In a world first, paleontologists working in northwestern China have discovered a cache of hundreds of ancient eggs laid by pterosaurs, the flying reptiles that lived alongside the dinosaurs. Some of the eggs contain the most detailed pterosaur embryos ever found.

Although scientists have studied pterosaurs for more than two centuries, no eggs were discovered until the early 2000s, and fewer than a dozen turned up in the intervening years. The new haul, discovered by Chinese Academy of Sciences paleontologist Xiaolin Wang, includes at least 215—and perhaps as many as 300— stunningly preserved pterosaur eggs.

His team also found 16 embryos within the eggs, and they suspect that more remain locked away in the stone. Wang and his colleagues