Relações filogenéticas e biogeográficas entre espécies do gênero Astyanax (Teleostei - Characidae) das bacias do rio Iguaçu, do alto rio Paraná e do rio Paraguai baseadas em seqüências de gene mitocondrial.

Abstract

Phylogenetic relationships among thirty-eight individuals of Astyanax from Iguaçu River and adjacent river basins, were examined by nucleotidic sequencing in the mitocondrial gene cytochrome b. Phylogenetic analysis of neighbor-joining, maximum-likelihood and bayesian approach were carried out using methodologies and specific computacional programs. The clades brought up in this study suggest the recognition of, at least, three groups that share similar origins with the endemic lambaris from Iguacu River, suggesting that there is poliphyletism in the ancestry in Astyanax from this location, suggesting that Astyanax from this river did not diversify from a unique ancestor group that was isolated when the Iguacu River basin was formed. Thus, polyphyletism of this genera in Iguaçu River would be intrageneric, when it refers to the possibility of three groups of Astyanax have been isolated during the formation of this river basin. Astyanax sp. B would have an origin shared with some especies from the 'complex altiparanae-bimaculatus' while Astyanax sp. C would be from the same group that also hosts A. aff. paranae and A. bockmanni. The divergence between Astyanax sp. E and Astyanax sp. F would have occured in a more recent past when compared to the differenciation of the species Astyanax sp. D. Geological and hidrological events that would have influenced the biogeography pattern of the analised species are discussed.