Marcusenius stanleyanus (Boulenger, 1897)
Species overview
Larger fish, body moderately elongate and deep, head uneven blunt-snouted, unpaired fins quite different in length; countershaded in coloration. Size observed: 400 mm TL.
M. stanleyanus(measurements)
Taxonomic description
-Body moderately elongate, laterally compressed, body depth 26-33 % SL, greatest depth near anal fin.
-Head length 23-27 % SL, head depth 17-23 % SL, 61-74 % body depth.
-Outline of back straight or slightly curved, upper profile of head convex, underside of head convex, outline of belly slightly convex.
-Snout obtusely pointed, 28-34 % head length, 52-66 % postorbital length.
-Mouth terminal, 12-20 % head length, its edge before anterior nostril, upper jaw on a level with centre of eye.
-Chin with big globular swelling.
-Teeth conical or truncate(?), 5-7/6.
-Nostrils separate, circular, closer together than both to rim of eye and to outline of head, anterior nostril on a level with upper rim of lens, posterior nostril on a level with centre of eye. Axis of nostrils cutting axis of head at an angle of about 45°.
-Eye diameter 13-19 % head length, 24-36 % postorbital length.
-Opercular cleft curved, 33-44 % head length, 47-56 % head depth.
-Dorsal fin 28-32 fin-rays, base of D 20-26 % SL, anal fin 35-40 rays, base of A 28-34 % SL, origin of D behind origin of A, end of D before end of A; predorsal length 58-65 % SL, preanal length 53-57 % SL.
-Pectoral fin pointed, extending to middle of pelvic fin. V is closer to P than to A.
-Caudal fin pointed, scaled lobes pointed, narrow, extending beyond middle of membranous lobes. 70-85 scales in lateral line; 12 round caudal peduncle.
-Caudal peduncle 15-20 % SL, its depth 5-7 % SL, 27-39 % its length.
-Coloration »Brown or brown above, and silvery below«, countershaded.
Type locality
»Stanley-Falls, 0° 50' N 25° 50' E«, to day Chutes Ngaliéma, Democratic Republic of Congo.
Distribution
Congo basin, Tanganyika Lake.