Tracks of the earliest vertebrates

The oldest evidence of four-legged animals walking on land has been discovered in southeast Poland.

Rocks from a disused quarry record the "footprints" of unknown creatures that lived about 397 million years ago.

Scientists tell the journal Nature that the fossil trackways even retain the impressions left by the "toes" on the animals' feet.

The team says the find means that land vertebrates appeared millions of years earlier than previously supposed.

"This place has yielded what I consider to be some of the most exciting fossils I've ever encountered in my career as a palaeontologist," said team member Per Ahlberg from Uppsala University, Sweden.

Posted by David on January 6, 2010 10:18 PM