2014 - 3D fossil eggs
A site in the Turpan-Hami Basin, south of the Tian Shan Mountains in Xinjiang, northwestern China, revealed pterosaur fossil remains of 40 individual pterosaurs, both male and female. Evidence suggests that they died in a storm about 120 million years ago. Amongst them were 5 egg fossils in excellent preservation. The egg shells pliable, with a thin, calcareous shell outside and a soft, thick membrane inside.
This is a clear indication that these pterosaurs were associated in a colony and died together in the same incident.
Xiaolin Wang, Alexander W.A. Kellner, Shunxing Jiang, Qiang Wang, Yingxia Ma, Yahefujiang Paidoula, Xin Cheng, Taissa Rodrigues, Xi Meng, Jialiang Zhang, Ning Li, Zhonghe Zhou. 2014. Sexually Dimorphic Tridimensionally Preserved Pterosaurs and Their Eggs from China. Current Biology; DOI: 10.1016/j.cub.2014.04.054