Genetic Diversification of Adelphobates quinquevittatus (Anura: Dendrobatidae) and the Influence of Upper Madeira River Historical Dynamics

The effect of large Amazonian rivers as barriers to distribution of species and gene flow has been the subject of debate for more than a century. The Madeira River is the largest tributary of the Amazon River, with the region comprising its basin undergoing complex changes from the Pliocene through the Holocene. Accordingly, the evolution of its drainage seems to have been an important factor in the biological diversification of different taxa. We characterize the phylogeographic pattern of Adelphobates quinquevittatus, focusing on the role of the Madeira River and the environmental changes in the region, as potential barriers to gene flow. For this, we used sequences of two mitochondrial genes from 65 individuals sampled in 15 locations. We identify population structure partially related to the current Madeira River configuration. However the most upstream session does not represent a historical barrier, suggesting that may have attained its current geomorphological configuration recently. Divergence among clades began in the last 1 million years, coinciding with documented changes in this landscape, and may be related to river dynamics associated with the presence of open vegetation areas. This phylogeographic pattern supports the dynamism of the drainage, and the historical complexity of the upper Madeira River.