"We know India was isolated, but … the biological evidence in the amber deposit shows that there was some biotic connection," says David Grimaldi, curator in the Division of Invertebrate Zoology at the American Museum of Natural History.
About 150 million years ago, the Indian tectonic plat separated from the African plate and began its 100 million year journey to Asia. During that long journey the subcontinent was isolated from all other continents, giving its wildlife the chance to evolve in distinctly different ways (much like the evolution of marsupials in Australia). Since the amber was deposited in the form of sticky tree resin 50 million years ago, it gives researchers insight into the insects that were adrift on the subcontinent.
"The amber shows, similar to an old photo, what life looked like in India just before the collision with the Asian continent," says Jes Rust, professor of Invertebrate Paleontology at the Universität Bonn in Germany. "The insects trapped in the fossil resin cast a new light on the history of the sub-continent."
Many of the arthropods found in the amber look very similar to those found in Asia at the time. The team reasoned that there much have been a connection between the two continents for some time before they actually merged, allowing life to connect through islands. The other possibility is that the slow movement of the Indian subcontinent happened earlier than previously believed.
In total, the team has identified more than 700 arthropods, a group of animals that includes insects, crustaceans and arachnids. "They are so well preserved. It's like having the complete dinosaur, not just the bones. You can see all the surface details on their bodies and wings. It's fantastic," Rust told the Guardian. The remains of two praying mantises were also found.
The treasure trove of amber is one of the biggest on record-150 kilograms of it has survived the last 52 million years. It was unearthed in India's Gujarat province from an open-pit mining operation, which brings these deep layers to the surface. The researchers collected the amber over the last three years.
The amber itself also yields new information. The original resin came from a tropical tree family called Dipterocarpaceae that today makes up about 80 percent of forest canopies in Southeast Asia. This means this tree family (and tropical forests in general) are twice as old as researchers previously thought.
By Jennifer Welsh
Reprinted with permission from Discover