Fossil of a four-legged snake found in Brazil

“The newly discovered species Tetrapodophis amplectus, which lived during the Early Cretaceous 146 to 100 million years ago, maintains many classic snake features, such as a short snout, long braincase, elongated body, scales, fanged teeth and a flexible jaw to swallow large prey”, said the study, led by British and German scientists.

The specimen lacks the long, laterally compressed tail typically found in aquatic animals, further suggesting that snakes did not evolve from marine ancestors.

“If something is not useful it can regress without any impact on the (animal’s) survival, or regression can even be positive, as for here if the leg was disturbing a kind of locomotion, like for burrowing snakes or swimming snakes”, according to Alexandra Houssaye from the National Museum of Natural History in Paris.

The discovery of the four-legged snake was via a fossil hunt in Brazil’s Crato Formation which opens up more questions about the evolution of the snake we know today.

The snake, aptly named Tetrapodophis amplectus, or grasping four-legged snake, was discovered in the Museum Solnhofen in Germany by paleobiologist David Martill of the University of Portsmouth, the UK, while on a field trip with students.

“It is generally accepted that snakes evolved from lizards at some point in the distant past”, says Dr Martill. “Interestingly, the researchers said, the fossilized snake also has the remains of its last meal in its guts, including some fragments of bone”.

“It is a ideal little snake, except it has these little arms and legs, and they have these unusual long fingers and toes”, said Dr. Longrich, snake-origin researcher from the University of Bath’s Milner Centre for Evolution. Grouped with a large Cretaceous collection, bearing barely visible limbs, the fossil had received no recognition for what it truly was-a snake with legs. “It was clear that no-one had appreciated its importance, but when I saw it I knew it was an incredibly significant specimen”.

“I was confident it might be a snake”, says Martill, of the 2012 find.

“The hands and feet are very specialized for grasping”.

The snake’s legs were too small to have been used for crawling. The head is the size of an adult fingernail, and the smallest tail bone is only a quarter of a millimeter long.

The front legs are just a centimetre long, with little elbows and wrists and palm that are just 5mm in length.

Rather, it’s believed the four limbs were used to hold on to prey or a clasping mechanism during mating. “So when snakes stopped walking and started slithering, the legs didn’t just become useless little vestiges-they started using them for something else”.

“Early snakes were carnivores and constrictors – constriction seems to be primitive for snakes, not advanced”.