Multilocus phylogeography of two Atlantic Forest species of Pyriglena (Aves: Thamnophilidae)

Phylogeography and population genetics are useful to understand diversification processes and to hypothesize historical events associated with the distribution of the genetic variation and of lineages. In the present study, we describe the multilocus phylogeography of Pyriglena atra and P. leucoptera, two hybridizing parapatric sister species endemic to the Atlantic Forest. We sequenced seven markers with different types of inheritance (one mitochondrial – mtDNA, three Z-chromosome linked, and three autosomal). It is expected that mtDNA exhibits a more pronounced population structure than nuclear DNA due to its lower effective population size and faster rate of evolution. Also, it is expected that autosomal genes present higher levels of introgression than the Z-linked and mtDNA genes. We recovered four non-reciprocally monophyletic lineages: one of P. atra and three of P. leucoptera. The two species share nuclear and mitochondrial haplotypes but the lineages showed varying levels of admixture, with P. atra most similar to the P. leucoptera lineage that occurs closer. One of our Z-linked markers presented higher differentiation between the two species than all the other markers, possibly due to lower introgression. In addition, the distribution of the lineages throughout the Atlantic Forest was roughly congruent with some large rivers. Even though these rivers do not seem to be primary barriers, it is possible that ecological factors or other variables associated with them could have influenced the allele frequencies of each lineage.