Systematic revision of the formerly monotypic genus Tanganikallabes (Siluriformes: Clariidae) Author Wright, Jeremy J. Author Bailey, Reeve M. text Zoological Journal of the Linnean Society 2012 2012-04-18 165 1 121 142 http://dx.doi.org/10.1111/j.1096-3642.2011.00789.x journal article 10.1111/j.1096-3642.2011.00789.x 0024-4082 5407190 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. ]. Table 3. Frequency distributions of select meristic data in Tanganikallabes species

Post-Weberian vertebral elements
Species	53		54 55 56				57	58	59	60 61			N	x
T. mortiauxi T. alboperca sp. nov.	1	2	8 1	12 1		10 11	12 23*	2 11	1 1	48 48	56.6 57.9
T. stewarti sp. nov.	13	11*	2	1		27	58.7
Dorsal fin rays
Species	65	66	67		68	69		70	71	72 73 74			75	76	77	78	79	80	81	82	83	N	x
T. mortiauxi	1	1	1	3	3	5	5	7	9	6	4	2	47	78.7
T. alboperca sp. nov.	1	1	13*	6	8	5	6	5	4	49	70.2
T. stewarti sp. nov.	1	2	3	4	7	1*	2	4	24	75.9
Anal fin rays
Species	55		56 57			58 59			60	61	62	63	64	65	66	67	68	69		N	x
T. mortiauxi	4	7	12	2	7	6	4	4	46	61.2
T. alboperca sp. nov.	3	7	7	5	13*		5	7	1	1	49	58.5
T. stewarti sp. nov.	3	4	7	5*	4	1	1	25	65.4
Pectoral fin rays
Species	I,7	I,8	I,9	N
T. mortiauxi	1	13	12	26
T. alboperca sp. nov. T. stewarti sp. nov.	6	4 7	9 1	13 14
Caudal fin rays
Species	22	23		24	25	26	N	x
T. mortiauxi T. alboperca sp. nov. T. stewarti sp. nov.	4 1 6	17 14* 16*		16 12 6	5 2	8	42 37 28	23.5 24.0 23.0

*Value for holotype. Figure 9. Dorsal, lateral, and ventral views of Tanganikallabes alboperca sp. nov. , Holotype, UMMZ 199862, 153 mm standard length. Scale bar: 1 cm. 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. Figure 10. Known distribution of Tanganikallabes alboperca sp. nov. T denotes the type locality. 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. Figure 11. Differences in the extent of lateral line between (A) Tanganikallabes stewarti sp. nov. and (B) Tanganikallabes alboperca sp. nov. White arrows indicate the posterior terminus of the lateral line. Table 4. Morphometric data for Tanganikallabes alboperca sp. nov.

Measurement	Holotype	Range ( N = 52)	Mean ± SD
1. Standard length	152.9 mm	47.3–161.0 mm
% Standard length
2. Snout to dorsal fin origin	32.8	29.3–34.9	32.9 ± 1.1
3. Snout to pectoral fin origin	19.9	18.4–21.2	19.7 ± 0.7
4. Snout to pelvic fin origin	41.2	37.3–42.0	39.7 ± 1.1
5. Snout to anal fin origin	48.3	45.2–49.0	47.0 ± 1.0
6. Pectoral fin origin to dorsal fin origin	16.0	15.5–19.4	17.3 ± 0.9
7. Pectoral fin origin to pelvic fin origin	22.6	19.8–24.7	22.2 ± 1.1
8. Dorsal fin origin to pelvic fin origin	14.3	12.8–17.7	15.4 ± 1.2
9. Dorsal fin origin to anal fin origin	19.9	18.4–22.8	20.3 ± 1.1
10. Dorsal fin origin to anal fin insertion	70.5	66.4–72.2	69.7 ± 1.5
11. Pelvic fin origin to dorsal fin insertion	64.7	54.1–64.8	62.3 ± 1.7
12. Pelvic fin origin to anal fin origin	8.3	6.9–9.0	7.8 ± 0.4
13. Pelvic fin length	7.3	6.0–7.7	6.9 ± 0.4
14. Anal fin origin to dorsal fin insertion	57.8	52.6–62.7	55.8 ± 1.5
15. Dorsal fin base length	69.9	66.1–73.1	69.7 ± 1.5
16. Anal fin base length	55.6	51.9–56.5	54.5 ± 1.2
17. Interorbital width	8.9	8.0–9.7	8.7 ± 0.4
18. Body width at pectoral fin origin	15.6	13.2–17.3	14.8 ± 0.7
19. Body depth at anus	12.4	11.7–14.6	13.3 ± 0.8
20. Head width	17.3	14.4–17.7	16.0 ± 0.7
21. Head length	21.8	20.0–23.7	21.4 ± 0.7
22. Snout length	4.8	4.4–6.0	5.1 ± 0.4
23. Eye diameter	1.4	0.8–1.6	1.3 ± 0.1
24. Pectoral fin length	9.6	8.9–11.0	9.5 ± 0.5
25. Pectoral spine length	4.3	3.6–5.3	4.3 ± 0.4
26. Caudal fin length	11.0	9.1–13.1	10.3 ± 1.0
27. Caudal peduncle depth	6.7	5.9–7.1	6.6 ± 0.3
28. Maxillary barbel length	14.1	13.1–30.1	19.6 ± 3.9
29. Nasal barbel length	12.0	10.6–19.5	13.8 ± 1.8
30. Lateral mandibular barbel length	13.7	13.1–28.8	18.3 ± 3.3
31. Medial mandibular barbel length	10.5	8.1–16.9	12.5 ± 1.8

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 .