In Depth
Ancient animals, especially pterosaurs are often known from only a few bones, and then often poorly preserved. The pterosaur Hamipterus however is very different. Not only is the complete animal known, but fossil remains of dozens, maybe even hundreds have been discovered. These include soft tissue impressions and eggs. This has all come from the fact that was found was not one random pterosaur here and another there, but a complete nesting colony that was buried under a mudslide back in the Cretaceous.
The discovery of this nesting colony has led to a few revelations about pterosaurs. In the case of the Hamipterus genus, the full growth pattern of the pterosaur can be established. The crest on top of the snout grew progressively more forwards as the individual reached maturity. The crest also developed more prominent ridges. Most telling though was that both males and females had crests on their snouts, though the crests on males are notably larger. This is hard evidence that the theory that only male pterosaurs had crests cannot apply to the whole pterosaur group. Maybe it could still apply to some pterosaur genera, but certainly not to Hamipterus.
Scans of embryos within eggs also show that when baby pterosaurs hatched, they could not fly straight away at the moment of hatching, their bones are just too poorly developed for that. Juvenile Hamipterus thigh bones however are already well adapted for walking, indicating that while baby Hamipterus could not fly, they could still amble about. The observations that so many fossils of adults and eggs were found together is seen as proof that pterosaurs did not just abandon eggs, but reared their young until they could be independent.
Further Reading
- Sexually dimorphic tridimensionally preserved pterosaurs and their eggs from China. - Current Biology. 24 (12): 1323–1330. - 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. - Egg accumulation with 3D embryos provides insight into the life history of a pterosaur. - Science 358(6367): 1197–1201. - Xiaolin Wang, Alexander W. A. Kellner, Shunxing Jiang, Xin Cheng, Qiang Wang, Yingxia Ma, Yahefujiang Paidoula, Taissa Rodrigues, He Chen, Juliana M. Say�o, Ning Li, Jialiang Zhang, Renan A. M. Bantim, Xi Meng, Xinjun Zhang, Rui Qiu & Zhonghe Zhou - 2017.
