Out of Amazonia again and again: episodic crossing of the Andes promotes diversification in a lowland forest flycatcher

Matthew J Miller, Eldredge Bermingham, John Klicka, Patricia Escalante, Fabio S Raposo do Amaral, Jason T Weir, Kevin Winker, Proceedings of the Royal Society B 275 :1133-1142 (2008).

Abstract

Most Neotropical lowland forest taxa occur exclusively on one side of the Andes despite the availability ofappropriate habitat on both sides. Almost all molecular phylogenies and phylogenetic analyses of species assemblages (i.e. area cladograms) have supported the hypothesis that Andean uplift during the LatePliocene created a vicariant barrier affecting lowland lineages in the region. However, a few widespreadplant and animal species occurring in lowland forests on both sides of the Andes challenge the generality ofthis hypothesis. To understand the role of the Andes in the history of such organisms, we reconstructed the phylogeographic history of a widespread Neotropical flycatcher (Mionectes oleagineus) in the context of theother four species in the genus. A molecular phylogeny based on nuclear and mitochondrial sequencesunambiguously showed an early basal split between montane and lowland Mionectes. The phylogeographic reconstruction of lowland taxa revealed a complex history, with multiple cases in which geographically proximate populations do not represent sister lineages. Specifically, three populations of M. oleagineus west of the Andes do not comprise a monophyletic clade; instead, each represents an independent lineage withorigins east of the Andes. Divergence time estimates suggest that at least two cross-Andean dispersal eventspost-date Andean uplift.