WRIGHT AND PAGE: Taxonomic revision of Lake Tanganyikan Synodontis km 0 5s 100 Figure 31. Known distribution of Synodontis tanganaicae. T denotes type locality. meristic differences between S. tanganaicae and types of S. lacustricolus, nor do the new characters exam- ined in this study indicate that the specimens represent two species. De Vos and Thys van den Audenaerde's decision is accepted here, though we retain the spelling of Borodin rather than using tanganyicae. KEY TO THE SPECIES OF Synodontis OF LAKE TANGANYIKA l a. Large, conspicuous axillary pore.......................2... lb. Axillary pore absent or very small.....................6... 2a. Mandibular teeth 13-29; eye large, 21.6-31.9% head length; skin smooth; many large black spots ............3... 2b. Mandibular teeth 22-51; eye smaller, 9.7-22.6% head length; skin covered with granula papillae; spots very sm all or absent............................. ......................4... 3a. Pectoral fin I, 8; eye 44.9-62.0% snout length; maxi- mum TL 280 mm........................ S. multipunctatus 3b. Pectoral fin 1,7, eye 64.2-81.0% snout length; maxi- mum TL 145 mm................. S. grandiops 4a. Premaxillary toothpad uninterrupted; humeral pro- cess length 253.8-437.2% humeral process width...... 5 4b. Premaxillary toothpad interrupted; humeral process length 172.9-255.4% humeral process width............... ......................................................... S. tanganaicae 5a. 22 mandibular teeth; secondary branches on medial mandibular barbel; eye 23.1% snout length....S. dhonti 5b. 28-51 mandibular teeth; no secondary branches on medial mandibular barbel; eye 31.2-50.2% snout length................... .....................S. granulosus 6a. Pectoral-fin spines white..................................7... 6b. Pectoral-fin spines dark...................................8... 7a. Very small axillary pore; black triangles on rayed fins lack light patches at base................S.... petricola 7b. Axillary pore absent; black triangles on rayed fins with distinct light patches at base...........S. lucipinnis 8a. Moderate to large spots; black triangles present on rayed fins; occipito-nuchal shield covered with sk in ............................................... ......................9... 8b. Small spots; black triangles absent on rayed fins; occipito-nuchal shield not covered with skin............... ............ ............ ......................... S. m elanostictus 9a. M andibular teeth 40-70.................................. 10 9b. Mandibular teeth 15-29...................... S. irsacae 10a. Body depth 20.2-27.0% SL; gut length 386.0- 554.6% TL; large hindgut chamber; body and head cov- ered with villous papillae..............................S. polli 10 Ob. Body depth 18.2-20.1% SL; gut length 78.0-136.2% TL; hindgut chamber absent; body and head covered with flattened, granulous papillae.............S. ilebrevis DISCUSSION The examination of 312 specimens of Synodontis from Lake Tanganyika has led to the recognition of 11 spe- cies of Synodontis from Lake Tanganyika. Ten of the species are endemic, and three are new to science. Synodontis irsacae and S. melanostictus are recog- nized as valid species. The rayed-fin color pattern and skin folds of the endemic Tanganyikan species of Synodontis offer sup- port for the monophyly of this group. Brooks (1950) suggested that, in the genera of Lake Tanganyikan fishes that are represented in the lake by a single non-endemic species and an endemic species flock (Mochokidae and Mastacembelidae), the endemic species probably arose from an ancient species due to cleavage of the lake ba- sin, while the non-endemic species in each group, e.g. S. melanostictus, is likely to be a recent addition to the