By: Jasmine Wang

In 2022, researchers from the University of Bath discovered the fossil of a new mosasaur species in Morocco. It is a terrifying fish lizard that is almost thirty feet in length. That’s ten feet longer than an orca, and nearly half the size of a blue whale, the largest mammal.

Scientists named it the Thalassotitan atrox(T. atrox) because “Thalassa” and “titan” mean sea giant and “atrox” means cruel or merciless.

“Thalassotitan was an amazing, terrifying animal,” study leader Dr. Nick Longrich said. “Imagine a Komodo dragon crossed with a great white shark crossed with a T. rex crossed with a killer whale.”

Mosasaurs comprised a diverse group of giant fish-like reptiles that lived in the ocean in the late Cretaceous period, while the T. rex was on land. These scaly fish-like reptiles used their paddle-like flippers and tail to propel themselves through the water. They went extinct 66 million years ago, at the same time as dinosaurs when a huge asteroid struck the earth.

The remains of T. atrox were dug up in an area of Morocco that was underwater during the Cretaceous period. Its enormous skull measured five feet long. Unlike other mosasaur species, which had thin teeth and long snouts, that were good for eating small fish, the T. atrox had a stout muzzle and gigantic teeth, good for eating big fish, and even other mosasaurs. When it was dug up, the T. atrox’s teeth were very chipped and broken. Scientists speculate that this was because the fish lizard would violently tear apart its prey.

Mosasaurs have been found in Morocco before, and more will probably be found in the future. Scientists believe the North African country was once home to 30 different mosasaur species.

Though T. atrox is large, it isn’t the biggest. Mosasaur species Mosasaurus Hoffmanni was found in Russia in 2014 and is estimated to be two times the length of T. atrox.