ABSTRACTSince the restriction of Astyanax fasciatus to Brazil, most authors have assigned Central American and southern Mexican forms of Astyanax to A. aeneus. However, molecular studies support the hypothesis that more than one taxon is involved. With the aim of clarifying the number and status of species hidden behind the name ‘A. aeneus’, this revision comprises 80 populations of Astyanax (and ‘Bramocharax’) from Panama to Texas, with comparative material from South America, based on morphological characters (mostly osteological). Astyanax aeneus is hereby restricted to the Pacific slope, from Rio Papagayo, Guerrero, to Honduras. Several species are resurrected from synonymy or redescribed: A. altior (restricted to north-western Yucatan), A. argentatus (Texas and northern Mexico), A. belizianus (central-southern Belize, Izabal, Caribbean Honduras), A. brevimanus (upper Usumacinta and Grijalva, Chiapas, Quiche, Alta Verapaz), A. finitimus (Veracruz, Tabasco, northern Chiapas), A. mexicanus (restricted t...