| Diagnosis: |
This species is distinguished from O. ercisianus by having a central pore in the supratemporal canal (vs. absent); a bold, dark-brown bar or vertically elongated blotch at the caudal fin-base, usually M-shaped or fused with a roundish or vertically elongate, dark-brown blotch at the vertical midline (vs. a mottled pigmentation not different from the flank pattern); usually with wide, dark-brown, bold bands on the caudal fin (vs. narrow, pale-brown, indistinct); no or a shallow dorsal and ventral adipose crest in individuals larger than 50 mm SL (vs. a short and high crest); longer and more slender caudal peduncle (caudal peduncle length 1.3-1.6 times its depth vs. 1.0-1.3); eye is larger with eye diameter 19-30% HL (vs. 14-19); a short prepelvic length, 48-53% SL (vs. 52-57).
It differs from O. hazarensis by the absence of suborbital groove in the male (vs. present); no scales on caudal peduncle (vs. present); shorter outer rostral barbel 22-34% HL (vs. 34-41); shorter maxillary barbel 24-30% HL (vs. 32-40).
It differs from O. kaynaki by having an incomplete lateral line (vs. complete); no scales on flank (vs. present); no pelvic axillary lobe (vs. present); absence or with a short dorsal adipose crest on the caudal peduncle (vs. a long adipose ridge).
It differs from O. tigris by having no scales on the flank (vs. present, usually isolated and deeply embedded); with a bold, dark-brown bar or a vertically elongated blotch on the caudal-fin-base or a bar fused with a roundish or vertically elongate, dark-brown blotch at the vertical midline (vs. 2 bold, black spots in most individuals, no pigmentation in others); no or a short dorsal-adipose crest on caudal peduncle not reaching to the vertical through the anal-fin base (vs. long adipose crest reaching beyond the anal-fin origin, usually below the last dorsal-fin rays when folded down); with a more slender caudal-peduncle, caudal peduncle length 1.3-1.6 times its depth (vs. 0.9-1.2).
This species is further distinguished from its congeners inhabiting the Euphrates drainage not belonging to the O. tigris species group by a combination of characters: it differs from O. araxensis by having an incomplete lateral line (vs. complete) and males without a suborbital groove (vs. present); differs from O. argyrogramma, O. bergianus, O. euphraticus, O. samanticus by the incomplete lateral line (vs. complete), a slightly emarginated caudal fin (vs. deeply emarginate or slightly forked), suborbital groove in the male absent (vs. present), and no black spots at the caudal-fin base (vs. having two bold black jet spots in O. argyrogramma, O. euphraticus); differs from O. paucilepis by having an incomplete lateral line (vs. complete) and no scales (vs. flank covered by isolated scales) (Ref. 120397). |