236-million-year-old fossil may rewrite the evolutionary history of live birth in mammals

Scientists have analysed a 236-million-year-old fossil of a mammal ancestor and found a bone feature suggesting its newborns were relatively large — more consistent with live birth than hatching from an egg. The finding offers indirect evidence that live birth may have evolved in mammal ancestors far earlier than previously thought. Researchers caution, however, that the evidence remains indirect.