A 200-million-year-old reptile is rewriting the rulebooks on how four-legged animals conquered the world.
Newly discovered fossils suggest Drepanosaurus had huge hooked claws to dig insects from bark, much like today's anteaters in the forests of Central and South America.
Scientists say the creature defies the convention on how reptiles evolved and flourished.
Their research is published in the journal Current Biology.
The new fossils, found in a New Mexico quarry, suggest Drepanosaurus was the size of a cat and lived in the trees.
It had a bird-like head on a chameleon-like body, but the most unusual feature was its forearms, said Dr Adam Pritchard, of Yale University, who led the research.
Massive arms
"Drepanosaurus itself has extremely massive arms and forearms - very muscular," he said.
"The index finger is much much larger than any of the other fingers and supports this gigantic claw, which is easily the most massive bone of the entire arm."