Icebound Giant Egg Redraws Mosasaur History

A fossilized Late Cretaceous egg found in Antarctica is the largest soft-shelled egg ever discovered and the second-largest egg of any non-avian dinosaur. Named Antarcticoolithus bradyi, the egg likely came from a mosasaur, suggesting these marine reptiles could lay very large eggs and may have been viviparous, though the exact parent species remains uncertain. The egg’s preservation in anoxic sediments helped keep its leathery shell intact.