Fossil discoveries suggest the earliest dinosaurs laid soft-shelled eggs

Finds force scientists to rethink the evolution of dinosaur eggs

soft-shelled dinosaur egg fossil

The eggs of Mussaurus, a dinosaur that lived more than 200 million years ago, had soft shells. Traces of a soft shell are visible here as the black egg-shaped halo surrounding the dinosaur embryo.

© Diego Pol

Eggs from the earliest dinosaurs were more like leathery turtle eggs than rigid bird eggs.