1 Birbal Sahni Institute of Palaeosciences, Lucknow 226007, India.
2 Palynova Ltd., Littleport, Cambridgeshire CB6 1PY, UK.
3 Earth Sciences Department, Royal Holloway, University of London, Egham, Surrey TW20 0EX, UK.
4 The Nature Conservancy Centre, New Delhi 110024, India.
5 Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai 400076, India.
6 Department of Biology and Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec H4B 1R6, Canada.
7 Quebec Centre for Biodiversity Science, Montreal, Quebec H3A 1B1, Canada.
8 Petroleum Laboratories, Research & Studies (PLRS), Ministry of Petroleum and Gas, Khartoum, Republic of Sudan.
9 Institut Français de Pondichéry, UMIFRE 21 CNRS-MAEE, Puducherry 605001, India.
10 Organismic and Evolutionary Biology, Harvard Un

The evolution and diversification of ancient megathermal angiosperm lineages with Africa-India origins in Asian tropical forests is poorly understood because of the lack of reliable fossils. Our palaeobiogeographical analysis of pollen fossils from Africa and India combined with molecular data and fossil amber records suggest a tropical-African origin of Dipterocarpaceae during the mid-Cretaceous and its dispersal to India during the Late Maastrichtian and Paleocene, leading to range expansion of aseasonal dipterocarps on the Indian Plate. The India-Asia collision further facilitated the dispersal of dipterocarps from India to similar climatic zones in Southeast Asia, which supports their out-of-India migration. The dispersal pathway suggested for Dipterocarpaceae may provide a framework for an alternative biogeographic hypothesis for several megathermal angiosperm families that are presently widely distributed in Southeast Asia.