A new species of Astyanax (Characiformes, Characidae) from the upper rio Bermejo basin, Salta, Argentina

Astyanax latens sp. n., from the Bermejo river basin, is described in this paper. Astyanax latens is diagnosed by a combination of characters: somewhat rhomboidal body; presence of 24-29 branched anal fin rays; 1-4 maxillary teeth; long pectoral fins (23.2-26.6% of SL) always reaching one third of pelvic fin; long pelvic fins (17.6-22.0% of SL) always surpassing anal fin origin; anal fin base long (32.3-36.7% of SL); 26-27 gill rakers on first branchial arch; lateral band extremely narrow; one large vertically elongated humeral spot and a second one very faint; relatively shallow caudal peduncle (10.0-11.4% SL); fifth tooth of inner premaxillary series very small and scarcely posterior to main series; origin of anal fin below dorsal fin.