Tropical niche conservatism explains the Eocene migration from India to Southeast Asia in Ochyroceratid spiders

Biological migrations between India and Southeast (SE) Asia provide an ideal system for exploring the effects of geology and climate on species ranges. Geologists have confirmed that the direct collision between India and Eurasia occurred in the Early Eocene, but most migrations occurred between the Indian subcontinent and SE Asia rather than the former and the southern margin of Eurasia. To explain this seemingly paradoxical disconnect between the routes of plate movement and biological migration, we studied the evolutionary history of the tropical spider family Ochyroceratidae based on 101 globally distributed species. We infer a robust dated phylogeny using both transcriptomic data and a dataset of classical markers and relate these to biogeographic and climatic analyses. Our results indicate that the monophyly of Ochyroceratidae is strongly supported, and the divergence times suggest a Cretaceous Gondwanan origin of the family. Reconstructed biogeographic histories support a dispers...