Mormyrus proboscirostris Boulenger, 1898
Species overview
Large fish, body moderately elongate and deep, head rather long with long, tapering, funnel-shaped snout, terminal mouth with thick lips. No conspicuous cutaneous sensory organs below the eye. Pectoral fin reaching origin of pelvic fin, caudal fin moderately large with rounded lobes. Variable in coloration. Size observed:
M. proboscirostris(measurement)
Taxonomic description
-Body both moderately elongate and deep, laterally compressed, cross section oblong-oval, body depth 19-24 % SL, greatest depth at origin of pectoral fin.
-Head length 20-31 % SL; head depth 13-19 % SL, 67-79 % body depth.
-Outline of back (dorsal fin inclusive) convex, upper profile of head up to tip of snout more or less straight, underside of head concave, outline of belly convex, base of anal fin in a slight step ascending to caudal peduncle.
-Snout tapering to form a rather long funnel or trunk, slightly directed downwards, 38-51 % head length, 78-111 % postorbital length.
-Mouth 8-13 % head length, terminal, lips, in particular lower lip, slightly protruding, edge of mouth far away from anterior nostril, edge of upper jaw on a level with lower edge of opercular cleft.
-Chin with moderate submental swelling, lower jaw less deep than upper part of snout.
-Teeth notched, 5-7/12-14.
-Nostrils separate, oval, distance between nostrils 4-10 % snout length, distance posterior nostril to eye 21-35 % snout length, anterior nostril well below lower rim of eye, posterior nostril below anterior. Axis of nostrils cutting axis of snout at an angle of about 45°.
-Eye diameter 7-15 % head length, 14-30 % postorbital length. No conspicuous tuberous organs below the eye.
-Opercular cleft curved 28-36 % head length, 33-54 % head depth.
-Dorsal fin 75-82 fin-rays, base of D 51-58 % SL, anal fin 17-20 rays, base of A 8-12 % SL, origin of D far before origin of A, halfway between bases of P and V, end of D far behind end of A; predorsal length 35-44 % SL, preanal length 55-64 % SL.
-Pectoral fin obtusely pointed, originating at lower third of opercular cleft, extending to base of pelvic fin. V is slightly closer to P than to A.
-Caudal fin rounded, the scaled lobes covering 3/4 of the entire fin. 95-130 scales in lateral line; 18-24 round caudal peduncle.
Caudal peduncle 9-14 % SL, its depth 5-6 % SL, 33-56 % its length.
-Coloration »Pinkish or brown, sometimes with a broad bluish-grey stripe extending along each side of the body and tail«.
Type locality
M. proboscirostris: »Upoto« Haute Congo, Democratic Republic of Congo (2° 00 ‘ N 21° 30 ‘ E)
M. bozasi: »Rivière Ouellé-Doungo«, 3° 37' N 28° 34' E. Central Africa (Congo français). Doungo river is a tributary of the Ouelle, which in turn is a tributary of the Ubangi. (Recently: Republic of Congo Brazzaville and Central African Republic.)
Distribution
Congo River basin.