A landmass that separated from the northwest of Australia about 150 million years ago may have played an important role in the origin of the diversity of the tropical forests of Southeast Asia. The conclusion comes from an international study that analyzed more than 3,000 fossils preserved in amber, found in Myanmar, and identified a plant community about 99 million years old.
The investigation, published in the scientific journal Nature Ecology & Evolution, identified at least 392 morphologically distinct types of flowering plants, in addition to ferns, conifers and other ancient plant groups. The fossils include flowers, fruits, leaves and seeds, preserved with a level of detail that allows reconstructing the vegetation that existed during the Cretaceous.
“It’s an extraordinary story of a landmass that split from the northwest of Australia, drifted northward through ancient oceans for millions of years, and ended up becoming part of Southeast Asia,” says Byron Lamont, professor at Curtin University and co-author of the study.
According to the researcher, the landmass, known as the West Burma Block, carried a tropical flora that evolved in relative isolation for tens of millions of years, remaining near the equator. “Over the course of this journey, 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 establish the foundations of the extraordinary plant diversity for which the region is today known,” he explains.
The collision occurred about 50 million years ago. The results thus suggest that the diversity of flowering plants in the region has older roots than previously thought, since they were already widely diversified in equatorial environments about 100 million years ago.
