A spectacular fossil find in China - a prehistoric egg extravaganza from 120 million years ago - is providing unique insight into the lifestyle and gender differences of pterosaurs, the flying reptiles that lived alongside the dinosaurs.
Until now, only four pterosaur eggs had ever been found, and all were flattened during the process of fossilization.
But Chinese scientists said on Thursday they had unearthed five pterosaur eggs preserved beautifully in three dimensions at a site in northwestern China that also includes no fewer than 40 adult individuals of a newly identified species that lived in a bustling colony near a large freshwater lake.
"This is definitely the most important pterosaur site ever found," said paleontologist Zhonghe Zhou, director of the Chinese Academy of Sciences' Institute of Vertebrate Paleontology and Paleoanthropology.
The creature, Hamipterus tianshanensis, had a crest atop its elongated skull, pointy teeth for catching fish and a wingspan of more than 11 feet (3.5 meters).
The five oblong eggs were "pliable" with a thin, hard outer layer marked by "cracking and crazing" covering a thick membrane inner layer, making them resemble the soft eggs of some modern snakes and lizards, said paleontologist Xiaolin Wang, another of the researchers.
"They are the best-preserved pterosaur eggs ever found," Wang said.