Mormyrus lacerda Castelnau, 1861
Species overview
Large fish, body both moderately elongate and deep, head short, snout blunt, funnel-shaped, slightly bent downwards, mouth terminal, upper jaw twice as deep as lower. No conspicuous cutaneous sensory organs below the eye. Caudal peduncle rather deep, caudal fin large. Countershaded. Size observed: 500 mm TL, about 2 kg.
M. lacerda(measurements)
Taxonomic description
-Body moderately elongate, laterally compressed, cross section oblong-oval, body depth 22-27 % SL, greatest depth at origin of dorsal fin.
-Head length 23-27 % SL; head depth 15-20 % SL, 68-81 % body depth.
-Outline of back (dorsal fin inclusive) slightly convex, upper profile of head convex, tip of snout rounded, underside of head concave, outline of belly, base of anal fin inclusive, slightly convex, no obvious step at base of A.
-Snout funnel-shaped, tip blunt, rounded, 28-34 % head length, 50-61 % postorbital length.
-Mouth 10-15 % head length, terminal, rather deeply incised, its edge far away from anterior nostril, edge of upper jaw on a level with upper edge base of pectoral fin.
-Chin with moderate submental swelling, lower jaw less deep than upper part of head.
-Teeth notched, 7-9/10-11.
-Nostrils separate, slightly oval, lower nostril on a level with lower rim of eye, their axis cutting axis of head at an angle of about 40°.
-Eye diameter 8-14 % head length, 14-24 % postorbital length. No conspicuous cutaneous sensory organs below the eye.
-Opercular cleft curved, 36-46 % head length, 50-68 % head depth.
-Dorsal fin 62-68 fin-rays, base of D 48-56 % SL, anal fin 17-21 rays, base of A 11-15 % SL, origin of D far before origin of A, well before of pelvic fin, end of D far behind end A; predorsal length 34-38 % SL, preanal length 61-65 % SL.
-Pectoral fin obtusely pointed, originating at lower third of opercular cleft, extending over 3/4 the distance to pelvic fin. V is slightly closer to P than to A or equally distant.
-Caudal fin obtusely pointed, the scaled lobes obtusely pointed, extending over 2/3 of its length. 80-92 scales in lateral line; 18-26 round caudal peduncle.
-Caudal peduncle 11-15 % SL, its depth 7-8 % SL 47-65 % its length.
-Coloration Brown, olive brown or grey on the back, more or less silvery or pale grey beneath, in large specimens a whitish band along the lateral line. Fins darker. Countershaded.
Type locality
M. lacerda: »Lac Ngami« Botswana (20° 37 ‘ S 22° 40 ‘ E); M. anchietae: »Cunene Caconda (R. Cuce) Angola« (16° 30 ‘ S 15° 00 ‘ E); M. ellenbergeri: »Haut-Zambêze, aux environs de Léalui, capitale indigène du pays des Barotsé ou Barotseland (North Western Rhodesia)«Western Zambia, (Barotseland: 15° 05 ‘ S 24° 00 ‘ E).
Distribution
Upper Zambesi above Victoria Falls, Cunene, Kafue and Okavanga river systems.