>Cynolebias roseus can be diagnosed from all species of C. porosus group, by having contact organs over the internal surface of all the pectoral-fin rays in males (vs. contact organs restricted to the dorsalmost pectoral-fin rays). It can be further separated from the two other species of the C. porosus group endemic to the São Francisco River basin, C. porosus and C. obscurus, by the possession of the following combination of characters: presence of ventral process of autopalatine (vs. absence in C. obscurus); flank with white dot on the center of each scale (vs. restricted to middle portion of the flank in C. obscurus); upper jaw not ventrally displaced (vs. ventrally displaced in C. porosus; and flank pale golden to light pink in males (vs. dark brown in C. obscurus), distal portion of anal-fin rays red in males (vs. grey in C. obscurus) (Ref. 97357).