Marcusenius mento (Boulenger, 1890)
Species overview
Medium-sized fish, body moderately elongate and deep, head uneven blunt-snouted, chin with strong globular swelling. Uniform dark. Size observed: 273 mm SL.
M. mento(measurements)
Taxonomic description
-Body moderately elongate, laterally compressed, body depth 25-28 % SL, greatest depth near anal fin.
-Head length 19-22 % SL, head depth 16-29 % SL, 61-65 % body depth.
-Outline of back slightly convex, upper profile of head convex, underside of head concave, outline of belly slightly convex.
-Snout 20-32 % head length, 39-51 % postorbital length.
-Mouth 14-18 % head length, terminal, its edge before anterior nostril, upper jaw on a level with lower edge opercular cleft.
-Chin with strong globular swelling, directed forward-downward.
-Teeth notched, 5/6.
-Nostrils separate, circular, closer to each other than to rim of eye and to front contour, anterior nostril on a level with centre of eye, posterior nostril above lower rim of eye; their axis cutting axis of head at an angle of about 45°.
-Eye diameter 15-21 % head length, 26-38 % postorbital length.
-Opercular cleft curved, 32-38 % head length, 35-44 % head depth.
-Dorsal fin 25-34 fin-rays, base of D 21-25 % SL, anal fin 33-39 rays, base of A 26-30 % SL, D originating behind origin of A, ending before end of A; predorsal length 58-61 % SL, preanal length 53-57 % SL.
-Pectoral fin pointed, extending beyond base of pelvic fin. V is closer to P than to A.
-Caudal fin pointed, scaled lobes. about half as long as entire fin. 76-87 scales in lateral line; 12 round caudal peduncle.
-Caudal peduncle 18-20 % SL, its depth 5-6 % SL, 25-31 % its length.
-Coloration »Uniform dark, sometimes almost blackish« described from west Africa, »Silvery with fine brown dots, which are crowded on the head and the dorsal and ventral lines« described from Gabon and Liberia.
Type locality
»Gabon«.
Distribution
Gabon, Portuguese Guinea, Cameroon, Sierra Leone - West Liberia, Gambia, Senegal, Upper Niger.