Fossil shows bird's last meal

'Pioneer among plant eaters' found in China

The fossilized remains of the Jeholornis prima, shown in an illustration, included about 50 well-preserved seeds in the bird's stomach.

(CNN) -- A turkey-sized bird that lived more than 100 million years ago is now giving paleontologists some important clues about how animals lived and evolved.

The fossil of this new species, Jeholornis prima, was found last year in the Liaoning area of northeast China. It's not just the bones of this big bird that scientists find revealing, but its diet. The fossil shows in great detail more than 50 seeds in the bird's stomach. This is the first direct evidence of seed eating in a bird, believed to be a new adaptation for birds of the Mesozoic era.

"The bird is approximately the size of a turkey, the whole skeleton is about 75 centimeters (30 inches) long, but with feathers in the tail, it could probably be close to one meter," said Zhonghe Zhou, of the Chinese Academy of Sciences. His findings are described in this week's issue of the British journal Nature.

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Scientists found the fossil in an area once covered with volcanoes and tropical lakes, where feathered dinosaurs, primitive birds and other mammals have also been unearthed. Jeholornis is slightly larger than Archaeopteryx, the earliest known bird that lived 145 million years ago.

The Cretaceous period, the third and last period of the Mesozoic era, is known for the development of flowering plants, and the disappearance of the dinosaurs.

Powerful flight

Scientists said the skeletal structure shows that this bird was capable of powerful flight, but was also built to sit in trees. Those discoveries provide a further relationship between birds and some theropods, the carnivorous dinosaurs of the Jurassic and Cretaceous periods that walked on two legs and had small, grasping forelimbs.

The fossil, between 110 million and 125 million years old, was found in China last year.

Because the seeds found in the stomach were intact, researchers say the birds may have eaten them whole, rather than breaking them up into smaller pieces. The seeds would have been "stored" in a crop, or pouch-like area, to be digested later in the gizzard.

"The other birds we know of at this time were probably meat eaters, fish, or insect eaters, based on their teeth," said Thomas Holtz Jr., a paleobiologist at the University of Maryland.

"This guy was sort of a pioneer, giving us the oldest evidence so far that birds ate plants," said Holtz.

Dinosaur link?

Each seed was about a centimeter long. While the seeds are similar in size to the gingko plant, common in that region of China, there is not enough evidence to determine what plant the seeds came from.

Although the seeds haven't been identified specifically, they give researchers a better insight to ancient birds' diets.

Jeholornis was also different from other birds of the period because of a very long tail. Paleontologists say this skeletal tail provides evidence linking birds with dromaeosaurids, dinosaurs that were small, fast, bipedal, and closely related to birds.

"This fossil really increases our understanding of the diversity of early birds," said Holtz. And the region in China where it was found is considered a treasure chest for fossils.

"It gives us an excellent picture of ecology, not only of birds and other dinosaurs, but also mammals, lizards, plants, and potentially insects," said Holtz.