Astyanax hermosus, a new species from the Primero River basin, Córdoba, Argentina (Characiformes, Characidae)

A new species of the characid genus Astyanax is described from the endorheic Primero River basin, in central Argentina: Astyanax hermosus sp. n. This species can be distinguished from all other in the genus by the following combination of characters: body relatively low (33.1-38.7% SL); head short (23.5-27.1% SL); snout short (18.3-26.6% HL); interorbital broad (34.9-41.5% HL); maxilla with 1-3 teeth, usually one; iv-v, 17-22 anal-fin rays; 35-38 perforated scales on the lateral line; transverse scales 7/6; and distinctive color pattern, with Y-shaped humeral spot, a broad grayish longitudinal stripe on the flanks, extending weakly onto the middle caudal-fin rays, and extremely dark opercular, subopercular and preopercular regions. In addition, the males of the new species are distinguished by the presence of bony hooks in all their fins.Facultad de Ciencias Naturales y Muse