Tanganikallabes stewarti Wright & Bailey 2012, SP. NOV.
Creators: name: Wright, Jeremy J.
name: Bailey, Reeve M.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Actinopterygii
Siluriformes
Clariidae
Tanganikallabes
Tanganikallabes stewarti

description: TANGANIKALLABES STEWARTI SP. NOV.  (FIGS 3C, 4B, 11–13; TABLES 3, 5)  
 Diagnosis: Tanganikallabes stewarti sp. nov. 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 (versus lateral line reaching the caudal peduncle in T. mortiauxi and extending much closer to the caudal peduncle in T. alboperca sp. nov.; Fig. 11), and by its relatively shallower body (body depth at anus 8.7–10.9% SL versus 12.3–17.2% SL in T. mortiauxi and 11.7–14.6% SL in T. alboperca sp. nov.).   
 Tanganikallabes stewarti sp. nov. is further separated from T. mortiauxi by its premaxillary toothpad shape (uniformly thin, broad crescent versus widest point anteroposteriorly thicker than the premaxillary toothpad in T. mortiauxi; Fig. 4), lack of a free lower orbital margin, io-iv and the suprapreopercle consisting of multiple separate elements (versus a single element in T. mortiauxi; Figs 3, 5), the extensions of the lateral ethmoid not reaching io-ii when viewed from above (versus nearly or completely overlaying io-ii in T. mortiauxi; Fig. 3), its proportionally shorter prepelvic (35.7–39.2% SL versus 39.7–44.4% SL in T. mortiauxi) and preanal (42.4–44.8% SL versus 47.1– 51.7% SL) lengths, longer anal fin (anal fin base 54.1–58.9% SL versus 47.6–54.2% SL in T. mortiauxi). It can additionally be distinguished from T. alboperca sp. nov. by its lack of a depigmented opercular margin, having longer pelvic fins (7.1–9.3% SL versus 6.0–7.7% in T. alboperca sp. nov.), which reach beyond the origin of the anal fin when adpressed, proportionately longer pectoral fin spines (5.0–6.8% SL versus 3.6–5.3% SL in T. alboperca sp. nov.), a shorter preanal length (42.4– 44.8% SL versus 45.2–49.0% SL in T. alboperca sp. nov.), and a (generally) higher number of dorsal fin rays [72–79 (modally 76) versus 65–74 (modally 70) in T. alboperca sp. nov.] and anal fin rays [63–69 (modally 65) versus 55–63 (modally 59) in T. alboperca sp. nov.].   
*Value for holotype.  
 Description: Morphometric data are presented in Table 5, with the frequency distributions of selected meristic data presented in Table 3. Maximum TL 170 mm, SL 155 mm. Body elongate, moderately compressed posterior to origin of dorsal fin. Predorsal   
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.  
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 margin 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.  
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.  
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.  
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 appearance 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.  
 Coloration in alcohol: Dorsum and flanks brown to dark brown, with ventral surfaces slightly lighter, although less so than in other Tanganikallabes species. Some specimens (including holotype) show marbled appearance, with randomly arranged regions of lighter and darker coloration; other specimens uniform in dorsum and flank coloration (Fig. 12). Maxillary barbels uniformly brown, sometimes 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.   
 Distribution: Most collections come from the northern part of Lake Tanganyika (Fig. 13), although a single collection from the southern Zambian coastline indicates that T. stewarti sp. nov., like the other two known Tanganikallabes species, has a lakewide distribution.   
 Habitat: Habitat details for this species are absent for the collections examined. It likely to inhabit rocky bottoms, over a range of depths, as is the case for T. mortiauxi.   
 Diet: The stomach of the single specimen examined (UMMZ 196154) contained only the eggs of unidentified fish species.   
 Etymology: The specific epithet of this species is a patronym in honour of American ichthyologist Donald J. Stewart, who collected the holotype and other material used in the description of this species, as well as assisting in the collection of much of the type series of T. alboperca sp. nov.   
 Material examined: Holotype: UMMZ 249379 (155 mm SL), between Mutumba and Magara among rocks, 3°40′S, 29°20′E, Burundi, Lake Tanganyika, X.1973. Paratypes: UMMZ 196154 (3 alc, 1 c&s; 48–87 mm SL), collection data as for holotype; SAIAB 86970 (1 alc; 131 mm SL), Chimba, 08°25.27′S, 30°27.44′E, Zambia, Lake Tanganyika, 07.III.2004; MRAC 130959–130970 (8 alc; 83–147 mm SL), Kalungwe, Lake Tanganyika, 11.VII.1961; MRAC 130828–130832 (5 alc; 68–113 mm SL), Luhanga, Lake Tanganyika, 7.VII.1961; MRAC 94662 (1 alc; 112 mm SL), northern Lake Tanganyika (no additional collection data); MRAC 125723–125725 (3 alc; 81–109 mm SL), Kalungwe, Lake Tanganyika, 11.II. 1959; MRAC 130972–130974 (3 alc; 103–146 mm SL), Kalungwe, Lake Tanganyika, 13.VII.1961; MRAC 130769–130771 (3 alc; 77–100 mm SL), Mbemba, Lake Tanganyika, 10.VII.1961; MRAC 94670, 94671 (2 alc; 78–131 mm SL), Luhanga, Lake Tanganyika, 29.VII.1954.
description: Published as part of Wright, Jeremy J. & Bailey, Reeve M., 2012, Systematic revision of the formerly monotypic genus Tanganikallabes (Siluriformes: Clariidae), pp. 121-142 in Zoological Journal of the Linnean Society 165 (1) on pages 132-136, DOI: 10.1111/j.1096-3642.2011.00789.x, http://zenodo.org/record/5407190