A new cave species of the genus Triplophysa (Teleostei, Cypriniformes, Nemacheilidae) from Guizhou, China

Integrating morphological and molecular evidence, we described a new species of Triplophysa, named Triplophysa xingyiensis sp. nov., from two subterranean river outlets in the Nanpanjiang River Basin, Guizhou Province, China. This new species can be distinguished from other species of Triplophysa by the following combination of characters: body naked and scaleless, eyes normal with diameter 9.1–17.3 % of head length; lateral line complete; posterior chamber of air bladder degenerated; out rostral barbel longest, length 34.3–48.0 % of head length; caudal fin emarginated, with 16 branched fin rays; and vertebrae 4 + 36.

Phylogenetic analysis, based on the 13 protein-coding genes of the mitochondrial genome, demonstrated that the new species forms a monophyletic group. Furthermore, analysis of genetic distances, based on the cytochrome b gene, revealed its close relationship with T. anlongensis, T. rongduensis and T. zhenfengensis, with pairwise distances ranging from 1.8 % to 2.4 %. This integrative taxonomic method supports the recognition of T. xingyiensis as a distinct taxon.