Description of a new species of Oreonectes (Cypriniformes, Nemacheilidae) from Guangxi, China

Fishes of the genus Oreonectes inhabit complex karst landscapes, and additional cryptic species may be present within Oreonectes. Specimens previously identified as O. platycephalus and collected from Fenzhan Village, Jinxiu County, Guangxi, may represent a new species, Oreonectes jinxiuensis. It is distinguished from all congeners by a degenerated swim bladder, adjacent anterior and posterior nostrils, 13 inner gill rakers on the first gill arch, a dorsal-fin origin posterior to the pelvic-fin origin, 10 branched pectoral-fin rays, 14–15 branched caudal-fin rays, a preanal length of 73.7 % – 77.3 % of SL, and a caudal-peduncle length of 13.3 % – 16.4 % of SL.

Its validity is further supported by its recovered monophyly in a molecular phylogenetic analysis based on mitochondrial COI and Cyt b gene sequences, as well as by species-level genetic divergence between the new species and its closest relatives.