Marcusenius nyasensis (Worthington, 1933)
Species overview
Medium-sized fish, body both moderately elongate and deep, head slightly longer than deep, uneven blunt-snouted; outline of back and outline of belly slightly approaching towards the head; almost uniform dark in coloration. Size observed: 269 mm SL.
M. nyasensis(measurements)1
M. nyasensis(measurements)2
M. nyasensis(measurements)3
Taxonomic description
-Body moderately elongate laterally compressed, body depth 22-32 % SL, greatest depth near anal fin or somewhat anterior to it.
-Head length 22-28 % SL, head depth 17-23 % SL, 71-95 % body depth.
-Outlines of back and belly slightly convex, upper profile of head convex, underside of head concave.
-Snout obtusely pointed, 19-28 % head length, 30-49 % postorbital length.
-Mouth moderate, terminal, edge of mouth before nostril, upper jaw on a level with centre of eye.
-Chin with globular appendage, moderately long.
-Teeth notched, 2-6/4-6.
-Nostrils separate, circular, posterior nostril on a level with centre of eye, anterior above it, both closer together than their distance from eye; distance from outline of snout about the same as distance between nostrils; axis of nostrils cutting axis of head at an angle of about 45°.
-Eye diameter 13-18 % head length, 21-30 % postorbital length.
-Opercular cleft curved, 34-46 % head length, 37-50 % head depth.
-Dorsal fin 20-22 fin rays, base of D 17-22 % SL, anal fin 29-31 rays, base of A 23-26 % SL, D originating behind origin of A, ending before end of A; predorsal length 61-67 % SL, preanal length 56-62 % SL.
-Pectoral fin pointed, extending to base of pelvic fin or slightly beyond. V is closer to P than to A.
-Caudal fin obtusely pointed, scaled lobes rounded, more than half as long as entire fin. 58-62 scales in lateral line; 12 round caudal peduncle.
-Caudal peduncle 17-21 % SL, its depth 7-8 % SL, 35-43 % its length.
(The type sample consists of 27 syntypes, some of which may belong to M. macrolepidotus, the proportions above are basing on 14 specimens that are matching the original description best.)
-Coloration »Uniform dark brown, paler beneath [countershaded]; small specimens more or less marbled with dull yellow«. Preserved specimens may have one or two dark bands between the unpaired fins.
Type locality
»Bar house and S. W. arm of Lake«, Nyasa Lake - L. Malawi.
Distribution
Lake Nyasa - Lake Malawi.