At the end of the Cretaceous Period, a type of giant reptile called mosasaurs occupied and dominated oceanic food webs. Mosasaurs had long bodies and were related to both snakes and monitor lizards.

Jormungandr, a 24-foot aquatic lizard that lived 80 million years ago, is found to be a transitional species between two well-known mosasaurs “If you put flippers on a Komodo dragon and made it really ...