Evolution of Neotropical primates

Geoffroy's spider monkey (Ateles geoffroyi)
Wikimedia Commons

Derek Wildman's Group at Wayne State University have re-examined the evolution of Neotropical primates (here). Using genomic data from 36 species they derive a tree with few surprises but better support than in other recent analyses.

What I found interesting is their attempt to place platyrrhine evolution in a biogeographical context. They suggest that the most recent common ancestor of extant species lived in what today is the Amazon rain forest, Guiana Shield and Northern Andes. Then, however, this was largely an area of lowlands and mountains. In support of their interpretation, known fossil sites are within this region. They further suggest that diversification of platyrrhines occurred with the establishment and development of the Amazon rain forest. 


Placenta of the white fronted capuchin (Cebus albifrons)
From Carter and Mess (here)

The founder of the Neotropical primates arrived in South America during the Oligocene when the continent was completely isolated from other land masses. Personally I favour the view (espoused here) that they came by a transatlantic route. However, Jameson Kiesling et al. suggest they may have come directly from Asia. In support they cite the occurrence of all the early fossils on the west side of the continent and recent evidence that platyrrhines may have emerged in Asia rather than Africa. In either case the means of dispersal was most likely by rafting (see previous post on sweepstakes distribution).