Mormyrops (Oxymormyrus) zanclirostris, (Günther, 1867)
Species overview
Medium-sized fish, body much elongate, low, head conical with long, tubular, straight, pipefish-like snout and small, terminal mouth; unpaired fins very different in base-length; purplish-black. Size observed: 280 mm SL, 296 mm TL.
M. zanclirostris(measurements)
Taxonomic description
-Body much elongate, moderately laterally compressed, cross section oval, body depth 10-16 % SL, greatest depth at about middle of trunk.
-Head with curved pipe-shaped snout, tapering, head length 27-32 % SL, head depth 10-13 % SL, 66-100 % body depth.
-Outlines of back and belly more or less straight, upper profile of head more or less straight, i. e. slightly concave with a feeble elevation at the proximal part of the snout, underside of head concave, but much less so than in the otherwise very similar Mormyrops boulengeri. Snout tubular, very long*, the end clearly thicker than the middle, tip of upper jaw on a level with lower rim of eye; snout length 35-43 % head length, 59-81 % postorbital length, greatly depending on size / age of the fish.
-Mouth very small, 5-8 % head length, 12-21 % snout length, terminal, its edge reaching to level of posterior nostril.
-Chin with moderate submental swelling, lower jaw about as deep as upper part of snout.
-Teeth truncate, in closed lines, 14/14.
-Nostrils separate, circular, anterior below the level of lower rim of eye, posterior even a little lower, their axis slightly tilted to the axis of the snout, less than 30°; distance between nostrils 3-9 % snout length, distance posterior nostril to eye 78-90 % snout length.
-Eye small, its diameter 3-5 % head length, 6-8 % postorbital length.
-Opercular cleft curved, 17-27 % head length, 46-76% head depth.
-Dorsal fin 19-21 fin-rays, base of D 11-18 % SL, anal fin 34-39 rays, base of A 26-31 % SL, origin of D well behind A, end of D well before end A; predorsal length 68-75 % SL, preanal length 60-66 % SL.
-Pectoral fin rounded, extending to about half its distance from pelvic fin. V is closer to P than to A.
-Caudal fin rounded, the scaled lobes rounded, covering half of the entire fin. 70-74 scales in lateral line; 12 round caudal peduncle.
-Caudal peduncle 7-13 % SL, its depth 4-5 % SL, 29-50 % its length.
-Coloration Purplish-black, fin-rays dark brown, fin membrane transparent.
*) The extreme shape of the snout changes with age/size of the fish, in juveniles it is much less obvious.
Type locality
»Gabon«.
Distribution
Gabon (very abundant), Middle Congo basin.
Electric organ discharges
M. zanclirostris(elec. organ)