Dinosaur from Middle-Late Jurassic period found in China

(CNN) -- A dinosaur from the Middle-Late Jurassic period, found in China, gives scientists new understandings of how birds evolved, according to a Wednesday report from the journal Nature.

The newly discovered species is called Aurornis xui. "Aurora" is Latin for "daybreak" or "dawn." Ornis is Greek for "bird." The last part of the name, xui, honors paleontologist Xu Xing.

The dinosaur lived about 150 million years ago, said Pascal Godefroit, lead author and researcher at the Royal Belgian Institute of Natural Sciences in Brussels.

The critter was 51 centimeters -- about 20 inches -- long. It had teeth and probably fed on insects, Godefroit said.

It was found in the Tiaojishan Formation of Liaoning Province, China.

This dinosaur appears to have had four wings, two along the arms and two along the legs, Godefroit said. It could probably glide but not actively fly off the ground.

The specimen, exceptionally preserved in a clay sediment, appears to be an adult.

Another fossil from about 150 million years ago, called Archaeopteryx, was previously considered the most primitive known bird. Godefroit said the newly discovered dinosaur throws that into question, as the new find appears to represent an even more primitive, older bird.

Alan Turner, assistant professor of anatomical sciences at Stony Brook University in New York, who was not involved in the study, said in an e-mail that the find was "a very interesting fossil discovery."

It demonstrates just how similar the earliest birds were to the earliest members of the dinosaur groups, dromaeosaurids and troodontids, Turner said. These groups are all theropods, small meat-eating dinosaurs that walked on two feet.

Because of how well-preserved and well-prepared the specimen is, it provides useful information about the creature's evolutionary position and the changes that were taking place in the lineage that led to birds, he said.

Still, Aurornis xui's exact position in its family tree is likely not set in stone, he said. The relationships between the earliest bird species and their dinosaur relatives can change in subtle ways depending on the data set being used by particular groups of researchers.

That means that species that were once called "birds" can become considered "troodontids," or vice versa. The exact details are still being worked out, Turner said.

"That's why new discoveries like Aurornis xui are both very exciting and frustrating because they often raise as many questions as they answer," he said.