First known four-legged snake fossil discovered

The first known fossil of a four-legged snake has been discovered by researchers.

The 20cm-long fossil, from Brazil, is 110 million years old and could help scientists to understand how snakes lost their legs.

The fossil has front legs which are about 1cm long, with elbows and wrists and hands that are just 5mm in length. The back legs are slightly longer and the feet are larger than the hands.

Dr Dave Martill, from the University of Portsmouth, said: "It is generally accepted that snakes evolved from lizards at some point in the distant past.

“What scientists don’t know yet is when they evolved, why they evolved, and what type of lizard they evolved from.

"This fossil answers some very important questions, for example it now seems clear to us that snakes evolved from burrowing lizards, not from marine lizards.”

It has been categorised as a snake, rather than a lizard, by the team due to a number of features:

• The skeleton has a lengthened body, not a long tail.

• The tooth implantation, the direction of the teeth, and the pattern of the teeth and the bones of the lower jaw are all snake-like.

• The fossil displays hints of a single row of belly scales, a sure fire way to differentiate a snake from a lizard.

Dr Nick Longrich, who also worked on the study, said: "It is a perfect little snake, except it has these little arms and legs, and they have these strange long fingers and toes.

“The hands and feet are very specialised for grasping. So when snakes stopped walking and started slithering, the legs didn’t just become useless little vestiges - they started using them for something else.

"We’re not entirely sure what that would be, but they may have been used for grasping prey, or perhaps mates.”