Ancient insects find shows India wasn't isolated 50mn yrs ago

Ancient insects find shows India wasn't isolated 50mn yrs ago

A team of German, Indian and US scientists have found a trove of insects in a newly-excavated amber deposit from the Vastan lignite mine, 30km northeast of Surat, in a geological zone called the Cambay Shale.

The arthropods -- bees, termites, spiders, and flies -- found in the Cambay deposit are not unique as would be expected on an island but rather have close evolutionary relationships with fossils from other continents, said the scientists detailing their findings in the journal Proceedings of the National Academy of Sciences.
It has long been assumed that India broke away from Africa about 150 million years ago and didn't join up with another landmass -- Asia -- until about 50 million years ago.

Thus, the scientists were believing that the insects found in the amber would differ significantly from those found elsewhere in Asia.

But, to their surprise, the organisms in the amber were found to be closely related to other species found in northern Europe, Australia, New Guinea and tropical America.
"The amber shows, similar to an old photo, what life looked like in India just before the collision with the Asian continent," said coauthor Jes Rust, Professor of Invertebrate Paleontology at the Bonn University in Germany reporting the findings in the journal.

"The insects trapped in the fossil resin cast a new light on the history of the sub-continent," Rust said.

The new amber and amber from Colombia that is 10 million years older indicate that tropical forests are older than previously thought.In the research paper, Grimaldi, Rust, and colleagues described the Cambay amber as the oldest evidence of tropical forests in Asia.

"The evidence is beginning to accumulate that tropical forests are ancient," Grimaldi said. "They probably go back to right after the K-T boundary," between the Cretaceous and Tertiary periods 65 million years ago, when non-avian dinosaurs went extinct.

The team plans to return to Gujarat in January to collect more samples, and the work in the lab is only beginning, the researchers said.
"We're still discovering all sorts of cool stuff in this amber," Grimaldi said. "Every day."
Amber from broadleaf trees is rare in the fossil record until the Tertiary, or after the dinosaurs went extinct. It was during this era that flowering plants rather than conifers began to dominate forests and developed the ecosystem that still straddles the equator today.

David Grimaldi, curator in the Division of Invertebrate Zoology at the American Museum of Natural History, said: "We know India was isolated, but when and for precisely how long is unclear. The biological evidence in the amber deposit shows that there was some biotic connection."

The similarity in the insects means Asia and India collided a few million years earlier than geological evidence suggests, Grimaldi said.

Or it could support the theory that there were small islands connecting the continents, allowing species to "hop" across, he added.

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