Amazonian Amphibian Diversity Traced to Andes

Colorful poison frogs in the Amazon owe their great diversity to ancestors that leapt into the region from the Andes Mountains several times during the last 10 million years, a new study from The University of Texas at Austin suggests.

This is the first study to show that the Andes have been a major source of diversity for the Amazon basin, one of the largest reservoirs of biological diversity on Earth. The finding runs counter to the idea that Amazonian diversity is the result of evolution only within the tropical forest itself.

"Basically, the Amazon basin is a 'melting pot' for South American frogs," says graduate student Juan Santos, lead author of the study. "Poison frogs there have come from multiple places of origin, notably the Andes Mountains, over many millions of years. We have shown that you cannot understand Amazonian biodiversity by looking only in the basin. Adjacent regions have played a major role."

Santos and Dr. David Cannatella, professor of integrative biology, published their findings this month in the journal PLoS Biology.

The tale of how the tropics became so diverse is a rather complicated one indeed.