Supporting the existence of two isolated evolutionary lineages of Gerres (Perciformes: Gerreidae) in America

For many years in America, many authors have considered that the Gerres genus contained a single species, the yellowfin mojarra Gerres cinereus (Walbaum, 1792); however, others have recognized two species in this genus in the Neotropics. In this study, specimens of G. cinereus (sensu lato) caught throughout its geographic range on both coasts of America were compared for the first time to analyse divergence among the sampled populations. A genetic analysis based on DNA sequences from three mitochondrial genes and one nuclear gene revealed a clear separation of two clades, one in the Pacific and one in the Atlantic. Geometric morphometric differences, based on body shape, sagittae otoliths and urohyal bone features, were significant between the two groups, including separation by an accurate classification a posteriori by a canonical variate analysis (CVA) > 82% in all data sets (overall mean >91%). Integration of the results of these approaches indicates that there is sufficient evidence to support species status for Gerres simillimus Regan, 1907, and it should be considered a valid species in the neotropical Pacific.