古生态研究组知识库

Dipterocarpaceae, a tropical plant family that forms a major component of low-lying rainforests in Southeast Asia, is represented by a large number of fossils from the Cenozoic sedimentary successions of India, but the origin and antiquity of this family has been actively debated. The earliest reliable dipterocarp megafossils so far reported in India come from Eocene (34-23 Ma) sediments of the Cambay Basin of western India and in Southeast Asia from Eocene (34-23 Ma) sediments within China. More recently, pollen attributable to the family was recovered from Maastrichtian sediments in India, but because pollen is highly durable, can be transported over long distances and offers only low taxonomic resolution, more definitive evidence is required to demonstrate, unequivocally, that the Dipterocarpaceae were in India prior to its contact with Eurasia early in the Paleogene. The Late Cretaceous (Maastrichtian) leaf fossils documented here have an affinity with the extant genus Dipterocarpus (family Dipterocarpaceae) and come from the Mandla Lobe Deccan Intertrappean Beds of Central India. They provide compelling evidence that this tropical rain forest element was present in India during Chron 29R, which spans the K-Pg transition, and when the bulk of the subcontinent was still in the Southern Hemisphere. We suggest that only later did their dispersal to Southeast Asia occur, consistent with the "Out-of-India" hypothesis. These fossil leaves represent the earliest reliable fossil record of the Dipterocarpaceae and, in particular, Dipterocarpus.