Astyanax tumbayaensis, a new species from northwestern Argentina highlands (Characiformes: Characidae) with a key to the Argentinean species of the genus and comments on their distribution

A new species of the characid genus Astyanax is described from a man-made small channel connected with the Río Grande basin, in Jujuy Province, northwestern Argentina. This species can be distinguished from its congeners by the following combination of characters: body relatively high (39.2-45.3% SL); head short and heavy (24.0-26.7% SL); snout very short (16.1-20.8% HL); eye small (28.9-35.0% HL); interorbital very wide (38.8-44.1% HL); mouth sub-superior; maxilla short with 1-2 teeth; iii-v, 19-22 anal fin rays; 33-36 perforated scales on the lateral line, and a distinctive color pattern, consisting in a reticulated body, with dorsal, pelvic, anal, and caudal fins with dark margins. A very narrow lateral dark stripe ending in a caudal spot, and one large vertically elongated humeral spot. In addition the males of Astyanax tumbayaensis have bony hooks in the dorsal, pelvic, anal and caudal fins. A key for Argentinean species of Astyanax is provided. The primary traits of the distribution of species in the country are discussed, with reference to the main basins and some zoogeographically important localities.Instituto de Limnología "Dr. Raul A. Ringuelet