Phylogeography, Historical Population Demography, and Climatic Modeling of Two Bird Species Uncover Past Connections Between Amazonia and the Atlantic Forest

We combined mitochondrial DNA sequence data and paleoclimatic distribution models to document phylogeographic patterns and investigate the historical demography of two manakins, <i>Ceratopipra rubrocapilla</i> and <i>Pseudopipra pipra</i>, as well as to explore connections between Amazonia and the Atlantic Forest. ND2 sequences of <i>C. rubrocapilla</i> (75 individuals, 24 sites) and <i>P. pipra</i> (196, 77) were used in Bayesian inference and maximum likelihood analyses. We estimated mitochondrial nucleotide diversity, employed statistical tests to detect deviations from neutral evolution and constant population sizes, and used species distribution modeling to infer the location of suitable climate for both species under present-day conditions, the Last Glacial Maximum (LGM), and the Last Interglacial Maximum (LIG). Mitochondrial sequence data from <i>C. rubrocapilla</i> indicate one Amazonian and one Atlantic Forest haplogroup. In <i>P. pipra</i>, we recovered a highly supported and differentiated Atlantic Forest haplogroup embedded within a large Southern Amazonian clade. Genetic and taxonomic structure in Amazonia differs widely between these two species; older <i>P. pipra</i> has a more marked genetic structure and taxonomic differentiation relative to the younger <i>C. rubrocapilla</i>. Both species have similar genetic patterns in the Atlantic Forest. Paleoclimatic distribution models suggest connections between southwestern Amazonia and the southern Atlantic Forest during the LIG, but not between eastern Amazonia and the northeastern Atlantic Forest, as suggested by previous studies. This indicates that multiple corridors, and at different locations, may have been available over the Pliocene and Pleistocene between these two regions.