Mormyrus casalis Vinciguerra, 1922
Species overview
Medium-sized fish, body moderately elongate and deep, head about as long as depth of body, snout blunt, funnel-shaped, slightly bent down, mouth terminal, two conspicuous cutaneous sensory organs below the eye. Caudal peduncle quite deep. A species close to M. kannume as stated by its author. Known only from the type. Size observed: 218 mm L, 250 mm TL.
M. casalis(measurements)
Taxonomic description
-Body moderately elongate, moderately laterally compressed, cross section oblong-oval, deep, depth of body 29 % SL, greatest depth at origin of dorsal fin.
-Head length 28 % SL; head depth 22 % SL, 75 % depth of body.
-Outline of back (dorsal fin excluded) convex, upper profile of head closer to tip concave, above eye feebly convex, underside of head concave.
-Outline of belly slightly convex up to origin of anal fin, the base of which clearly ascends to caudal peduncle.
-Snout funnel-shaped, blunt, bent down, moderately compressed, 38 % head length, 71 % postorbital length.
-Mouth small, 9 % head length, terminal, edge of mouth far away from anterior nostril, edge of upper jaw on a level with lower edge base of pectoral fin.
-Chin with moderate submental swelling, lower jaw about as deep as upper part of snout.
-Teeth notched, 7/10.
-Nostrils separate, anterior circular, posterior oblong, anterior on a level with lower rim of eye, posterior nostril deeper; axis of nostrils cutting axis of head at an angle of about 40°.
-Eye diameter 14 % head length, 26 % postorbital length. Below the eye (the type best shows it on the right side of the head) two conspicuous sensory organs, tuberous or knollenorgans, special electroreceptors.
-Opercular cleft curved, 34 % head length, 45 % head depth.
-Dorsal fin 60 fin-rays, base of D 46 % SL, anal fin 25 rays, base of A 46 % SL, origin of D far before origin of A, a little before origin of pelvic fin, end of D well behind end A; predorsal length 42 % SL, preanal length 63 % SL.
-Pectoral fin obtusely pointed, its origin at lower end of opercular cleft, extending over 4/5 the distance to pelvic fin. V is slightly closer to A than to P.
-Caudal fin with obtusely pointed membranes and pointed scaled lobes extending over 3/4 of the length of the fin. 92 scales in lateral line; 26 round caudal peduncle.
-Caudal peduncle 12 % SL, its depth 8 % SL, 67 % its length.
-Coloration »Uniform chestnut-brown, somewhat lighter below« (countershaded).
Type locality
»?basso corso dello Uebi Scebeli; fiume della Somalia italiana«.
Distribution
Somalia, (type locality) Webi Shebeli (Mouth at 0° 12 ‘ S 42° 45 ‘ E)