Oxynoemacheilus euphraticus can be diagnosed from the other congeners in the Euphrates and Tigris drainage by a combination of characters, none of them unique. It shares with other members of a group of species (O. argyrogramma, O. bergianus, O. erdali, O. hanae, O. karunensis, O. longipinnis, O. kurdistanicus, O. parvinae, and O. paucilepis) in having a suborbital groove in males (vs. absent in O. chomanicus, O. frenatus, O. gyndes, O. hazarensis, O. kaynaki, O. kiabii and O. zagrosensis) and a deeply emarginate or forked caudal fin (vs. slightly emarginate or truncate in O. chomanicus, O. frenatus, O. gyndes, O. hazarensis, O. kaynaki, O. kiabii and O. zagrosensis) (Ref. 115649).