The discovery of a feathered – and completely flightless – dinosaur from the Jurassic period has cast doubt on previous theories on how birds evolved from dinosaurs.
The 30cm-long Eosinopteryx lived around 140 million years ago, says Gareth Dyke, senior lecturer in vertebrate palaeontology at the University of Southampton.
The flightless dinosaur predates other dinosaurs that were believed to have evolved into flying birds in the early Cretaceous period, which followed the Jurassic period in which Eosinopteryx lived.
"This discovery sheds further doubt on the theory that the famous fossil Archaeopteryx - or 'first bird' as it is sometimes referred to - was pivotal in the evolution of modern birds," says Dr Dyke.
Eosinopteryx's remains were found in northeastern China. It had a small wingspan and a bone structure that ruled out flying. Instead, its leg and tail feathers would have made it suitable for running along the ground quickly.
"Our findings suggest that the origin of flight was much more complex than previously thought," says Dr Dyke.