A new cave‐dwelling loach, Triplophysa xichouensis sp. nov. (Teleostei Nemacheilidae) from Yunnan, China

Abstract

A new cave-dwelling loach of the genus Triplophysa, T. xichouensis, is described from an outlet of a subterranean river in Xisa Town, Xichou County, Yunnan Province, China. It can be distinguished from its congeners by the following characters: dorsal-fin rays iii, 8; anal-fin rays ii, 6; pectoral-fin rays i, 9 or 10; pelvic-fin rays i, 5 or 6; branched caudal-fin rays 16(8+8); eyes highly degenerated to a very tiny black dot; dorsal-fin origin closer to snout tip than to caudal-fin base and anterior to vertical line of pelvic-fin origin; pectoral fin length about two-thirds the distance between pectoral-fin origin to pelvic-fin origin; caudal peduncle slender, its length about three times its depth; caudal fin emarginate; body smooth and scaleless; lateral line complete and straight; anterior chamber of air bladder wrapped in dumbbell-shaped bony capsule and the posterior one well developed, long, oval; intestine short, bending in zigzag shape behind stomach. A key for the cave-dwelling species of Triplophysa is provided. urn:lsid:zoobank.org:pub:9162FFB1-7911-47C3-AE50-6A00E9590327.

Triplophysa anshuiensis, a new species of blind loach from the Xijiang River, China (Teleostei, Nemacheilidae)

“…The new species can be distinguished from T. lihuensis and T. huanjiangensis by 8 gill rakers in inner row on first gill arch (vs. 10–13 in T. lihuensis and T. huanjiangensis , whereas unknown in T. dongganensis and T. fengshanensis ), from T. fengshanensis by 14 branched caudal-fin rays (vs. 16), and caudal peduncle depth 6.6–6.9 times in standard length (vs. 5.0–5.3), and from T. dongganensis by caudal peduncle depth 10.2–11.2 times in standard length (vs. 11.4–16.9), and caudal peduncle depth 1.5–1.7 times in its length (vs. 1.8–2.9). In addition to the species of Triplophysa from Guangxi, there are ten more troglobitic Triplophysa species recorded in the Xijiang River, including T. aluensis , T. gejiuensis , T. longibarbata , T. nasobarbatula , T. qiubeiensis , T. shilinensis , T. xiangshuingensis , T. yunnanensis , and T. zhenfengensis (Chen 1992, Chu and Chen 1979, Wang and Li 2001, Chen and Yang 2005, Yang et al 2016, Liu et al 2017). Triplophysa anshuiensis can be easily distinguished from T. nasobarbatula , T. xiangshuingensis , T. yunnanensis , and T. zhenfengensis by eyes absent (vs. normal), body colorless (vs. body with color pattern), scaleless (vs. scaled in T. nasobarbatula , T. xiangshuingensis , T. yunnanensis , and T. zhenfengensis ), and 14 branched caudal-fin rays.…”

“…The diversity of species is very high in many isolated rivers, especially in caves. So far, 27 cave-dwelling species in the genus Triplophysa have been described in China (Romero et al 2009, Kottelat 2012, Lan et al 2013, Yang et al 2016, Li and Li 2017, Li and Lan 2017, Liu et al 2017). According to Lan et al (2013), these species can be placed into three groups according to their eye development, viz.…”

A new species of <i>Triplophysa</i> (Cypriniformes, Nemacheilidae) from Weihe River in Gansu Province, China

“…Species of the genus Triplophysa Rendahl 1933 are the most common fish among the nemacheilids found in the Qinghai-Tibet Plateau (QTP) ( Wu & Wu, 1992 ; Zhu, 1989 ). These fish are found in almost all water bodies in the region, with new species of Triplophysa still being reported ( Huang et al, 2019 ; Liu et al, 2017 ; Wu et al, 2018 ; Yang et al, 2016 ). As a result, a total of 147 valid species of Triplophysa have been recorded to date ( Froese & Pauly, 2019 ).…”

Triplophysa wulongensis, a new species of cave-dwelling loach (Teleostei, Nemacheilidae) from Chongqing, Southwest China

“…Triplophysa is distinguished from other genera of Nemacheilidae by a marked sexual dimorphism, in which males have tubercle-bearing, elevated skin on the side of the head, and a thickened tuberculated pad on the dorsal surface of the thickened and widened rays of the pectoral fin. Species of Barbatula Linck, 1790 share the same sexual dimorphism, but Triplophysa can be distinguished from Barbatula by the closely situated nostrils (Bănărescu and Nalbant 1968;Prokofiev 2010;Yang et al 2012;Liu et al 2017).…”