A 113 million-year-old Brazilian fossil, recently examined for the first time, has provided what some experts believe is the first evidence that snakes had four legs at one stage in their evolution. While there is some controversy as to how closely related to modern day snakes the fossil is, the authors of a new study that examines the fossil are certain this proves snakes have always been land-based animals, using the delicate limbs for burrowing and “hugging” their prey, rather than for swimming.
The 19.5cm-long (7.7in) snake fossil had been sitting, unexamined and unexplained, first in a private collection, and later in a museum in Solnhofen, Germany before Dr. Dave Martill of the University of Portsmouth, UK stumbled upon it while leading students on a field trip. Speaking to the BBC, Dr. Martill explained that his “jaw dropped” upon seeing the fossil, prompting him to ask the museum for permission to examine it more closely.
The delicate limbs that protrude from the snake are remarkably tiny—just four and seven centimeters long, but have what are described as “long skinny fingers and toes with claws on the end.” The scientists examining the fossil believe these would have been used for burrowing as well as for “hugging” the prey caught by the snake. While previously in their evolution, the snakes may have used these limbs for walking, by the time this particular fossil was slithering around, they had weakened to be used only for hunting and burrowing.
But what is most surprising to experts is just how many features this four-legged-snake shares with the snakes alive today. From hooked teeth to a flexible jaw and spine, and snake-like scales, study author Dr Nick Longrich explained: “It was pretty unambiguously a snake. It’s just got little arms and little legs.” The newly-discovered snake has been named Tetrapodophis amplectus, Tetrapodophis being the new genus for the four-legged snake, and amplectus being the Latin for “embrace,” referencing the way the snake’s limbs held its prey.
Images via Dave Martill/University of Portsmouth, and Julius T. Cstonyi