Astyanax endy (Characiformes: Characidae), a new fish species from the upper Rio Bermejo basin, northwestern Argentina

Astyanax endy, new species, is described from the upper Rio Bermejo basin. This species is distinguished from its congeners by the following combination of characters: markedly convex snout profile, deep body (36.6 - 42.2 % SL), relatively large orbital diameter (36.0 - 40.9 % HL), relatively short interorbital distance (31.9 - 37.6 % HL), deep caudal peduncle (11.7 - 14.1 % SL), long caudal peduncle (12.6 - 15.9 % SL), short upper-jaw length (34.4 - 40.2 % HL), maxilla scarcely reaching anterior margin of the eye, maxilla meeting mouth commissure at an oblique angle, 35 - 37 perforated scales in lateral line, 7/6 transverse scales, 17 - 24 branched anal-fin rays, tricuspidate or pentacuspidate teeth on outer premaxillary row, 1 - 2 tricuspidate or pentacuspidate maxillary teeth, 4 gradually decreasing dentary teeth followed by 1 intermediate and 3 - 6 small tricuspidate or conical teeth, and 19 - 21 gill-rakers in first branchial arch. A key for identification of the species of Astyanax from the Rio Bermejo basin is provided.