Testing main Amazonian rivers as barriers across time and space within widespread taxa

Aim: Present Amazonian diversity patterns can result from many different mechanisms and, consequently, the factors contributing to divergence across regions and/or taxa may differ. Nevertheless, the river-barrier hypothesis (RBH) is still widely invoked as a causal process in divergence of Amazonian species. Here we use model-based phylogeographic analyses to test the extent to which major Amazonian rivers act similarly as barriers across time and space in two broadly distributed Amazonian taxa.
Local: Amazon rainforest.
Taxon: The lizard Gonatodes humeralis (Sphaerodactylidae) and the tree frog Dendropsophus leucophyllatus (Hylidae).
Methods: We obtained RADseq data for samples distributed across main river barriers, representing main Areas of Endemism previously proposed for the region. We conduct model-based phylogeographic and genetic differentiation analyses across each population pair.
Results: Measures of genetic differentiation (based on FST calculated from genomic data) sho...