India was not isolated before colliding with Eurasia: study

Scientists assumed for a long time that the subcontinent was largely isolated during its long journey through the ocean and unique species of plants and animals were therefore able to develop on it.

Berlin, Jan 13: India may not have been as isolated as previously thought while gradually drifting away from Africa and Madagascar towards the north before colliding with the Eurasian plate, a new study has found.

Scientists assumed for a long time that the subcontinent was largely isolated during its long journey through the ocean and unique species of plants and animals were therefore able to develop on it.

However, paleontologists at the University of Bonn in Germany are now showing using tiny midges encased in amber that there must have been a connection between the apparently cut off India and Europe and Asia around 54 million years ago that enabled the creatures to move around. India harbours many unique species of flora and fauna that only occur in this form on the subcontinent. The prerequisite for such a unique development of species is that no exchange takes place with other regions.

For a long time, scientists assumed that India was isolated in this way due to continental drift. The super-continent Gondwana, which included South America, Africa, Antarctica, Australia, Madagascar and India, broke up over the course of geological history. What is now India also began moving towards the north east around 130 million years ago.

It was common belief among researchers that, before it collided with the Eurasian plate, India was largely isolated for at least 30 million years during its migration. However, according to new findings, the Indian subcontinent may not have been as isolated on its journey as we have thought.

"Certain midges that occurred in India at this time display great similarity to examples of a similar age from Europe and Asia," said lead author Frauke Stebner from University of Bonn. These findings are a strong indicator that an exchange did occur between the supposedly isolated India, Europe and Asia, researchers said. Stebner mined for amber in seams of coal near the city of Surat.

Small midges, among other things, were encased in tree resin 54 million years ago and preserved as fossils. Paleontologists investigated a total of 38 biting midges encased in amber and compared them with examples of a similar age from Europe and China.

"There was significant conformity with biting midges in amber from the Baltic and Fushun in north-east China," said Stebner. "It also seems to have been possible for birds and various groups of mammals to cross the ocean between Europe and India at the time," Stebner said.

However, it has now been possible for the first time, with the aid of biting midge fossils, to also demonstrate an exchange between India and Asia in this period. Stebner assumes that a chain of islands that existed at that time between India, Europe and Asia could have helped the biting midges to spread. The finding was published in the journal PLOS ONE.

PTI