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Cephalic portion of the lateral line in Dadyanos insignis. A: post larvae recently hatched, B: 14-day-old postlarvae, C: juvenile / Porción cefálica de la línea lateral en Dadyanos insignis. A: postlarva recién eclosionada, B: postlarva de 14 días de vida, C: juveniles
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Zoarcids are well represented in the intertidal zone of the Patagonian coast. They are typically oviparous with parental care, but so far there is little information on their ontogenetic development. The aim of this study was to describe the early developmental stages of 3 zoarcid species: Iluocoetes elongatus, Phucocoetes latitans and Dadyanos ins...
Citations
... H1 assumes that the sensory canals and the anterior morphology (neurocranium, oral jaw apparatus) have different, but complementary functions (i.e., prey detection and capture, respectively), especially under low-light conditions (Mogdens 2019), such as the turbid, coastal waters of west Patagonia (>4 NTU, Castillo-Hidalgo et al. 2018). By contrast, H2 is a hypothesis of developmental modularity derived from the observation that zoarcid have different rates of ossification during larval development (Voskoboinikova & Laius 2003), and the opercular region (where the preoperculo-mandibular canal is located) increases its relative size during early development (Marcinkevicius & Gosztonyi 2013). Integration between modules was measured using the covariance ratio test (CR), which can be defined as the ratio of the overall covariation between modules relative to the overall covariation within modules (Adams 2016). ...
... In terms of modularity, analyses showed a modular development between the suborbital and the preoperculomandibular canals of the cephalic lateralis system. Pores of the cephalic system can be observed from the hatching (Matallanas et al. 1990;Marcinkevicius & Gosztonyi 2013), but its relative location in the head vary throughout early development, with larger displacements of the preoperculo-mandibular canal than the suborbital canal in larval stages (Marcinkevicius & Gosztonyi 2013). Additionally, intraspecific shape variability in juvenile and adults of A. depressiceps was focused on the suborbital canal, while the preoperculo-mandibular canal showed slight variation only in PC2 (14% of the shape variation). ...
... In terms of modularity, analyses showed a modular development between the suborbital and the preoperculomandibular canals of the cephalic lateralis system. Pores of the cephalic system can be observed from the hatching (Matallanas et al. 1990;Marcinkevicius & Gosztonyi 2013), but its relative location in the head vary throughout early development, with larger displacements of the preoperculo-mandibular canal than the suborbital canal in larval stages (Marcinkevicius & Gosztonyi 2013). Additionally, intraspecific shape variability in juvenile and adults of A. depressiceps was focused on the suborbital canal, while the preoperculo-mandibular canal showed slight variation only in PC2 (14% of the shape variation). ...
Phenotypic variation in organisms depends on the genotype and the environmental constraints of the habitat that they exploit. Therefore, for marine species inhabiting contrasting aquatic conditions, it is expected to find covariation between the shape and its spatial distribution. We studied the morphology of the head and cephalic sensory canals of the eelpout Austrolycus depressiceps (4.5‐22.5 cm TL) across its latitudinal distribution in South Pacific (45°S‐55°S). Geometric morphometric analyses show that shape varied from individuals with larger snout and an extended suborbital canal to individuals with shorter snouts and frontally compressed suborbital canal. There was size variation across the sampled populations, but that size does not have a clear latitudinal gradient. Only 8% of the shape variation relates to this size variation (allometry), represented by a decrease of the relative size of the eye, and a depression of the posterior margin of the head. There were spatial differences in the shape of the head, but these differences were probably caused by allometric effects. Additionally, two of the canals of the cephalic lateralis pores and the head shape showed modularity in its development. This study shows that the morphology of marine fish with a shallow distribution varies across distances of hundreds of kilometres (i.e., phenotypic modulation). This article is protected by copyright. All rights reserved
... It is known that newborn Phucocoetes latitans Jenyns, 1842 are 20 mm long and attain 35 mm in two months (Gosztonyi, 1977) and that newborn Austrolycus depressiceps (Berg, 1895) are 22-25 mm long (Matallanas et al., 1990). The coloration pattern and cephalic lateral line pore distribution in post-larvae of P. latitans Jenyns, 1842, Dadyanos insignis (Steindachner, 1898) and Iluocoetes elongatus (Smitt, 1898) are similar to those in adults, although coloration in younger stages is fainter (Marcinkevicius and Gosztonyi, 2013). ...
... Egg masses of the three species studied were collected at Isla Quinta, Deseado River Estuary, Santa Cruz Province, Argentina (Fig. 1), and kept in controlled aquaria at 10°C until hatching and maintained as detailed in Marcinkevicius and Gosztonyi (2013). Postlarve of Iluocoetes elongatus (n = 50; 17.5-30 mm standard length (SL)), Phucocoetes latitans (n = 50; 18-29 mm SL) and Dadyanos insignis (n = 44; 22-36 mm SL) were cleared and stained with Alizarin red and Alcian blue for bone and cartilage respectively, following the Potthoff technique (1984). ...
Zoarcids are abundant in the intertidal zone of the Argentine Patagonian coast. However, their osteological development has not yet been described. Thus, the aim of this work is to describe the ontogeny of the axial skeleton and that of the paired and unpaired fins of the zoarcids Iluocoetes elongatus, Phucocoetes latitans and Dadyanos insignis. The three species studied showed a high degree of development at hatching and meristic counts coincide with those of the adults. At hatching, most of the structures showed that the appearance of bones was in progress. In the three species studied, this process occurred in a cephalo-caudal direction and, in most of the structures, the appearance of bones is observed from the middle to the rim.
