Phylogenetic analysis of the Thraupis sayaca – T. episcopus – T. glaucocolpa species complex

The genus Thraupis includes highly abundant species, whose taxonomy and phylogenetic relationships remain unclear. Thraupis sayaca, T. episcopus and T. glaucocolpa have been a source of discussion and taxonomic instability. These taxa are constantly changed in their specific and subspecifc status. To clarify this, we used muscle tissue samples from 15 countries that adequately represent the geographic distribution of the complex. Preliminary results, based on two mitochondrial markers (cyt-b and ND2) and one alosomal nuclear intron (MUSK) within maximum likelihood and Bayesian inference frameworks, show that T. s. glaucocolpa is sister to the rest of species in the genus.Thraupis sayaca and T. episcopus are sister groups, replacing each other in the ecotone between Amazon and dryer areas as such as the Cerrado and the Caatinga. We identified hybrid individuals along this ecotone. Hybrids were known before only from Beni, Bolivia. Thraupis episcopus shows geographic genetic structure. The taxon from the pacific coast (Peru, Ecuador and Colombia) is the most divergent (Thraupis episcopus quaesita) and it is isolated to the East by the Andes and to the North by the Darién. The other samples form two groups: T. episcopus cana in Colombia and Central America, and the nominate group (formed by several subspecies including T. e. episcopus) on the east side of the Eastern Cordillera of Colombia. Apparently, the Andes and moist forested regions are the most important biogeographical barriers for this group.