Frogs re-evolved 'lost' lower teeth after more than 200mn yrs.
Tree-dwelling Gastrotheca guentheri are the only frogs with teeth on both their upper and lower jaw.
The reappearance of these lower teeth after such a long time fuels debate about whether complex traits are lost in evolution or if they can resurface.
Scientists suggest this new evidence identifies a "loophole" in previous theories.
The Gastrotheca genus, commonly known as "marsupial frogs", carry their eggs in pouches.
Unlike marsupial mammals such as kangaroos however, the frogs' pouches are on their backs.
The species Gastrotheca guentheri is even more unusual, being the only known frog to have teeth on its lower jaw.
Dr John Wiens led a team of scientists from Stony Brook University, New York to investigate this exceptional feature.
"I combined data from fossils and DNA sequences with new statistical methods and showed that frogs lost their teeth on the lower jaw more than 230 million years ago, but that they re-appeared in G. guentheri within the past 20 million years," the BBC quoted Dr Wiens as saying.he findings are reported in the journal Evolution. (ANI)
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