Scientists Find First Fossil of Four-Legged Snake

Posted on July 24, 2015

Fossil of Tetrapodophis amplectus

Scientists have discovered the fossil of a four-legged snake. The 113-million-year-old fossil found in Brazil is the first fossil of a four-legged snake ever found. The ancient legged snake is thought to be an ancestor of modern snakes. It suggests that snakes evolved from burrowing and not swimming ancestors.

The newly discovered species has been named Tetrapodophis amplectus. It lived during the Cretaceous period. The ancient legged snake has many classic snake features including a a short snout, elongated body, flexible jaw, scales and fanged teeth. It also has the vertebrate structure and long braincase seen in modern snakes.

Fossil feet of Tetrapodophis amplectus

The big obvious difference between T. amplectus and modern snakes are the ancient snake's four limbs. A close up of the snake's feet are pictured above. They were likely too small to be used for locomotion. Scientists think the T. amplectus used its small limbs to seize prey or clasp during mating.

Dr. Dave Martill from the University of Portsmouth led the research. He says in the announcement, "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."

Dr. Martill talks about the significant fossil discovery in the following video. He explains why the creature is a snake and not a lizard. Take a look:

Dr Nick Longrich, a study co-author from the University of Bath's Milner Centre for Evolution, says, "It is a perfect little snake, except it has these little arms and legs, and they have these strange long fingers and toes. 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."

Artist's interpretation of Tetrapodophis amplectus, a four legged snake

A research paper on the four-legged snake can be found here in the journal, Science.

Fossil Photo: Dave Martill, University of Portsmouth
Artist's Interpretation: Julius T. Cstony