The Amazonian region is actually much older than thought, a new study reveals. An international team of scientists have found that it is result of the Andean mountain uplift over millions of years.

The findings from this study based on research by Dr John Lundberg, leading biologist and his team from the Academy of Natural Sciences in Philadelphia has been published as a review article in the journal Science.

Lundberg and his team of scientists compared current diversity patterns with geological and molecular datasets and found that the highest number of species is found on a vast expanse of more than a million square kilometers range in the Andean region, developed over 23 million years.

Now, there is need for further study to find how the mega-diversity evolved in the Amazonian basin.

There are various theories about the origin and complex nature of the world’s largest ecosystem. Although scientists believed that the Andes Mountain range played a crucial role in the formation of the diversity, still there was little information on timing and causes.

In their review article, lead author Dr. Carina Hoorn of the University of Amsterdam, Lundberg, and their co-authors list the flora and fauna in the rainforest that have evolved over the years due to a reshuffling of the Pacific tectonic plates and resultant uplifts in the Andes.

A vast wetland was also formed during the course of these geological changes and dried up when the Amazon River came up nearly 10 million years ago. The dried up land was later inhabited by plants and animals.

The pre-Quaternary flora and fauna in Amazonia has shown a really high number of species mostly reptiles and plants, even higher than found today.

“The Amazonian region, from its highest mountains to immense lowland rivers, supports a tremendous biological richness of species," said Lundberg, curator and Chaplin chair of ichthyology at the Academy of Natural Sciences in Philadelphia. "Many previously unseen species are discovered and documented every year."