For a long time, the reproduction methods of pterosaurs has been debated. From early fossil finds it was not possible to determine if they laid eggs or gave birth to live young. The skeletons do not clearly show any evidence of this. Speculation was also made about whether the young pterosaurs could fly from birth or if they needed parental care whilst they developed. Such an option would require some sort of nest or protective shelter to guard against predators.
There were a few fossil remains that suggested juvenile specimens, but without confirmation such assumptions were difficult to sustain in an argument about development, especially since many of the debates centred around single or partial specimens. The rarity of pterosaur remains made such discussion difficult.
When the first pterosaur fossil egg was found in 2004, the speculation became an issue for research and analysis. Since then it has become clear that pterosaurs were egg layers and their young emerge in a well developed state with completely formed wings.
2004 Chinese Finds Eggs showing the articulated skeleton of an embryo and the shell structure.
2004 Argentinian Find An egg that is clearly of the species Pterodaustro.
2009 Chinese Find A specimen of Darwinopteryx fossilised with an egg present.
2014 3D fossil eggs Hamipterus tianshanensis