Norse Mythology Meets Reality: Ancient Sea Creature Discovered in North Dakota

In the depths of the Western Interior Seaway, which once bisected North America during the late Cretaceous Period, roamed a creature as monstrous as the mythical Jormungandr, the Midgard Serpent of Norse mythology. This ancient sea predator, named Jormungandr walhallaensis after its serpentine namesake, has been identified as a new species of mosasaur, a giant marine reptile that lived alongside dinosaurs.

The discovery, made by a team of paleontologists led by Amelia Zietlow of the American Museum of Natural History, is based on a fossilized skull and jaw unearthed near the town of Walhalla, North Dakota. The name Jormungandr walhallaensis pays homage to both the Norse serpent and the town's Scandinavian heritage.

Jormungandr walhallaensis, estimated to have measured between 18 and 24 feet long, possessed a unique blend of features that distinguished it from other known mosasaurs. It shared characteristics of both the smaller, more primitive Clidastes and the larger, more formidable Mosasaurus, suggesting an evolutionary bridge between these two genera.

While the classification of Jormungandr walhallaensis as a new genus has sparked debate among some paleontologists, the discovery nonetheless sheds valuable light on the evolutionary trajectory of mosasaurs. Michael Caldwell, a mosasaur expert at the University of Alberta, acknowledged the significance of the find, emphasizing its contribution to our understanding of these ancient marine reptiles.

The presence of tooth marks on some of Jormungandr walhallaensis's vertebrae suggests that it may have been attacked by another predator, possibly of its own kind. The absence of the rest of the skeleton when it was discovered further hints at the possibility of scavenging.

Zietlow, who hopes her work will ignite interest in mosasaurs, highlights the importance of further research on these understudied creatures. With only a small fraction of North America's mosasaur fossils having been thoroughly examined, there's still much to be learned about these fascinating denizens of the ancient seas.