Systematics of the genus Cnesterodon Garman, 1895 (Cyprinodontiformes: Poeciliidae: Poeciliinae) Author Lucinda, Paulo H. F. Laboratório de Ictiologia Sistemática, Universidade Federal do Tocantins, Campus de Porto Nacional, rua 3, quadra 17, s / n, Jardim dos Ipês, Caixa Postal 136, 77500 - 000 Porto Nacional, TO, Brazil. lucinda@uft.edu.br text Neotropical Ichthyology 2005 2005-06-30 3 2 259 270 http://dx.doi.org/10.1590/s1679-62252005000200003 journal article 274287 10.1590/s1679-62252005000200003 73eee54f-3a01-4ba8-8a03-f33c31c75071 1982-0224 5418097 F943EF65-FFB0-47E9-B9E6-F6DFB1F2C61C Cnesterodon brevirostratus Rosa & Costa, 1993 ( Fig. 9 ) Cnesterodon brevirostratus Rosa & Costa, 1993: 705 , fig. 17. Type -locality: Brazil, Rio Grande do Sul, Cambará do Sul, Parque Nacional dos Aparados da Serra, Arroio Camisa, tributary to Rio das Antas. Diagnosis. Cnesterodon brevirostratus is diagnosed by the following autapomorphies: (1) snout blunt; (2) presence of small scales covering lateral and ventral region of body below pectoral fin in adult females; (3) bony style of ray 3 of gonopodium of fully developed mature males large and sinuous, covered with few membranous tissue ( Rosa & Costa, 1993 ; fig. 11). Furthermore, C. brevirostratus is readily distinguished from C. omorgmatos and C. raddai by dark brown blotches along body sides (forming bars vs. circular or irregular, respectively). Cnesterodon brevirostratus is distinguished from C. carnegiei , C. hypselurus , and C. septentrionalis by dark bars on sides of body, mostly confined to midline, covering less than three scales in a transverse row, never extending to dorsal and ventral profiles (vs. dark bars of body very elongate reaching dorsal and ventral profiles, covering more than four scales in a transverse row). The absence of a longitudinal dark brown band along flank differentiates C. brevirostratus from C. hypselurus . Distribution. Cnesterodon brevirostratus inhabits the upper portion of the rio Pelotas and rio Canoas of the rio Uruguay drainage, the rio Jacuí, the headwaters of the rio Maquiné in the Tramandaí system, and the headwaters of rio Itajaí - Açu drainage. Remarks. The color pattern of C. brevirostratus is quite variable. It can be a typical Cnesterodon pattern with vertical bars along flanks, a pattern of bars irregularly set and shaped, or even dotted.