus strong, noticeably curved; main clawheavy, reaching past middle of propodus; auxiliary claws slightly longer thanhalf of main claw ....................................................... 4. A. alaskensis (p. 110)13(12). Proboscis pyriform, consisting of conical basal part and large oviform part;propodus relatively thin, curved; main claw curved, reaching middle ofpropodus; auxiliary claws hardly reach middle of main claw ................................................................................................................ 5. A. gracilipes (p. 111)106

14(1). Trunk completely or partially segmented.15(18). Trunk completely segmented, all segments separated.16(17). Ocular tubercle conical, eyes situated in middle of it, proboscis relativelyslender, almost cylindrical ....................................... 6. A. segmentata (p. 111)17(16). Ocular tubercle very tall, cylindrical, eyes situated at its top; proboscis oval,swollen medially ............................................................... *A. superba (p. 112)18(15). Trunk not completely segmented, no articulation line between segments 3and 4.19(20). Ocular tubercle tall, cylindrical; two conical tubercles with truncated topsbearing spines situated dorsally on frontal margin of trunk, on ends of lateralprocesses and 1st coxae of legs .................... 7. A. echinata orientalis (p. 113)20(19). Ocular tubercle low, conical, frontal margin smooth, lateral processes bear 2–3tubercles with spines on tops ................................ 8. A. kamtschatica (p. 114)1. Achelia borealis (Schimkewitsch, 1895)(Pl. IX, figs. 1–5)Schimkewitsch, 1895: 36–40, pl. 2, figs. a–b; 1930: 139–144, figs. 34–37 (Ammotheaborealis); Losina-Losinsky, 1933: 57–59, fig. 9 (Ammothea borealis var. japonica); Losina-Losinsky, 1961: 52 (Achelia borealis spp. japonica); Hedgpeth, 1949: 286–287, fig. 41 k–m(Achelia borealis).Description. Trunk elongated, unsegmented, smooth. Cephalic segment small,without tubercles. Lateral processes long, twice as long as broad, separated byintervals, broadening distally; each has small tubercle without spine on anterior distalangle. Proboscis oval, slightly shorter than trunk. Ocular tubercle tall, cylindrical, withflat top, situated near frontal margin; eyes pigmented, placed almost on top. Abdomenalmost 1/5 longer than trunk, swollen in distal half, tapered towards end. Cheliforeslightly longer than half of proboscis; scape cylindrical; chela vestigial, withoutfingers. Palp 8- segmented, longer than proboscis; segment 2 longest; segment 4shorter; other segments short; segments 7 and 8 shortest. Oviger twice as long astrunk; segment 10 bears two compound spines; segments 7 to 9 bear 1–2 simplespines. Legs thin, 6 times longer than trunk; coxa 1 bears tubercle with small spine, astall as 3/4 of coxal length; other segments without tubercles and spines, armed onlywith setae. Tibia 1 longest; propodus almost straight, long, slender, without heel andisolated large spines; smaller spinules scattered over entire surface of sole. Main clawalmost 4 times shorter than propodus; auxiliary claws slightly shorter than main one.Measurements of male: trunk 1.4 mm, proboscis 1.2 mm, chelifore 0.6 mm, palp2.8 mm, 2nd leg 8.2 mm, propodus 0.9 mm, main claw 0.2 mm.Geographical distribution. A. borealis is a boreal-arctic species. The subspeciesA. borealis japonica (Losina-Losinsky) has been recorded for Peter the Great Bay (theSea of Japan). The nominative subspecies occurs in the White and Kara seas, in thestraits of the New Land Archipelago.Vertical distribution. It was found in Peter the Great Bay at a depth of 130 m.Vertical distribution of the nominative subspecies ranges from 6 to 40 m depth.107

2. Achelia bituberculata Hedgpeth, 1949(Pl. XI, figs. 1–6)Hedgpeth, 1949: 287–289, fig. 41a–g; Nakamura & Child, 1983: 6–7; Kim, 1984: 537,fig. 6a–i; Kim & Hong, 1986: 46; Nakamura, 1987: 18–19, pl. 16 (Achelia bituberculata);Utinomi, 1951: 163, fig. 2; 1954: 18–20, fig. 6; 1971: 330 (Achelia ohshimai).Description. Trunk compact, rounded, unsegmented; mid-dorsal line bears 2 talltubercles having 2–3 tops with spines near abdomen base. Lateral processescontiguous; several tubercles with spines situated on each lateral process dorsodistally.Same tubercles with spines situated near frontal margin of trunk. Ocular tubercle tall,with flattened top and pigmented eyes. Proboscis large, oval, elongated, almost equalto trunk length. Abdomen long, swollen in basal part, extended almost horizontally,reaching beyond distal ends of 1st coxae of 4th legs. In adults abdomen tuberculatedand slightly curved upward, so that trunk looks saddle-shaped in lateral view.Chelifore 3–4 times shorter than proboscis; scape cylindrical, almost 4 times longerthan its diameter, with tubercles on dorsal side and distal end; chela small, globular.Palp 8-segmented; segment 2 longest, almost 6 times as long as broad; segment 4 withdorsal swellings bearing stiff setae. Oviger 10-segmented; segments 4 and 5 in malesalmost twice longer than segment 3; segment 6 bearing 2 simple spines pointed toproximal end of segment; distal segments bear compound spines: 2 on segment 10,and 1–3 (number differs from specimen to specimen) on other segments. Legs armedwith strong spines, situated on small tubercles; coxa 2 in males bears long genital spuron ventral side; femur longest of all segments, bears tubercle with cement glandopening on dorsal side; propodus robust, almost equal in length to tibia 2, noticeablycurved, bears 3 large spines on sole proximally. Main claw slightly longer than half ofpropodus, strong, curved; auxiliary claws slightly longer than half of main one.Measurements of holotype: trunk 1.5 mm, proboscis 1.25 mm, abdomen 0.6 mm, 3rdleg 4.63 mm.Geographical distribution. The species occurs near the Pacific coast of Japan,near the Korean Peninsula in the Sea of Japan and the East China Sea, also in Peter theGreat Bay.Habitat. A. bituberculata is a littoral and high sublittoral species, recorded to adepth of 75 m. It was found in Peter the Great Bay among the fouling of specialexperimental plates.*Achelia brevirostris Losina-Losinsky, 1961(Pl. IX, figs. 6–11)Losina-Losinsky, 1961: 95–97, fig. 19; Nakamura & Child, 1991: 3–5, fig. 1a–f; Child,1995: 3.Description. Trunk rounded, unsegmented. Lateral processes robust, placed incontact. Low tubercles without spines on angles of lateral processes and of frontalmargin of trunk. Ocular tubercle low, with conical top, situated near anterior margin ofcephalic segment; eyes in middle part of tubercle. Proboscis twice shorter than trunk,rather slender, pointed downward. Abdomen long, robust, slightly curved upward.Chelifore with vestigial chelas lacking fingers, almost twice shorter than proboscis.Palp 8-segmented; segment 2 longest; segment 4 slightly shorter than segment 2; other108

segments short, cylindrical; 4 distal segments covered with dense short setae. Ovigernot longer than trunk; segment 4 longest; segment 5 shorter; segment 3 even shorter;other segments short; segment 10 bears two compound spines; segment 9 bears onecompound spine. Legs twice longer than trunk, with sparse short setae; each coxa 2 of3rd and 4th legs ventrally bears tall conical tubercle with genital pore; femur greatlyexpanded distally, bears projection with spine on margin of dorsal side; tibiae 1 and 2equal, longer than femur; propodus quite robust, curved, bears 3 large spines on soleproximally. Main claw almost equal to propodus in length, slightly curved; auxiliaryclaws small, similar to basal spines on sole. Trunk length of adult specimens1.4–1.5 mm.Remarks. The above given diagnosis is the one of A. brevirostris, a holotype ofwhich was found in the Sea of Okhotsk, near the South Sakhalin (Tyuleniy Island), ata depth of 48 m. Specimens from other places, assigned to this species, differ from theholotype in the less compact trunks, taller ocular tubercles and presence of tubercleson distal margins of lateral processes. Specimens collected near Japan, from depths to479 m, have longer palps, relatively short main claws, and longer auxiliary claws(Nakamura & Child, 1991; Child, 1995).The distribution pattern of A. brevirostris presupposes that the species may occurin the northern part of the Sea of Japan.*Achelia latifrons (Cole, 1904)(Pl. X, figs. 13–15)Cole, 1904: 263–266, pl. 11, fig. 3, pl. 16, figs. 1–9, pl. 17, figs. 1–3 (Ammothealatifrons); Kim & Hong, 1986: 46–48, fig. 8 (Achelia latifrons); Nakamura & Child, 1983: 8–10, fig. 2 (Achelia orpax).A. latifrons is widespread on the continental shelf of the Northern Pacific. It hasbeen recorded off California at a depth of 650 m, in the Bering Sea near the Pribilofand Unalaska islands, in Sagami Bay at a depth of 30 m, and in the Korea Strait. It hasnot been registered in the Sea of Japan yet, but in future may be found in its southernpart.3. Achelia kurilensis Losina-Losinsky, 1961(Pl. X, figs. 1–7)Losina-Losinsky, 1961: 98–100, fig. 21; Nesis, 1967: 249.Description. Trunk disk-shaped, unsegmented. Anterior part of cephalic segmentshort, bears two tubercles with spines on tops. Lateral processes broad, placed incontact, each bears two rather tall tubercles with spines distally, of which posteriortubercle larger, situated near middle of distal margin. Ocular tubercle cylindrical, withrounded apex; eyes near apex. Proboscis oval, as long as trunk. Abdomen almost equalto trunk, swollen distally, with several large setae on dorsal side. Chelifore slightlylonger than 1/2 of proboscis; scape long, with 3 tubercles on medial part and 3 thinspines on distal margin; chela small, globular. Palp 6–8 segmented; in holotype (male)palp 6-segmented, as long as proboscis, with segment 4 longest; in paratype (female)palp 8-segmented, with segment 2 longest; distal segments sparsely covered with109

