Diagnosis: Luciobarbus mascarensis is distinguished from other Luciobarbus species from the African Mediterranean basin, except L. chelifensis and L. leptopogon, by having usually 41 + 1-2 lateral line scales, vs. 49-51 + 1-2 in L. biscarensis, 43-47 + 1-2 in L. callensis, 43-45 + 1-3 in L. rifensis and L. setivimensis, 42-45 + 1-2 in L. yahyaouii; only L. chelifensis and L. leptopogon have regularly 41 lateral-line scales on the flank (Ref. 115559). Luciobarbus mascarensis is distinguished from L. chelifensis by having a longer anal fin, 19-22% of standard length vs. 18-19%, and the dorsal fin serrated at 2/3 of its length vs. serrated along almost its entire length, and from L. leptopogon by having a deeper body, body depth at dorsal-fin origin 26-31% of standard length vs. 20-27%, and a wider caudal peduncle, caudal peduncle depth 74-84% of caudal peduncle length vs. 60-74% (Ref. 115559). Luciobarbus mascarensis is also distinguished from L. biscarensis by having 7.5 scale rows between the lateral line and the dorsal-fin origin vs. 8.5-9.5, 4.5-5.5 scale rows between the lateral line and the pelvic-fin origin vs. 7.5-8.5, 4 unbranched dorsal-fin rays vs. 5, the dorsal-fin origin situated in front or above the pelvic-fin origin vs. behind, a longer anal fin, 19-22% of standard length vs. 17-20%, a short caudal peduncle, caudal peduncle length 15-17% of standard length vs. 16-19%; it is further distinguished from L. callensis and L. rifensis by having a longer anal fin, 19-22% of standard length vs. 17-19% in L. callensis and 16-19% in L. rifensis, a wider anal-fin base, 7-10% of standard length vs. 6-8% in L. rifensis, and a wider caudal peduncle, caudal peduncle depth 74-84% of caudal peduncle length vs. 60-78% in L. rifensis; it is also distinguihed from L. setivimensis by having a more narrow interorbital distance, 36-40% of head length vs. 40-44%; it is also distinguished from L. yahyaouii by having 4 unbranched dorsal-fin rays vs. usually 5, a greater distance between the pelvic and anal-fin origins, 24-28% of standard length vs. 21-24%, and a shorter caudal peduncle, caudal peduncle length 15-17% of standard length vs. 16-19.4% (Ref. 115559).

Description: Middle sized and stout species, with a moderately long head; dorsal profile with a well-marked discontinuity between head and back; body deepest at about midline between nape and dorsal-fin origin; depth decreasing continuously towards caudal-fin base; greatest body width between pectoral and dorsal-fin origins (Ref. 115559). Caudal peduncle compressed, 1.2-1.3 times longer than its depth (Ref. 115559). Section of head roundish, flattened on ventral surface; snout blunt; mouth inferior (Ref. 115559). Dorsal-fin origin in front or almost above pelvic-fin origin; anal-fin origin slightly behind vertical of middle between dorsal and caudal-fin origins; anal fin reaching to caudal-fin base; pectoral fin reaching approximately 59-77% of distance between pectora-fin origin and pelvic-fin origin; pelvic fin not reaching vertical of tip of last dorsal-fin ray when folded down; pelvic fin reaching to a short distance in front of anus; posterior dorsal-fin margin straight or slightly convex; posterior pectoral-fin margin convex; posterior anal-fin margin convex; caudal fin forked with rounded lobes of equal size; dorsal fin with 4 unbranched and 8.5 branched rays, last unbranched ray ossified and serrated at 2/3 of its length; anal fin with 3 unbranched and 5.5 branched rays; pectoral fin with 13-16 rays and pelvic fin with 7-8 rays (Ref. 115559). Lateral line with 41 and 43 scales on flank and 1-2 scales on caudal-fin base; between dorsal-fin origin and lateral line 7.5 scale rows and 4.5-5.5 scale rows between pelvic-fin origin and lateral line (Ref. 115559). Pharyngeal teeth in three rows: 4+3+2 (Ref. 115559).

Colouration: Body yellowish brown in life and preserved individuals without colour pattern; head plain brown, cheeks and ventral head and body whitish; fins hyaline, usually with yellowish rays (Ref. 115559).