A historic four-legged snake fossil was discovered in a German museum.

Now described in the journal Science, the specimen had previously languished in a private collection for decades before the museum acquired it and displayed it as an "unknown fossil".

Although several other fossil snakes have been discovered with hind limbs, this is the first to have both arms and legs - and it is estimated to be a direct ancestor of modern snakes.

Speaking to the Today progreamme on BBC Radio 4, Dr David Martill of the University of Portsmouth recalled how he first stumbled on the fossil.