Insects Frozen In Amber Offer Clues To India's Past

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    Insects like this fungus gnat have been fossilized for 50 to 52 million years in a deposit of amber excavated in India.
    David Grimaldi/American Museum of Natural History
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    This male spider from the amber deposit is one of the oldest records of the family Pholcidae, which is still around today.
    David Grimaldi/American Museum of Natural History
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    Leaf hoppers like this one thrived in an ancient tropical rainforest in the northwestern Indian state of Gujarat.
    David Grimaldi/American Museum of Natural History
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    Scientists believe spiders and insects from Asia may have arrived in India by "island-hopping" along a chain of islands.
    David Grimaldi/American Museum of Natural History
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    The amber that encases this fly, a member of the family Chironomidae, was made from the resin of 50 to 52 million-year-old tropical broadleaf trees.
    David Grimaldi/American Museum of Natural History
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    This booklouse from western India is one of 700 arthropods from 55 different genera discovered in the amber deposit.
    David Grimaldi/American Museum of Natural History
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    The amber included one of the earliest records of mantis.
    David Grimaldi/American Museum of Natural History

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In these golden-hued images, the tiny inhabitants of a once vibrant forest are frozen in the sticky geological preservative of amber. The photographs come from a paper published in this week's Proceedings of the National Academy of Sciences, the work of paleontologists at the American Museum of Natural History in New York and the Universitat Bonn in Germany.

They describe an impressively intact collection of insects in an ancient amber deposit that oozed from a tropical forest in the Indian state of Gujarat. The insects are between 50 million and 52 million years old — so primeval that they're shaking up theories about the age of the oldest tropical forest and the biogeography of a continent.

Scientists believe India split off from Africa about 160 million years ago and languidly floated east for about 110 million years. When it finally smashed into Asia it raised a huge bulge — what we now know as the Himalayas.

Around that time, the northwest region that is now Gujarat was covered with a rain forest of Dipterocarpaceae, a family of tropical broadleaf trees. The excavation of the amber deposit from that forest has yielded more than 700 arthropods from 55 different genera — mostly insects, but also spiders and plants. What's unusual is that many of these species are also found in other parts of the world like Europe, Australia and even in Central America, and are not native to India alone.

Dr. Jes Rust, a paleontologist at the Universitat Bonn and a lead author of the paper, says the finding suggests India may not have been isolated at all in its drift from Africa to Asia. Instead, there may have been long chains of volcanic islands between the continental plates — similar to Japan or Indonesia today. The insect species of Asia might have made the trip to India simply by "island-hopping."

Dr. David Grimaldi, an invertebrate zoologist at the American Museum of Natural History and another author, says he was also struck by the age of the forest, especially because it's still around today.

"Here's a snapshot of a modern type of tropical forest going back 50 million years," said Grimaldi. "For a long time there's been a controversy about ages of tropical forest and this is a rare instance of insight into it."

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