Photo Credit: Hanna Lazar
Scientific Frontline: Extended "At a Glance" Summary: The Origins of Southeast Asian Plant Biodiversity
The Core Concept: A geological landmass that detached from northwestern Australia approximately 150 million years ago drifted north, serving as an equatorial evolutionary refuge that ultimately seeded the highly diverse tropical forests of Southeast Asia.
Key Distinction/Mechanism: Contrary to the long-held paradigm that Southeast Asia's flowering-plant ecosystems evolved relatively recently, paleontological evidence from 99-million-year-old amber demonstrates that these plants had already diversified extensively during the Cretaceous period in isolation.
Origin/History: The West Burma Block separated from Australia 150 million years ago, drifted near the equator for 100 million years, and collided with Southeast Asia approximately 50 million years ago.
Major Frameworks/Components:
- Analysis of over 3,000 mid-Cretaceous fossil specimens preserved in Myanmar amber, including flowers, fruits, leaves, and seeds.
- Identification of 392 distinct morphological types of flowering plants, alongside ancient fern and conifer lineages.
- Integration of tectonic drift models with the fossil record to demonstrate how prolonged equatorial isolation fostered plant diversification.
Branches of Science: Paleobotany, Evolutionary Biology, Historical Geology, Biogeography.
Future Application: Enhances predictive models regarding how ancient tectonic shifts and long-term geographic isolation influence modern biodiversity, providing critical baseline data for the conservation of equatorial biological hotspots.
Why It Matters: This discovery redefines the evolutionary timeline of one of the world's richest tropical ecosystems, establishing a direct biogeographical connection between ancient Australian geology and the deep evolutionary roots of modern Southeast Asian flora.
A landmass that broke away from northwestern Australia about 150 million years ago and drifted north for the next 100 million years helped lay the foundations for Southeast Asia’s extraordinarily diverse tropical forests, new research has revealed.
An international study of more than 3,000 fossil specimens preserved in amber in Myanmar has uncovered a diverse plant community dating back about 99 million years, providing a remarkable window into the ancient flora carried north by the West Burma Block before it collided with Southeast Asia about 50 million years ago.
Curtin University coauthor Professor Byron Lamont said the findings revealed a remarkable connection between Australia’s geological past and the origins of one of the world’s richest tropical plant regions.
“It’s an amazing story of a landmass breaking away from northwestern Australia, drifting north across the ancient oceans for millions of years, and eventually becoming part of Southeast Asia,” Professor Lamont said.
“Along the way, it carried a rich tropical flora that evolved in relative isolation near the equator for tens of millions of years. When the landmass eventually joined Southeast Asia, it helped provide the foundations for the extraordinary plant diversity the region is renowned for today.
“We identified at least 392 morphological types of flowering plants in the amber, alongside an array of ferns, conifers, and other ancient plant groups.
“These fossils give us a rare glimpse of that ancient world and help explain the deep evolutionary roots of Southeast Asia’s tropical forests.”
Professor Lamont said the diversity is among the highest recorded for a single fossil plant assemblage from the early to mid-Cretaceous period, when dinosaurs still roamed the Earth.
“Preserved in exceptional three-dimensional detail, the fossils include flowers, fruits, leaves, and seeds that offer evidence of a flourishing tropical plant community 100 million years ago,” Professor Lamont said.
“Because the West Burma Block drifted north while remaining close to the equator for tens of millions of years, this prolonged tropical environment provided a refuge in which ancient plant lineages could survive and diversify.
“The findings challenge the long-held view that Southeast Asia’s diverse flowering-plant ecosystems largely originated much more recently, showing that flowering plants had already diversified extensively in equatorial environments during the Cretaceous period.”
Published in journal: Nature Ecology & Evolution
Title: A mid-Cretaceous island as a cradle of Southeast Asian plant biodiversity
Authors: Chao Shi, Bing-pu Wang, Michael S. Engel, Thet Thet Mar Win, Huan Wang, Bing-yue Zhu, Jing Yang, Qiang Zhang, Qian-hui Lin, Zhen-ping Shi, Hua-Sheng Huang, Hao-hong Cai, Yan-jing Shi, Xiao-chen Zhao, Dian-Xiang Zhang, Xu Guo, Quan Jiang, Ya Li, Yong Fan, Byron B. Lamont, Xian-Chun Zhang, Zhong-Jian Liu, De-Zhu Li, Yong-Dong Wang, Ye-Ming Cheng, Guang-Hai Shi, Zin-Maung Maung-Thein, Kyaing Sein, Robert A. Spicer, and Shuo Wang
Source/Credit: Curtin University | Lucien Wilkinson
Edited by: Scientific Frontline
Reference Number: pal102826_01
