Diagnosis: Tanganikallabes stewarti is distinguished from all congeners by having an incomplete lateral line, which terminates at a vertical through a point approximately two-thirds of the distance along the anal fin base, vs. lateral line reaching the caudal peduncle in T. mortiauxi and extending much closer to the caudal peduncle in T. alboperca ; and by its relatively shallower body, body depth at anus 8.7-10.9% of standard length vs. 12.3-17.2% in T. mortiauxi and 11.7-14.6% in T. alboperca (Ref. 90118). Tanganikallabes stewarti is further separated from T. mortiauxi by its premaxillary toothpad shape, uniformly thin, broad crescent, vs. widest point anteroposteriorly thicker; lack of a free lower orbital margin; io-iv and the suprapreopercle consisting of multiple separate elements, vs. a single element; the extensions of the lateral ethmoid not reaching io-ii when viewed from above, vs. nearly or completely overlaying io-ii; its proportionally shorter prepelvic length, 35.7-39.2% of standard length vs. 39.7-44.4%; its proportionally shorter preanal length, 42.4-44.8% of standard length vs. 47.1-51.7%; longer anal fin, anal fin base 54.1-58.9% of standard length vs. 47.6-54.2% (Ref. 90118). It can additionally be distinguished from T. alboperca by its lack of a depigmented opercular margin; having longer pelvic fins, 7.1-9.3% of standard length vs. 6.0-7.7%, which reach beyond the origin of the anal fin when adpressed; proportionately longer pectoral fin spines, 5.0-6.8% of standard length vs. 3.6-5.3%; a shorter preanal length, 42.4-44.8% of standard length vs. 45.2-49.0%; and a generally higher number of dorsal fin rays, 72-79 vs. 65-74, and anal fin rays, 63-69 vs. 55-63 (Ref. 90118).

Description: Body elongate, moderately compressed posterior to origin of dorsal fin; predorsal profile convex, with distinct hump formed between origin of dorsal fin and basioccipital; only slightly convex from basioccipital to snout; prepelvic profile slightly convex; skin on body forming numerous vertical ridges and folds; extending onto and encasing all fins (Ref. 90118). Head depressed and broad; skin thick; lateral cranial muscles hypertrophied, forming trough in centre of head over bones of skull; 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; lacking free margin; interorbital area broad, flat (Ref. 90118). Mouth terminal; lips narrow and papillate; jaws equal, or upper jaw slightly longer; mandibular, premaxillary, and vomerine teeth pointed, unicuspid, arranged in multiple transverse rows; toothpads granular in apearance because of embedding of teeth in fleshy pad for most of their length; 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 (Ref. 90118). Nasal barbel short; not extending to any aspect of opercular flap; maxillary and lateral mandibular barbels extending to, or slightly beyond, tip of adpressed pectoral fin spine; medial mandibular barbel extending slightly beyond lower opercular margin; all barbels smooth, with very narrow basal membrane (Ref. 90118). Dorsal fin elongate, lacking spine, with 72-79 soft rays; origin located well behind vertical through posterior tip of adpressed pectoral fin; posterior margin not joined with caudal fin; pectoral fin I,7-9; strong spine, well-developed venom glands present; spine approximately two-thirds the length of pectoral fin; posterior matgin of spine with between zero and five very small, retrorse serrations; adipose fin absent; pelvic fin i,5; tip of adpressed fin reaches beyond origin of anal fin; anal fin elongate, with 63-69 branched rays; posterior margin not joined with caudal fin; caudal fin i,7,8,i; rounded (Ref. 90118).

Colouration: In alcohol, dorsum and flanks brown to dark brown, with ventral surfaces slightly lighter, although less so than in other Tanganikallabes species; some specimens show marbled appearance, with randomly arranged regions of lighter and darker colouration; other specimens uniform in dorsum and flank colouration; maxillary barbels uniformly brown, wometimes with slightly lighter pigmentation near tips; nasal and mandibular barbels brown on proximal half, with distal portions becoming noticeably lighter; all rayed fins uniformly brown, with distinct, thin, white margin in smaller individuals (Ref. 90118).