By Charles Q. Choi, LiveScience Contributor | January 13, 2014 11:34am ET
The closest known relative of the ancestors of limbed animals such as humans likely evolved the foundation for rear legs even before the move to land, researchers say. This ancestor may have even been able to walk underwater, they added.
These findings reveal that a key step in the evolution of hind limbs happened in fish, challenging previous theories that such appendages evolved only after the move to land.
Scientists investigated fossils of a 375-million-year-old fish known as Tiktaalik roseae, discovered in 2004 in northern Canada’s Ellesmere Island. Possessing a broad flat head and sharp teeth, Tiktaalik resembled a cross between a fish and a crocodile, growing to a length of 9 feet (2.7 meters) as it hunted for prey in shallow freshwater. [See Images of Bizarre Tiktaalik Fish Fossils]
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