Biogeography and spatio-temporal diversification of Selenidera and Andigena Toucans (Aves: Ramphastidae)

Andean uplift, Plio-Pleistocene climatic fluctuation, and river dynamics in the Amazon basin have all been implicated in the diversification of the South American avifauna. We reconstructed phylogenetic relation- ships in the genus Selenidera, which has served as a classic case of putative refugial speciation, and the closely related genus Andigena, to better understand the processes driving their diversification. Using mitochondrial and nuclear DNA sequences, we constructed a phylogeny to estimate the pattern and tim- ing of divergence within and between seven lowland Selenidera toucanets and the five species of Andigena mountain-toucans, which together form a single clade. All phylogenetic analyses supported the mono- phyly of the montane genus Andigena, but indicated that the genus Selenidera is likely paraphyletic with respect to Andigena. Our time tree analysis is consistent with the orogenic uplift of the northern Andean range having initiated the divergence between Selenidera and Andigena, and that the movement and frag- mentation of montane habitats in response to Pleistocene climatic oscillations likely influenced diversi- fication within Andigena. Estimated divergence times for lowland Amazonian Selenidera did not support the Last Glacial Maximum (LGM) refuge hypothesis as an important biogeographic factor for the diversi- fication of lineages studied here. The timing of divergence within Selenidera is consistent with the hypothesis that geographic isolation of areas of endemism generated by Amazonian river dynamics dur- ing the Plio-Pleistocene contributed to Selenidera speciation and current species distributions.