Sixty six million years ago, sea monsters really existed. They were mosasaurs, huge marine lizards that lived at the same time as the last dinosaurs. Growing up to 12 meters long, mosasaurs looked like a Komodo dragon with flippers and a shark-like tail. They were also wildly diverse, evolving dozens of species that filled different niches. Some ate fish and squid, some ate shellfish or ammonites.
October 8, 2022
Sixty six million years ago, sea monsters really existed. They were mosasaurs, huge marine lizards that lived at the same time as the last dinosaurs. Growing up to 12 meters long, mosasaurs looked like a Komodo dragon with flippers and a shark-like tail. They were also wildly diverse, evolving dozens of species that filled different niches. Some ate fish and squid, some ate shellfish or ammonites.
Now we’ve found a new mosasaur preying on large marine animals, including other mosasaurs.
The new species, Thalassotitan atrox, was dug up in the Oulad Abdoun Basin of Khouribga Province, an hour outside Casablanca in Morocco.
At the end of the Cretaceous period, sea levels were high, flooding much of Africa. Ocean currents, driven by the trade winds, pulled nutrient-rich bottom waters to the surface, creating a thriving marine ecosystem. The seas were full of fish, attracting predators—the mosasaurs. They brought their own predators, the giant Thalassotitan. Nine meters long and with a massive, 1.3 meter-long head, it was the deadliest animal in the sea.
Most mosasaurs had long jaws and small teeth to catch fish. But Thalassotitan was built very differently. It had a short, wide snout and strong jaws, shaped like those of a killer whale. The back of the skull was wide to attach large jaw muscles, giving it a powerful bite. The anatomy tells us this mosasaur was adapted to attack and tear apart large animals.
The massive, conical teeth resemble the teeth of orcas. And the tips of those teeth are chipped, broken and ground down. This heavy wear—not found in fish-eating mosasaurs—suggests Thalassotitan damaged its teeth biting into the bones of marine reptiles like plesiosaurs, sea turtles and other mosasaurs.
At the same site we’ve found what look like the fossilized remains of its victims. The rocks producing Thalassotitan skulls and skeletons are full of partially digested bones from mosasaurs and plesiosaurs.