setae. Oviger relatively short; oviger in males shorter than whole trunk; oviger infemales shorter than 1/2 of trunk length. Segments 4 and 5 of male oviger longest;segment 7 of irregular shape with long setae; segment 8 bears one compound spine;segment 10 rounded, very small. Legs 4.5–5 times as long as trunk; coxa 1 bears talltubercle on dorsal side; laterally coxa 1 armed with setae and spines; similar setae andspines on all other segments; femur bears tubercle with spine on distal end; tibia 2 inmales bears tubercles with spines, while female tibia 2 lacks them; femur, tibiae 1 and2 subequal in males, while in females femur longer than both tibiae; propodus curved;heel absent; sole bears several thin setae and, proximally, 3 relatively large spines.Main claw slightly longer than half of propodus, auxiliary claws longer than half ofmain one. Measurements: trunk 1.08 mm, proboscis 1.08 mm, abdomen 1.06 mm,chelifore 0.64 mm, palp 1.06 mm, oviger 2.08 mm, leg 5.14 mm.Geographical distribution. Type locality is Kunashir Island. A. kurilensis isfound in the Sea of Japan in Peter the Great Bay (Sivuchya and Vityaz Bays), and alsonear the South Sakhalin.Vertical distribution. It occurs in the littoral and high sublittoral zones to adepth of 20 m.4. Achelia alaskensis (Cole, 1904)(Pl. X, figs 8–12)Cole, 1904: 266–268, pl. 12, fig. 4, pl. 17, figs. 4–12; Schimkewitsch, 1929: 151–156,figs. 42–45; Losina-Losinsky, 1933: 60, fig. 10 (Ammothea alaskensis); Losina-Losinsky,1961: 91 (Achelia alaskensis).Description. Trunk globular, unsegmented; anterior part of cephalic segmentsquare, expanded at place of chelifore and palp implantations. Lateral processes aslong as trunk width, expanded distally, contiguous; each bears one small tubercle withshort spine on distal margins of dorsal side. Ocular tubercle low, conical or cylindricalwith conical apex; eyes large, situated in middle of tubercle. Proboscis as long astrunk, spindle-shaped, convex dorsally and almost straight ventrally. Abdomen long,slender, with tapered distal end, reaching middle of coxa 1 of 4th leg, bears 3–4spinules and several long setae on dorsal side. Chelifore shorter than 1/2 of proboscis;scape with triangular projection on end; chela small, globular. Palp 8-segmented;segments 2 and 4 longest, subequal; 4 distal segments small, rounded, ventrally armedwith strong dense setae. Oviger in females as long as palp; all its segments relativelyshort and broad; segment 7 bears one compound spine; segments 8 through 10 bear 2compound spines each. Oviger in males twice as long as in females; segments 3 to 6elongated and rather thin; number of compound spines equal to that in females. Legsstrong, especially in females; coxa 1 short, with tall conical tubercle on dorsal side;male coxa 2 bears tall genital spur ventrally; femur, tibiae 1, and 2 equal, beartubercles with spines on dorsal sides, each of these 3 segments nearly as long as all 3coxae combined; propodus robust, curved, without heel, sole bears several smallspinules and, proximally, 3 large spines. Main claw heavy, gently curved, reachingbeyond half of propodus; auxiliary claws as long as 1/2 of main one. Body length ofmale 3 mm, width 13 mm.Remarks. A. alaskensis bears a very strong resemblance to A. gracilis. Maindifferences between these two species are in the shapes of proboscis and propodus.110

However, these differences sometimes are barely perceptible, and in such cases it ishard to distinguish these species.Geographical distribution. A. alaskensis is distributed along Alaska andKamchatka shores, near the Commander Islands and in the Tatar Strait.Vertical distribution. The species is sublittoral, occurring to a depth of 180 m.5. Achelia gracilipes (Cole, 1904)(Pl. XII, figs. 1–5)Cole, 1904: 269–270, pl. 12, fig. 5, pl. 18, figs. 1–6 (Ammothea gracilipes); Losina-Losinsky, 1933: 60–61, fig. 11 (Ammothea gracilipes var. borealis); Nesis, 1967: 250 (Acheliagracilipes).Description. Trunk oval, unsegmented; cephalic segment slightly expandedanteriorly; corners rounded, with small unarmed tubercles. Lateral processescontiguous, each bearing small conical tubercle on distal margin of dorsal side. Oculartubercle low, conical; eyes in its middle part. Proboscis equal to trunk in length,pyriform, consists of short basal part and ovoid distal one. Abdomen rather slender,reaches distal ends of coxae 1 of 4th legs. Chelifore shorter than half of proboscis;scape bears small prominence with spine on distal end; chela as long as half of scapeor shorter. Palp 8-segmented, slightly longer than proboscis; segments 2 and 4 equal;segments 5 to 8 short, densely covered with setae on ventral side. Oviger in femalesequal in length to palp, in males twice as long as palp; segments 4 and 5 longest;segment 7 bears projection covered with setae; other 3 segments small, only segment10 bears 2 compound spines. Legs about twice as long as trunk, rather slender,especially in males; coxa 1 bears specific finger-shaped projection, almost equal tosegment’s length; coxa 2 one and half times as long as coxa 1; male coxa 2 of 3rd and4th legs bears genital spur; femur and both tibiae subequal; female femur broadened;propodus long and rather thin, gently curved and has poorly developed heel with 3curved spines and row of small spinules on sole. Main claw strong, gently curved,reaching half of propodus; auxiliary claws as long as half of main claw. Legs almostunarmed, having only few setae on coxae 2 and 3. Trunk length 1.5–2 mm, width8 mm.Remarks. The specimens collected in the Tatar Strait were referred by Losina-Losinsky to A. gracilipes var. borealis. They differ from the typical forms in theabsence of noticeable tubercles on the anterior margin of the cephalic segment, in thelonger abdomen, shorter scape, and larger body (body length – 3 mm, width of bodywith legs – 11.5 mm).Geographical distribution. A. gracilipes has been recorded along the Californiashore, off the Commander Islands, near Kamchatka, the South Kurils, and the SouthSakhalin (in the Tatar Strait).Vertical distribution. The species is found in shallow waters (to 5 m depth).6. Achelia segmentata Utinomi, 1954(Pl. XI, figs. 7–11)Utinomi, 1954: 20, fig. 9; 1971: 330; Nesis, 1967: 249.111

Description. Utinomi’s collection included only females and juveniles, so thedescription below is a description of a female.Trunk smooth, relatively narrow, segmented; cephalic segment broader than itslength, with smooth frontal margin. Lateral processes separated by narrow intervals,expanding distally. Ocular tubercle large, conical, situated medially on cephalicsegment; eyes small. Proboscis almost cylindrical, slightly shorter than trunk, pointeddownward. Abdomen slightly longer than 4th lateral processes, truncated, protrudedupward. Chelifore about 3 times shorter than proboscis; scape straight; chela vestigial,with reduced fingers. Palp thin, 9-segmented; 4 proximal segments combined equal inlength to proboscis, smooth, unarmed; distal segments short, ventrally covered withsetae. Oviger completely absent in some specimens. Legs long, equally thin all alongtheir length, without tubercles or projections, with sparse setae on most segments. All3 coxae short, coxa 2 longest of them; femur, tibiae 1 and 2 subequal, each one'slength almost equal to length of coxae combined; propodus curved, expandedproximally, having small heel with 3 strong short spines. Main claw as long as half ofpropodus, auxiliary claws as long as 2/3 of main one. Trunk length of largest female0.88 mm.Geographical distribution. A. segmentata has been recorded near HokkaidoIsland and in Peter the Great Bay.Vertical distribution. This is a sublittoral species. In Peter the Great Bay it hasbeen found to a depth of 20 m.*Achelia superba (Loman, 1911)(Pl. XII, figs. 6–11)Loman, 1911: 11–13, pl. I, figs. 14–15; pl. II, figs. 16–24 (Ammothea superba);Nakamura, 1987: 21–23, pls. 18, 36; Turpaeva, 1990: 19–20, fig. 2; Child, 1995: 8 (Acheliasuperba).Description. Trunk compact, but segmented; cephalic segment broad, almostsquare, as long as half length of trunk; frontal margin slightly concave. Lateralprocesses slightly longer than width of trunk in its narrowest part, separated by narrowintervals, bear small tubercles on distal angles. Ocular tubercle very tall, cylindrical,situated near frontal margin; eyes small, placed on top. Proboscis large, thick, spindleshaped.Abdomen long, almost equal to trunk, protruded obliquely upward. Cheliforeslender; scape only slightly shorter than trunk and longer than 1/2 of proboscis; chelavery small, with immovable reduced fingers. Palp thin, 8-segmented; segment 2 aslong as scape, bears tubercle with spine on distal margin; segment 3 very short, alsohas tubercle with spine; segment 4 almost twice shorter than segment 2, or sometimesas long as 2/3 of segment 2; 4 distal segments very thin, cylindrical; their combinedlength almost equal to length of segment 2. Oviger in males longer than in females;segment 4 longest; segment 5 as long as 3/4 of segment 4; distal segments elongated,oval (typical shape for whole genus), bear two compound spines each. Legs of averagelength; coxa 1 has 2–3 small tubercles on distal margin; male coxa 2 bears tall genitalspur ventrally near distal margin; femur as long as all coxae combined, has tall processwith spine and cement gland opening dorsodistally; tibiae 1 and 2 equal, both thinnerand longer than femur; propodus thin, curved, without heel, about as long as half of112

tibia 2; propodal sole bears row of small spinules and 2–3 larger spines on proximalpart. Main claw thin, longer than half of propodus; auxiliary claws longer than half ofmain one. Measurements: trunk 1.5 mm, proboscis 2 mm, ocular tubercle almost1 mm, abdomen 1 mm, male oviger 6 mm, 2nd leg 10 mm.Geographical distribution. The species is known from the coastal regions of thenorth-west part of the Pacific Ocean. A. superba is distributed off the Pribilof andAleutian islands, near the coast of Japan, and near Sakhalin Island in the Sea ofOkhotsk. There is also a possibility that it may be found in the Tatar Strait.Vertical distribution. The species is found between 7 and 428 m depth.7. Achelia echinata orientalis Losina-Losinsky, 1933(Pl. XIII, figs. 1–7)Losina-Losinsky, 1933: 55–57, fig. 8 (Ammothea echinata ssp. orientalis); Lou, 1936:19, figs. 7–9, pls. II–IV (Ammothea (Achelia) echinata var. sinensis); Nesis, 1967: 249;Nakamura, 1987: 19–21, pls. 17, 35; 1994: 14 (Achelia echinata sinensis).Description. Trunk rounded; segments 1, 2, and 3 divided; segments 3 and 4fused. Lateral processes placed in contact. Frontal margin of cephalic segment anddistal amgles of lateral processes provided with 2 conical truncated tubercles withspines on tops. Ocular tubercle tall, cylindrical, with flat top, bearing tubercle in itscentre; eyes near top. Proboscis spindle-shaped, longer or equal to trunk, taperedproximally and distally. Abdomen cylindrical, reaching middle of coxae 2 of 4th legs,curved upward. Chelifore 3 times shorter than proboscis; scape bears tubercle, oftenbicuspidate and with spines on both tops, on outer distal end; chela small with twotubercles (reduced fingers). Palp 8-segmented, slightly longer than proboscis, thin;segments 2 and 4 longest; segment 2 almost equal in length to scape; segment 4shorter than scape. Oviger in males much longer than in females; segments 4 and 5equal and longest of all; other segments short; segments 6 ,7, 8 and 10 armed with 2compound spines; segment 9, with 1 compound spine (presence of compound spineson segment 6 of oviger – characteristic feature of A. echinata). Legs 4 times as long astrunk, strong, with short setae on ventral side and long setae on tubercles of dorsalside; coxa 1 in males provided distally with 2 tubercles with spines, sometimes forked;coxa 2 bears tubercles medially and distally; femur bears dorsodistal process withcement gland duct, pointed forward and armed with spine; femur, tibiae 1 and 2 equalin length; propodus 1.5 times shorter than tibia 2, strong, curved; its dorsal sidecovered with long setae; sole armed with row of short spines and, proximally, with 3–4 long spines. Main claw twice shorter than propodus; auxiliary claws longer than halfof main one.Remarks. This subspecies differs from the nominative species in the larger size(body length 3–3.5 mm), longer proboscis (which is also more than in North Atlanticspecimens tapered proximally and distally), and in the greater number of compoundspines on the distal segments of the oviger. Later a subspecies A. echinata sinensis(Lou) distributed farther south was described, characterized by another shape of theproboscis, the stronger armature, and another proportions of the palp and longsegments of the legs. However, these differences may be considered a result ofintraspecies variability, well displayed in the Sagami Bay collection (Nakamura,1987).113

