
A fossilized bird dating back about 110 million years is discovered in Yumen, Northwest China's Gansu Province. (Photo/China News Service.com)

This photo shows the dinosaur-era bird fossil with an unlaid egg. (Provided by the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences)

A fossilized bird dating back about 110 million years is discovered in Yumen, Northwest China's Gansu Province. (Photo/China News Service.com)

A fossilized bird dating back about 110 million years is discovered in Yumen, Northwest China's Gansu Province. (Photo/China News Service.com)

Artistic reconstruction of the dinosaur-era birds and their living environment. (Provided by the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences)