Scientists find ancient snake with hidden legs

Last Updated 03 May 2018, 05:51 IST

A three-dimensional reconstruction of the bones could help understand how snakes evolved to lose their legs, said the researchers who made the discovery in Lebanon.

They believe the fossil of the slithery creature is from an era when snakes had not yet completely lost the hind limbs left by their lizard ancestors, LiveScience reported.

The new finding, the researchers said, will answer the much-debated question among paleontologists that whether these leggy ancestors were ocean-living swimmers or land-dwelling burrowing lizards.

One-inch-long fossilised leg bone is visible on the surface of the fossilised Lebanese snake, but half the pelvis (where another leg would be expected) is buried in rock.

The 19-inch-long (50cm) snake, called Eupodophis descouensi, is one of only three snake fossils with its hind limbs preserved, so breaking it open to look for the other leg was out of the question, said study researcher Alexandra Houssaye of the Museum National d'Histoire Naturelle in Paris.

Instead, the researchers used a technique called synchrotron-radiation computed laminography (SRCL), which like CT scan uses X-rays to image the internal structure of an object, but at 1,000 times higher resolution.

"Only 3D [scanning] could reveal the inner structure of the bones without damaging them, and the same is true to observe the complete second leg," Houssaye said.

The scanning revealed a hidden leg, bent at the knee but lacking foot and toe bones. The setup of the bones is similar to that of terrestrial lizards, Houssaye said, adding that one study couldn't settle the "land ancestor versus water ancestor" debate.

However, the anatomy of the bones suggests that evolution took snakes' legs not by altering the way they grew. Instead, it looks as though the limbs grew either slower or for a shorter period of time, she said.

According to Houssaye, this experiment was the first to use the SRCL technique in paleontology and there's much more to analyse.

The next steps, she said, include analysing other hind-limb snake fossils, studying the limbs of living snakes and lizards and analysing the fossils of the oldest snakes known.

The researchers reported their findings in the Journal of Vertebrate Paleontology.

(Published 08 February 2011, 11:58 IST)

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