Scientists discover fossils of giant sea lizard that ruled the oceans 66 million years ago

Researchers discover fossils of giant sea lizard that ruled the oceans 66 million years ago
Artist’s illustration of Thalassotitan atrox. Credit: Andrey Atuchin

Researchers have found an enormous new mosasaur from Morocco, named Thalassotitan atrox, which stuffed the apex predator area of interest. With large jaws and enamel like these of killer whales, Thalassotitan hunted different marine reptiles—plesiosaurs, sea turtles, and different mosasaurs.

At the top of the Cretaceous interval, 66 million years in the past, sea monsters actually existed. While dinosaurs flourished on land, the seas had been dominated by the mosasaurs, large marine reptiles.

Mosasaurs weren’t dinosaurs, however huge marine lizards rising as much as 12 meters (40 ft) in size. They had been distant family members of contemporary iguanas and monitor lizards.

Mosasaurs appeared like a Komodo dragon with flippers as a substitute of legs, and a shark-like tail fin. Mosasaurs turned bigger and extra specialised within the final 25 million years of the Cretaceous, taking niches as soon as stuffed by marine reptiles like plesiosaurs and ichthyosaurs. Some advanced to eat small prey like fish and squid. Others crushed ammonites and clams. The new mosasaur, named Thalassotitan atrox, advanced to prey on all the opposite marine reptiles.

The stays of the brand new species had been dug up in Morocco, about an hour outdoors Casablanca. Here, close to the top of the Cretaceous, the Atlantic flooded northern Africa. Nutrient wealthy waters upwelling from the depths fed blooms of plankton. Those fed small fish, feeding bigger fish, which fed mosasaurs and plesiosaurs—and so forth, with these marine reptiles changing into meals for the enormous, carnivorous Thalassotitan.

Researchers discover fossils of giant sea lizard that ruled the oceans 66 million years ago
Nick Longrich with the mosasaur fossil. Credit: Nick Longrich

Thalassotitan, had an unlimited cranium measuring 1.4 meters (5 ft lengthy), and grew to just about 30 ft (9 meters) lengthy, the dimensions of a killer whale. While most mosasaurs had lengthy jaws and slender enamel for catching fish, Thalassotitan had a brief, large muzzle and large, conical enamel like these of an orca. These let it seize and rip aside enormous prey. These variations recommend Thalassotitan was an apex predator, sitting on the prime of the meals chain. The large mosasaur occupied the identical ecological area of interest as in the present day’s killer whales and nice white sharks.

Thalassotitan’s enamel are sometimes damaged and worn, nonetheless consuming fish would not have produced this type of tooth put on. Instead, this means that the enormous mosasaur attacked different marine reptiles, chipping, breaking, and grinding its enamel because it bit into their bones and tore them aside. Some enamel are so closely broken they’ve been virtually floor all the way down to the basis.

Fossilized stays of prey

Remarkably, attainable stays of Thalassotitan’s victims have been found. Fossils from the identical beds present harm from acids, with enamel and bone eaten away. Fossils with this peculiar harm embody massive predatory fish, a sea turtle, a half-meter lengthy plesiosaur head, and jaws and skulls of a minimum of three totally different mosasaur species. They would have been digested in Thalassotitan’s abdomen earlier than it spat out their bones.

Researchers discover fossils of giant sea lizard that ruled the oceans 66 million years ago
Size comparability of Thalassotitan atrox. Credit: Nick Longrich

“It’s circumstantial evidence,” mentioned Dr. Nick Longrich, Senior Lecturer from the Milner Center for Evolution on the University of Bath and lead creator on the research, revealed in Cretaceous Research.

“We cannot say for sure which species of animal ate all these different mosasaurs. But we now have the bones of marine reptiles killed and eaten by a big predator.

“And in the same location, we find Thalassotitan, a species that fits the profile of the killer—it’s a mosasaur specialized to prey on other marine reptiles. That’s probably not a coincidence.”

Thalassotitan was a menace to every part within the oceans—together with different Thalassotitan. The enormous mosasaurs bear accidents sustained in violent fight with different mosasaurs, with accidents to their face and jaws sustained in fights. Other mosasaurs present comparable accidents, however in Thalassotitan these wounds had been exceptionally widespread, suggesting frequent, intense fights over feeding grounds or mates.

“Thalassotitan was an amazing, terrifying animal,” mentioned Dr. Nick Longrich, who led the research. “Imagine a Komodo Dragon crossed with a great white shark crossed with a T. rex crossed with a killer whale.”

The new mosasaur lived within the ultimate million years of the Age of Dinosaurs, a up to date of animals like T. rex and Triceratops. Along with current discoveries of mosasaurs from Morocco, it means that mosasaurs weren’t in decline earlier than the asteroid impression that drove the Cretaceous mass extinction. Instead, they flourished.

Researchers discover fossils of giant sea lizard that ruled the oceans 66 million years ago
Map of distribution of Thalassotitan. Credit: Nick Longrich

Professor Nour-Eddine Jalil, a co-author on the paper from the Museum of Natural History in Paris, mentioned: “The phosphate fossils of Morocco supply an unparalleled window on the paleobiodiversity on the finish of Cretaceous.

“They tell us how life was rich and diversified just before the end of the ‘dinosaur era,” the place animals needed to specialize to have a spot of their ecosystems. Thalassotitan completes the image by taking over the function of the megapredator on the prime of the meals chain.”

“There’s so much more to be done,” mentioned Longrich. “Morocco has one of the richest and most diverse marine faunas known from the Cretaceous. We’re just getting started understanding the diversity and the biology of the mosasaurs.”

Giant sea lizard fossil reveals range of life earlier than asteroid hit

More data:
Nicholas R. Longrich et al, Thalassotitan atrox, a large predatory mosasaurid (Squamata) from the Upper Maastrichtian Phosphates of Morocco, Cretaceous Research (2022). DOI: 10.1016/j.cretres.2022.105315

Dr. Longrich has written a weblog in regards to the analysis right here:

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University of Bath

Scientists uncover fossils of large sea lizard that dominated the oceans 66 million years in the past (2022, August 24)
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