Diagnosis: 16-50 gill rakers on first gill arch (much more reduced compared to Clarias gariepinus), subject to geographical variations (Ref. 57129). Head oval-shaped to rectangular in dorsal outline; snout broadly rounded; eyes rather lateral in position and, together with relatively broad head, make for a relatively large interorbital distance; number of gill rakers on first branchial arch subject to much variation, 16-40, rarely exceeding 40; dorsal fin base situated close to occipital process; dorsal fin always terminates before caudal fin base, distance between both small; anal fin originates closer to caudal fin base than to tip of snout, nearly reaching caudal fin but never confluent; pelvic fin base slightly closer to tip of snout than to caudal fin base, reaching base of first anal fin rays; pectoral fin extend from operculum to base of first dorsal fin rays; pectoral spine slightly curved and robust, serrated only on its outer side, number of serrations increases with increasing standard length; lateral line appears as a small, white line running from posterior end of head to middle of caudal fin base; openings of secondary sensory canals clearly marked, showing a regular pattern (Ref. 248).
Description: number of gill rakers on first gill arch is subject to geographical variations, i.e., from 16 (specimen of 62mm SL) to 27 (specimen of 541mm SL) in the Chad basin, from 18 (83mm SL) to 37 (309mm SL) in coastal basins of Togo, in the Volta, coastal basins of Côte d’Ivoire and Gambia, as well as in the River Senegal, up to 40 in Mauritania, and 50 in the artificial lakes Kossou (Côte d’Ivoire) and Nungua (Ghana)(Ref. 57129).
Coloration: 2 colour patterns can be discerned: the uniform and the marbled pattern (Ref. 248). In uniform pattern, specimens are uniform dark-brown, blackish brown or reddish brown on dorsal side and on flanks as well as on upper surface of paired fins, belly and lower surface of paired fins light brownish to beige (Ref. 248). In
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