Brienomyrus (Brienomyrus) brachyistius (Gill, 1863)
Species overview
Medium sized fish, elongate; head round-snouted, snout short, slightly protruding mouth, dorsal fin much shorter than anal. Uniform brown. Size observed: 132 mm SL.
B. brachyistius(measurements)1
B. brachyistius(measurements)2
B. brachyistius(measurements)3
Taxonomic description
-Body elongate, laterally compressed cross section oblong-oval, body depth 19-23 % SL, greatest depth about middle of trunk, head length 18-23 % SL, head depth 14-20 % SL, 68-94 % body depth.
-Outline of back straight to slightly curved, upper profile of head convex, underside of head concave, outline of belly slightly convex.
-Snout rounded, 15-29 % head length, 23-46 % postorbital length, slightly protruding mouth; mouth subterminal, 12-22 % head length; edge of mouth below anterior nostril, upper jaw on a level with midline of head.
-Chin inconspicuous, without appendage.
-Teeth small, notched, 3-7/5-8.
-Nostrils round, nearly at middle of snout, anterior on a level with centre of eye, posterior on level of lower rim of orbit; axis of nostrils cutting axis of head at an angle of about 30°.
-Eye 9-17 %, 14-26 % postorbital length.
-Opercular cleft slightly rounded, 35-47 % head length, 41-57 % head depth.
-Dorsal fin 15-19 fin-rays, base of D 13-18 % SL, anal fin 25-31 rays, base of A 23-30 % SL, D originating well behind origin of A, ending before end of A.; predorsal length 62-70 % SL, preanal length 53-63 % SL Pectoral obtusely pointed, extending to base of pelvic. V is closer to P than to A.
-Caudal fin obtusely pointed, its basal lobe densely scaled and about half as long as total fin. 53-67 scales in lateral line, 12 round caudal peduncle.
-Caudal peduncle slender, 14-20 % SL, its depth 5-7 % SL, 21-43 % its length.
(Description based on types of B. brachyistius and M. liberiensis only; see also B. longianalis .)
-Coloration, uniform brown, no markings on body or fins.
Type locality
B. brachyistius: »No data, probably sent from Liberia«;
M. liberiensis: »?aus dem Suleymah und Junk-Flusse und den in den Fischermann See einmündenden Flüssen«.
Distribution
»Coastal drainages from Gambia to Zaïre (Democratic Republic of Congo)«, upper Senegal river.
Electric organ discharges
Biphasic, head positive, +/- , rather long discharge, no detailed information available
B. brachyistius(EOD)