Campylomormyrus mirus (Boulenger, 1898)
Species overview
Large fish, moderately elongate and deep, head trunk-shape snouted, snout deep, strongly compressed, barbel thin, about 3/4 as long as snout. Brown, back darker, countershaded.
Size observed: 300 mm SL, 343 mm TL.
C. mirus(measurements)
Taxonomic description
-Body moderately elongate, laterally compressed, 25-29 times in SL, greatest depth close to anal fin, clearly decreasing towards the head; head short, 19-22 % SL measured without snout, 31-33 % SL, snout inclusive, head depth 19-23 % SL, 74-84 % body depth.
-Outlines of back more or less straight, upper profile of head strongly convex, underside of head strongly concave, outline of belly slightly convex.
-Snout or rostrum, steeply bent down, but rather short, 80-95 % head length, its least depth equals twice the eye diameter. (The extreme shape of the snout changes with age/size of the fish, in juveniles it is much less obvious).
-Mouth directed downward, small, 5-10 % snout length, edge of mouth very far away from anterior nostril, upper jaw well below head.
-Chin with submental swelling and a thin barbel, about 3/4 as long as snout.
-Teeth conical, 3/4.
-Nostrils separate, circular, at same level before and below eye, anterior nostril 1.5 times the distance between nostrils away from front contour, posterior about 1.3 times eye diameter away from eye; axis of nostrils runs more or less parallel to axis of head.
-Eye medium, 28-43 % postorbital length.
-Opercular cleft curved, 36-41 % shortest head length, rather steep.
-Dorsal fin 34 rays, base of D 24-27 % SL, anal 35, base of A 25-29 % SL, origin of D behind origin of A, ending more or less opposite the end of A; predorsal length 55-60 % SL, preanal length 53-57 % SL.
-Pectoral pointed, its base close to opercular cleft, extending to middle of pelvic fin. V is closer to P than to A.
-Caudal fin with short scaled lobes, membranes pointed. 78 scales in lateral line, 12 around caudal peduncle. Length of caudal peduncle 12-17 % SL, its depth 5-6 % SL, 30-35 % its length.
-Coloration Uniform brown, darker above, slightly countershaded.
Type locality
»Upoto« Upper Congo (02° 00 ‘ N 21° 30 ‘ E) Democratic Republic of Congo.
Distribution
Congo basin.