Hippopotamyrus psittacus (Boulenger, 1897)
Species overview
Medium-sized fish body moderately deep, back keeled, head round-snouted, snout rounded, short, dorsal fin originating clearly anterior but ending opposite to anal fin. Silvery with darker back countershaded. Size observed: 240 mm SL.
H. psittacus(measurements)
Taxonomic description
-Body moderately deep, strongly laterally compressed, back keeled, body depth 25-32 % SL, greatest depth near dorsal fin, head length 19-25 % SL, head depth 19-24 % SL, 65-74 % body depth.
-Outline of back nearly straight between neck and dorsal fin, on head sloping steeper; upper profile of head strongly convex, underside of head concave, outline of belly slightly convex. Bases of unpaired fins straight.
-Snout rounded, feebly protruding mouth, snout length 21-26 % head length, 37-46 % postorbital length.
-Mouth small, terminal or slightly subterminal, edge of mouth below posterior nostril, upper jaw on a level with upper edge base of pectoral fin.
-Chin with moderate submental swelling.
-Teeth notched, 5-7/6-8.
-Nostrils separate, circular, axis of nostrils cutting axis of head at an angle of about 45°. Anterior nostril on a level with centre of eye, posterior on a level with lower rim of eye, both nearer eye than tip of snout.
-Eye moderately large, its diameter equals length of snout.
-Opercular cleft about 1/3 head depth.
-Dorsal fin 30-37 fin-rays, its base 31-36 % SL, anal 22-27 rays, its base 19-22 % SL, D originating well before origin of A but ending behind it; predorsal length 50-55 % SL, preanal length 55-60 % SL; longest rays of A clearly longer than those of D.
-Pectoral fin pointed, extending to base of pelvic fin. V closer to P than to A.
-Caudal fin with both long pointed scaled and membranous lobes. 61-72 scales in lateral line, 12 around caudal peduncle.
-Caudal peduncle 17-21 % SL, its depth 5-7 % SL, 26-34 % its. length.
-Coloration »Silvery, dark grey at the back«. Countershaded
Type locality
»Stanley Falls« Upper Congo, to day Chutes Ngaliéma, »Upper Congo« corresponds to Democratic Republic of Congo north of Matadi.
Distribution
Congo river, basins of Niger, Benoué and Volta rivers, and of l’ Ouemé and l’ Ogun.