Long before humans existed, giant marine predators ruled the warm prehistoric seas that once covered much of North America. Among them was a newly identified species called Tylosaurus rex, a massive mosasaur that stretched nearly 43 feet in length and lived more than 80 million years ago.

There’s a new T. rex in the fossil record, only this one terrorized the ancient seas. New research uncovers a new, massive species of mosasaur, a marine reptile that lived during…

Researchers say species had finely serrated teeth and was formidable marine predator