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Dorsal spines (total): 0-0; Dorsal soft rays (total): 61-67; Anal spines: 0-0; Anal soft rays: 53-58. Diagnosis: Among clariids, Pseudotanganikallabes prognatha most closely resembles young Tanganikallabes specimens in external appearance, but can be easily distinguished from members of this genus by a number of characters: the number of post-Weberian vertebral elements in P. prognatha is lower than that of Tanganikallabes, 50-51 vs. 53-61; it further differs from T. mortiauxi by its relative shorter prepelvic length, 35.8-39.7% of standard length vs. 39.7-44.4%, and pre-anal length, 43.2-46.7% of standard length vs. 47.1-51.7%, shallower body, body depth at anus 9.1-10.3% of standard length vs. 12.3-17.2%, shorter snout, 4.1-5.5% of standard length vs. 5.7-8.2%, and lower total number of dorsal and anal-fin rays, 61-67 vs. 72-81 dorsal rays and 53-58 vs. 58-65 anal rays; it can be further separated from T. alboperca by its relative shallower body, body depth at anus 9.1-10.3% of standard length vs. 11.7-14.6%, and from T. stewarti by its relatively greater predorsal length, 31.4-34.4% of standard length vs. 28.0-31.2%, shorter dorsal fin, 66.7-69.7% of standard length vs. 70.3-75.4%, and lower total number of dorsal and anal-fin rays, 61-67 vs. 72-79 dorsal rays and 53-58 vs. 63-69 anal rays (Ref. 116742).
Description: Body elongate, moderately compressed posterior to distinct, bilateral swellings directly behind head; predorsal profile convex, initial downward slope gentle, increasing at vertical through middle of pectoral fin; dorsal profile posterior to origin of dorsal fin broadly convex; prepelvic profile relatively flat; broad, shallow concavity evident from anterior of pelvic fin to tip of snout; postpelvic profile with slight downward slope; skin on body forming numerous vertical ridges and folds (Ref. 116742). Head depressed and broad; skin thick; lateral cranial muscles hypertrophied; snout short, with bluntly rounded margin when viewed dorsally; acute, narrow margin when viewed laterally; anterior nostrils tubular; posterior nostrils poorly visible, located at posterior base of nasal barbel; opercular flap extending over base of pectoral-fin spine; eye small, located dorsolaterally, circular, completely subcutaneous; interorbital area broad, flat (Ref. 116742). Mouth terminal, slightly upturned; lips narrow and papillate; lower jaw distincly longer than upper; mandibular, premaxillary and vomerine teeth unicuspid, arranged in multiple transverse rows; teeth appear pointed, no fleshy pad present; mandibular toothpad wide, crescentic; premaxillary toothpad broadly curved, rectangular, noticeably wider than vomerine toothpad; vomerine toothpad located immediately posterior to premaxillary; narrow; broadly curved; crescentic; outer portions flared, rounded (Ref. 116742). Nasal barbel extends approximately to upper origin of opercular flap; maxillary barbel extends slightly beyond posterior margin of pectoral fin; lateral mandibular barbel extending to middle of pectoral fin; medial mandibular barbel extending just to, or slightly beyond lower opercular margin; all barbels smooth, with very narrow basal membrane (Ref. 116742). Dorsal fin elongate, lacking spine, with 61-67 soft rays; origin located slightly posterior to vertical through posterior tip of adpressed pectoral fin; posterior margin not joined with caudal fin; pectoral fin with 1 unbranched and 8-9 branched rays; anterior unbranched ray only partially ossified at proximal end; adipose fin absent; pelvic fin with 1 unbranched and 5 branched rays; tip of adpressed fin reaches beyond origin of anal fin; anal fin elongate, with 53-58 soft rays; posterior margin not joined with caudal fin; caudal fin with 24-25 total rays, 15 principal rays; rounded (Ref. 116742).
Colouration: Colouration in alcohol: dorsum and flanks yellowish brown to olive brown, ventral surfaces noticeably lighter, particularly on head and belly; stripe of darker, pinkish brown pigmentation begins behind head and extends, midlateraly, down majority of flank; all barbels lightly pigmented or entirely lacking pigmentation; all fins with brownish base and broad, depigmented border; operculum with wide, depigmented margin, extending onto underside of head; all fins with dark, brownish colouration at base, with clear margins; clear margins wider on paired and caudal fins than on dorsal and anal fins (Ref. 116742). |