Accepted by M.R. de Carvalho: 26 Mar. 2013; published: 27 May 2013 ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Copyright © 2013 Magnolia Press Zootaxa 3664 (3): 361–368 www.mapress.com/ zootaxa/ Article 361 http://dx.doi.org/10.11646/zootaxa.3664.3.6 http://zoobank.org/urn:lsid:zoobank.org:pub:CD7D727A-FBE8-4C50-BA7C-3AAFACC271D3 A new miniature species of Characidium Reinhardt (Ostariophysi: Characiformes: Crenuchidae) from the headwaters of the rio Araguaia, Brazil ANDRÉ L. NETTO-FERREIRA 1 , JOSÉ L. O. BIRINDELLI 1,2 & PAULO A. BUCKUP 3 1 Museu de Zoologia da Universidade de São Paulo, Caixa Postal 42494, CEP 04218-970, São Paulo, SP, Brazil. E-mail: alnferreira@gmail.com 2 Departamento de Biologia Animal e Vegetal, Universidade Estadual de Londrina, Caixa Postal 6001, CEP 86051-980, Londrina, PR, Brazil. E-mail:josebirindelli@yahoo.com 3 Museu Nacional, Universidade Federal do Rio de Janeiro, Departamento de Vertebrados, Quinta da Boa Vista, 20940-040 Rio de Janeiro, RJ, Brasil. Email: buckup@acd.ufrj.br Abstract Characidium mirim is described from the rio das Mortes, rio Araguaia basin in Central Brazil. The new species is distin- guished from its congeners by having an incomplete lateral line, a conspicuous dark longitudinal stripe and dark transverse bars not extending ventrally to the lateral line, and by lacking the adipose fin and the dark caudal blotch. A phylogenetic hypothesis based on the available data on the phylogenetic relationships of the subfamily Characidiinae is presented. Re- sults suggest that the new species is closely related to C. bahiensis, C. interruptum, C. lagosantense, C. nupelia, C. lanei, C. laterale, C. occidentale, C. orientale, C. rachovii, C. stigmosum, C. vestigipinne and C. xavante. Key words: Phylogenetic relationships, Neotropical, Freshwater fish, Teleostei, Characidiinae Resumo Characidium mirim, proveniente do rio das Mortes, bacia do rio Araguaia no Brasil Central, é descrita. A nova espécie difere de suas congêneres por apresentar a linha lateral incompleta, uma conspícua faixa longitudinal e barras transversais não se estendendo ventralmente à linha lateral, e pela ausência da nadadeira adiposa e da mancha caudal escura. Uma hipó- tese filogenética é apresentada, com base nos dados disponíveis sobre as relações filogenéticas de Characidiinae. Os re- sultados sugerem que a nova espécie seja proximamente relacionada a C. bahiensis, C. interruptum, C. lagosantense, C. nupelia, C. lanei, C. laterale, C. occidentale, C. orientale, C. rachovii, C. stigmosum, C. vestigipinne e C. xavante. Introduction Characidium Reinhardt is the largest genus of the family Crenuchidae and one of the most species-rich of the order Characiformes, with 55 valid species distributed in the Neotropical region from Panama to Argentina (Breder, 1925; Géry et al., 2001). Monophyly of the genus is supported by the presence of a dark spot on the base of median caudal-fin rays, despite being secondary lost in some species (Buckup, 1993a,b; Melo & Buckup, 2002). The taxonomy of the genus is still poorly known (Buckup, 1993b), although several species have been recently described (Graça & Pavanelli, 2006; Taphorn et al., 2006; Graça et al., 2008) or redescribed clarifying, at least in part, the identity of problematic species such as Characidium pterostictum, C. rachovii, C. tenue, C. zebra (Buckup & Reis, 1997), and C. borellii (Géry et al., 2001). During a field trip to the Chapada dos Guimarães and the rio das Mortes Plateau, an undescribed miniature species (sensu Weitzman & Vari, 1988) of Characidium easily distinguished from most congeners was discovered. The new species is herein described and its phylogenetic relationships are discussed.