By Anastasia Christakou
The first four-legged fossil snake ever found is forcing scientists to rethink how snakes evolved from lizards.
Although it has four legs, Tetrapodophis amplectus has other features that clearly mark it as a snake, says Nick Longrich, a palaeontologist at the University of Bath, UK, and one of the authors of a paper describing the animal in Science1.
The creature’s limbs were probably not used for locomotion, the researchers say, but rather for grasping prey, or perhaps for holding on to mating partners. Such speculation inspired the snake’s name, which loosely translates as ‘four-legged hugging snake’.
Scientists have long argued over whether snakes evolved from land or marine animals. Tetrapodophis lacks adaptations for marine life, such as a tail useful for swimming. But its skull and body proportions are consistent with adaptations for burrowing. Longrich says that the finding unequivocally shows that snakes originated in the Southern Hemisphere and strongly supports a terrestrial origin.