Marcusenius ussheri (Günther, 1867)
Species overview
Medium-sized fish, body moderately deep, head uneven blunt-snouted, tip of upper jaw rather sharp, bases of unpaired fins equal in length. Size observed: 260 mm SL, 305 mm TL, weight 240 g.
M. ussheri(measurements)
Taxonomic description
-Body moderately elongate and deep, laterally compressed, body depth 26-39 % SL, greatest depth near unpaired fins.
-Head length 20-29 % SL, head depth 16-25 % SL, 60-85 % body depth.
-Outline of back more or less straight, upper profile of head convex, tip of upper jaw rather sharp, underside of head concave, outline of belly slightly convex, somewhat wavy.
-Snout obtusely pointed, 17-32 % head length, 35-57 % postorbital length.
-Mouth terminal, 10-20 % head length, its edge before anterior nostril, upper jaw on a level with lower edge of opercular cleft.
-Chin with big globular swelling, directed forward-downward.
-Teeth notched, 5/6.
-Nostrils separate, circular, anterior nostril on a level with centre of eye, posterior with lower rim; axis of nostrils cutting axis of head at an angle of about 45°.
-Eye diameter 14-23 % head length, 27-56 % postorbital length.
-Opercular cleft curved, 30-41 % head length, 42-49 % head depth.
-Dorsal fin 22-29 fin-rays, base of D 17-27 % SL, anal fin 27-34 rays, base of A 21-29 % SL, origin of D behind origin of A, end of D before end of A; predorsal length 56-67 % SL, preanal length 55-66 % SL.
-Pectoral fin pointed, extending to middle of pelvic fin. V is closer to P than to A.
-Caudal fin pointed, scaled lobes half as long as entire fin. 50-65 scales in lateral line; 12 round caudal peduncle.
-Caudal peduncle 16-21 % SL, its depth 6-8 % SL, 24-54 % its length. (G. bruyerei has 8 circumpeduncular scales, not 12 as indicated by Pellegrin.)
-Coloration M. ussheri: »Brown« G. bruyerei: Quite dark all over, small specimens with traces of a dark vertical band between origin of D and A, gradually fading with increasing length. Original description indicates a countershaded coloration, »silvery, darker on the back«.
Type locality
M. ussheri: »Bossumprah River, Gold Coast« = Pra River (6° 26 ‘ N 1° 47 ‘ W)
G. bruyerei: »Riv. Lahou ou Bandama. Rapides de Tiassalé à 80 km de la côte (Côte d’ Ivoire)« (Bandama River, 5° 10 ‘ N 04° 58 ‘ W, Tiassalé, 5° 54 ‘ N 4° 50 ‘ W.)
Distribution
M. ussheri: »Liberia to Gold Coast«.
G. bruyerei: »Ivory Coast (from Cavally to Bia River)«.