About 66 million years ago, when the land was ruled by dinosaurs, the giant marine predators in the oceans were called mosasaurs. And, now, researchers have discovered the fossil of a new species of mosasaur called Thalassotitan atrox. Mosasaurs were like giant sea lizards that could reach 12 meters in length. They were distant relatives of modern monitor lizards and iguanas and closely resembled the Komodo dragon. While they were marine, mosasaurs did not have shark-like fins, instead they had flippers. These reptiles evolved to become larger and more distinct in the last 25 million years of the Cretaceous period. While some species went on to feed on small fish and squid, Thalassotitan atrox ruled the seas, devouring every other sea creature.
The fossil was unearthed outside the Moroccan city of Casablanca. According to the researchers, the length of Thalassotitan was about 9 meters, while its skull was 1.4 meters long. Most mosasaurs had long jaws and slender teeth that were effective at catching small fish, but Thalassotitan was found to have a short, wide snout and large teeth, with the conical structure seen in an orca. They enabled hunters to isolate huge prey.
According to the researchers, these features suggested that Thalassotitan was an apex predator and was located at the top of the food chain. They had the same ecological niche as the killer whale and the great white shark found today.
The broken and worn out condition of the teeth of Thalassotitan suggested that it did not hunt fish, but hunted other marine reptiles by breaking, chipping and grinding them in the process.
“The Thalassotitan was a wonderful, terrifying animal. Imagine a Komodo dragon crossed with a great white shark, crossed with a T. rex, crossed with a killer whale,” says the Milner Center for Dr Nick Longrich, Senior Lecturer at Evolution said. University of Bath, He is the lead author of the study published in Cretaceous Research.
In addition to the thalassotiton fossil, researchers believe they also stumbled upon the remains of a predator’s prey. Fossils from the same bed where Thalassotitan was found were damaged by acid and eaten away at their bones and teeth. These fossils are of large predatory fish, half a meter long plesiosaur head, a sea turtle and the skulls and jaws of three different mosasaur species.
According to Dr. Longrich, although they can’t confirm what ate other mosasaurs, they do have at least the bones of marine reptiles killed by larger predators. He added that Thalassotitan was found at the same location and it also fits the profile of the killer. “It is a mosasaur specialized to hunt other marine reptiles. This is probably not a coincidence,” said Dr. Longrich.