Oxynoemacheilus ercisianus

Common name. Van loach.

Diagnosis. Distinguished from other species of Oxynoemacheilus in adjacent Euphrates drainage by: ○ scales absent / ○ lateral line incomplete not reaching or reaching below dorsal base / ○ suborbital groove absent in male / ○ caudal slightly emarginate / ○ supratemporal canal without central pore / ○ pelvic axillary lobe absent / ○ dorsal adipose crest on caudal peduncle high, not reaching to vertical through last anal ray base in individuals larger than 50 mm SL / ○ caudal–peduncle length 1.0–1.3 times its depth / ○ body width at dorsal origin 13–17 % SL / ○ flank with a marmorated pattern or with large, irregularly shaped and narrowly spaced dark-brown bars or blotches, usually more prominent on flank behind dorsal base / ○ caudal base with mottled colour pattern, without bold, black bar or bold, black spots upper and lower caudal base. Size up to 82 mm SL.

Distribution. Türkiye: Lake Van and its tributaries Zilan, Deli, Bendimahi and Karasu.

Habitat. Moderately flowing streams and rivers with gravel or rock substrate. Also, in microbialites of Lake Van itself, at a maximum depth of 13 m and about 500 m offshore.

Biology. No data.

Conservation status. VU; appears to be declining within its small range.

Remarks. Nemacheilus pulsiz is a synonym.

Further reading. Erk’akan & Kuru 1986 (description); Krupp 1992a (description of Nemacheilus pulsiz); Freyhof et al. 2019b (diagnosis, distribution); Akkuş et al. 2021 (habitat in Lake Van).