New fossil shows dinosaur-bird link

A well-preserved, 130-million-year-old fossil of a small dinosaur found in China strengthens the theory that birds evolved from dinosaurs, according to a new study.

The dinosaur, called Sinovenator changii, was slightly larger than a chicken and had many bird-like features.

"This dinosaur, which was probably feathered, is closely related to and almost the same age as the oldest known bird, Archaeopteryx," said study co-author Peter Makovicky, in a statement.

The fossil reveals that structural changes showing evolution from dinosaurs to birds happened much earlier than previously thought, said Makovicky.

"These findings help counter, once and for all, the position of paleontologists who argue that birds did not evolve from dinosaurs," said Makovicky.

The fossil comes from the Yixian Formation in China, the site of many significant fossil finds, including feathered dinosaurs.

The new fossil doesn't include the dinosaur's feathers because it was preserved in a river bank, but the skeleton's three-dimensional structure was left intact.

Sinovenator was a troodontid, which is a type of theropod, the group of dinosaurs that includes Tyrannosaurus. Troodontids tended to evolve toward a smaller body size, however.

"Although big dinosaurs may be more spectacular, we can acutally learn more about evolution from the often overlooked smaller dinosaurs because they tend to be more primitive," said Makovicky.

Troodontids have other features, such as serrated teeth and sickle claws on their feet, that have made them difficult to classify. Paleontologists earlier grouped them with dinosaurs such as the Velociraptor.

The study appears in Thursday's issue of the journal Nature.