Brienomyrus (Brienomyrus) longicaudatus Taverne, Thys van den Audenaerde, Heymer and Géry, 1977
Species overview
Medium sized fish, underside of head concave, dorsal fin slightly shorter than anal, caudal peduncle strikingly long, caudal fin large, its membrane pointed, longer than the obtusely pointed scaled lobe. Size observed: 143 mm SL, 157 mm TL.
B. longicaudatus(measurements)
Taxonomic description
-Body quite elongate, laterally compressed, body depth 16-18 % SL, greatest depth at about middle of trunk, Length of head 20-23 % SL, head depth 13-16 % SL, 77-92 % body depth.
-Outline of back rather straight, upper profile of head straight or slightly convex, snout round, pointed or somewhat truncate, underside of head concave, outline of belly straight or slightly convex.
-Snout slightly protruding, 18-26 % head length, 27-39 % postorbital length.
-Mouth slightly subterminal, 14-17 % head length, upper jaw on a level with lower edge of opercular cleft.
-Chin with moderate submental swelling.
-Teeth notched, 5/6.
-Nostrils circular, both situated at a level underneath the centre of eye, anterior closer to front than posterior to eye, above posterior, but inclination relative to axis of head flat, about 30°.
-Eye small, 8-10 % head length, 11-15 % postorbital length.
-Opercular cleft slightly S-shaped, 29-33 % head length, 42-49 % depth of head.
-Dorsal fin 19-21 fin-rays, base of D 17-19 % SL, anal fin 24-25 rays, base of A 20-22 % SL; origin of D a little posterior to that of A, last rays of both fins opposite. Predorsal length 55-59 % SL, preanal length 52-56 % SL. Base of pectoral close to opercular cleft, P pointed, extending a little posterior to base of pelvic. V closer to P than to A.
-Caudal fin pointed, scaled lobes obtusely pointed, somewhat shorter membrane. 70-78 scales in lateral line, 12-14 round caudal peduncle.
-Caudal peduncle 25-27 % SL, its depth 5-6 % SL, 18-22 % its length.
-Coloration Head dark brown, body brown or dark brown, in that case somewhat countershaded. Bases of D and A brown, tips darker. Fin membranes transparent.
Type locality
»Rivière Ivindo, près de M’ Passa, Makokou, Gabon«. (Mouth of Ivindo river, tribuatry of Ogowe river: 0° 25 ‘ N 12° 48 ‘ E)
Distribution
Ivindo river, North Gabon, (types localities).