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Four-Legged Snakes

July 28, 2015

A fossil of a four-legged snake links snakes with their lizard ancestors.

Transcript

BOB HIRSHON (host):

The four-legged snake Tetrapodophis amplectus subdues a gondwanatherian mammal.  Julius T. Cstonyi

Artist’s depiction of the four-legged snake Tetrapodophis amplectus subduing a mammal. (Julius T. Cstonyi)

A four-legged snake. I’m Bob Hirshon and this is Science Update.

A fossilized four-legged snake sat, unappreciated, in a museum for years until University of Portsmouth paleobiologist David Martill noticed it and told paleontologist Nicholas Longrich, at University of Bath. At first, Longrich doubted it could really be a fossil representing the evolutionary step from lizards to snakes.

NICHOLAS LONGRICH (University of Bath):

The odds of finding it seemed so ridiculously small I thought it was pretty unlikely it was actually a snake.

HIRSHON:

But seeing the complete skeleton convinced him.

LONGRICH:

You could look at the entire thing and just see snake-like features in the jaws, in the teeth, in the vertebrae, in the proportions, and even preserved scales.

HIRSHON:

In the journal Science, the researchers describe how the Cretaceous period snake likely used its long-fingered limbs to grasp prey. The skeleton also provides evidence that snakes descended from land, rather than marine, animals. I’m Bob Hirshon, for AAAS, the science society.