Overview
- A peer‑reviewed PLOS ONE paper presents strong direct evidence that some mammal ancestors laid eggs using an embryonic Lystrosaurus preserved in ovo as the key case.
- The tiny skeleton’s unfused lower jaw and tightly curled posture mark it as an embryo that could not feed, which fits an animal that died inside an egg.
- Researchers used high‑resolution CT and synchrotron imaging at the European Synchrotron in France to build 3D views of the delicate bones without extracting them from the rock.
- The fossil was first found in 2008 in the Karoo Basin at Oviston and later studied by a team from the University of the Witwatersrand with support from the National Museum in Bloemfontein.
- The authors infer soft, leathery, relatively large eggs that were rich in yolk and propose that precocial hatchlings could have helped Lystrosaurus endure harsh post–end‑Permian conditions.