Before the final collision of Eurasia and the Indian subcontinent, land bridges between the landmasses may have served as 'freeways' of biodiversity exchange that flowed in both directions, says a research led by Grismer.
The paper shows that as India was approaching Eurasia and was connecting by ephemeral land bridges, it was these land bridges that allowed for dispersal and exchange of all these species.
There were two areas of suitable habitat separated by unsuitable oceans.
But once that new area was exposed, the species were allowed to disperse into mainland Asia or India, respectively, areas that these species had not been able to previously exploit.
For about 60 million years during the Eocene epoch, the Indian subcontinent was a huge island. Having broken off from the ancient continent of Gondwanaland, the Indian Tectonic Plate drifted toward Eurasia.
During that gradual voyage, the subcontinent witnessed a blossoming of exceptional wildlife and when the trove of unique biodiversity finally made contact with bigger Eurasia, the exchange of animals and plants between these areas laid the foundations for countless modern species.
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To derive the conclusion, Grismer and his colleague performed a phylogenomic analysis of Indian Dragon Lizards, revealing multiple origins in Southeast Asia.
Importantly, the team showed that two land bridges connected the Indian subcontinent to Eurasia at two different times during the early to middle Eocene, some 35 to 40 million years ago.
It also added that conservation of certain species of Dragon Lizards and keeping them out of the international pet trade would help make possible more opportunities for understanding the history of this unique group of family of lizards.
The study has been published in BMC Evolutionary Biology.