For the first time, scientists have discovered fossil evidence of an endangered, living tropical tree species. The unprecedented find was made in Brunei, a country on the large island of Borneo, and reveals a critical piece of the ancient history of Asia’s rainforests, highlighting the urgent need for conservation in the region, according to researchers at Penn State who led the discovery.
The research team published their findings in the American Journal of Botany.
The fossils, at least two million years old, represent the first direct evidence of an endangered tropical tree species in the fossil record. The research study, conducted in collaboration with the University of Brunei among other international partners, identified fossilized leaves of Dryobalanops rappa, known locally as the Kapur Paya. It is a towering dipterocarp tree that still exists today but is endangered and found in the carbon-rich peatlands of Borneo, including Brunei.
“This discovery provides a rare window into the ancient history of Asia’s wet tropical forests,” said Tengxiang Wang, a doctoral student in the College of Earth and Mineral Sciences at Penn State and lead author on the paper. “We now have fossil proof that this magnificent tree species has been a dominant part of Borneo’s forests for millions of years, emphasizing its ecological importance and the need to protect its remaining habitats.”
Until now, the fossil record of Asia’s wet tropical forests has been surprisingly scarce compared to the Amazon and Africa, said Peter Wilf, professor of geosciences at Penn State and co-author.
The team identified the fossils by analyzing microscopic features of the preserved leaf cuticles, which revealed a perfect match with modern Dryobalanops rappa, down to the last cellular detail.
“Our findings highlight that these forests are not just rich in biodiversity today but have been home to iconic tree species for millions of years,” Wang said. “Conserving them is not only about protecting present-day species but also about preserving a legacy of ecological resilience that has withstood millions of years.”
Dipterocarps, the dominant tree family in Asia’s rainforests, are critical for carbon storage and biodiversity. However, the researchers said, they are increasingly threatened by deforestation and habitat destruction. By revealing the deep historical roots of these trees, this discovery adds an important new perspective to conservation efforts.
“The findings add a new dimension to conservation; we are not only protecting modern species but ancient survivors that have been key components of their unique ecosystems for millions of years,” Wang said. “This historical perspective makes both the endangered trees and their habitats even more valuable for conservation. Our study also shows how fossil evidence can strengthen conservation strategies for threatened species and ecosystems based on their historical significance.”
Understanding the history of tropical forests is essential for their conservation, especially as many key species face rapid decline, Wilf said.
“Penn State’s paleobotany group is making exciting fossil discoveries with our international partners in several Southeast Asian countries, illuminating the poorly known history of the region’s magnificent and severely threatened tropical forests,” Wilf said. “Our finding fossils of living, endangered, giant tree species provides a vital historical foundation for conserving tropical Asia’s keystone trees, the rapidly disappearing dipterocarps.”
Two collaborators on the paper are Penn State alumni: Michael Donovan, The Field Museum; and Xiaoyu Zou, University of California San Diego. Additionally, collaborators from other institutions include Antonino Briguglio, Università degli Studi di Genova; László Kocsis, University of Lausanne; and Ferry Silk, Universiti Brunei Darussalam.
The research was supported by the U.S. National Science Foundation, Universiti Brunei Darussalam research grants and a Penn State Institute of Energy and the Environment seed grant.