The scale of the find is striking. According to the authors, the morphospecies richness and clade diversity of this ancient flora rank among the highest recorded for any single Early to mid-Cretaceous plant megafossil assemblage.

The study also explains how such a diverse flora came to be in Southeast Asia. The plants reached the region rafted on the West Burma Block, an arc-shaped microplate that separated from the northwestern corner of the Australian Plate during the Jurassic and drifted northwards, finally colliding with Sundaland by the Eocene. Crucially, the Burma Terrane remained low-lying and at low latitudes during the intervening 100 to 50 million years. The authors describe this long stable interval as a sanctuary for clade preservation, a cradle for the diversification of modern clades, and a conduit for transferring flourishing Gondwanan angiosperm lineages into Asia.

Together, these findings suggest that the origins of what ultimately became Southeast Asia’s angiosperm-dominated tropical forests reach back more than 100 million years, far earlier than the recent Cenozoic origin often assumed for the region’s flora. Rather than being assembled from scratch in the aftermath of the Cretaceous, the region’s plant diversity appears to have deep roots in a mid-Cretaceous island ecosystem that both preserved ancient lineages and generated new ones. The Kachin amber assemblage thus reframes Southeast Asian biodiversity not as a late arrival, but as the product of a hundred-million-year history of drift, survival and diversification on a low-latitude island arc.

Subject of Research: A mid-Cretaceous amber-preserved plant assemblage from Myanmar and the role of the West Burma Block in the origins of Southeast Asian plant biodiversity.

Article Title: A mid-Cretaceous island as a cradle of Southeast Asian plant biodiversity

Article References: Shi, C., Wang, B.-P., Engel, M. S., Mar Win, T. T., Wang, H., Zhu, B.-Y., Yang, J., Zhang, Q., Lin, Q.-H., Shi, Z.-P., Huang, H.-S., Cai, H.-H., Shi, Y.-J., Zhao, X.-C., Zhang, D.-X., Guo, X., Jiang, Q., Li, Y., Fan, Y., … Wang, S. (2026). A mid-Cretaceous island as a cradle of Southeast Asian plant biodiversity. Nature Ecology & Evolution. https://doi.org/10.1038/s41559-026-03219-7

Image Credits: AI Generated

DOI: 10.1038/s41559-026-03219-7

Keywords: mid-Cretaceous, amber fossils, Kachin Myanmar, angiosperms, West Burma Block, Southeast Asia, plant biodiversity, paleobotany, Gondwanan lineages, tropical forests, morphospecies, plate tectonics