Oxynoemacheilus frenatus Common name. Mesopotamian loach. Diagnosis. Distinguished from other species of Oxynoemacheilus in Tigris drainage by: ○ lateral line incomplete, terminating in front of or above anal base / ○ caudal slightly emarginate / ○ flank mottled or marbled without bars / ○ colour pattern on anterior part of flank, often interrupted by an unpigmented zone along lateral line /○ a shallow dorsal crest on caudal peduncle / ○ one central pore in supratemporal canal / ○ suborbital groove absent in male / ○ scales present on back and flank in front of anus. Size up to 75 mm SL. Distribution. Mosul and upper Tigris drainage down to Batman drainage. Habitat. Moderately fast-flowing to standing waters of springs, streams, and rivers with muddy or gravelly bottoms. Biology. No data. Conservation status. LC. Remarks. Recently not recorded from rivers downstream of Batman. Superficially, very similar but genetically very different loaches occur in Iranian Lesser Zab, and these have also been identified as O. frenatus. It is impossible to say whether the populations from the upper Tigris are the same as those from Mosul. Only when new material from Mosul becomes available will the identity of Anatolian and Iranian populations be finally resolved. Further reading. Heckel 1843 (description); Freyhof et al. 2017a (discussion of Anatolian and Iranian populations); Sayyadzadeh & Esmaeili 2020 (discussion of Iranian and Anatolian populations).

Published as part of Freyhof, Jörg, Yoğurtçuoğlu, Baran, Jouladeh-Roudbar, Arash & Kaya, Cüneyt, 2025, Handbook of Freshwater Fishes of West Asia, GmbH, Berlin / Boston :De Gruyter on page 505, DOI: 10.1515/9783111677811, http://zenodo.org/record/17881367