Geographical distribution. A. echinata orientalis is distributed near the coastsof Japan, in the Sea of Japan and the Yellow Sea, and near the South Sakhalin. In theSea of Japan it occurs in Peter the Great Bay.Vertical distribution. The subspecies is found in the littoral zone to a depth of130 m (mainly from 0 to 15 m).8. Achelia kamtschatica Losina-Losinsky, 1961(Pl. XIII, figs. 8–13)Losina-Losinsky, 1961: 92–93, fig. 17.Description. Trunk almost rounded, not completely segmented. Two posteriorsegments without articulation lines on dorsal side. Anterior part of cephalic segmentshort; no tubercles. Broad lateral processes almost in contact, distally provided with 2–3 unarmed or bearing short spines tubercles. Ocular tubercle low, conical, situatednear frontal margin, bears large eyes at 1/2 of its height. Proboscis slightly shorter thantrunk, thin, tapering from middle to end. Abdomen shorter than proboscis, slightlybroadened distally, tapered towards end, reaching distal margin of 4th leg coxa 1.Chelifore almost 3 times shorter than proboscis; scape bears tubercle distally; chelatwice as short as scape, oval in outline, without fingers. Palp 8-segmented, slightlylonger than proboscis; segment 2 longest; segment 4 slightly shorter than segment 2;other segments short, armed with setae as long as segment’s width. Oviger in malesalmost twice longer than trunk; segment 3 longest; distal segments gradually decreasein length; no compound spines on them. Legs 12 times as long as trunk, armed withsparse short spines; coxa 1 bears dorsodistal tubercle (its height almost equal to coxa’slength), and 2–3 lateral tubercles with spines; coxa 2 and femur bear large (but lowerthan that of coxa 1) tubercle each; femur and tibia 1 equal in length; tibia 2 longer;propodus robust, curved, without heel, having 3 large spines on sole proximally. Mainclaw longer than half of propodus; auxiliary claws 3 times shorter than main claw.Measurements: trunk 0.90 mm, proboscis 0.72 mm, abdomen 0.50 mm, chelifore0.27 mm, palp 0.97 mm, oviger 1.65 mm, leg 10.81 mm.Geographical distribution. The description of A. kamtschatica was made usingthe specimens collected near the southeastern coast of Kamchatka Peninsula(Akhomten and Morzhovaya Bights) at 30–50 m depths. A. kamtschatika was alsofound in the fouling of experimental plates and cages from Alekseev and VityazBights (in Peter the Great Bay), and in the samples taken from the high sublittoralzone of Medny Island (the Commander Islands).Vertical distribution. The species inhabits the high sublittoral zone.*Genus Tanystylum Miers, 1879Type species: Nymphon stylygerum Miers, 1875.Trunk shield-shaped, flat, unsegmented. Lateral processes broad; placed incontact in some species, separated by narrow intervals in others. Ocular tubercle ofvarious shapes, with well-developed eyes. Proboscis slightly longer than trunk,tapering forward. Chelifores present as rudimentary tubercles, rarely with vestigialchelas. Palp consists of 4–7 segments, slightly longer or shorter than proboscis. Oviger114

10-segmented, better developed in males, armed with several not serrate, butsometimes forked spines. Legs strong; tarsus short; propodal sole armed with basalspines proximally and small spinules in front of them. Auxiliary claws always present.Two species of this genus are found in the Sea of Japan.KEY TO THE SPECIES OF THE GENUS TANYSTYLUM1(2). Cephalic segment of trunk separated from 1st lateral processes by 1/2–1/3 theirdiameters; distal margins of lateral processes provided with 1–2 small tubercleswith spines on tops; proboscis broad at base and strongly tapered in distal third;palps 6-segmented ...............................................................*T. scrutator (p. 115)2(1). Cephalic segment of trunk in close contact with 1st lateral processes; lateralprocesses bear one short spine each on margins; proboscis broad, cylindrical,slightly tapered on end; palps 5-segmented .................... *T. ulreungum (p. 115)*Tanystylum scrutator Stock, 1954(Pl. XIV, figs. 1–4)Stock, 1954: 142–145, fig. 70; Kim & Hong, 1986: 50.T. scrutator is a sublittoral species. It was originally found near the eastern coastof Japan, later – off the south-eastern coast of Korea.*Tanystylum ulreungum Kim, 1983(Pl. XIV, figs. 5–8)Kim, 1983: 467, figs. 1, 2 (Tanystylum ulreungum); Nakamura & Child, 1983: 39–41, fig.13 (Tanystylum nabetensis).These are tiny animals, with span of legs 5.7 mm. The species inhabits thesublittoral zone. It is known from the southern part of the Sea of Japan (Namyang andUllung-do islands) and from Sagami Bay.2. Genus Lecythorhynchus Böhm, 1879Type species: Corniger hilgendorfi Böhm, 1879.Trunk strong, segmented, with well-developed cephalic segment and lateralprocesses, separated by relatively small intervals. Ocular tubercle conical, situatedslightly forward from centre of cephalic segment. Proboscis shorter than trunk, oval,cylindrical. Abdomen rather long, inserted on anterior margin of caudal trunksegment, fused with trunk. Chelifore in shape of 1-segmented rudimentary bud. Palp9-segmented; segment 6 attached to segment 5 at angle. Oviger 10-segmented, S-shape curved in males, without curve in females; distal segments bear simple orcompound spines, placed irregularly; no terminal claw. Legs almost twice longer thantrunk, strong; propodus curved, with isolated basal spines on sole.Only one species has been recorded in the Sea of Japan.115

1. Lecythorhynchus marginatus Cole, 1904(Pl. XV, figs. 1–7)Cole, 1904: 259–262, pl. 11, figs. 1–2, pl. 15, figs. 1–8; Schimkewitsch, 1929: 50–53,figs. 7, 8, 9; Losina-Losinsky, 1933: 61; Stock, 1954: 139, fig. 69 (Lecythorhynchusmarginatus); 1956: 43–45; Nesis, 1967: 250–251; 1976: 77, fig. 179 (Lecythorhynchushilgendorfi); Nakamura & Child, 1983: 13; Hong & Kim, 1987: 143 (Ammothea hilgendorfi).Description. Trunk strong, almost smooth, segmented. Lateral processes shorterthan trunk width, separated by 2–3 times less their own diameters. Cephalic segmentshorter than its width, bears small processes of palps and ovigers; its anterior marginslightly juts out over proboscis base. Ocular tubercle relatively tall, cylindrical withconical acutely pointed or rounded apex; eyes large, pigmented. Proboscis almostequal to trunk in length, oval, cylindrical, has constriction separating proximal third ofits length. Abdomen rather long, cylindrical, slightly swollen distally, reaching beyonddistal ends of coxae 1 of 4th legs. Chelifore 1-segmented, in shape of rounded orconical bud. Palp 9-segmented; segments 2 and 4 longest, equal or segment 2 slightlylonger than arcuate segment 4; other segments short; segment 5 ovoid; segment 6attached to its lateral side, forming strong curve; 4 distal segments armed with shortsetae. Oviger 10-segmented; male segments 2, 3, 4, and 5 long; segment 6 slightlyshorter than segment 5, gently curved; segment 7 arcuate; its convex side bears talltubercle with tuft of setae; segment 8 attached to segment 7 lateral side; 4 distalsegments armed with compound spines. Legs more than twice longer than trunk, bearsparse setae; coxa 2 of all legs in males swollen ventrally; coxa 2 in females swollenonly on first 3 pairs of legs; propodus robust, strongly curved; propodal sole usuallyprovided with 5 large spines proximally and row of spinules medially and distally.Main claw strong, curved, equal or longer than half of propodus; auxiliary claws equalor longer than half of main one. Body length of female found in Peter the Great Bay –about 3 mm, width – about 20 mm. Males have smaller size.Geographical distribution. L. marginatus is widespread in the North Pacific. Itsrange of distribution is from the Californian coast to the Russian Far East, China,Japan, and the Hawaiian Islands. As for the Sea of Japan, it has been recorded in Peterthe Great and Possjet bays.Vertical distribution. This is a common littoral and high sublittoral species,occurring in the littoral zone to a depth of 113 m (near the South Primorye, in 34–40 mdepths).*Genus Nymphonella Ohshima, 1927Type species: Nymphonella tapetis Ohshima, 1927.Trunk elongated, well segmented. Chelifore 2-segmented, shorter than proboscis;chela small, vestigial, with reduced fingers devoid of teeth. Palp longer than trunk,consists of 17–20 segments; distal 10 segments thin, short, whip-shaped. Ovigercharacteristic for family, bears compound spines on distal segments. Distal segmentsof 1st legs also whip-shaped owing to secondary segmentation of tarsus and propodus;propodus without terminal claw. 2nd, 3rd, and 4th legs 8-segmented, with long slendermain claws and without auxiliaries.Only one species of this genus is known from the Sea of Japan.116

*Nymphonella tapetis Ohshima, 1927(Pl. XVI, figs. 1, 2)Ohshima, 1927: 257–263, figs. 1–4; Hedgpeth, 1949: 236, tabl. I; Utinomi, 1971: 331–332.This species parasitize on bivalve mollusks. In the Sea of Japan it inhabits thehigh sublittoral zone of the western coast of Japan.3. Genus Cilunculus Loman, 1908Type species: Lecythorhynchus armatus Böhm, 1879.Trunk elongated, well segmented. Anterior margin of cephalic segment coverspeak-like (or hood-like) insertions of chelifores. Ocular tubercle tall, thin, situatednear frontal margin. Proboscis oval, with flat apex. Chelifore 2–3-segmented; adultfingers of chela reduced. Oviger 10-segmented, with extremely long segment 2;terminal claw absent. Femur in males provided with thin cement gland duct, pointeddistally, often longer than femur’s diameter. Auxiliary claws present.One species of this genus has been recorded in the Sea of Japan.1. Cilunculus armatus (Böhm, 1879)(Pl. XV, figs. 8–13)Böhm, 1879b: 141 (Lecythorhynchus armatus); Schimkewitsch, 1909: 4, fig. 2(Ammothea armata); Nakamura & Child, 1983: 33; Nakamura, 1987: 33–34, pls. 30, 39(Cilunculus armatus).Description. Trunk elongated, segmented; each of first 3 segments dorsodistallybear one tall tubercle with several setae. Anterior part of cephalic segment covers 1stlateral processes hood-like. Lateral angles of anterior "hood" bear tubercles with setae,lower than dorsal tubercles. Lateral processes long, separated by less their owndiameters. Several small tubercles with rather long spines situated on distal margins oflateral processes. Ocular tubercle situated near anterior margin of cephalic segment,conical, with acutely pointed top, as tall as distal tubercles on trunk segments; no eyes.Proboscis large, elongated, oval, with flat apex, as long as trunk. Abdomen cylindrical,slightly swollen distally, convex dorsally, armed with strong spines on tubercles,reaches middle of 2nd coxae of 4th legs. Chelifore small; scape 2-segmented; segment1 short; segment 2 twice longer, bearing tubercles with spines on dorsal and lateralsides; chela small, globular, without fingers. Palp 9-segmented; segment 2 longest, 9times as long as its own diameter; segment 4 about 1/3 shorter than segment 2, withseveral setae dorsally; 5 distal segments almost equal in length, ventrally armed withdense setae twice or more longer than diameters of these segments. Oviger 10-segmented; segment 2 longest, straight; male segments 6 and 7 covered with longsetae distally; segments 8 and 9 bear one compound spine each; segment 10 bears 2compound spines. Compound spines thin, long, with numerous blunt lateral teeth.Legs armed with numerous setae; coxa 1 bears long setae laterally and dorsally; coxa2 twice in males and 1.5 times in females longer than coxa 1; femur, tibiae 1 and 2subequal; cement gland duct thin, long, situated on distal third of femur at angle tofemur’s end; propodus slender, noticeably curved, about 1.5 times shorter than tibia 2,117

