250-million-year-old fossil proves mammal ancestors laid eggs
April 15, 2026 3 min read Add Us On GoogleAdd SciAm 250-million-year-old fossil proves mammal ancestors laid eggs Laying eggs may have helped mammal ancestors thrive after Earth’s worst mass extinction By Kate Wong edited by Jeanna Bryner This reconstruction of a Lystrosaurus embryo shows the little creature in its partially preserved shell. Detailed imaging…
