Mormyrus macrophthalmus Günther, 1866
Species overview
Larger fish, body moderately elongate, tapering towards caudal peduncle, head strongly curved with very large eyes, snout quite short, its upper portion much deeper than lower jaw, mouth terminal. No conspicuous cutaneous sensory organs below the eye. Caudal peduncle slender. Size observed: 280.5 mm SL, 333 mm TL.
M. macrophthalmus(measurements)
Taxonomic description
-Body moderately elongate, tapering towards tail, laterally compressed, cross section oblong-oval, body depth 20-29 % SL, greatest depth close to origin of dorsal fin.
-Head length 19-23 % SL; head depth 15-20 % SL, 73-83 % body depth.
-Outline of back (dorsal fin inclusive) convex, upper profile of head strongly convex up to end of snout, underside of head concave, outline of belly slightly convex, a moderate step at base of anal fin.
-Snout very short, blunt, feebly protruding mouth, its length, measured from rim of eye to tip of upper jaw 27-34 % head length, 52-61 % postorbital length.
-Mouth 10-16 % head length, slightly subterminal, its edge below anterior nostril, tip of upper jaw on a level below underside of head.
-Chin with moderate submental swelling, lower jaw about as deep as upper jaw.
-Teeth very small, feebly notched, 5-8/6-9.
-Nostrils separate, but rather close to each other, slightly oval, anterior nostril on a level with lower rim of lens, posterior nostril on a level with lower rim of eye. Axis of nostrils cutting axis of head at an angle of about 45°.
-Eye large, orbit slightly oval, very close to outline of head, eye diameter 21-27 % head length, 39-53 % postorbital length. No conspicuous cutaneous sensory organs below the eye.
-Opercular cleft curved, 33-40 % head length, 38-48 % head depth.
-Dorsal fin 59-68 fin-rays, base of D 51-56 % SL, anal fin 18-22 rays, base of A 10-14 % SL; origin of D far before origin of A, slightly in before of pelvic fin, end of D far behind end of A; predorsal length 32-36 % SL, preanal length 48-58 % SL.
-Pectoral fin pointed, extending to or slightly beyond base of pelvic fin. V is clearly closer to P than to A.
-Caudal fin pointed, the scaled lobes extending over 3/4 the length of the entire fin. 78-92 scales in lateral line; 12-16 round caudal peduncle.
-Caudal peduncle slender, 11-16% SL, its depth 4-5 % SL 27-49 % its length.
-Coloration »Generally silvery with greenish-grey back and bright belly« Countershaded.
Type locality
»West Africa« Niger.
Distribution
Niger, Benue and Volta basins.