Review of the species of the genus Serrapinnus Malabarba, 1998 (Teleostei: Characidae: Cheirodontinae) from the rio Tocantins-Araguaia basin, with description of three new species Author Malabarba, Luiz R. Departamento de Zoologia, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500. 91501 - 970 Porto Alegre, RS, Brazil. Author Jerep, Fernando C. Universidade Estadual de Londrina, Programa de Pós-Graduação em Ciências Biológicas, Departamento de Biologia Animal e Vegetal, Centro de Ciências Biológicas, 86057 - 970 Londrina, PR, Brazil. fjerep @ gmail. com & Research Associate, Division of Fishes, Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, D. C. text Zootaxa 2014 2014-08-06 3847 1 57 79 journal article 5344 10.11646/zootaxa.3847.1.3 17adfe62-71be-4ddf-bbe2-9137253a2007 1175-5326 4928753 93242732-2B5A-4083-8EC5-6FA53BD83E7D Key to the species of the Cheirodontinae occurring in the Atlantic drainages of northeastern Brazil , from the rio Tocantins-Araguaia to the rio Paraguaçú drainages 1. Lower lobe of caudal fin of males covered with cone shaped or papilla-like organs (see Malabarba et al. , 2004 : figs. 1 to 4). A conspicuous small black spot present at midlength of first branched anal-fin ray of males (see Malabarba et al. , 2004 : figs. 5–6 and 8). A dark brown nearly isosceles triangular shaped mark present in the area covering pelvic bone in males (see Malabarba et al. , 2004 : fig. 9)....................................................................2 ( Kolpotocheirodon ) 1´. Lower lobe of caudal fin of males not covered with cone shaped or papilla-like organs. Conspicuous black spots lacking on branched anal-fin rays. Triangular mark in area covering pelvic bone absent....................................... 3 2. Dorsal fin lacking conspicuous black spots. 3–5 very small, vertical bars crossing lateral body stripe between pseudotympanum and area ventral to dorsal fin (see Malabarba et al. , 2004 : fig. 8). Twelfth to the 14 th or 15 th principal caudal-fin rays of males bearing hooks................................................................................................... Kolpotocheirodon theloura (headwaters of São Francisco and Paraná river basins near Brasília, DF, Brazil ) 2´. Conspicuous small black spot present on soft tissue between midlength of first and second, and second and third dorsal-fin branched rays (see Malabarba et al. , 2004 : figs. 5 and 6). Vertical bars crossing lateral body stripe and hooks on caudal fin absent................................................. Kolpotocheirodon figueiredoi (Paraguaçu River drainage) 3. Base of lower caudal-fin lobe with hypertrophied group of scales forming small pouch................................ Compsura heterura (São Francisco River basin and northeastern coastal drainages; absent in Tocantins-Araguaia River basin) 3´. Base of lower caudal-fin lobe without hypertrophied scales................................................... 4 4. Ventral procurrent caudal-fin rays not hypertrophied or exposed along ventral margin of caudal peduncle of mature males. Thirteenth to 14 th caudal-fin rays bearing hooks associated with hypertrophied skin flaps in mature males ( Malabarba & Weitzman, 1999 : figs. 3–6).................... Acinocheirodon melanogramma (São Francisco and Jequitinhonha river basins) 4´. Ventral procurrent caudal-fin rays hypertrophied and exposed ventrally in mature males. Caudal-fin rays without hooks or hypertrophied skin flaps in mature males.................................................................. 5 5. First through fourth or fifth branched anal-fin rays of mature males slab-shaped ( Malabarba & Jerep, 2012 : fig. 3). Distal tip of ventral procurrent caudal-fin rays conical in mature males ( Malabarba & Jerep, 2012 : fig. 3). Anal-fin rays iv–v, 14–17. Lateral line completely pored with 32–36 scales................... Ctenocheirodon pristis (Tocantins-Araguaia River basin) 5´. First through sixth or eighth branched anal-fin rays of mature males slab-shaped ( Fig. 4 ). Distal tip of ventral procurrent caudal-fin rays spatulate or scimitar-shaped in mature males ( Fig. 2 ). Anal-fin rays iii–iv,16–21.............. 6 ( Serrapinnus ) 6. Three central cusps of dentary teeth expanded relative to other cusps and form a sharp-cutting edge. Lateral line completely pored.................... Serrapinnus heterodon (São Francisco River basin and northeastern Atlantic coastal drainages) 6´. Three central cusps of dentary teeth similar in shape to remaining cusps ( Figs. 3 , 7 , 9 , 11 ). Lateral line incomplete, with 5–10 pored scales (variable in S. tocantinensis , ranging from 6–36 scales)............................................. 7 7. Longitudinal black stripe wide and conspicuous, one or one and half scale deep, extending from posterior margin of opercle to caudal spot ( Fig. 8 ).................................................. S. sterbai (Tocantins-Araguaia River basin) 7´. Longitudinal black stripe narrow, extending from region below dorsal-fin base to caudal spot......................... 8 8. Longest unbranched dorsal- and pelvic-fin rays of males prolonged as filament ( Fig. 10 )........................................................................................... S. tocantinensis (Tocantins-Araguaia River basin). 8´. Longest unbranched dorsal- and pelvic-fin rays of males not prolonged as filament.................................. 9 9. Ventral procurrent caudal-fin rays 17–19................................ S. lucindai (Tocantins-Araguaia River basin) 9´. Ventral procurrent caudal-fin 16 or fewer.................................................................. 10 10. Ventral procurrent caudal-fin rays of mature males spatulate, forming keel along posterior ventral margin of caudal peduncle...................................... S. piaba (São Francisco River basin and northeastern coastal Atlantic drainages) 10´. Ventral procurrent caudal-fin rays of mature males scimitar-shaped and forming semicircle, with portion of ventral procurrent caudal-fin rays having resultant star-shape form with multiple points ( Fig. 2a ).................................... 11 11. Premaxillary teeth with 7 to 9 cusps ( Fig. 3a )............................... S. aster (Tocantins-Araguaia River basin). 11´. Premaxillary teeth with 5 cusps (see Jerep & Malabarba, 2014 : fig. 3).......................................................................................... S. potiguar ( Ceará-Mirim River basin in Rio Grande do Norte state ) .