Mormyrus kannume Forskål, 1775
Species overview
Large fish, body both moderately elongate and deep, head short with tapering, funnel-shaped snout, slightly shorter than postorbital part of head; mouth terminal with thick lips. Two conspicuous cutaneous sensory organs rim the eye. Caudal peduncle deep, caudal fin large. Countershaded. Size observed: 500 mm TL.
M. kannume(measurements)
Taxonomic description
-Body moderately elongate, laterally compressed, cross section oblong-oval, body depth 23-28 % SL, greatest depth near origin of dorsal fin.
-Head length 22-29 % SL; head depth 16-20 % SL, 65-85 % body depth.
-Outline of back (dorsal fin inclusive) convex, upper profile of head more or less straight up to the eye, above snout straight or feebly concave, underside of head concave, outline of belly, base of anal fin inclusive, slightly convex, with a light step to outline of caudal peduncle.
-Snout tapering, funnel-shaped, blunt, 40-51 % head length, 77-96 % postorbital length, moderately bent downward.
-Mouth 7-12 % head length, terminal, lips thick, edge of mouth far away from anterior nostril, the edge of upper jaw on a level clearly below underside of head.
-Chin with moderate submental swelling, lower jaw about as deep as upper part of snout.
-Teeth notched, 5-7/8-10.
-Nostrils separate, posterior nostril oval, anterior nostril on a level with lower rim of eye, axis of nostrils cutting axis of head at an angle of about 40°.
-Eye diameter 8-12 % head length, 17-26 % postorbital length. Two conspicuous tuberous organs, special electroreceptors, rim the eye, *).
-Opercular cleft curved 30-36 % head length, 36-62 % head depth.
-Dorsal fin 57-75 fin-rays, base of D 47-62 % SL, anal fin 18-21 rays, base of A 10-12 % SL, origin of D far before origin of A, opposite base of pelvic fin, end of D far behind end A; predorsal length 36-42 % SL, preanal length 58-62 % SL.
-Pectoral fin pointed, its origin at lower end of opercular cleft, extending to base of pelvic fin. V is slightly closer to P than to A.
-Caudal fin large, obtusely pointed, the scaled lobes extending over 3/4 of the entire fin. 80-115 scales in lateral line; 26-30 round caudal peduncle.
-Caudal peduncle rather deep, 11-15 % SL, 5-7 % SL 40-64 its length.
*) These cutaneous organs are very conspicuous but have not yet been used as taxonomic characters, though they are to be seen in very early drawings of mormyrids, see examples. They are confined to a few taxa only and consist of either one giant sensory cell each (in M. caschive, M. kannume, M, niloticus, M. jubelini and their synonyms) or of three to four giant sensory cells (M. thomasi ).
-Coloration »Brownish or olive above, white beneath«. Countershaded.
Rifaud, who made drawings of one of the synonyms, Mormyrus bachiqua , shows a brightly colored fish, pehaps in nuptial colouring.
Type locality
M. kannume: »Egypt«; M. oxyrhynchus, bachiqua, nacra: »Nil«; M. hildebrandti: »Adi River, Ukamba, E. Africa,.
Distribution
»Nile, Lakes Victoria (1° 00 ‘ S 33° 00 ‘ E), Kyoga (1° 30 ‘ N 25° 12 ‘ E), Albert (1° 40 ‘ N 31° 00 ‘ E), Edward (0° 25 ‘ S 29° 30 ‘ E) and George (0° 00 ‘ 30° 12 ‘ E); Victoria (2° 14 ‘ S 31° 26 ‘ E) and Murchison Niles, probably in the Athi (Adi) River, Kenya (2° 59 ‘ S 38° 31 ‘ E)«.