Missing link’ in the evolution of lizards found

evolution of lizardsA new species of lizard that roamed southern Brazil eighty million years ago could be a ‘missing link’ in evolution of reptiles in South America.

The ancient iguana, named Gueragama sulamericana, may have been one of the first members of the Iguania group of reptiles to live in the New World during the lower Cretaceous period.

Scientists have described the creature as a possible ‘origin of the group’ and roamed Brazil at a time when it was a desert.

Every single species of iguana comes from the US down to the tip of South America.

Yet its closest relatives, including chameleons and bearded dragons, are concentrated in the Old World – and details about how the two groups split has remained a relative mystery, until now.

Professor Michael Caldwell said: ‘The roughly 1700 species of iguanas are almost without exception restricted to the New World – primarily the Southern United States down to the tip of South America.

‘This fossil is an 80 million year old specimen of an acrodontan in the New World.

‘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 back in the lower part of the Cretaceous the southern part of Pangaea was still a kind of single continental chunk.’

The researchers, who have described the new lizard in the journal Nature Communications, found it had its teeth fused to the top of its jaws, known as acrodonta, much like lizards living in the Old World.

However, almost all iguanas living in the New World are non-acrodontans, meaning their teeth are not fused to the top of the jaws.

source: http://www.dailymail.co.uk/sciencetech/article-3211692/Missing-link-evolution-lizards-Brazil-80-million-year-old-fossils-reveal-clues-spread-reptiles.html

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