Millions of years ago, the megalodon shark was one of the scariest creatures to ever lurk in our seas. And even before that, the mosasaurs reigned supreme, terrorizing every ocean creature in sight.

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 ...