Campylomormyrus numenius (Boulenger, 1898)
Species overview
Large size fish, moderately elongate and deep, head trunk-shape snouted, snout extremely long, thin, slightly curved down. Back brownish, whitish belly, juveniles lighter, with two dark bands between unpaired fins, countershaded. Size observed: 581 mm SL, 650 mm TL.
C. numenius(measurements)
Taxonomic description
-Body laterally compressed, depth 20-23 % SL, or 4.5-5 times in SL, greatest depth close to anal fin.
-Head length, without snout, 12-19 % SL, 33-46 % SL snout inclusive, head depth 15-20 % SL, 60-80 % body depth.
-Outline of back more or less straight, outline of belly slightly convex, underside of head concave. Upper profile of head concave, sloping at an angle of about 60°, a shape which is found in small as well as in large specimens and in small ones continuing on the snout, which is 2-3 times as long as postorbital length. In large specimens the snout is a very long compressed tube, feebly curved and moderately bent down at an angle of no more than about 30°, 4-5 times postorbital length and up to 20 times its least depth or about as deep as eye diameter. (The extreme shape of the snout changes with age/size of the fish, in juveniles it is much less obvious).
-Mouth small, 2-5 % snout length, directed forward, edge of mouth very far away from anterior nostril, upper jaw much below head.
-Chin with moderate submental swelling fleshy and a small barbel, about as long as eye diameter.
-Teeth conical 6-8/4-6.
-Nostrils oval, separate, anterior one slightly above posterior, which is at level of lower rim of eye, and in smaller fish 1/2, in larger ones about one eye diameter away from the eye; axis of nostrils runs more or less parallel to axis to of head.
-Eye diameter 15-27 % head length.
-Opercular cleft S-shaped, 37-45 % head depth.
-Dorsal fin 27-34 fin-rays, anal 36-37, base of D 18-20 % SL, base of A 23-24 % SL, D originating behind origin of A, ending more or less opposite end of A; predorsal length 63-71 % SL, preanal length 56-64 % SL.
-Pectoral pointed, extending to tip of pelvic. V is closer to P than to A.
-Caudal obtusely pointed, scaled portion short. Lateral line 76-82 scales, 16 round caudal peduncle, which is 13-17 % SL in length, its depth 4-5 % SL, 24-30 % its length.
-Coloration »Younger specimens dark brown with two blackish vertical band between D and A, which are lacking in larger fish with a brownish back and whitish underside,« countershaded.
Type locality
C. numenius : »Upoto«, upper Congo (02° 00 ‘ N 21° 30 ‘ E), C. ibi: »Banzyville Ubanghi«, recently Mobayi-Mbengo (04° 18 ‘ N 21° 11 ‘ E), district Équateur, Democratic Republic of Congo.
Distribution
Congo basin, Congo river and Ubangi river.