Isichthys henryi Gill, 1863
Species overview
Larger fish, much elongate, eel-like in habit, head truncate-snouted, unpaired fins rather long, caudal fin small, V closer to A than to P. Size observed: 287 mm SL.
I. henryi(measurements)
Taxonomic description
-Body much elongate, more or less oval in cross-section, body depth 8-9 % SL, greatest depth anterior to dorsal or to pelvic fin.
-Head short, head length 13-15 % SL, head depth 7-9 % SL, 87-93 % body depth.
-Outlines of back and belly rather straight; upper profile of head sloping, convex, underside of head concave.
-Snout rounded, 21-25 % head length, 28-35 % postorbital length.
-Mouth medium, subterminal, its edge below posterior nostril, upper jaw on a level with upper edge base of pectoral fin.
-Chin inconspicuous.
-Teeth on jaws rather large, notched 5-6/5-7, minute conical teeth on parasphenoid and tongue.
-Nostrils separate, anterior nostril on a level with upper rim of eye, equally distant from each other and from eye, their axis inclined about 60° to axis of head; posterior nostril oval, twice as large as anterior, on a level with below lower rim of eye.
-Eye small, its diameter 6-7 % head length, 8-10 % postorbital length.
-Opercular cleft S-shaped, about 1/4 head length, 1/2 head depth.
-Dorsal fin 34-54 fin-rays, base of D 44-48 % SL, anal fin 33-51 rays, base of A 39-41 % SL; D originating well before origin of A, ending before end of A; predorsal length 39-45 % SL, preanal length 46-52 % SL.
-Pectoral fin obtusely pointed, shorter than half its distance from pelvic fin. V is nearer to A than to P.
-Caudal fin very short, obtusely pointed, scaled lobes round, about half as long as fin. 120-163 scales in lateral line, 14-20 scales round caudal peduncle. (Scale counts as well as fin-ray counts display great local differences.) Caudal peduncle 8-10 % SL, its depth 3-5 % SL, 28-35 % its length.
-Coloration -Body and fin-rays dark brown, fin membranes transparent.
Type locality
Isichthys henryi: »?from Liberia?«, Mormyrus cobitiformis: »Tooxlong River, West Africa«.
Distribution
West Africa, coastal basins from Guinea, Sierra-Leone and Liberia, and West-Nigeria, lower Niger river to Mayumba, Gabon, Ivindo river.
Electric organ discharges
I. henryi(elec. organ)