A new study has found that the incredible biodiversity of the Amazon region is over 20 million years older than thought.
An international team of scientists, including a leading evolutionary biologist from the Academy of Natural Sciences in Philadelphia, said that the Amazonian diversity was evolved as a by-product of the Andean mountain uplift over millions of years, despite previous focus on the more recent history.
By comparing modern biodiversity patterns with geological and molecular datasets, the researchers found that the highest diversity of species was in a region spanning over a million square kilometres that originated with the rising Andes.
The authors concluded that they have found a strict connection between the rich diversity Amazon rainforests and the rise of the Andes over 20 million years ago.
Dr Carina Hoorn of the University of Amsterdam, and co-authors listed in their review the extraordinary flora and fauna that have evolved in the dynamic Amazonian landscape, which in turn has developed at a pace dictated by the reshuffling (Pacific) tectonic plates and subsequent uplift in the Andes.
The paleogeographic evolution dictated by this geological reconfiguration included the formation of a vast wetland that, after the onset of the Amazon River around 10 million years ago, dried up and was open to colonization by plants and animals.
In the case of Amazonia, the pre-Quaternary flora and fauna already showed a very high level of species richness that was, in the case of 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 John G. Lundberg, Curator and Chaplin Chair of Ichthyology at the Academy of Natural Sciences in Philadelphia.
The findings are published in this week's edition of Science.