Ancient Iguana Discovery Could Solve Mysteries Of Lizard Evolution

By R. Siva Kumar - 30 Aug '15 17:36PM

Lizards may not look pretty to us, but they might be the key to a lot of secrets---even though you may not particularly want to know them.

At least, that is what scientists think. They have discovered a new species of lizard that dwelt in Southern Brazil not too long back---just 80 million years ago. They could indeed help to solve an evolutionary mystery.

Finding the "Old World" lizard might reshape what we know about the evolutionary history of reptiles that exist today, according to the University of Albertza

"The roughly 1,700 species of iguanas are almost without exception restricted to the New World, primarily the Southern United States down to the tip of South America," said Michael Caldwell, biological sciences professor from the University of Alberta and one of the study's authors.

Iguanas are closely related to chameleons and bearded dragons from the Old World. This ancient species called Gueragama sulamericana---which is a species with teeth fused to the top of its jaw--- discovered in South America, suggests that the entire species in the New World went through a "worldwide distribution" before the Pangaea separated.

"This fossil is an 80 million year old specimen of an acrodontan in the New World," Caldwell said. "It's a missing link in the sense of the paleobiogeography and possibly the origins of the group, so it's pretty good evidence to suggest that back in the lower part of the Cretaceous, the southern part of Pangaea was still a kind of single continental chunk."

Some insights into Pangaea can be gained by studying the distribution of plant and animal fossils. "The scientists believe that after the Pangaean break up, the acrodontans and chameleon groups ruled the Old World while the iguanid group was left alone in South America," according to hngn.

"South America remained isolated until about 5 million years ago. That's when it bumps into North America, and we see this exchange of organism north and south. It was kind of like a floating Noah's Arc for a very long time, about 100 million years. This is an Old World lizard in the new world at a time when we weren't expecting to find it. It answers a few questions about iguanid lizards and their origin," Caldwell said.

The findings were published in a recent edition of the journal Nature Communications.

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