But the latest report in the peer-reviewed U.S. journal Science is based on the biggest collection to date - 215 fossilized eggs that were found in a 10-foot (three-meter) long sandstone block in northwestern China's Hami City, Xinjiang Uygur Autonomous Region.
The pterosaurs were an order of flying reptiles that went extinct some 66 million years ago.
The palaeontologists who made the discovery note both the "extraordinary quantity of eggs", and the fact some of them contain "the first pterosaur three-dimensional embryos". The eggs fossilised in lake sediments disturbed by fast-moving water, a sign that storms may have flooded a nesting site and sent the eggs bobbing into a large lake, where soupy mud entombed them.
The intact eggs were about 3 inches long and they were pliable.
The fossils, some of them of embryos with the bones preserved in three dimensions, were found in 2015-2016 in the northeastern Chinese region of Hami, and they were analysed and described in a joint project by Brazilian and Chinese dinosaur experts.
A total of 215 fossilized pterosaur eggs have been found in China, allowing researchers to get a sense of how babies were cared for in the early stages of their lives.
"The specimens can be attributed to Hamipterus tianshanensis, the sole species in this bonebed". Could raise their young together mean pterosaurs were social and nurtured approaching one another?
The discovery of 215 eggs of a species of pterosaur with an 11-foot wingspan and pointy teeth has shed light on the lives of the ancient carnivores. Furthermore, the eggs were a wide variety of sizes, indicating that they had been laid at different times by different animals.
"We want to find more eggs to make a much more detailed picture of embryonic development", Alexander Kellner, a paleontologist with Laboratório de Sistemática e Tafonomia de Vertebrados Fósseis, told Newsweek.
Hamipterus not only fed in this long-lost paradise, it also bred there, likely burying clutches of eggs in vegetation or on shorelines. When the pterosaurs thrived, the place was most likely a lush lake shore.
The paper says that H. tianshanensis hatchlings wouldn't have been able to fly immediately because several of the eggs the team examined showed wing bones that were less developed than expected. One embryo, which the team classified as the most mature, had partially developed wings and skull bones, as well as a complete lower jaw. But with paleontologists working more and more on the case, it only seems like only a matter of time now. Perhaps the largest embryos the team found weren't quite ready to hatch, which would throw off the developmental time line. Others boasted wild and insane crests, which may have been used to attract the opposite sex, as has been suggested with H. tianshanensis.
"The work is a crucial advance in understanding pterosaur reproduction", said Charles Deeming, from the University of Lincoln. Number two: "I wish we would find eggs in situ-that means 'not moved.' We would learn a lot from that".