Thalassotitan atrox was not a friendly lizard. The remains that have been found of this species of mosasaur that lived in the seas during the Late Cretaceous indicate that the beast fed on animals that were very difficult to sink its teeth into. We are referring to sea turtles, plesiosaurs and other mosasaurs. Thalassotitan atrox spread terror in the waters 66 million years ago .
The newly discovered species was probably at the top of the food chain since other mosasaurs did not feed on such large prey. It would therefore keep predators at bay.
Mosasaurs could reach 12 meters in length , about twice the length of a crocodile, and would have been very well adapted to water . They possessed a reptilian head, fins, and tail with shark fins. In the words of one of those responsible for the study published in Cretaceous Research , paleontologist and evolutionary biologist Nicholas Longrich, from the University of Bath (United Kingdom): “Thalassotitan was an incredible and terrifying animal”, it was like “a Komodo dragon crossed with a great white shark crossed with a T. rex crossed with an orca” .
Mosasaurs are thought to have been predators as they do not appear to have a good sense of smell. It is also thought that they were specialized to hunt different prey , given the different teeth they present. Some animals had small, pointed teeth, ideal for consuming fish and squid, and others had blunter teeth and crushing jaws, perfect for hunting shelled animals. Analyzes suggest that mosasaurs fed on fish, cephalopods, turtles, molluscs, other mosasaurs, and even birds. The Thalassotitan appears to have been one of the fiercest of the family.
The remains of the giant lizard have been found in Morocco , in phosphate deposits, an area that is rich in well-preserved fossils from the Cretaceous and Miocene. Among the remains found there are skulls, vertebrae, limb bones and phalanges. Paleontologists have been able to make a complete description of Thalassotitan ‘s skull, jaw, and teeth, as well as the skeleton, shoulders, and forelimb.
The team of researchers has determined that the animal could reach a length of between 9 and 10 meters, slightly larger than an orca. However, its skull was almost twice as long as that of the cetacean, with a length of 1.5 meters.
Unlike other mosasaurs that featured slender snouts, Thalassotitan ‘s jaw was wide and short, with large conical teeth that would have been perfect for grasping and tearing at prey. Precisely in the teeth, the paleontologists found another clue about the feeding of the great lizard and that is that many were broken and worn. This indicates that the reptile would have fed on animals that had hard surfaces like turtles, as well as large bones. This claim is supported by remains of large predatory fish, a sea turtle shell, a plesiosaur skull, and the bones of at least three different species of mosasaur found near the Thalassotitan fossils.
Although, as the researchers explain, this is circumstantial evidence, the remains of what is believed to have been their prey are worn out by the action of an acid. This could have happened perfectly when the giant lizard had ingested them, putting them in contact with gastric acids and then regurgitating them outside. “We can’t say for sure what species of animal ate all these other mosasaurs,” Longrich explains. “But we have the bones of marine reptiles killed and eaten by a large predator. And in the same place we found Thalassotitan , a species that fits the profile of the killer: it is a mosasaur specialized in preying on other marine reptiles. It is probably not a coincidence “.
Mosasaurs specialized and diversified in the last 25 million years of the Cretaceous . The recent discovery of Thalassotitan suggests that mosasaurs may have been even more diverse than previously believed. Their ecosystem would have been especially rich, diversified enough to provide so many different prey to support that many different predators.
As a consequence of the above, perhaps in the times prior to the mass extinction 65 million years ago, instead of reducing biodiversity, as some defend, the opposite occurred, it flourished, possibly as a result of a smaller extinction event that occurred in the middle of the Cretaceous. Be that as it may, there is still much to investigate to validate this hypothesis.
“Morocco has one of the richest and most diverse marine faunas known from the Cretaceous. We are just beginning to understand the diversity and biology of mosasaurs,” Longrich said.
Reference: Longrich , N. , Jalil , N. , et al. al. Thalassotitan atrox, a giant predatory mosasaurid (Squamata) from the Upper Maastrichtian Phosphates of Morocco. Cretaceous Research. 2022. DOI: https://doi.org/10.1016/j.craters.2022.105315
