Fossils excavated in Liaoning province have challenged the theory that the Archaeopteryx is indeed the earliest known bird.

Research of the fossils led by Pascal Godefroit and his team from the Royal Belgian Institute of Natural Sciences in Brussels revealed that the dinosaur-bird Aurornis xui, like the Archaeopteryx, existed nearly 150 million years ago.

Godefroit told British-based Daily Mail, "This new comprehensive phylogeny, or evolutionary development, shows that point of origin avialans, or dinosaur-birds, were already diversified in northern China during the Middle-Late Jurassic".