ears 4 large spines on sole proximally and about 8 medially and distally. Main clawcurved, reaches middle of propodus; auxiliary claws longer than 2/3 of main one.Geographical distribution. The species has been recorded in the Sea of Okhotskand the Sea of Japan (west of Sakhalin), also near Japan on the Pacific side (offHokkaido Island and in Sagami Bay).Vertical distribution. C. armatus occurs in the high sublittoral zone to a depthof 700 m.*Genus Ascorhynchus Sars. 1877Type species: Ascorhynchus abyssi Sars, 1877.Trunk elongated, segmented, smooth or with conical tubercles and setae.Cephalic segment with long neck. Lateral processes long, separated by broad intervals.Ocular tubercle varied in shape; eyes present not in all species. Proboscis large, curveddownwards; proximal part thin; distal part pyriform. Abdomen long, slender.Chelifore 2–3-segmented; chela with reduced fingers. Palp 9–10-segmented, thin,longer than proboscis. Oviger 10-segmented; segments 4 and 5 longest; segment 6also long; segments 7 through 10 bear several rows of compound spines; terminalclaw present. Legs long; tarsus short or elongated, but shorter than propodus;propodus lacks basal spines; main claw of various lengths; no auxiliaries.There are three species of the genus in the Sea of Japan.KEY TO THE SPECIES OF THE GENUS ASCORHYNCHUS1(2). Dorsal side of trunk smooth, mid-dorsal line devoid of tubercles .............................................................................................................. *A. glaberrimum (p. 118)2(1). Tubercles present on trunk, lateral processes, and coxae 1 of legs.3(4). Coxa 2 bears finger-shaped projections, as long as half diameter to diameter ofcoxa 2 ................................................................................. *A. ramipes (p. 118)4(3). Projections on coxa 2 very short ...................................... *A. glabroides (p. 119)*Ascorhynchus glaberrimum Schimkewitsch, 1913(Pl. XVII, figs. 1–5)Schimkewitsch, 1913: 242, pl. 3, figs. 8–14; Nakamura, 1987: 29–30, pls. 25, 26.A. glaberrimum occurs off the western and eastern coasts of Japan from shallowwaters to 300 m depth.*Ascorhynchus ramipes (Böhm, 1879)(Pl. XVII, figs. 6–11)Böhm, 1879a: 56, fig. 1 (Gnaptorhynchus ramipes); Nakamura, 1987: 31–32, pl. 28.A. ramipes is a widespread species. It inhabits the Indian Ocean, the Gulf ofSiam, the East China and Yellow seas, and the Sea of Japan; it also occurs near thewestern and eastern coasts of Japan in 10–200 m depths.118

*Ascorhynchus glabroides Ortmann, 1891(Pl. XVI, figs. 3, 4)Ortmann, 1891: 160, pl. 24, fig. 3a, b; Hedgpeth, 1949: 291, 293; Utinomi, 1971: 333.A. glabroides provisionally is endemic from the Sea of Japan; it occurs in70–250 m depths.*III. Family CALLIPALLENIDAE Hilton, 1942Trunk elongated or compact, segmented or with fused segments. Chelifore 2-segmented; scape straight, cylindrical; chela almost equal to scape, with fingers, orsmall, vestigial, without fingers. Palp absent or consists of 1–4 segments. Oviger 9–10-segmented in both males and females, provided with compound spines or setae ondistal segments.KEY TO THE GENERA OF THE FAMILY CALLIPALLENIDAE1(2). Trunk disk-shaped, unsegmented; palp absent; propodal sole bears only 2 spines,of which 1st very large, situated in middle; second spine smaller, situated infront of first one .................................................................... *Decachela (p. 119)2(1). Trunk segmented, compact, or elongated.3(4). Trunk compact; lateral processes placed closely together; chelifore shorter thanproboscis; fingers of chela without teeth; palp 3-segmented in both sexes .................................................................................................... *Bradypallene (p. 121)4(3). Trunk elongated; lateral processes separated by intervals; chelifore longer thanproboscis; fingers with teeth on inner margins; palp absent or present only inmales.5(6). Palp present only in males, 2-segmented; auxiliary claws absent ....................................................................................................................... *Propallene (p. 121)6(5). Palp absent in both sexes; auxiliary claws present ............. *Callipallene (p. 122)*Genus Decachela Hilton, 1939Type species: Decachela discata Hilton, 1939.Animal small, length no more than 3 mm. Trunk disk-shaped, unsegmented, withsolid integument. Chelifore short, 2-segmented; chela vestigial, without fingers. Nopalps. Oviger 10-segmented, with very small distal segments, without compoundspines. Proboscis cylindrical. Ocular tubercle low. Legs robust; propodus bears only 2spines in centre of sole: adults have one very large spine with one smaller spine infront of it; juveniles have both spines equal in length.There are 2 species in the genus.KEY TO THE SPECIES OF THE GENUS DECACHELA1(2). Trunk smooth; lateral processes placed closely together; chelifore only slightlylonger than proboscis ............................................................ *D. discata (p. 120)119

2(1). Lateral processes and coxae 1 of legs bear several conical, truncated tubercles,larger ones of which have 2–4 tops; lateral processes separated by narrowintervals; chelifore slightly shorter than proboscis ................ *D. dogieli (p. 120)*Decachela discata Hilton, 1939(Pl. XVIII, figs. 1, 2)Hilton, 1939: 34; Hedgpeth, 1949: 280, fig. 37.Type specimen of this species was found off the Californian coast. Hedgpeth(1949) identified it in the samples collected during the R/V Albatross’ voyage in 1906near the western shore of Hokkaido Island at a depth of 100 m.*Decachela dogieli Losina-Losinsky, 1961(Pl. XVIII, figs. 3–6)Losina-Losinsky, 1961: 88–90, fig. 16; Hong & Kim, 1987: 155–158, figs. 13, 14.Description. Trunk of males disk-shaped, with firm opaque integument,unsegmented. Frontal margin of cephalic segment expanded and bears irregularshapedtubercles without spines. Ocular tubercle low with unpigmented eyes androunded top, situated medially on anterior part of cephalic segment. Proboscis short, 3times shorter than trunk, broad, cylindrical; cephalic segment projections overhangbase of proboscis. Abdomen more than twice longer than proboscis, cylindrical,reaching beyond distal ends of coxae 2 of 4th legs. Lateral processes broad, placedalmost closely together; each provided with several small tubercles in middle and 3tubercles, some of which with two tops, on distal margin. Chelifore shorter thanproboscis; scape robust, bear several tubercles distally; chela vestigial, withoutfingers. Oviger 10-segmented; segment 1 oval, broader than its own length; segment 3longest; segments 4 and 5 equal; segments 7 and 8 short and broad; 2 distal segmentsvery small, thin, cylindrical. Legs short, with robust, very short segments; coxa 1 bearsseveral large tubercles, of which one has several tops; coxa 2 ventrally bears talltubercle with genital pore and, dorsally, several small tubercles with spines; femur hasone tall tubercle dorsally and several small ones laterally; tarsus so small that can beseen only from ventral side; propodus slightly shorter than tibia 2; distal end of solearmed with large spine, forming kind of chela in combination with terminal claw; solealso bears small spine in front of large one. Main claw robust, curved, as long as 1/2 ofpropodus. Measurements of male: trunk 2.0 mm, proboscis 0.63 mm, abdomen4.12 mm.Females of D. dogieli differ from males in absence of large tubercles on lateralprocesses and shorter ovigers, distal segments of which armed with only severalsmooth setae.Geographical distribution. First specimens of D. dogieli were found on thestarfish Pteraster, taken in the Sea of Okhotsk off the northern tip of Sakhalin Islandat a depth of 84 m. Later Hong and Kim (1987) found D. dogieli in the Sea of Japanoff the Korean coast in the ambulacra of Pteraster.120

*Genus Bradypallene Kim & Hong, 1987Type species: Bradypallene espina Kim & Hong, 1987.Trunk smooth, compact, segmented. Ocular tubercle low, situated on anteriorpart of cephalic segment. Proboscis robust, with expanded flat apex. Chelifore 2-segmented; chela with fingers; fingers lack teeth. Palp short, 3-segmented in bothsexes. Oviger 10-segmented, in both sexes without compound spines and terminalclaws. Legs smooth; propodus without heel and spines on sole. Main clawrudimentary; auxiliary claws well developed, slightly longer than main claw; cementgland situated on dorsal side of femur.The genus is monotypic.*Bradypallene espina Kim & Hong, 1987(Pl. XIX, figs. 1–4)Kim & Hong, 1987: 272–276, figs. 1, 2.Bradypallene espina provisionally is endemic from the Sea of Japan, it wasfound in the south-western part of this sea, near Ullung-do Island (37˚28′N, 130˚51′E)at depths of 5–7 m.*Genus Propallene Schimkewitsch, 1909Type species: Pallene longiceps Böhm, 1879.Trunk elongated, completely segmented; cephalic segment shorter than 3 otherscombined; its anterior part moderately expanded; neck of medium length, ratherbroad. Lateral processes separated by intervals. Ocular tubercle low, situated opposite1st lateral processes; eyes developed. Abdomen conical, with notch on end. Chelifore2-segmented; scape almost equal to proboscis, chela oval, elongated; fingers ofmedium length, thin, with teeth on inner margin. Palp only in males, 2-segmented.Oviger 10-segmented both in males and females; segment 5 in males bears bladeshapedprojection distally; 4 distal segments provided with one row of compoundspines, each spine denticulate, with larger denticles in basal part and smaller in upperpart; no terminal claw. Legs long; male femur bears cement gland pores; tarsus verysmall; propodus with isolated basal spines; no heel and auxiliary claws. Genital poreson 3rd and 4th legs in males, on all legs in females.Only one species of this genus is found in the Sea of Japan.*Propallene longiceps (Böhm, 1879)(Pl. XIX, figs. 5–9)Böhm, 1879a: 59 (Pallene longiceps); Nakamura, 1987: 14, pl. 11 (Propallenelongiceps).P. longiceps is an endemic of the Sea of Japan. It is found in depths from thelittoral zone to 40 m.121

