According to a university press statement, researchers at the University of Bath uncovered fossilized bones of a giant mosasaur, a marine contemporary of the Tyrannosaurus rex (T.rex) and Triceratops. The remains were discovered in Morocco.
The Atlantic flooded northern Africa 66 million years ago, near the close of the Cretaceous period, when nutrient-rich waters gave rise to plankton blooms. Small fish ate the plankton and became food for larger fish, which were later eaten by marine reptiles like mosasaurs and plesiosaurs. While the T.rex dominated the land food chain, a comparable predator was lacking in the waters. As a result, a mosasaur evolved to inhabit this location.
What exactly are mosasaurs?
Mosasaurs were not dinosaurs, but rather large marine lizards that could grow to be 40 feet (12 meters) long. Mosasaurs, distant ancestors of modern-day monitor lizards and iguanas, resembled Komodo dragons but had flippers instead of feet and even a shark-like tail fin.
According to the news release, mosasaurs grew larger and specialized in taking up niches originally inhabited by plesiosaurs and ichthyosaurs during the last 25 million years of the Cretaceous era. Some mosasaurs ate small fish, others clams and ammonites, while still others developed to consume other marine reptiles. Thalassotitan atrox is the name given to a predator discovered recently in Morocco.
What do we know so far about Thalassotitan atrox?
Thalassotitan had a five-foot-long (1.5-meter) cranium and grew to the size of a killer whale at 30 feet (9 meters). While other mosasaurs had long jaws and slender teeth for capturing fish, Thalassotitan had a short wide nose with large conical teeth contained inside, similar to an orca.
The fossil shows that the Thalassotitan teeth are worn and cracked, which is not consistent with eating small fish. As a result, it is likely that the mosasaur attacked other marine reptiles, and as it tore them apart and bit into their bones, its teeth chipped and broke away, and some were crushed down to the root.
Large predatory fish, sea turtles, plesiosaur heads, and jaws and skulls of at least three mosasaur species, all likely victims of the Thalassotitan, were discovered in the same beds. The remains have been damaged by acids, and teeth and bone have been eaten away, which researchers believe are indicators of digestion in the gigantic reptile’s stomach.
Thalassotitan posed a threat not just to marine species, but also to other Thalassotitans, as the fossils reveal injury marks from conflicts for feeding sites or mates.
“Thalassotitan was an incredible, scary animal,” said Nick Longrich, a senior lecturer at the University of Bath who led the fossil research. “Imagine a Komodo Dragon crossbred with a great white shark, a T. rex, and a killer whale.””
The researchers have only recently begun to investigate mosasaurs. “Morocco boasts one of the richest and most diversified Cretaceous marine faunas known. “We’re just just getting started in terms of understanding the diversity and biology of mosasaurs,” Longrich noted.
The findings were reported in the journal Cretaceous Research.