World's Oldest Snake Fossils Uncover Evolutionary History of These Reptiles (VIDEO)

Scientists have discovered the fossilized remains of four ancient snakes that lived between 140 and 167 million years ago that may just change the way we think about the origins of these reptiles. The recent discovery actually rolls back the clock on snake evolution by nearly 70 million years.

The oldest known snake is called Eophis underwoodi. First found near Southern England, this snake was only identified from very fragmentary remains and was relatively small. The largest snake was found in Portugal and is called Portugalophis lignites and was at least a meter in length.

What's interesting is that it's clear that the sudden appearance of snakes about 100 million years ago reflects a gap in the fossil record rather than an explosive radiation of early snakes. From 167 to 100 million years ago, snakes were radiating and evolving toward the elongated and limbless shape that is now well-known. Just 90 million years ago, marine snakes from the West Bank, Lebanon and Argetina still possessed small rear limbs.

"The study explores the idea that evolution within the group called 'snakes' is much more complex than previously thought," said Michael Caldwell, one of the researchers, in a news release. "Importantly, there is now a significant knowledge gap to be bridged by future research as no fossil snakes are known from between 140 to 100 million years ago."

The new study's identification of definitive snake skull features reveals that the fossils represent a much earlier time frame for the first appearance of snakes.

"Based on the new evidence and through comparison to living legless lizards that are not snakes, the paper explores the novel idea that the evolution of the characteristic snake skull and its parts appeared long before snakes lost their legs," said Caldwell.

The findings are published in the journal Nature Communications.

Want to learn more? Check out the video below, courtesy of YouTube.

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