Tanganikallabes, POLL, 1943

Wright, Jeremy J. & Bailey, Reeve M., 2012, Systematic revision of the formerly monotypic genus Tanganikallabes (Siluriformes: Clariidae), Zoological Journal of the Linnean Society 165 (1), pp. 121-142 : 124-126

publication ID	https://doi.org/ 10.1111/j.1096-3642.2011.00789.x
persistent identifier	https://treatment.plazi.org/id/03BD87B9-4945-F626-FF74-F9E9FD2F43D4
treatment provided by	Marcus
scientific name	Tanganikallabes
status

Treatment

GENUS TANGANIKALLABES POLL, 1943 View in CoL View at ENA

Tanganikallabes Poll, 1943: 127 View in CoL . Type species: Tanganikallabes mortiauxi Poll, 1943 View in CoL . Type by monotypy. Gender: feminine.

Diagnosis: Tanganikallabes is distinguished from all African clariid genera except for Platyallabes Poll and possibly Uegitglanis Gianferrari (see additional comments below) by the complete lack of both a suprabranchial chamber and an arborescent respiratory organ. Some authors ( Gianferrari, 1923; David, 1936) mentioned the presence of a vestigial suprabranchial organ in Uegitglanis , whereas others ( Chardon, 1968; Burgess, 1989) have indicated that this genus does not possess an accessory respiratory organ. Because of the lack of well-preserved material of Uegitglanis available for analysis, and the low probability that new material will become available in the near future, the utility of this character in diagnosing these two genera remains questionable. Adequate material does exist, however, to indicate that these genera can easily be distinguished by the presence of well-developed swimbladder capsules in Tanganikallabes (versus absent in Uegitglanis ), absence of body pigmentation in the cave-dwelling Uegitglanis versus extensive body pigmentation in Tanganikallabes , and differences in number of both dorsal fin (65–83 in Tanganikallabes versus 48–55 in Uegitglanis ) and anal fin (55–69 in Tanganikallabes versus 36–45 in Uegitglanis ) elements.

Tanganikallabes can additionally be distinguished from nearly all clariid genera except for Dinotopterus Boulenger , Platyallabes Poll and Uegitglanis Gianferrari by the absence of a well-developed, anteriorly directed process on the cleithral bone in adult specimens ( Fig. 2A View Figure 2 ). This structure can sometimes (albeit rarely) be observed in juvenile Tanganikallabes specimens, but was never present in adults. Similarly, such a structure can be observed in juvenile Dinotopterus specimens only ( Fig. 2C View Figure 2 ), but has never been documented in Platyallabes specimens of any size.

Tanganikallabes is distinguished from the anguilliform clariid genera [defined as having an abdominal body depth <11.6% of the standard length (SL); Devaere et al., 2005, 2006] Channallabes Günther, Dollichallabes Poll , Gymnallabes Günther , Platyallabes Poll , and Platyclarias Poll by generally having a more fusiform body shape (body depth at anus 8.7– 17.2% SL), and from all but the last of these genera [as well as from Clariallabes attemsi (Holly, 1927) , Clariallabes brevibarbis Pellegrin, 1913 , Clariallabes centralis (Poll & Lambert, 1958) , Clariallabes heterocephalus Poll, 1967 , Clariallabes melas (Boulenger, 1887) , Clariallabes petricola Greenwood, 1956 , Clariallabes simeonsi Poll, 1941 , Clariallabes uelensis (Poll, 1941) , Clariallabes variabilis Pellegrin, 1926 ] in having dorsal and/or anal fins that are not fused with the caudal fin (with the exception of three abnormal specimens found in MRAC 130952-954, radiographs of which also showed numerous skeletal deformities). Tanganikallabes also differs from several of the aformentioned anguilliform genera in its number of dorsal fin rays (65–83 in Tanganikallabes versus 86–160 in Channallabes , 130–140 in Platyallabes , and 85–87 in Platyclarias ) and anal fin rays (55–69 in Tanganikallabes versus 75–155 in Channallabes , 115–125 in Platyallabes , and around 80 in Platyclarias ).

Tanganikallabes is further distinguished from the fusiform genera Dinotopterus and Heterobranchus Saint-Hilaire by the absence of an adipose fin and the presence of a correspondingly longer dorsal fin, with a larger number of rays (65–83 versus 47–54 in Dinotopterus and 24–45 in Heterobranchus ). Tanganikallabes can be further differentiated from the Lake Malawi-endemic genus Bathyclarias Jackson by having dorsal and anal fins that extend all the way to the origin of the caudal fin (versus fins separated by varying, but always clearly visible, distances in Bathyclarias species ), and from the Lake Victoriaendemic Xenoclarias Norman by having 53–61 post- Weberian vertebral elements, rather than 51 or 52.

Differences in cranial osteology further distinguish Tanganikallabes from Bathyclarias , Heterobranchus , and Xenoclarias , as well as from Clarias Scopoli and Clariallabes (for illustrations of Bathyclarias neurocranium, see Anseaume & Teugels, 1999; for illustrations of Clariallabes , see Cabuy et al. 1999; for Clarias , see Fig. 3 View Figure 3 ). These differences include reductions of nearly every bone in the neurocranium, but are perhaps most evident in the infraorbital bones (particularly infraorbital iv) and the suprapreopercle, which are small and mostly tubular in Tanganikallabes versus large and plate-like in these other genera. Additional differences between these genera and Tanganikallabes can be easily observed in the size and shape of the lateral ethmoid, frontal, sphenotic, pterotic, and post-temporo supracleithrum.