Panbiogeographic analysis of the distribution patterns of the freshwater species of Sciaenidae (Actinopterygii: Perciformes) in the Amazon Basin
The Sciaenidae include four genera (Pachypops, Pachyurus, Petilippinis and Plagioscion) and about 20 species restricted to freshwater, distributed in South American rivers. In this paper, the distribution of 10 species of freshwater Sciaenidae occurring in the Amazon Basin, belonging to the genera Pachypops, Pachyurus, Petilippinis and Plagioscion, was analyzed by the panbiogeographic quantitative methods. By means of track analysis, three generalized tracks and six biogeographic nodes were found. The main massing of the species studied is located in the Lower Amazon (Óbidos), where six of the species do occur. The results of the track analysis suggest that the distribution of the South American freshwater Sciaenidae correspond to vicariant events associated to the formation of the Amazonas and Orinoco river basins and the events related to the formations of the Paraná, Paraguai and Prata river basins. The Guyanas shield constitutes an important geotectonic feature in the configuration of the distribution patterns of these species. These patterns are congruent with those observed in other lineages derived from marine groups in South America.