Moelants, T.,  Snoeks, J. & Vreven, E. 2018. ‘Distichodus kasaiensis and D. ingae, two new distichodontid species (Characiformes: Distichodontidae) from the Congo basin’. Ichthyological Exploration of Freshwaters 28 : 177-192. München, Germany : Verlag Dr. Friedrich Pfeil. ISSN: 0936-9902.  (PR).

Article in a scientific Journal / Article in a Journal

Two new distichodontid species are described, Distichodus kasaiensis, from the Kasai River system and D. ingae, from Inga on the Lower Congo. A redescription of D. atroventralis is also provided and a lectotype is designated. These three very similar species differ from their congeners in having an inferior mouth, a high number of lateral line scales in front of the end of the hypural complex (57-73), a high number of pelvic-fin rays (10-11, generally 11), a low number of blackish, vertical bars on the flanks (6-9) and blackish pelvic fins. The latter two characteristics are only diagnostic for specimens smaller than about 200 mm SL, as these dark markings appear to fade in large specimens. Distichodus kasaiensis is distinguished from D. atroventralis by having more dorsal-fin rays (27-29 vs. 22-24), fewer teeth in the outer row of the upper jaw (15-25 vs. 18-36), and by its longer dorsal-fin base (24.9-33.7 % SL vs. 20.1-28.8). The partial overlap for the latter two characters is due to positive allometry. Distichodus kasaiensis is distinguished from D. ingae mainly by having fewer lateral line scales in front of the end of the hypural complex (57-65 vs. 69-73) and more dorsal-fin rays (27-29 vs. 26). Distichodus ingae is distinguished from D. atroventralis by having more dorsal-fin rays (26 vs. 22-24), and longer dorsal (23.6-24.2 % SL vs. 12.0-21.9), anal (16.9-17.5 % SL vs. 9.9-15.7) and pectoral (21.6-22.7 % SL vs. 14.2-20.5) fins.