Fossilized egg with 250-million-year-old embryo discovered
Researchers have found a fossilized egg containing a 250-million-year-old embryo in Africa, providing the first direct evidence that early mammalian ancestors such as therapsids laid eggs. The fossil belongs to Lystrosaurus, a herbivorous animal that lived approximately 252 to 250 million years ago and is known for surviving a major extinction event. This discovery resolves a long-standing scientific debate about the reproductive methods of early mammalian lineages.