Scientists have described an ancient marine predator the size of a bus

The new species has been named Tylosaurus rex - "king of the tylosaurs". The name refers to the famous Tyrannosaurus rex, but it is not a dinosaur. Tylosaurus rex was a mosasaur, a large marine reptile that hunted in the oceans of the Cretaceous period.

The discovery was made through a review of museum collections. Some of the bones found in Texas decades ago were long thought to be the remains of another species. Now scientists have come to the conclusion: there was a separate, larger and more powerful predator before them.

Details

Tylosaurus rex fossils have been found primarily in northern Texas. When this animal was alive, much of North America was covered by a warm inland sea. It was home to fish, sea turtles, other reptiles - and large predators such as mosasaurs.

The new species was remarkable for its impressive size. Researchers estimate that adults could have been between 7.5 and 13 metres long. The animal had powerful jaws, a strong neck and teeth with fine serrations. All this suggests that the scientists were facing a dangerous marine hunter, standing close to the top of the food chain.

The main specimen of the new species is kept at the Perot Museum of Nature and Science in Dallas. It was found back in 1979 near a man-made pond near the city. Other similar fossils also lay in various museum collections and used to belong to the already known species Tylosaurus proriger.

One specimen nicknamed Black Knight is particularly interesting. It has an injured snout and a broken lower jaw. Scientists believe that such injuries could have been inflicted by another large tylosaur. This hints that these animals may have not only hunted prey, but also violently clashed with each other.

Why it matters

The story of Tylosaurus rex shows that important discoveries sometimes wait years in museum collections. Bones have already been found, exhibited or described, but only a new comparison has made it possible to see them as a separate species.

The find also helps to better visualise the ancient seas of North America. These were not calm bodies of water with a few large animals, but complex ecosystems where huge reptiles competed, hunted and perhaps fought among themselves.

For a general audience, the important point here is simple: the age of the dinosaurs was a time of giants not just on land. The seas were also home to predators that rivalled the most famous land monsters in size and strength.

Background

Mosasaurs were large marine reptiles that lived during the Cretaceous period. They were not dinosaurs, although they existed at the same time as them. Their distant modern relatives are considered to be lizards and snakes.

Tylosaurs are one of the well-known groups of mosasaurs. Previously, many large finds from North America were attributed to the species Tylosaurus proriger. But a new study has shown that some of the Texas specimens are markedly different: they are younger, larger and have other features of teeth and skull.

So the scientists separated them into a new species, Tylosaurus rex. In abbreviation, it is also T. rex, but it should not be confused with Tyrannosaurus: one was a land dinosaur, the other a marine reptile.

Source

Amelia R. Zietlow, Michael J. Polcyn, and Ronald S. Tykoski, "A Gigantic New Species of Tylosaurus (Squamata: Mosasauridae) from Texas, and a Revised Character List for Phylogenetic Analyses of Mosasauridae," Bulletin of the American Museum of Natural History, 2026.

In the study, palaeontologists described a new species of mosasaur from fossils from Texas that are about 80 million years old. The animal was named Tylosaurus rex and could reach about 13 metres in length.