*Genus Callipallene Flinn, 1929Type species: Pallene brevirostris Jonston, 1837.Ocular tubercle placed in posterior part of cephalic segment of trunk. Probosciscylindrical. Chelifore 2-segmented; scape elongated; chela short; fingers armed withteeth on inner margin. Palp absent in both sexes. Segment 5 of oviger distally bearsspade-shaped projection. Oviger without claw. Legs with auxiliary claws.There is one species of the genus in the Sea of Japan.*Callipallene phantoma amaxana (Ohshima, 1933)(Pl. XIX, figs. 10–12)Ohshima, 1933: 216–219, figs. 8–12; Hong & Kim, 1987: 153 (Pallene amaxana);Utinomi, 1971: 322–323 (Callipallene phantoma amaxana).C. phantoma amaxana has been recorded in the Strait of Malacca and near thecoast of Japan, from the high sublittoral zone to 200 m depth.IV. Family PHOXICHILIDIIDAE Sars, 1891Trunk in most species elongated, in other ones compact, in most speciessegmented, in others – several or all segments fused. Cephalic segment has short orlong projection over base of proboscis, bearing chelifores anteriorly and oculartubercle dorsally. Proboscis inserts to this projection ventrally. Chelifore shorter orlonger than proboscis, 2-segmented, chelas with fingers. Palps absent. Oviger only inmales, 5–9-segmented, without terminal claw, with simple spines or without spines.KEY TO THE GENERA OF THE FAMILY PHOXICHILIDIIDAE1(2). Chelifore much longer than proboscis ............................. 1. Pycnosomia (p. 122)2(1). Chelifore equal to proboscis or longer; fingers of chela reach mouth.3(4). Oviger in males 5-segmented; auxiliary claws well developed ..................................................................................................................... *Phoxichilidium (p. 124)4(3). Oviger in males 6-segmented; auxiliary claws rudimentary or absent ....................................................................................................... 2. Anoplodactylus (p. 124)1. Genus Pycnosomia Losina-Losinsky, 1961Type species: Pycnosoma strongylocentroti Losina-Losinsky, 1933.Trunk elongated, cylindrical, with firm integument, without articulation on dorsalside or partially articulated. Cephalic segment broad, square. Ocular tubercle hardlyrises over dorsal surface. Proboscis cylindrical. Lateral processes separated byintervals. Abdomen short, thick. Chelifore 2-segmented; fingers of chela much shorterthan proboscis. No palps. Oviger only in males, 5-segmented; terminal claw absent.Legs robust, strongly curved, with short segments. Main claw present; auxiliary clawsabsent. Tubercles with genital pores present in males on coxae 2 of 3rd and 4th legs, infemales on all legs.122

Originally, Losina-Losinsky (1933) gave this genus name Pycnosoma, butreplaced it for Pycnosomia in his work of 1961, because the name Pycnosoma turnedout to have been preoccupied (Insecta).One species of the genus is found in the Sea of Japan.1. Pycnosomia strongylocentroti (Losina-Losinsky, 1933)(Pl. XVIII, figs. 7–11)Losina-Losinsky, 1933: 43–47, fig. 1 (Pycnosoma strongylocentroti); Hilton, 1942b: 40(Pigrogromitus robustus); Losina-Losinsky, 1961: 86; Turpaeva, 1994: 133–134 (Pycnosomiastrongylocentroti).Description. Trunk robust, elongated, with firm integument. Segments of trunkfused completely or partially on dorsal side, but separated by articulation lines onlateral and ventral sides. Lateral processes about as long as broad, separated by 0.2 to0.5 their own diameters. Ocular tubercle almost not rising over surface, situated nearerto anterior margin of cephalic segment; eyes well developed, entirely or partiallypigmented. Proboscis slender, cylindrical, much longer than half of trunk, directedobliquely downward. Abdomen thick, short, protruded horizontally. Chelifore almosttwice shorter than proboscis, smooth; scape cylindrical; chela smaller than scape;fingers without teeth. Oviger 6-segmented, devoid of setae; segment 6 longest;segment 3 shortest, others equal to one another; segment 6 smooth, swollen distally.Legs less than 1.5 times as long as whole body (with proboscis and abdomen), robust,unarmed; femur longest; tibia 1 slightly shorter than femur; tibia 2 shorter than tibia 1;tarsus short, caliciform; propodus as long as tibia 2, robust, curved, with welldevelopedheel, which bears up to 8 strong, but short spines. Main claw as long as halfof propodus, strong, curved. No auxiliary claws. Coxae 2 in both sexes ventrally beartall tubercles, which are broader in females. Measurements of holotype: trunk1.75 mm, proboscis 1.65 mm, abdomen 0.6 mm, chelifore 1.25 mm, oviger 2.95 mm,leg 5.47 mm.Remarks. Recent investigations of supplementary material allows someadditions to the foregoing description to be made. Usually the palps are vestigial, inshape of oval tubercles on both sides of the proboscis. The ocular tubercle in the Seaof Japan individuals is relatively tall, up to as tall as half of the diameter of thetubercle at the base. The genital gland is unusual for the pycnogonids. All longsegments of the legs are robust and swollen in the middle, especially in females, likeat the figure from the Losina-Losinsky’s book (1933). In females collected near IturupIsland (Kurils) and in the Sea of Japan maturing egg masses were visible even in tibiae2 of the legsGeographical distribution. This species was originally found on the sea urchinsStrongylocentrotus sp., collected in the northern part of the Sea of Japan (the TatarStrait) at a depth of 70 m. Later it was recorded in the Bering Sea, near the AleutianIslands and in the Gulf of California, on the rim of the hydrothermal area Guaymas(Losina-Losinsky, 1961; Turpaeva, 1994). It was found also in Peter the Great Bay onthe sea urchin Strongylocentrotus cf. pallidus at a depth of 155 m.Vertical distribution. P. strongylocentroti occurs in depths from 2 to 2000 m.123

*Genus Phoxichilidium Milne-Edwards, 1840Type species: Nymphon coccineum Jonston, 1828.Trunk cylindrical, elongated, segmented; cephalic segment has small projectionover base of proboscis and bears short processes of ovigers; relatively short lateralprocesses separated by broad intervals. Proboscis short, cylindrical, attached to ventralside of cephalic segment, pointed obliquely downward. Ocular tubercle situated overproboscis base. Abdomen short. Chelifore well developed, smooth, 2-segmented;scape long, cylindrical; chela shorter than scape; fingers curved, short with smoothinner margin, or longer, with teeth on inner margin. Oviger in males 5-segmented,short, without claw; segment 5 bears 2 rows of hook-shaped spines. Legs rather long;tarsus small; propodus well developed, curved, with basal spines. Main claw large;auxiliary claws present.One species of the genus is found in the Sea of Japan.124*Phoxichilidium ungellatum Hedgpeth, 1949(Pl. XX, figs. 1–4)Hedgpeth, 1949: 281–283, fig. 38; Losina-Losinsky, 1961: 52, pl. 1; Turpaeva, 1990: 17–18, fig. 1 (1–3).P. ungellatum is widely distributed in the north-western part of the PacificOcean. It occurs off the Aleutian, Kuril, and Japan islands, in the Sea of Japan nearOki Island, and in Toyama Bay. It is found in depths from 150 to 1000 m.2. Genus Anoplodactylus Wilson, 1878Type species: Phoxichilidium petiolatum Kroyer, 1844–1845.Trunk slender and elongated or robust and compact, distinctly or not distinctlysegmented. Cephalic segment projects over base of proboscis. In species withelongated trunk this projection usually thin, long, with expanded anterior part, andlateral processes separated by broad intervals. In species with compact trunk cephalicsegment projection short and broad, lateral processes robust, separated by narrowintervals or placed in contact. Ocular tubercle situated near frontal margin, varies inshape and height. Proboscis cylindrical or swollen medially or distally. Abdomenshort, in many species shorter than 4th lateral processes, directed obliquely upward.Chelifore 2-segmented; scape straight, rather thin, usually shorter than proboscis;chela may be longer than proboscis, with fingers, in some species armed withirregularly placed teeth. Palps absent or present in shape of small tubercles, or 1-segmented appendages. Oviger 6-segmented (or even 7–9-segmented, see:Schimkewitsch, 1929: 205), short; distal segment very small, well separated frompenultimate one, bears setae or small spines. Legs long, slender, covered with setae, insome species with spines; propodus has heel with large or sometimes small spines.Propodal sole bears small spinules; in several species propodal sole bears chitinouscutting lamina, transversely striped, long or short, adjoining main claw with one end.Main claw long, curved or almost straight; auxiliary claws absent, or rudimentary andhardly visible. Genital pores in females on 2nd coxae of all legs, in males on two distalpairs of legs, on tops of tubercles or on flat surface. Cement glands situated on femur,

open through one long or short duct, or through several slits or pores on dorsal side offemur medially or proximally.One species has been found in the Russian waters of the Sea of Japan. The Keyalso includes four more species which can be found in this region in future. The recordof Anoplodactylus inermis for Peter the Great Bay (Turpaeva, 2006) was made bymistake; as it turned out, that male specimen was collected not in the Sea of Japan, butin the Indian Ocean.KEY TO THE SPECIES OF THE GENUS ANOPLODACTYLUS1(2). Trunk rounded, unsegmented .......................................... 1. A. pygmaeus (p. 125)2(1). Trunk partially or completely segmented.3(6). Lateral processes smooth, without tubercles or spines; fingers of chela bear smallteeth on inner margins.4(5). Anterior part of cephalic segment has long narrow projection over base ofproboscis; intervals between lateral processes noticeably broader than processes’diameters; proboscis long, cylindrical, with smooth rounded apex; male cementgland opens through short tube in middle of femur .............. *A. gestiens (p. 126)5(4). Cephalic segment projection short and broad; intervals between lateral processesnoticeably narrower than diameters of processes; proboscis short, barrel-shaped,with flat apex, bearing broad conical tubercles; cement gland opens through 5–8transverse slits situated proximally on dorsal side of femur ...... ...................................................................................................................... *A. pycnosoma (p. 126)6(3). Each lateral process bears one tubercle with spine on top on distal margin ofdorsal side; fingers of chela without teeth on inner margin.7(8). Lateral processes placed in contact to each other, sometimes contiguous; legsbear rudimentary auxiliary claws; cement gland opens through very short duct ...................................................................................... *A. viridintestinalis (p. 126)8(7). Lateral processes separated by about 1/3 their diameters; legs lack auxiliaryclaws; cement gland opens on top of conical tubercle, as tall as half diameter offemur ................................................................................... *A. carnatus (p. 127)1. Anoplodactylus pygmaeus (Hodge, 1864)(Pl. XXII, figs. 1–5)Hodge, 1864: 116, pl. 13, figs. 16, 17 (Pallene pygmaea); Dohrn, 1881: 34, 36, 56, 76,99, 181–184, pl. 12, figs. 19–22 (Phoxihilidium exiguum); Losina-Losinsky, 1929: 551–553,fig. 5; 1933: 47–49, fig. 2; 1961: 52, pl. 1 (Halosoma derjungini); Hedgpeth, 1948: 224–225;Stock, 1954: 77; Turpaeva, 2006: 453–454, fig. 5 (Anoplodactylus pygmaeus).Description. Trunk almost rounded, shield-shaped, unsegmented, without setae.Lateral processes contiguous proximally; each bears one tubercle with spine on distalmargin. Cephalic segment has short and narrow projection over base of proboscis.Ocular tubercle tall, conical, with "shoulders", situated a little distally from frontalmargin of cephalic segment, in its narrow part; eyes oval, pigmented. Proboscis twiceshorter than trunk, thick; its length slightly more than its diameter, noticeably broaderthan frontal part of cephalic segment. Abdomen short, thick, erect. Cheliforesrelatively long; scapes of both chelifores placed close to each other, reach somewhat125

