The missing link in lizard evolution has been found in Brazil. Paleontologists from the University of Alberta discovered the 80-million-year-old fossil remains of a lizard more closely related to the chameleons and bearded dragons — Old World lizards found in Africa and Asia — than to the 1,700 species of iguanas found in South and Central America.
The Old World lizards are acrodontal, meaning their teeth are fused to the top of their jaws. The teeth of New World iguanas — their closest relatives — are not.
The new speciman is the first acrodontan iguanian ever found in South America. Michael Caldwell, one of the study's authors, said it is "pretty good evidence to suggest that back in the lower part of the Cretaceous [Period], the southern part of Pangaea was still a kind of single continental chunk."
The supercontinent Pangaea began to break apart into the continents we know today about 175 million years ago, as the landmasses drifted apart so did the plants and animals that lived there. As Millenia passed the animals evolved separately into new species.
The study, published in Nature Communications, concludes "after the break up, the acrodontans and chameleon group dominated in the Old World, and the iguanid side arose out of this acrodontan lineage that was left alone on South America."
"It answers a few questions about iguanid lizards and their origin," noted Caldwell.