Dinosaur Fossil Carries Bird-Like Eggs Inside
Date: 15-Apr-05
Country: USA
Author: Maggie Fox
Like birds, the dinosaur probably would not have been able to lay its entire clutch at once, but like a crocodile, she had two ovaries to make eggs, they write in Friday's issue of the journal Science.
While the fossil does not answer the ultimate question of whether birds descended from dinosaurs, it will help answer questions about how birds, reptiles and dinosaurs are related, the international team of scientists said.
The fossil, found in China's southern Jiangxi Province, consists of little more than the animal's pelvis and some vertebrae.
But it clearly belonged to an oviraptorosaurian -- a type of dinosaur called a theropod, which are believed by many experts to have been the ancestors of modern birds.
It would have been about 12 feet or 4 metres long.
These dinosaurs were known to have made nests with more than a dozen eggs inside.
The discovery of two mature eggs inside suggests this species made two eggs, laid them, and then repeated the process until her nest was full.
Birds do this, one egg at a time.
Animals such as crocodiles lay a full clutch at once. And they have leathery shells, while the shells of these dinosaur eggs were hard, like a bird's, said Tamaki Sato of the Canadian Museum of Nature in Ottawa, Canada, who led the study.
"They are similar to bird eggs, but the shells are too incomplete to be really sure," she said in a telephone interview.
And the shape of the eggs, pointed at one end, "suggests that the females came to the centers of the nests to lay neat, multilayered, ring-shaped clutches," the researchers wrote.
The hillside site where the fossil was found dates to the Upper Cretaceous period, which lasted from 98 to 65 million years ago. Many different dinosaurs arose during this period, as well as modern trees such as oaks, maples and walnuts.
