Egg accumulation with 3D embryos provides insight into the life history of a pterosaur.

Fossil eggs and embryos that provide unique information about the reproduction and early growth of vertebrates are exceedingly rare, particularly for pterosaurs. Here we report on hundreds of three-dimensional (3D) eggs of the species from a Lower Cretaceous site in China, 16 of which contain embryonic remains. Computed tomography scanning, osteohistology, and micropreparation reveal that some bones lack extensive ossification in potentially late-term embryos, suggesting that hatchlings might have been flightless and less precocious than previously assumed.

Sexually dimorphic tridimensionally preserved pterosaurs and their eggs from China.

Background: The pterosaur record is generally poor, with little information about their populations, and pterosaur eggs are even rarer, with only four isolated and flattened eggs found to date.

Results: We report here a population of a new sexually dimorphic pterosaur species (Hamipterus tianshanensis gen. et sp.