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.