Paraschistura nielseni

Common name. Helleh loach.

Diagnosis. Distinguished from other species of Paraschistura in West Asia by: ○ 6–11 regularly set and shaped dark-or pale-brown or grey bars, wider than interspaces, absent or very faint on flank in front of dorsal origin / ○ suborbital groove present in male / ○ a faint dark-grey spot at base of first dorsal rays / ○ black bar at caudal base faint or dissociated o two blotches, rarely complete / ○ snout blunt / ○ no dorsal adipose crest / ○ lateral line incomplete / ○ caudal deeply emarginate / ○ back and flank fully covered by scales / ○ body depth at dorsal origin 15–17 % SL / ○ pelvic reaching to about 1–2 eye diameters in front of anus / ○ pelvic origin below first or second branched dorsal ray / ○ 7½ branched dorsal rays. Size up to 52 mm SL.

Distribution. Iran: Helleh and Mond drainages.

Habitat. Fast to slow-flowing streams and springs with gravel substrate.

Biology. No data.

Conservation status. LC.

Further reading. Nalbant & Bianco 1998 (description); Freyhof et al. 2015 (diagnosis).