Nematocharax costai, new species is described from the Contas river basin, northeastern Brazil. The new species is included in the genus Nematocharax by possessing elongated branched dorsal-, anal- and pelvic-fin rays; two rows of pre-maxillary teeth in adults and practically complete row of teeth along the free ventral maxillary border. It differs from N. venustus, unique congener, by the number of maxillary teeth in adult males; absence of hooks and spinules on dorsal and pelvic fins; reduced number of anal-fin rays with spinules; presence of a long dark pink horizontal mark on caudal peduncle; number of supraneurals and pelvic-fin filament yellow.
Key words: Characidae, Neotropical, Northeastern Brazil, Systematics, Taxonomy
Bragança, P.H.N.d., Barbosa, M.A. & Mattos, J.L. 2013. A New Nematocharax Species from the middle Contas River basin, Northeastern Brazil (Characiformes: Characidae). Vertebrate Zoology. 63 (1): 3-8.