Why so little uniqueness?

Now, India, along with Madagaskar, broke away from Africa some 160 million years ago. Don’t know why. Possibly both of them were pissed off. She spent more than 100 million years in isolation before colliding with Asia and thus giving birth to Himalyas and Tibet Plateau. Unlike Madagaskar, despite of more than 100 millions years in isolation, why so little unique species are found on India? And why ‘fourteen orders and more than 55 families and 100 species of arthropod inclusions have been discovered thus far, shows affinities to taxa from the Eocene of northern Europe, to the Recent of Australasia, and the Miocene to Recent of tropical America.’ Why so little biological insularity?

A paper with a scary title of “Biogeographic and evolutionary implications of a diverse paleobiota in amber from the early Eocene of India” sheds some lights on this fact. The Hindu has written editorial about it even if no one seems to care about it. Recent excavations of rich outcrops of 50–52-million-year-old amber with diverse inclusions from the Cambay Shale of Gujarat, western India address were studied/reviewed in this paper. Now, since Cambay amber occurs in lignitic and muddy sediments concentrated around shores and are very partially polymerized and readily dissolves in organic solvents, they allow ‘extraction of whole insects whose cuticle retains microscopic fidelity’.

Fourteen orders and more than 55 families and 100 species of arthropod inclusions have been discovered thus far, which have affinities to taxa from the Eocene of northern Europe, to the Recent of Australasia, and the Miocene to Recent of tropical America. Thus, India just prior to or immediately following contact shows little biological insularity. A significant diversity of eusocial insects are fossilized, including corbiculate bees, rhinotermitid termites, and modern subfamilies of ants (Formicidae), groups that apparently radiated during the contemporaneous Early Eocene Climatic Optimum or just prior to it during the Paleocene-Eocene Thermal Maximum. Cambay amber preserves a uniquely diverse and early biota of a modern-type of broad-leaf tropical forest, revealing 50 Ma of stasis and change in biological communities of the dipterocarp primary forests that dominate southeastern Asia today.

Now, than there is one explanation which Hindu supports,

If a land bridge link between the drifting Indian landmass and Africa and Asia was once proposed to explain the mammal movement, insects preserved in the amber strengthen that argument. A chain of islands or any such land connection must have existed between India and Asia before their collision. The alternative explanation of a much earlier collision can be ruled out; there is overwhelming geological evidence that India collided with Asia 50 million to 55 million years ago.

When it comes to natural wealth, India is not so unique after all.

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About Dilawar

Graduate Student at National Center for Biological Sciences, Bangalore.
This entry was posted in Animal Kingdom, Evolution, India and tagged , , . Bookmark the permalink.

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