Comparative Phylogeography of Two Bird Species, Tachyphonus phoenicius (Thraupidae) and Polytmus theresiae (Trochilidae), Specialized in Amazonian White-sand Vegetation

White-sand vegetation (WSV) harbors a unique avifauna within Amazonia, including species with patchy distributions. The history of these species' populations is likely related to variation in the availability and connectivity among WSV patches though time. By investigating the phylogeographic history of WSV bird species, we aim to better understand the dynamic evolution of forested and open habitats in Amazonia. Here, we perform a phylogeographic analysis of two WSV specialist bird species, a tanager, Tachyphonus phoenicius, and a hummingbird, Polytmus theresiae. We obtained and analyzed sequences of one mitochondrial and one nuclear gene region from 152 individuals. Results indicate that the two species have different histories. Tachyphonus phoenicius split from its Atlantic Forest/Cerrado sister clade at about 11 Ma and includes two divergent lineages, north and south of the Amazon River. Polytmus theresiae split from its Tepuian sister group at about 2.5 Ma and shows no genetic structure within Amazonia. Both lineages of T. phoenicius and P. theresiae show signs of recent population expansion. Although the two WSV species originated at different moments, and show distinct patterns of population structure, both seem to have expanded their population sizes recently, indicating that availability of white-sand habitats may have been increasing historically and the connectivity among different white-sand patches may have been higher in the recent past.