SKULKING around an ancient floodplain 250 million years ago, the earliest known dinosaur ancestors left footprints just 1 to 2 centimetres long.

The prints, recently discovered in the Holy Cross mountains of central Poland by Steve Brusatte of the American Museum of Natural History in New York, show distinctive toe marks only seen in the dinosaur family. They were made by a four-footed animal no bigger than a domestic cat, that was likely to have been prey to local 8-metre-long crocodiles.

The tracks are 5 million years older than any other dino fossils. They push back the origins of the …