Abstract. Morphology features and sequences of mitochondrial cytochrome b (cyt b) gene were analyzed of the species Cobitis Linnaeus, 1758 from the River Pearl basin of China. Three new species of C. leptosoma sp. nov., C. wumingensis sp. nov., and C. obtusirostra sp. nov. were described. C. leptosoma is distinguishable from its congeners by a long knife-shaped lamina circularis; a sharp and nearly filamentous tip of the pectoral-fin ray in males; four Gambetta pigment lines, [L.sub.2] usually being absent, [L.sub.5] consisting of 10-12 oval blotches; and a round or oblong spot smaller than or equal to the eye diameter on the upper part of the caudal peduncle. C. wumingensis is distinguishable by small barbels, maxillo-mandibular barbels shorter than eye diameter; a long fingerlike lamina circularis; a sharp and nearly filamentous tip of the pectoral-fin ray in males; [L.sub.5] showing sexual dimorphism; a deeper bluish band pigment in females; a surface pigment with 13-14 blotches in males; and a conspicuous jet-black roundish spot smaller than or equal to the eye diameter on the upper part of the caudal peduncle. C. obtusirostra is distinguished by a cystiform lamina circularis; a sharp and nearly filamentous tip of the pectoral-fin ray in males; [L.sub.5]consisting of 8-10 rounded blotches; and a conspicuous jet-black arcuate spot smaller than the eye diameter on the upper part of the caudal peduncle.

Key words: loaches, taxonomy, Guangxi, Guangdong Province, molecular phylogeny

Introduction

The cobitid fish genus Cobitis L., 1758, one of the largest in the subfamily Cobitinae, is widely distributed throughout Eurasia (excluding the Tibetan Plateau), its adjacent islands, and northwestern Africa (Chen 1981, Sawada 1982). Over 241 species have been described (Froese & Pauly 2014), and 15 of those are from China. Their high diversity and widespread distribution have made cobitids one of the most difficult groups of fish to understand taxonomically and systematically (Nalbant 1993, Slechtova et al. 2008). Various researchers have attempted to classify these fish and decipher their phylogenetic history. A number of species once referred to as Cobitis now belong to other genera like Iksookimia, Koreocobitis, and Microcobitis. One of the latest efforts employing phylogenetic systematics indicated that the genera Cobitis, Iksookimia, and Niwaella are not monophyletic (Slechtova et al. 2008). Similar results were also found in studies by Tang et al. (2005, 2006). The genera Cobitis, Iksookimia, Kichulchoia, Koreocobitis, Misgurnus, Niwaella, Paramisgurnus, Sabanejewia, and Microcobitis together form a monophyletic lineage within the family Cobitidae (Slechtova et al. 2008). Cobitis is in most cases diagnosed by the characteristics: one lamina circularis is present on the second pectoral-fin ray in males, the bifid suborbital spine situated in front of eyes, and three distinct longitudinal rows of black pigmentation on the body sides; one along the dorsal line, one along the lateral line and one at about half distance between these two (Bohlen & Harant 2010). Southeast Asia is believed to be the origin of Cobitidae due to their higher diversification in this area (Chen 1981, Chen & Zhu 1984, Banarescu 1990). Southern China, one origin...