Recently, the new research "Diversification of rhacophorid frogs provides evidence for accelerated faunal exchange between India and Eurasia during the Oligocene" on tree frog was online in the journal "Proceedings of the National Academy of Sciences".
The accretion of the Indian subcontinent to Eurasia triggered a massive faunal and floral exchange, with Gondwanan taxa entering into Asia and vice versa. The traditional view on the Indian−Asian collision assumes contact of the continental plates during the Early Eocene. Many biogeographic studies rely on this assumption. However, the exact mode and timing of this geological event is still under debate.
Jia-tang Li et al., cooperation with Ya-ping Zhang (Kunming Institute of Zoology, Chinese Academy of Sciences) and David M. Hillis (University of Texas at Austin), constructed an extensive phylogenetic and biogeographic analysis of rhacophorid tree frogs. The study indicated that rhacophorid tree frogs showed an early dispersal from India to Asia between 46–57 Ma, as reconstructed from the fossil record. During the Middle Eocene, however, faunal exchange ceased, followed by increase of rhacophorid dispersal events between Asia and the Indian subcontinent during the Oligocene that continued until the Middle Miocene.
This corroborates recent geological models that argue for a much later final collision between the continental plates. The study also predict that the Oligocene faunal exchange between the Indian subcontinent and Asia, as shown here for rhacophorid frogs, also applies for other non-volant organisms with an Indian–Asian distribution, and suggest that previous studies that deal with this faunal interchange should be carefully reinvestigated.
This work was supported by grants from the National Basic Research Program of China (973 Program, Grant), the National Natural Science Foundation of China (31101618, 31071894), China Postdoctoral Science Foundation Funded Project (No. 20100471689), and the U.S. National Science Foundation (EF-0334952).
The study entitled "Diversification of rhacophorid frogs provides evidence for accelerated faunal exchange between India and Eurasia during the Oligocene" has been onlined in Proceedings of the National Academy of Sciences.
Author contact: Dr. Jia-tang Li