Paris - Snakes evolved their curious body shape on land, not in water, and are probably the descendants of small burrowing lizards, scientists have deducted from 70-million-year-old fossil remains.

Closely examining jaw, tooth and spinal fragments of Coniophis, biologists in the United States concluded it was the most primitive animal of its kind - the missing link in snake evolution.

They found that Coniophis was “a transitional snake, combining a snake-like body and a lizard-like head” with burrowing habits - suggesting it evolved from a land-dwelling lizard.

The beast had an elongated body with hooked snake-like teeth, and most likely fed on medium-sized, soft-bodied prey.

It did not have the flexible jaws that allow modern-day snakes to swallow prey many times their own body size.

“This thing quite probably would have had small legs,” Yale University co-author Nicholas Longrich told AFP, adding it would have looked more like a snake than a lizard.

Published in Nature, the paper seeks to settle a longstanding scientific debate as to whether snakes evolved their elongated, slithering body as an adaptation for burrowing in soil or for swimming.

The disagreement partly arose from a lack of transitional animal fossils to study, with Coniophis hitherto overlooked, said the paper.

Longrich said the first Coniophis remains were discovered in Montana in the 1890s and more fragments in the 1950s, but had mostly been left to gather dust in a museum since then. - Sapa-AFP