A new genus and species of mosasaur being named Jormungandr walhallaensis has been discovered by American Museum of Natural History Ph.D. student Amelia Zietlow and colleagues. Reconstruction of Jormungandr walhallaensis shown engaging in intraspecific combat. Image credit: Henry Sharpe. Mosasaurs were a group of large, carnivorous aquatic reptiles that inhabited all of the world’s oceans during the Late Cretaceous epoch, between 90 and 66 million...