A climatic or tectonic control on early primate dispersal? A new approach to investigate species dispersal in deep time

Recent studies show that the distribution of many modern terrestrial species can be explained by a handful amount of large-scale dispersals and that these episodes will likely become more numerous under climatic stress. However, the underlying mechanisms governing these dispersals remain nebulous. Long-distance dispersals across marine barriers, often referred to sweepstakes dispersals, have always been assumed to be an unpredictable process in which taxa overcome a geographic barrier in a random manner. Yet, there are many instances of dispersals across marine barriers that appear coordinated and non-random. New paleontological findings show that during a short time period marked by intense climate variations, 40 to 35 million years ago, Asian anthropoid primates and rodents crossed 500 km of Tethys Sea to reach Africa and 800 km of South Atlantic Ocean to reach South America. This proposal aims to build an empirical and theoretical basis for the origins and mechanisms of long-distance dispersals by resolving: how did primates and other mammals disperse across two major seaways? What are the external forcing mechanisms that make transoceanic dispersals non-random? This project proposes a combination of paleoclimatic, paleogeographic, and paleontological approaches to evaluate the mechanisms of species dispersal and diversification in deep time, applied to the early dispersal of anthropoid primates. This research will set the founding steps of a holistic method to evaluate the mechanisms of all dispersal events in deep time, allowing new interpretations about the modern, past and future distribution of species; it will additionally solve one of the biggest mysteries in paleontology, as this episode ranks among the most pivotal events during all of primate evolutionary history.