Paleontologist Michael Caldwell was poking through the drawers of lizard fossils at a London museum. He saw a specimen marked as an ancient lizard – but everything about it screamed snake!
On closer examination, Caldwell noticed that this “ancient lizard” had backward-curved teeth and strong jawbones. These characteristics allow snakes to keep their prey from escaping from their mouths. But there was yet another surprise in store…
Until now, paleontologists had believed that snakes appeared 100 million years ago during the middle of the Cretaceous period. However, dating this newly-discovered fossil revealed that snakes had been around for 167 million years – starting in the Jurassic era.
In fact, four snake fossils dating from 140-167 million years have been uncovered in England, Portugal, and North America. These snakes lived in swampy coastal areas of ancient Europe, or in the river beds of Colorado.
Where Did Snakes Come From?
Snakes are believed to have originated from four-legged lizard-like reptiles – either land lizards, or marine lizards known as “mosasaurus”. Over time, these reptiles evolved to where their fore and hind limbs shortened and eventually disappeared. Scientists attribute this pivotal change to survival -- perhaps this ancient snake needed to burrow underground or swim in the water, in which case it did not need to use its limbs.
Are all legless reptiles snakes? No. There are many legless lizards that spend their lives underground - they have tiny limbs that distinguish them from snakes. Other distinguishing features of snakes include the absence of eyelids and external ears and longer bodies with a short tail.
The New Discovery
What makes the study of snakes difficult is that the bones of these fragile creatures do not preserve well over time. Paleontologists have very little to go by – fossil fragments of vertebrae or jawbones. It is up to artists to visualize the animals based on scientific data.
The question of whether a snake’s head evolved first or its body, has been a matter of debate in the scientific community. Previously, researchers had suggested that the snake ancestor evolved to become limb-less and then its cranium (skull bone) developed into its now distinctive shape. However, Caldwell claims the opposite is true. The earliest snakes were four-legged creatures with a snake-like head.
The recent discovery has set the clock back on when these slithering snakes first appeared, and scientists will be looking to fill in the gaps. However, one thing is certain – snakes continue to evoke fear and disgust in many. It is no wonder that ancient civilizations worshipped them, and modern authors such as J.K Rowling have created characters such as Nagina – a loyal servant to the evil Voldemort in the Harry Potter series!
Courtesy CSMonitor, BBC, LiveScience