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.; and Mosannona, 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 and plastid and nuclear encoded sequence markers, revealing similar patterns of geographically restricted clades. Using molecular dating we showed that the timing of diversifications in the different areas largely overlap and are consistent with Andean vicariance and Central American geodispersal. In apparent contradiction of high dispersal abilities of rainforest trees, Cremastosperma clades within Amazonia are also geographically restricted, with a southern/montane clade that appears to have diversified in 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 niche conservatism, particularly within Cremastosperma. Niche similarity and recent common ancestry of Amazon and Guianan Mosannona species contrasts with dissimilar niches and more distant ancestry of Amazon, Venezuelan and Guianan species of Cremastosperma suggesting that this element of the similar patterns of disjunct distributions in the two genera had different biogeographic 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.
|Date made available||2018|
Pirie, M. D. (Creator), Maas, P. J. M. (Creator), Wilschut, R. (Creator), Chatrou, L. W. (Creator) (2018). Parallel diversifications of Cremastosperma and Mosannona (Annonaceae), tropical rainforest trees tracking Neogene upheaval of the South American continent