Newly discovered snake fossils have recently revealed that snakes may have first appeared 167 million years ago, which pushes back its origins by nearly 70 million years.
Fossilized remains of four ancient snakes have been dated between 140 and 167 million years old, nearly 70 million years older than the previous record of ancient snake fossils.
The oldest known snake, from Southern England, near Kirtlington, Eophis underwoodi, is known only from very fragmentary remains and was a small individual, though it is hard to say how old it was at the time it died.
The largest snake, Portugalophis lignites, from coal deposits in Portugal, near Guimarota, was a much bigger individual at nearly a meter or more in length.
Several of these ancient snakes (Eophis, Portugalophis and Parviraptor) were living in swampy coastal areas on large island chains in western parts of ancient Europe, while the North American species, Diablophis gilmorei, was found in river deposits from some distance inland in Western Colorado.
This new study makes it clear that the sudden appearance of snakes, some 100 million years ago, reflects a gap in the fossil record, not an explosive radiation of early snakes.
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From 167 to 100 million years ago, some 70 million years, snakes were radiating and evolving towards the elongate, limb-reduced body plan characterizing the now well known, 100-90 million year old, marine snakes from the West Bank, Lebanon, and Argentina, that still possess small but well developed rear limbs.
As was always the case, the distribution of these newer oldest snakes, and the anatomy of the skull and skeletal elements, makes it clear that even older snake fossils are waiting to be found.
The study is published in the journal Nature Communications.
