Mormyrops (Mormyrops) caballus Pellegrin, 1927
Species overview
Large fish, body elongate, moderately laterally compressed, low; head moderately tapering with concave upper and lower profile with eyes on upper side, snout blunt, rounded, mouth subterminal; caudal fin rather large; brown, slightly countershaded. Size observed: 460 mm SL.
M. caballus(measurements)
Taxonomic description
-Body much elongate, moderately laterally compressed, cross section oblong-oval, body depth 13-16 % SL, greatest depth not precisely to locate.
-Head length 26-29 % SL, head depth 9-13 % SL, 74-89 % body depth.
-Outlines of back and belly straight, running parallel to each other; upper profile as well as underside of head concave, making the profile horse-like; seen from above it looks like the beak of a duck.
-Snout rather long and feebly bent down, with rounded end, both seen in profile and from above, 23-26 % head length, 32-37 % postorbital length.
-Mouth 7-10 % head length, subterminal, its edge below posterior 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 snout.
-Teeth truncate, small, in closed line, 14-24/12-22.
-Nostrils separate, circular, distance between nostrils 8-12 % snout length, distance posterior nostril to eye 60-70 % snout length, both on a level with centre of eye, their axis running parallel to axis and upper contour of head.
-Eye positioned more on upper side of head than laterally of it, small, diameter 3-5 % head length, 5-7 % postorbital length.
-Opercular cleft slightly curved, 22-28 % head length, 47-64 % head depth.
-Dorsal fin 26-35 fin-rays, base of D 22-25 % SL, anal fin 39-45 rays, base of A 28-34 % SL, origin of D well behind origin of A, end of D well before end of A; predorsal length 64-67 % SL, preanal length 56-61 % SL.
-Pectoral fin rounded, about half as long as distance between pectoral and pelvic fin. V is slightly closer to P than to A, distance P - V 14-17 % SL, V - A 15-19 Caudal fin rounded, the scaled lobes rounded, extending over 3/4 of the entire fin. 82-113 scales in lateral line; 12-22 round caudal peduncle.
-Caudal peduncle 8-13 % SL, its depth 4-5 % SL, 33-50 % its length.
-Coloration Uniform dark, slightly lighter beneath, (slightly countershaded).
Type locality
M. caballus: »Riv. Sanaga, à Nanga-Eboko; et Riv. Nyong à Dehane (Cameroun)« (Nanga-Eboko (04° 41 ‘ N 12° 22 E; Nyong R. 03° 17 ‘ N 09° 34 ‘ E.)
M. bachrachi: »?in den Nachtigallenschnellen des Sanagaflusses, Kamerun« , co-ordinates see above.
Distribution
Sanaga and Nyong Rivers, Cameroon; Benoue River, Nigeria; Sewa and Jong Rivers, Sierra Leone and Konkure River, Rep. Guinea.