Researchers have discovered the first three-dimensionally preserved eggs of ancient winged reptiles that lived more than 120 million years ago in China, Live Science reported.

Five intact eggs of a new type of pterosaur, a group of prehistoric winged reptiles that dominated the skies during the time of dinosaurs, were found along with dozens or more adult fossils.

"It was most exciting to find many male and female pterosaurs and their eggs preserved together. Five eggs are three-dimensionally preserved, and some are really complete," said Dr. Xiaolin Wang from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, who is the lead author of a paper published in the journal Current Biology.

With only four isolated and flattened pterosaur eggs known to the paleontological science to date, these creatures included some of the largest flying animals to ever exist.

Discovered in 2005 in the Turpan-Hami Basin, located south of the Tian Shan Mountains in Xinjiang, in northwestern China, the new pterosaur fossil-rich site harbors thousands of bones, including male and female skulls and the first three-dimensional eggs, Sci-News.com reported.

"We found a lot of pterosaur bones which belong to different individuals in the sites, with five eggs," said study researcher Wang.

During the early Cretaceous period, the newly uncovered pterosaurs likely perished in a storm about 120 million years ago, Wang said.

"Wang and his team found that the eggs were soft and pliable, with a thin, hard outer shell and a thick, soft inner membrane, similar to the eggs of some snakes," according to Live Science. "The pterosaurs probably buried their eggs in the sandy shore of an ancient lake to prevent them from getting dried out, the researchers said."

"The researchers also uncovered many adult pterosaur fossils nearby. They examined 40 male and female adult specimens, and found differences in the size, shape and robustness of the animals' head crests."

"The newly found cluster of fossils suggests these pterosaurs lived together in large social groups, the researchers said."

Wang and his colleagues reported their findings in the journal Current Biology on June 5.