eyond proboscis; chelas much shorter than scapes, directed downward; fingers thinand weak, with minute hair-looking denticles. Both segments of chelifore armed withsparse short setae. Palps in shape of rudimentary tubercles, situated on both sides ofcephalic segment. Oviger 6-segmented, slightly longer than proboscis; longestsegments 2 and 3 subequal; segment 4 shorter than segment 3; segment 5 shorter thansegment 4; segment 6 twice shorter than segment 5, oval, bears brush of simple thinspines ventrally. Legs 2.5 times longer than trunk with proboscis and abdomen; coxa 1short, expanded distally, on lateral sides bears 2 small tubercles with spines on tops;coxa 2 has small swelling with genital pore ventrally and 2 tubercles with spinesdorsally; femur longest of all segments, bears short cement gland duct pointed distally;tibia 1 shorter than femur; tibia 2 shorter than tibia 1; tarsus very small; propodusequal in length to tibia 2, curved, has well-developed heel, bearing 2–3 basal spines;propodal sole bears several small spine-like setules. Main claw strong, reaching up to2/3 of propodus; auxiliary claws absent. All legs covered with setae, more dense onlongest segments; each long segment bearing also one long seta on distal end.Measurements of holotype: body with proboscis and abdomen 1.00 mm, proboscis0.3 mm, chelifore’s scape 0.3 mm, oviger 1.24 mm, 1st leg 2.71 mm.Geographical distribution. A. pygmaeus is a boreal-subtropical species,widespread in the Atlantic Ocean, from Sweden to the western Africa and fromVirginia to Florida, in the Mediterranean, Red, Caribbean seas, and the Gulf ofMexico. It has been recorded in the Pacific Ocean without any notice of a site. In theSea of Japan the species is registered in Peter the Great Bay and in Possjet Bay.*Anoplodactylus gestiens (Ortmann, 1891)(Pl. XX, figs. 5–8)Ortmann, 1891: 166, pl. 24, fig. 8a–d (Phoxichilidium gestiens); Nakamura, 1987: 15–16,pl. 12 (Anoplodactylus gestiens).A. gestiens provisionally is endemic from the waters surrounding the JapaneseIslands. It is distributed mainly along the eastern coast of Japan; it is likely to be foundin the eastern part of the Sea of Japan and in Peter the Great Bay. It occurs from thelittoral zone to 479 m depth.*Anoplodactylus pycnosoma (Helfer, 1938)(Pl. XX, figs. 9–12)Helfer, 1938: 176–177, fig. 7 (Peritrachia pycnosoma); Nakamura & Child, 1983: 50;Hong & Kim, 1987: 161 (Anoplodactylus pycnosoma).It is a widespread high sublittoral species. It occurs in the eastern and westernparts of the Indian Ocean (near Tanzania and the western part of Australia), near thecoast of Japan (Sagami Bay) and in the southern part of the Sea of Japan.*Anoplodactylus viridintestinalis (Cole, 1904)(Pl. XXI, figs. 1–6)Cole, 1904: 286, pl. 14, fig. 11, pl. 24, figs. 6–8, pl. 25, figs. 1–4 (Halosomaviridintestinalis); Kim, 1986: 3, fig. 2; Kim & Hong, 1986: 44; Hong & Kim, 1987: 161(Anoplodactylus viridintestinalis).126

A. viridintestinalis is a littoral and high sublittoral species. It is distributed in theeastern part of the Pacific Ocean from the Californian shore up to Panama. It has alsobeen found in the southern part of the Sea of Japan near Dagelet Island and HornetIsland.*Anoplodactylus carnatus Nakamura & Child, 1983(Pl. XXI, figs. 7–10)Nakamura & Child, 1983: 42–44, fig. 14; Nakamura, 1994: 15.Anoplodactylus carnatus provisionally is endemic from the waters surroundingthe Japanese Islands. It was found near the eastern coast of Japan in Suruga andSagami Bays at depths of 7–15 m, and in the Sea of Japan in the littoral zone ofToyama Bay.*V. Family COLOSSENDEIDAE Hoek, 1881Trunk segmented or unsegmented, sometimes with traces of articulation lines.Lateral processes separated by intervals. Neck absent. Ocular tubercle situatedanteriorly on cephalic segment. Adults usually lack chelifores; in some juveniles 3-segmented chelifores present (adults of some deep-water species have similar 3-segmented chelifores (Turpaeva, 1989). Palp 8–9-segmented. Oviger 10-segmented,with terminal claw and compound spines, placed in several rows on 4 distal segments.Legs long; propodus lacks heel. Coxae 2 of all legs bear genital pores in both malesand females.Two genera are represented in the Sea of Japan. They presumably occur in theRussian waters, too.KEY TO THE GENERA OF THE FAMILY COLOSSENDEIDAE1(2). Trunk unsegmented, eyes not developed ........................... *Colossendeis (p. 127)2(1). Trunk segmented, eyes large, pigmented ............................. *Hedgpethia (p. 128)*Genus Colossendeis Jarzynsky, 1870Type species: Colossendeis borealis Jarzynsky, 1870.Trunk unsegmented; cephalic segment slightly larger than next segment.Proboscis robust, usually straight, but in some species tapers toward end and may benoticeably longer than trunk. Palp 8–9-segmented. Oviger with false chela, or, moreoften, has normal shape. Four pairs of legs present; tarsus and propodus equal inlength, or tarsus longer; no cement glands on femur; no auxiliary claws.Hedgpeth (1949) recorded two species of the genus Colossendeis in the waterssurrounding Japan, namely, C. nasuta Hedgpeth and C. macerrima Wilson. Hedgpetherroneously named the latter species C. japonica Hoek. Both species were found nearthe south-western coast of Kyushu Island at 700–800 m depths. Assuming theoccurrence of these two species in the deep waters of the Sea of Japan, a key for theiridentification is given below.127

KEY TO THE SPECIES OF THE GENUS COLOSSENDEIS1(2). Ocular tubercle hardly rises over surface; proboscis straight, almost cylindrical;segment 4 of palp longer than segment 2; tarsus longer than propodus ....................................................................................................... *C. macerrima (p. 128)2(1). Ocular tubercle rather tall, conical; proboscis long, swollen medially, taperingnoticeably in distal third; segment 4 of palp almost twice shorter than segment2; tarsus and propodus subequal ............................................ *C. nasuta (p. 128)*Colossendeis macerrima Wilson, 1881(Pl. XXIII, figs. 1–3)Wilson, 1881: 246–247, pl. 1, fig. 2, pl. 4, figs. 9–12, pl. 5, fig. 32; Fry & Hedgpeth,1969: 53, figs. 7, 8; Stock, 1975: 985–987, fig. 11a–b.C. macerrima are large animals, greatly varied in proportions (Fry & Hedgpeth,1969). The distribution range is wide: C. macerrima occurs in the bathyal zones of thePacific, Atlantic and Indian Oceans.*Colossendeis nasuta Hedgpeth, 1949(Pl. XXIII, figs. 4–6)Hedgpeth, 1949: 302–303, fig. 46e–h.Only one find has been recorded up to now, south-west of Kyushu Island at adepth of 710 m.*Genus Hedgpethia Turpaeva, 1973 2Type species: Colossendeis articulata Loman, 1908.Trunk elongated, segmented; segment 1 longest. Lateral processes separated bynot more than their diameters. Proboscis robust, much longer than trunk, greatlyexpanded medially, in some species with short “neck”. Abdomen very small, situatedalmost ventrally and pointed vertically downward. Chelifores absent; palps andovigers 10-segmented.One species is found in the Sea of Japan.*Hedgpethia californica chitinosa (Hilton, 1943)(Pl. XXII, figs. 6–11)Hilton, 1943: 4; Hedgpeth, 1949: 301, fig. 47e–h; Losina-Losinsky & Turpaeva, 1958:23–26, fig. 1; Losina-Losinsky, 1961: 109; Nakamura, 1987: 36–37, pl. 33 (Colossendeischitinosa); Turpaeva, 1973: 186–189, pl. 3 (Hedgpethia californica).2 A.F. Pushkin (1990: Trudy ZIN AN SSSR, V. 218) established the family Hedgpethiidae forthe genera Hedgpethia and Rhopalorhynchus. – Editorial note.128

Description. Trunk smooth, oval, elongated, segmented. Segments 1–3 of trunkdorsodistally bear chitinous thickenings in shape of ridges with small conical tuberclesin middle. Some specimens have small tubercles on sides of frontal margin. Lateralprocesses shorter than trunk width, separated by less than their own diameters. Oculartubercle with tall conical top, situated medially on cephalic segment; eyes pigmented,swollen, situated lower than middle of ocular tubercle. Proboscis more than 1.5 timeslonger than trunk, robust, curved downward, tapered towards both ends, with short“neck”. Abdomen very short, pointed downward. Palp 1/3 longer than proboscis, withsparse short setae on distal segments; segment 3 longest; segment 5 about twiceshorter than segment 3; of all distal segments segment 6 shortest and segment 8longest. Oviger 3 times longer than trunk; segments 4 and 6 equal; distal segmentsshort, thick and slightly curved in shape of spiral, bear 7 rows of long lanceolatecompound spines ventrally; segment 10 has false chela formed by strong terminalclaw and large spine with denticulate edge opposed to it. Legs 8 times longer thantrunk; coxae short; femur more than twice longer than trunk; tibia 1 longer and thinnerthan femur; tibia 2 slightly shorter than femur; tarsus and propodus of almost equallength, straight (in some specimens propodus slightly curved), bear row of short setaeon sole. Main claw equal to about 1/4 of propodus length, gently curved; auxiliaryclaws absent. Measurements: trunk 5.5 mm, proboscis 8.9 mm, palp 14.25 mm, oviger16.55 mm, 3rd leg 43.5 mm.Remarks. C. californica is a greatly polymorphic species. The variablecharacters are: the general measurements and proportions of the body, the shape andheight of the ocular tubercle, the size of frontal tubercles, and also some othercharacters. The study of polymorphism in this species made it possible to divide it intothree subspecies: H. claifornica californica, inhabiting waters off the western coast ofthe South America, H. californica bicornis from the Sea of Okhotsk, and H.californica chitinosa.Geographical distribution. H. californica chitinosa is widespread in the northwesternpart of the Pacific Ocean: in the Bering Sea, off the Aleutian Islands, near theeastern coast of Japan up to the Tsushima Strait, and in the Sea of Japan nearHokkaido Island.Vertical distribution. It is found in 20–3500 m depths.VI. Family PYCNOGONIDAE Wilson, 1878Trunk segmented, broad, compact. No chelifores; no palps. Only male ovigerwith terminal claw and compound spines. Four or five pairs of legs present.Species of one genus inhabit the Sea of Japan.1. Genus Pycnogonum Brunnich, 1764Type species: P. littorale (Stroem, 1762).Trunk flattened dorsoventrally, often with conical truncated tubercles along middorsalline and on lateral processes. Lateral processes short, separated by smallintervals, sometimes placed quite close to each other, but still separated. Proboscisconical or almost conical, smooth, protruded horizontally or obliquely down.129

Abdomen cylindrical, pointed horizontally. Ocular tubercle low, situated on anteriormargin of cephalic segment. Oviger present not in all species. Legs short, robust, withsparse setae; tarsus very short; propodus curved, without basal spines. Main claw welldeveloped; auxiliary claws small, rudimentary, or absent.The genus Pycnogonum is divided into three subgenera (Stock, 1968):1. Subgenus Pycnogonum, type species P. littorale (Stroem, 1762); oviger in malesconsists of 8–9 segments, with terminal claw.2. Subgenus Retroviger Stock, type species P. sivertseni Stock, 1955; oviger in malesconsists of 4–7 segments, terminal claw absent.3. Subgenus Nulloviger Stock, type species P. africanum Calman 1938; no ovigers inmales.Two species of the subgenus Pycnogonum have been found in the Sea of Japan.KEY TO THE SPECIES OF THE SUBGENUS PYCNOGONUM1(2). Mid-dorsal line bears tall tubercles; lateral processes smooth; proboscis narrow,with elongated apex; no auxiliary claws ............................... 1. P. tenue (p. 130)2(1). Mid-dorsal line bears very low tubercles; lateral processes bear similar lowtubercles (mostly conspicuous on 4th lateral processes); proboscis thick, withflattened apex; auxiliary claws very small ........................ *P. koreanum (p. 130)1. Pycnogonum (Pycnogonum) tenue Slater, 1879(Pl. XXIII, figs. 7–9)Slater, 1879: 283; Schimkewitsch, 1929: 15; Losina-Losinsky, 1961: 53 (Pycnogonumlittorale var. tenue); Kishida, 1927: 989, fig. 1905; Nakamura, 1987: 37, fig. 34 (Pycnogonumtenue).Description. Surface of trunk covered with small rounded tubercles. Trunkcompletely segmented. Mid-dorsal tubercles tall, armed with several short setae.Lateral processes more broad than long, separated by narrow intervals, smooth. Oculartubercle rounded; eyes pigmented, 2 anterior eyes larger than 2 posterior ones.Proboscis long, narrow, with elongated apex. Oviger 9-segmented, terminal clawcurved, longer than distal segment. Auxiliary claws absent.Geographical distribution. P. tenue occurs mainly in the East China Sea, nearthe eastern coast of Japan and in the southern part of the Sea of Japan. A subspecies P.littorale tenue (Slater) has been found in the Russian waters of the Sea of Japan.Vertical distribution. The species is distributed in depths of 27–300 m.*Pycnogonum (Pycnogonum) koreanum Kim & Stock, 1984(Pl. XXIII, figs. 10–12)Kim & Stock, 1984: 685–687, figs. 1–6; Kim & Hong, 1986: 50; Hong & Kim, 1987:161.P. koreanum was originally found in the littoral zone of Ulreung Island (on sandyground with stones). Later, it was periodically recorded on hard bottoms near theeastern, southern, and western coasts of the South Korea.130

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Turpaeva, E.P. 2004b. Shallow-water sea spiders (Pycnogonida) from the Kuril,Commander and Yamskii islands. 3. Nymphonidae. Report 2 // Zool. Zhurnal.V. 83, N 10. P. 1229–1236. (In Russian).Turpaeva, E.P. 2006. Shallow-water sea spiders (Pycnogonida) from the Kuril,Commander, and Yamskii islands. 4. Phoxchilidiidae family // Zool. Zhurnal.V. 85 (4). P. 448–461 (In Russian).Utinomi, H. 1951. On some pycnogonids from the sea around Kii Peninsula // Publ.Seto Mar. Biol. Lab. V. 1. P. 159–168.Utinomi, H. 1954. The fauna of Akkeshi Bay. XIX. Littoral Pycnogonida // Publ.Akkeshi Mar. Biol. Stat. V. 3. P. 1–28.Utinomi, H. 1955. Report on the Pycnogonida collected by the Soyo-Maru Expeditionmade on the continental shelf bordering Japan during the years 1926–1930 //Publ. Seto Mar. Biol. Lab. V. 5. P. 1–42.Utinomi, H. 1971. Records of Pycnogonida from shallow waters of Japan // Publ. SetoMar. Biol. Lab. V. 18. P. 317–347.Wilson, E.B. 1881. Report on the Pycnogonida. Reports on the results of dredging,under the supervision of Alexander Agassiz, in the Gulf of Mexico, 1877–78, bythe U.S. coast survey steamer Blake, etc. // Bull. Mus. Comp. Zool. Harvard,V. 8, N 12. P. 239–256.134

Plate I. Schematic display of the external morphology of Pycnogonida (fig. 1 – bodywith appendages; fig. 2 – 1st appendage (chelifore). 1 – cephalic segment ofbody; 2 – ocular tubercle; 3 – dorsal ridge of segment of trunk; 4 – lateralprocess; 5 – proboscis; 6 – abdomen; 7 – scape; 8 – palm of chela; 9 – immovablefinger; 10 – movable finger; 11 – 2nd appendage (palp); 12 – 3rd appendage(oviger); 13 – segments 1–3 of leg (coxae: coxa 1, coxa 2, and coxa 3); 14 –segment 4 of leg (femur); 15 – segment 5 of leg (tibia 1); 16 – segment 6 of leg(tibia 2); 17 – segment 7 of leg (tarsus); 18 – segment 8 of leg (propodus); 19 –main claw; 20 – auxiliary claws135

Plate II. Nymphon grossipes (from Sars, 1891): 1 – trunk, dorsal view; 2 – trunk, lateralview; 3 – ocular tubercle; 4 – chela; 5 – palp; 6 – distal segments of leg.Nymphon brevirostre (from Sars, 1891): 7 – trunk, dorsal view; 8 – trunk, lateralview; 9 – ocular tubercle; 10 – chela; 11 – palp; 12 – compound spine; 13 – distalsegments of leg136

Plate III. Nymphon bisseratum (from Losina-Losinsky, 1961): 1 – trunk, dorsal view;2 – ocular tubercle; 3 – chela; 4 – palp; 5 – compound spines; 6 – distal segmentsof leg.Nymphon striatum (from Losina-Losinsky, 1933): 7 – trunk, dorsal view; 8 –trunk, lateral view; 9 – chela; 10 – palp; 11 – compound spine; 12 – distal segmentsof leg137

Plate IV. Nymphon longitarse longitarse (from Sars, 1891): 1 – trunk, dorsal view;2 – trunk, lateral view; 3 – chela; 4 – palp; 5 – distal segments of leg.Nymphon longitarse brevicollis (from Losina-Losinsky, 1935): 6 – trunk, dorsalview; 7 – ocular tubercle; 8 – chela; 9 – palp; 10 – compound spines and claw ofoviger; 11 – distal segments of leg.Nymphon longitarse elongatum (from Hedgpeth, 1949): 12 – chela; 13 – palp;14 – compound spine; 15 – distal segments of leg138

Plate V. Nymphon hodgsoni: 1 – trunk, dorsal view; 2 – ocular tubercle, lateral view;3 – chela and portions of fingers: immovable (upper) and movable (lower); 4 –palp; 5 – distal part of segment 10 of oviger, with terminal claw and compoundspine; 6 – distal segments of 3rd leg.Nymphon braschnikowi: 7 – trunk, dorsal view; 8 – ocular tubercle, lateral view;9 – chela of female; 10 – chela of male and portion of movable finger; 11 – palp;12 – distal part of segment 10 of oviger, with terminal claw and compoundspines; 13 and 14 – distal segments of legs of female (13) and of juvenile (14)139

Plate VI. Nymphon japonicum (from Nakamura, 1987): 1 – trunk, dorsal view; 2 –trunk, lateral view; 3 – chela; 4 – palp; 5 – oviger; 6 – compound spine; 7 – terminalclaw of segment 10 of oviger; 8 – distal segments of leg.Nymphon uniunguiculatum (from Losina-Losinsky, 1933): 9 – trunk, dorsalview; 10 – ocular tubercle; 11 – chela; 12 – palp; 13 – distal segments of oviger;14 – compound spines; 15 – coxae 1, 2, and 3 of leg; 16 – distal segments of leg140

Plate VII. Nymphon micropedes (from Hedgpeth, 1949): 1 – trunk, dorsal view; 2 –chela; 3 – palp; 4 – compound spines; 5 – distal segments of leg.Nymphon kodanii (from Hedgpeth, 1949): 6 – trunk, dorsal view; 7 – chela; 8 –palp; 9 – segment 10 of oviger and compound spine; 10 – distal segments of leg141

Plate VIII. Nymphon stocki (from Utinomi, 1955): 1 – trunk, ventral view; 2 – chela;3 – palp; 4 – segments 8, 9, and 10 of oviger; 5 – distal segments of leg.Nymphon albatrossi (from Hedgpeth, 1949): 6 – trunk, dorsal view; 7 – chela;8 – palp; 9 – compound spine; 10 – distal segments of leg142

Plate IX. Achelia borealis: 1 – male, dorsal view; 2 – female, dorsal view; 3 – oculartubercle of female; 4 – palp; 5 – distal segments of leg.Achelia brevirostris (from Losina-Losinsky, 1961): 6 – trunk, dorsal view;7 – trunk, lateral view; 8 – palp; 9 – oviger; 10 – compound spine; 11 – leg143

Plate X. Achelia kurilensis (from Losina-Losinsky, 1961): 1 – trunk, dorsal view; 2 –ocular tubercle; 3 and 4 – palps of male (3) and female (4); 5 – distal part of maleoviger; 6 – leg of male; 7 – distal segments of female leg.Achelia alaskensis (from Losina-Losinsky, 1933): 8 – trunk, dorsal view; 9 –ocular tubercle; 10 – chelifore; 11 – palp; 12 – leg.Achelia latifrons (from Kim & Hong, 1986): 13 – trunk, dorsal view; 14 – palp;15 – leg144

Plate XI. Achelia bituberculata (from Nakamura, 1987): 1 – trunk of male, dorsalview; 2 – trunk, lateral view; 3 – dorsal spine; 4 – palp; 5 – distal part of maleoviger; 6 – leg of male.Achelia segmentata (from Utinomi, 1954): 7 – trunk, dorsal view; 8 – trunk, lateralview; 9 – palp; 10 – oviger; 11 – distal segments of leg145

Plate XII. Achelia gracilipes (from Losina-Losinsky, 1933): 1 – trunk, dorsal view;2 – trunk, lateral view; 3 – palp; 4 – oviger; 5 – distal segments of leg.Achelia superba (from Nakamura, 1987): 6 – trunk, dorsal view; 7 – trunk, lateralview; 8 – palp; 9 – distal part of female oviger; 10 – leg of male; 11 – distal partof male femur146

Plate XIII. Achelia echinata orientalis (from Nakamura, 1987): 1 – trunk, dorsalview; 2 – trunk, lateral view; 3 – ocular tubercle; 4 – chelifore; 5 – distal part ofoviger; 6 – leg of male; 7 – distal part of male femur.Achelia kamtschatika (from Losina-Losinsky, 1961): 8 – trunk, dorsal view; 9 –ocular tubercle; 10 – chelifore; 11 – palp; 12 – oviger; 13 – leg147

Plate XIV. Tanystylum scrutator (from Stock, 1954): 1 – trunk, dorsal view; 2 – palp;3 – segment 10 of oviger with compound spines; 4 – leg.Tanysytlum ulreungum (from Nakamura & Child, 1983): 5 – trunk, dorsal view;6 – palp; 7 – distal part of oviger with forked spine; 8 – leg148

Plate XV. Lecythorhynchus marginatus: 1 – trunk, dorsal view; 2 – ocular tubercle,lateral view; 3 – palp; 4 – oviger; 5 – segments 7 to 10 of oviger; 6 – 3rd leg;7 – distal segments of leg.Cilunculus armatus (from Nakamura, 1987): 8 – trunk, dorsal view; 9 – trunk,lateral view; 10 – chelifore; 11 – palp; 12 – leg; 13 – distal segments of leg149

Plate XVI. Nymphonella tapetis (from Ohshima, 1927): 1 – male, ventral view; 2 –female, dorsal view.Ascorhynchus glabroides (from Ortmann, 1891): 3 – trunk, dorsal view; 4 – 1stsegment of trunk with proboscis, chelifores, palp, and oviger, ventral view150

