The re-examination of the holotype of Gerres peruvianus Cuvier, 1830 revealed that it is distinct from “Diapterus peruvianus” [s. l.], a well-known species along the tropical eastern Pacific coast. Morphological and meristic examinations of the syntypes of G. brevirostris Sauvage, 1879 show that it is a valid species, corresponding to the Diapterus-like specimens traditionally assigned to D. peruvianus (non Cuvier). Thus, D. brevirostris is herein reinstated as a valid gerreid species, and G. peruvianus is considered as incertae sedis until its status is resolved.