Dinosaur or bird? New study restores famed fossil to 'bird' branch

An Archaeopteryx fossil discovered in Germany. (Humboldt Museum für Naturkunde Berlin)

A raven-sized creature that lived about 150 million years ago is back on its perch, a new study says.

Widely pegged as the earliest known bird, Archaeopteryx's status was called into question two years ago by Chinese scientists. They proposed yanking the prehistoric creature off the "bird" branch of the evolutionary family tree and moving it onto a closely related lineage of birdlike dinosaurs.

Now an international team led by the Royal Belgian Institute of Natural Sciences believes Archaeopteryx (ahr-kee-AHP'-teh-rihx) should indeed be considered a bird.

The famed fossil was discovered in 1861 in Germany and quickly became an evolutionary icon. Archaeopteryx possessed part-bird, part-reptile traits. It sported broad wings and feathers like a bird, but it also had three-fingered claws, sharp teeth and a long bony tail similar to a dinosaur.

Fossil discoveries of feathered dinosaurs in northeastern China over the past two decades have challenged Archaeopteryx's place in bird evolution.

The latest evidence suggesting Archaeopteryx had more in common with birds than dinosaurs comes from the discovery of an intact, well-preserved skeleton of a previously unknown dinosaur dubbed Aurornis xui. It lived during the middle to late Jurassic era in China's Liaoning province where many early birds and feathered dinosaurs roamed.

Belgian researcher Pascal Godefroit and his team compared the anatomy of the newly discovered dinosaur fossil to a variety of birds and dinosaurs to determine their relationship. The analysis, published in Thursday's issue of the journal Nature, classifies Archaeopteryx back into the bird category.

Lawrence Witmer, a bird evolution expert at Ohio University, called the analysis compelling. But he said it's still tough to tease apart that segment of the family tree.

"All of these little feathered species running and flapping around ... were all very similar," Witmer, who had no role in the research, said in an email.