Plate XVII. Ascorhynchus glaberrimum (from Nakamura, 1987): 1 – female trunk,dorsal view; 2 – chelifore; 3 – palp; 4 – oviger of male; 5 – leg.Ascorhynchus ramipes (from Nakamura, 1987): 6 – female trunk, dorsal view;7 – female trunk, lateral view; 8 – palp; 9 – segments 3 to 10 of male oviger; 10 –leg; 11 – lateral process, coxae 1 and 2 of female151

Plate XVIII. Decachela discata (from Hedgpeth, 1949): 1 – trunk, dorsal view;2 – distal segments of leg.Decachela dogieli (from Losina-Losinsky, 1961): 3 – trunk, dorsal view; 4 –coxae 1 and 2 of leg, dorsal view; 5 – coxae 1 and 2 of leg, ventral view; 6 – leg.Pycnosomia strongylocentroti (from Losina-Losinsky, 1961): 7 – trunk, dorsalview; 8 – trunk, lateral view; 9 – oviger of male; 10 – leg of male; 11 – leg offemale152

Plate XIX. Bradypallene espina (from Kim & Hong, 1987): 1 – trunk, dorsal view;2 – trunk, lateral view; 3 – palp; 4 – distal segments of leg.Propallene longiceps (from Nakamura, 1987): 5 – trunk, dorsal view; 6 – trunk,lateral view; 7 – chela; 8 – oviger; 9 – distal segments of leg.Callipallene phantoma amaxana (from Stock, 1968): 10 – trunk, dorsal view;11 – ocular tubercle; 12 – distal segments of leg153

Plate XX. Phoxichilidium ungellatum (from Hedgpeth, 1949): 1 – trunk, dorsal view;2 – chela; 3 – distal segments of oviger; 4 – distal segments of leg.Anoplodactylus gestiens (from Nakamura, 1987): 5 – trunk, dorsal view; 6 –trunk, lateral view; 7 – chela; 8 – distal segments of leg.Anoplodactylus pycnosoma (from Kim, 1984): 9 – trunk, dorsal view; 10 – trunk,lateral view; 11 – chela; 12 – distal segments of leg154

Plate XXI. Anoplodactylus viridintestinalis (from Kim, 1986): 1 – trunk of male, dorsalview; 2 – trunk of female, dorsal view; 3 – trunk of female, lateral view; 4 –distal part of scape and chela; 5 – distal segments of leg; 6 – cement gland.Anoplodactylus carnatus (from Nakamura & Child, 1983): 7 – trunk, dorsalview; 8 – trunk, lateral view; 9 – chela; 10 – distal segments of leg155

Plate XXII. Anoplodactylus pygmaeus (from Turpaeva, 2006): 1 – male, dorsal view;2 – chela; 3 – oviger; 4 – 4th leg; 5 – distal segment of leg.Hedgpethia californica chitinosa (from Losina-Losinsky & Turpaeva, 1958):6 – trunk, dorsal view; 7 – trunk, lateral view; 8 – segment 10 of oviger; 9 –compound spine; 10 – large spine, forming false chela of oviger; 11 – distal segmentsof leg156

Plate XXIII. Colossendeis macerrima (from Hedgpeth, 1949): 1 – trunk, lateral view;2 – palp; 3 – distal segments of leg.Colossendeis nasuta (from Hedgpeth, 1949): 4 – trunk, lateral view; 5 – palp;6 – distal segments of leg.Pycnogonum tenue (from Nakamura, 1987): 7 – trunk, dorsal view; 8 – trunk,lateral view; 9 – distal segments of leg.Pycnogonum koreanum (from Kim & Stock, 1984): 10 – trunk, dorsal view;11 – distal segments of leg; 12 – distal segment of leg157

INDEX OF LATIN NAMES *AAcanthomysis 60Achelia 105, 106alaskensis, Achelia 110, 111albаtrossi, Nymphon 104amaxana, Callipallene phantoma 122Ammotheidae 105andersoni, Neomysis 56, 57anomala, Holmesiella 47Anoplodactylus 124, 125Arachnomysis 46arctopacifica, Exacanthomysis 60Archaeomysis 45armata, Thysanoessa 85armatus, Cilunculus 117, 118articulata, Archaeomysis 45Ascorhynchus 118Austrodecidae 94avirostris, Penilia 12–14awatschensis, Neomysis 56BBentheuphausiidae 81bicornis, Hedgpethia californica 129bipes, Nebalia 38, 39bisseratum, Nymphon 100bituberculata, Achelia 108borealis, Exacanthomysis 61borealis, Ammothea gracilipes 111borealis, Thysanoessa 84Boreoacanthomysis 58Boreomysidae 43braschnikowi, Nymphon 103Bradypallene 121Branchiopoda 9brevicollis, Nymphon longitarse 100brevirostris, Achelia 108brevirostre, Nymphon 97, 98Ccalifornica, Hedgpethia californica 129californica, Inusitatomysis 51Callipallene 122Callipallenidae 119camtschatica, Stilomysis 53carnatus, Anoplodactylus 127Cercopagidae 10Chelicerata 92chitinosa, Hedgpethia californicа 128, 129Cilunculus 117Cladocera 9Colossendeidae 127Colossendeis 127Crustacea 9Ctenopoda 11czerniawskii, Neomysis 56, 57DDecachela 119Decolopodidae 94derjungini, Halosoma 125dimorpha, Hemiacanthomysis 59Disacanthomysis 53discata, Decachela 120dogieli, Decachela 120dybowskii, Disacanthomysis 54Eechinata, Achelia 113elongatum, Nymphon longitarse 99Endeidae 94Erythropini 46espina, Bradypallene 121Eucarida 81Eucopiidae 43Euphausia 86Euphausiacea 81Euphausiidae 82, 83Evadne 21Exacanthomysis 60exiguum, Phoxihilidium 125Ffranciscorum, Neomysis 55* Synonims are italicized, and principal taxa from subgenera to families are printed in bold.158

GGastrosaccinae 44gestiens, Anoplodactylus 126glaberrimum, Ascorhynchus 118glabroides, Ascorhynchus 119Gnathophausiidae 43gracile, Nymphon 98gracilipes, Achelia 111grandis, Stilomysis 52, 53grebnitzkii, Archaeomysis 45grossipes, Nymphon 96, 97HHedgpethia 128Hedgpethiidae 128hessleri, Nebalia 39heterospinum, Nymphon 97hilgendorfi, Lecythorhynchus 116Hemiacanthomysis 59hodgsoni, Nymphon 102Holmesiella 47Iinermis, Anoplodactylus 125inermis, Thysanoessa 84insolita, Inusitatomysis 51inspinata, Thysanoessa 83intermedia, Heteromysis 56intermedia, Neomysis 56intermedius, Podon 10Inusitatomysis 50isaza, Neomysis 56Jjaponica, Achelia borealis 107japonica, Archaeomysis 45japonica, Exacanthomysis 60japonicum, Nymphon 101Kkamtschatica, Achelia 114kodanii, Nymphon 101koreanum, Pycnogonum 130kurilensis, Achelia 109, 110kurilensis, Nymphon brevirostre 98latifrons, Achelia 109Lecythorhynchus 115Lepidomysidae 43Leptodora 9Leptodorida 9Leptostraca 37leuckarti, Podon 20, 21longiceps, Propallene 121longipes, Thysanoessa 85, 86longitarse, Nymphon longitarse 99Lophogastrida 43Lophogastridae 43Mmacerrima, Colossendeis 128maculata, Archaeomysis 45maculata, Callomysis 45major, Stilomysis 53Malacostraca 37marginatus, Lecythorhynchus 116Meterythrops 47microcollis, Nymphon 98micropedes, Nymphon 101microphthalma, Meterythrops 48mirabilis, Neomysis 57Mysida 44Mysidacea 42Mysidae 44Mysidellinae 43Mysinae 46Mysini 49Nnakazawai, Neomysis 57nasuta, Colossendeis 128Nebalia 38Nebaliidae 38Nebaliopsidae 37neglecta, Thysanopoda 84Neomysis 54Nematoscelis 83nemurensis, Nebalia 38nigra, Neomysis 56nigrognatum, Nymphon 97Nipponerythrops 46nordmanni, Evadne 23, 24Nulloviger 130Nymphon 95Nymphonella 116Nymphonidae 94159

Oochoticum, brevirostre Nymphon 98oculospinum, Nymphon 97оhshimai, Achelia 108Onychopoda 14orientalis, Achelia echinata 113, 114orientalis, Penilia 12orpax, Achelia 109Ppacifica, Euphausia 86, 87Pantopoda 92Paracanthomysis 61, 62Paranebaliidae 37Penilia 11Peniliinae 11Peracarida 42Petalophthalmidae 43Petalophthalmina 43Phoxichilidiidae 122Phoxichilidium 124Phyllocarida 37Pleopis 14, 15Podon 19, 20Podonidae 14Polyphemoidea 10polyphemoides, Pleopis 16, 17Propallene 121Pseudevadne 17, 18Pseudeuphausia 83pseudomacropsis, Xenacanthomysis 52Pycnogonida 92Pycnogonidae 129Pycnogonum 129, 130Pycnosoma 123pycnosoma, Anoplodactylus 126Pycnosomia 122pygmaeus, Anoplodactylus 125, 126Rramipes, Ascorhynchus 118raschii, Thysanoessa 85rayii, Neomysis 55Retroviger 130Rhopalophthalminae 43Rhopalorhynchus 128Rhynchothoracidae 94robusta, Meterythrops 48robustus, Pigrogromitus 123Sschmackeri, Penilia 12schmackeri, Pleopis 15, 16schrencki, Boreoacanthomysis 58, 59scrutator, Tanystylum 115segmentata, Achelia 111, 112serrata, Inusitatomysis 51shikhotaniensis, Paracanthomysis 62Sididae 11similis, Euphausia 83sinensis, Achelia echinata 113Siriellinae 43spadix, Paracanthomysis 62spinifera, Evadne 22stelleri, Exacanthomysis 60, 61Stilomysis 52stocki, Nymphon 102striatum, Nymphon 98strongylocentroti, Pycnosomia 123Stygiomysidae 43Stygiomysina 43Stylocheiron 81superba, Achelia 112, 113TThalassomysinae 43Tanystylum 114, 115tapetis, Nymphonella 117tenue, Pycnogonum 130tergestina, Pseudevadne 18, 19Thysanoessa 83toion, Neomysis 55Uulreungum, Tanystylum 115uniunguiculatum, Nymphon 104ungellatum, Phoxichilidium 124Vviridintestinalis, Anoplodactylus 126, 127XXenacanthomysis 51160

Научное изданиеБИОТА РОССИЙСКИХ ВОДЯПОНСКОГО МОРЯТом 1, часть 2РАКООБРАЗНЫЕ (ВЕТВИСТОУСЫЕ, ТОНКОПАНЦИРНЫЕ,МИЗИДЫ, ЭВФАУЗИИДЫ) И МОРСКИЕ ПАУКИОтпечатано с оригинал-макета,подготовленного в Институте биологии моря ДВО РАН,минуя редподготовкуИзд. лиц. ИД № 05497 от 01.08.2001 г. Подписано к печати 24.02.2007 г.Бумага офсетная. Формат 70х108/16. Печать офсетная. Гарнитура «Times New Roman»Усл.п.л. 15,66. Уч.-изд. л. 13,98. Тираж 300 экз. Заказ 159.Отпечатано в типографии ФГУП Издательство «Дальнаука» ДВО РАН690041, г. Владивосток, ул. Радио, 7

биота российских вод японского моря - Materials of Alexey Shipunov

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