New blind loach found in China

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Chinese scientists have described an unusual new species of loach from a cave system in Guangxi, China.

Zhen-Ling Zhang, Ya-Hui Zhao, and Chun-Guang Zhang of the Chinese Academy of Sciences described the new loach as Oreonectes translucens in the latest issue of the journal Zoological Studies.

Oreonectes translucens, which is a member of the loach subfamily Nemacheilinae, was described from three specimens caught in a cave in Xia'ao Village, Du'an County, Guangxi Zhuang Autonomous Region of southern China.

The loach, which was first discovered in 1999, has vestigial eyes and well-developed "crests", which help differentiate it from others in the genus.

The authors wrote: "The new species shares with the similar O. furcocaudalis Zhu et Cao possession of dorsal and ventral crests, a forked caudal fin, and 8 (6) dorsal (anal)-fin rays, but can be distinguished from the latter by having vestigial eyes (normal in the latter), well-developed crests (dorsal crest depth of the former 78.0%-87.0% of caudal peduncle depth vs. 31.1%-38.1% in the latter), and fewer vertebrae (4 + 32 vs. 4 + 35).

"The new species shares with the similar O. anophthalmus Zheng possession of vestigial eyes, a semitransparent body when fresh, and a 4 + 32 vertebrae count, but differs from the latter by having crests, a forked caudal-fin (rounded in the latter), and the origin of the dorsal fin vertically opposite to those of the pelvic fins."

The Oreonectes genus now contains five species: O. platycephalus, O. anophthalmus, O. furcocaudalis, O. retrodorsalis, and O. translucens sp. nov.

O. translucens and O. anophthalmus are the only two troglodytic species in the genus and both have transparent bodies and vestigial eyes, which are typically lost through evolution for life underground.

For more information see the paper: Zhen-Ling Z, Ya-Hui Z, and Chun-Guang Z (2006) A new blind loach, Oreonectes translucens (Teleostei: Cypriniformes: Nemacheilinae), from Guangxi, China. Zoological Studies 45(4): 611-615.