Parallel diversifications ofCremastospermaandMosannona(Annonaceae), tropical rainforest trees tracking Neogene upheaval of the South American continent

This preprint has been reviewed and recommended by Peer Community In Evolutionary Biology (<ext-link xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="uri" xlink:href="http://dx.doi.org/10.24072/pci.evolbiol.100033">http://dx.doi.org/10.24072/pci.evolbiol.100033</ext-link>).Much of the immense present day biological diversity of Neotropical rainforests originated from the Miocene onwards, a period of geological and ecological upheaval in South America. We assess the impact of the Andean orogeny, drainage of lake Pebas, and closure of the Panama Isthmus on two clades of trees (Cremastosperma, c. 31 spp.; andMosannona, c. 14 spp.; both Annonaceae) found in humid forest distributed across the transition zones between the Andes and Western (lowland) Amazonia and between Central and South America. We inferred phylogenies based on c. 80% of recognised species of each clade using plastid and nuclear encoded sequence markers, revealing similar patterns of geographically restricted clades. Using molecular dating we showed that diversifications in the different areas occurred in parallel, with timing consistent with Andean vicariance and Central American geodispersal. In apparent contradiction of high dispersal abilities of rainforest trees,Cremastospermaclades within Amazonia are also geographically restricted, with a southern/montane clade that appears to have diversified along the foothills of the Andes sister to one of more northern/lowland species that diversified in a region once inundated by lake Pebas. Ecological niche modelling approaches show phylogenetically conserved niche differentiation, particularly withinCremastosperma. Niche similarity and recent common ancestry of Amazon and GuiananMosannonaspecies contrasts with dissimilar niches and more distant ancestry of Amazon, Venezuelan and Guianan species ofCremastospermasuggesting that this element of the similar patterns of disjunct distributions in the two genera is instead a biogeographic parallelism, with differing origins. The results provide further independent evidence for the importance of the Andean orogeny, the drainage of Lake Pebas, and the formation of links between South and Central America in the evolutionary history of Neotropical lowland rainforest trees.