Ancient snake fossils that were unearthed in Portugal, England and the U.S suggest that snakes have slithered on Earth much earlier than previously believed.

Michael Caldwell, a paleontologist from the University of Alberta, and colleagues, have found fossils of four ancient snake species, which could be the oldest known remains of the slithering animals as these date back to about 143 to 167 years ago.

Researchers said that these remains may be 70 million years older compared with the previous oldest that dates back to about 100 million years ago. The discovery is likewise helping scientists better understand the evolution of these slithering beasts.

Caldwell accidentally identified the first and the youngest of the four snake species, the 143-million-year-old Parviraptor estesi, in a drawer at the Natural History Museum in London in 2004. The fossil was initially described as a type of lizard but after carefully examining the animal's maxilla, the bone in the face bearing the teeth, the researcher realized that it was a snake.

The three other snake species, the Eophis, Portugalophis lignites and Diablophis gilmorei, were also previously misidentified as lizards, to which Caldwell said is something understandable. For one, the fossils were not complete.

Although the remains included fragments of the animals' backbones, ribs, hips and partial skull, they were not enough to indicate details about the animals' length and shape. Lizards and snakes also resemble each other, they are both reptiles, scaly and some lizards are long and legless.

The researchers, however, pointed out that the anatomy of the animals' skull and the structure of their teeth, have a lot in common with present-day snakes with the remains being most similar with existing snakes that are believed to be primitive members of the snake family such as the genus Cylindrophis in Southeast Asia and the anilioids in Southern Central America.

"We report here on snake fossils that extend the record backwards in time by an additional ~70 million years (Middle Jurassic-Lower Cretaceous)," the researchers wrote. "These ancient snakes share features with fossil and modern snakes (for example, recurved teeth with labial and lingual carinae, long toothed suborbital ramus of maxillae) and with lizards (for example, pronounced subdental shelf/gutter)."

Caldwell and colleagues said that all four possibly had some form of reduced forelimbs and hind limbs albeit this does not mean that the creatures walked.

"It seems probable that they were slithering, so to speak, though the limbs might still have been used for grasping," Caldwell said.

ⓒ 2021 All rights reserved. Do not reproduce without permission.