This ancient sea creature roamed the waters of North Dakota | ET REALITY

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In Norse mythology, a monstrous sea serpent coiled in the waters of the world. His name was Jormungandr.

The ancient Norse also believed in a place called Valhalla, or heaven. And in North Dakota, there is a small town called Walhalla, a name that reflects the area’s Scandinavian heritage.

It was near there that a new type of mosasaur, a type of giant sea creature, was discovered, scientists announced last week. They called him Jormungandr walhallaensis.

Jormungandr walhallaensis, which lived about 80 million years ago, has been considered a new species and genus of mosasaur, an ancient lineage of marine reptile predators that inhabited Earth’s waters almost 100 million years ago.

“There are a lot of papers published every year about dinosaurs, but not many about mosasaurs because there simply aren’t many people in the world working on them,” said Michael Caldwell, a leading mosasaur expert and biologist. science professor at the University of Alberta in Canada who did not work on the discovery.

Mosasaurs were essentially giant lizards with fins that allowed them to live in the sea, with some species growing up to 60 feet.

They became extinct at the same time as the dinosaurs.

Amelia Zietlow, a doctoral student at the Richard Gilder Graduate School of the American Museum of Natural History and lead author of the new study, said Jormungandr walhallaensis has a unique mix of physiological traits from what is perhaps the best-known genus of mosasaurs, the school. -bus size mosasaur (represented, although large, in the movie “Jurassic World”) and its smaller and more primitive predecessor, the clidasts.

An analysis by computer software did not return an exact match for the fossil in the mosasaur fossil record, leading Zietlow and his co-authors to conclude that their fossil was not only a new species, but an entirely new genus that places somewhere among the clidasts. and mosasaurus in the mosasaur lineage.

However, there is a healthy debate on this point.

“Do I necessarily agree that this is a new genus and species?” Dr. Caldwell said. “Well, no, I don’t. But those are kind of scientific objections, right?

It is more likely, Dr. Caldwell said, that the fossil described in the study is simply a new species of the genus clidastes. According to this view, it would take the name Clidastes walhallaensis.

Still, the paper adds “extremely valuable” data for future research to consider as the field develops what is still a nascent understanding of mosasaur evolution, Dr. Caldwell said.

Although Zietlow and his co-authors only had the skull and jaw of Jormungandr walhallaensis to analyze, they were able to obtain important details about how it lived and died.

Jormungandr walhallaensis was probably between 18 and 24 feet long, Zietlow said.

The shape of its teeth indicates that it fed on fish and other small creatures when it prowled the Western Interior Seaway, which divided North America in half through the Midwestern states during the late Cretaceous Period.

Some of the animal’s vertebrae show tooth marks that appear not to heal, Zietlow said, suggesting that it had been attacked by another animal, possibly even another mosasaur, not long before it died.

The fact that the rest of the skeleton was missing when it was discovered suggests that it may have been eaten.

Zietlow hopes his work on Jormungandr walhallaensis will spark interest in mosasaurs, which he called understudied despite collections of their fossils in museums across the continent.

“Of the 4,000 mosasaurs in North America,” Ms. Zietlow explained, “only about 5 percent have been included in the scientific literature.”

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