A team of scientists has achieved a rare opportunity with the discovery of a prehistoric dinosaur egg dating back 120 million years ago.

According to Reuters, the egg will give researchers insight to the gender differences of the pterosaur; a reptile with the ability to fly that lived alongside the dinosaurs. Previously, only four such eggs have been found, but in a fossilized, 2-D state.

Chinese scientists found the egg and four others just like it preserved pristinely in the country's northwestern region.

"This is definitely the most important pterosaur site ever found," paleontologist Zhonghe Zhou, director of the Chinese Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology, told Reuters.

Fellow paleontologist Xiaolin Wang said the eggs were covered by a hard outer layer that was also quite supple. Beneath is a thick layer that mostly resembles the soft eggs laid by modern snakes and some lizards.

"Five eggs are three-dimensionally preserved, and some are really complete," Wang said in a press release.

The site was definitely once a colony for the pterosaur, as the scientists identified more than 40 male and female individuals who lived there. The researchers concluded there could have been hundreds at its peak.

"One of the significant (aspects) of this discovery - hundreds of individuals and eggs together from one site - is that it confirmed that pterosaurs were gregarious, and the population size is surprisingly large," Zhou said.

Paleontologists first discovered this site in the Xinjiang province in 2005 and they determined its inhabitants lived in the Cretaceous period before being wiped out by a storm.

"I have been truly amazed by the abundance of bones and the number of eggs as well the great potential of more discoveries from the site," Zhou told Reuters.

The team's new study is published in the journal Current Biology. The researchers examined a new species of pterosaur, named Hamipterus tianshanensis, which roughly means "the wing of Hami, in the Tianshan mountains."