Ancient reptile tracks unearthed

The earliest evidence for the existence of reptiles has been found in Canada. The 315 million-year-old fossilised tracks give an insight into a key milestone in the history of life, when animals left water to live on dry land. The footprints suggest reptiles evolved between one and three million years earlier than previously thought. They were found by UK scientist Dr Howard Falcon-Lang in fossil-rich sea cliffs at New Brunswick. "The discovery was pure luck," he said. "As I walked along remote sea-cliffs at the end of a long day in the field, I passed a recent rock fall. "One large slab of rock was covered with hundreds of fossil footprints! The Sun was low in the sky and I probably wouldn't have seen them if it hadn't been for the shadows," the University of Bristol researcher explained. Diverse ecology: The ancient trackway gives an insight into a time when vertebrates were evolving through amphibians to reptiles. How the reptile might have looked The origin of reptiles, in particular the appearance of eggs protected by a shell, allowed four-legged animals to avoid having to go back into water to lay eggs, heralding life on dry land. "The evolution of reptiles was one of the most important events in the whole history of life," Dr Falcon-Lang told BBC News. "That paved the way for the diverse ecology that we have on our planet today." Scientists believe the tracks preserved in sandstone were left by reptiles gathering around a watering hole on river plains that were dry for at least part of the year.

List of suspects: Using a bit of biological detective work, Dr Falcon-Lang and colleagues in the UK and Canada tracked down the likely maker of the footprints. We can be confident the footprints are older than the skeletons Howard Falcon-Lang "There were only a few species capable of making prints like this around at the time so we came up with a shortlist of suspects," said Professor Mike Benton, also of the University of Bristol, who co-authored the study.