Phylogeography and historical demography of Myrmeciza loricata and Myrmeciza squamosa (Aves, Thamnophilidae): an analysis of species limits, speciation and diversification processes in the Atlantic Forest
The Atlantic Forest stands among the forests with the highest number of endemisms in the world, being ranked as one of Earth's five top biodiversity hotspots. Phylogenetic and phylogeographic studies comprising Atlantic Forest species are still incipient, and the few available studies suggest that complex processes occurring in different timescales may have operated during the biome's evolution. Due to this reason, the addition of novel inferences including taxonomically diverse species and clades is crucial to the refinement of hypotheses concerning the pattern and processes involving the evolutionary history of the Atlantic Forest. The bird genus Myrmeciza is composed of 20 species, and stands as one of the largest genus of antbirds (Family Thamnophilidae). Although recent studies do not support monophyly of Myrmeciza as currently accepted, the three Altantic Forest endemic species of the genus (M. squamosa, M. loricata and M. ruficauda) comprise a monophyletic clade, with M. squamosa and M. loricata as sister species. M. squamosa and M. loricata are small insectivore birds that occupy the lower stratum of the forest, and whose combined geographic distributions extends throughout most of the biome. Despite their almost allopatric distributions, an undersampled potential area of sympatry exists between the north of the state of São Paulo and the south of the state of Rio de Janeiro. The taxonomic history of this species pair is controversial: although some authors recognize them as a single species, they have been considered by most authors as two different species in the recent literature. The goals of this project are: 1) Test the reciprocal monophyly between M. loricata and M. squamosa using mitochondrial and nuclear data, as a way to evaluate their status as independent evolutionary units; 2) Investigate the existence of phylogeographic discontinuities in each taxon, and if they exist, compare them with patterns found in other endemic birds; 3) Infer a temporal framework of the diversification of the lineages, using populational data and molecular clock estimates; 4) Understand patterns of historical demography of both species, and evaluate such results under premises of models of diversification proposed for the Neotropics; 5) Evaluate the existence of syntopy and, using molecular data, hybridization of the two species, based on specimens collected in the overlaping distribution area.
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