Building Blocks: Dinocephalosaurus' Baby Bump

Birds don’t give birth to live young, but their distant ancestors did. Archosauromorphs, which existed about 250 million years ago, were the creatures that evolved into crocodiles, dinosaurs, birds and pterosaurs. Experts thought these beasts laid eggs, much like their modern descendants. But a new Nature Communications paper details the fossilized remains of an archosauromorph mother and her unborn baby. The mom — the marine-dwelling Dinocephalosaurus — and her preserved pregnancy could give paleontologists a better idea of how her kind lived and evolved.