An enormous sea snake from Norse legend, which was fathered by the trickster god Loki and grew large enough to encircle the globe, has inspired the name of a newly discovered species of mosasaur. Paleontologists recently uncovered the fossils of this massive, meat-eating marine reptile near the North Dakota town of Walhalla. In honor of the town’s Norse mythology namesake, and the mythological sea serpent Jormungandr, the scientists named the mosasaur Jormungandr walhallaensis. The researchers detailed their findings in a recent publication in the Bulletin of the American Museum of Natural History.
The fossil, known as NDGS 10838, includes a nearly complete skull with distinctive features such as a bony ridge over the eyes and jaws, as well as skeletal parts including ribs and vertebrae. Lead study author Amelia Zietlow, a paleontologist and doctoral candidate at the American Museum of Natural History’s Richard Gilder Graduate School, described the mosasaur as measuring approximately 24 feet (7.3 meters) in length, with a slender face compared to its cousins.
While Jormungandr walhallaensis shared similarities with other mosasaurs, it also possessed unique traits that made it challenging to classify. The shape of its ear bones resembled those of Mosasaurus, while its teeth were similar to those of a smaller genus called Clidastes. Additionally, the angle and number of teeth on the bony palate differed from both of these groups. These distinct features led the researchers to conclude that Jormungandr walhallaensis represented a new genus and species of mosasaur.
The fossilization process may have caused distortions in the bone, leading to the unique characteristics observed in Jormungandr walhallaensis. Due to the uncertainties surrounding this specimen, additional fossils of the newfound species could help determine its precise place on the mosasaur family tree.
Alongside dinosaurs, mosasaurs thrived during the Late Cretaceous Period, approximately 98 million to 66 million years ago. Despite their abundance in the fossil record, scientists believe there is much more to learn about the diversity and evolutionary history of mosasaurs. The recent research on Jormungandr walhallaensis contributes valuable anatomical data that will aid in further study of these fascinating creatures.
By thoroughly documenting the unique attributes of this specimen, the researchers hope to encourage future investigations into mosasaur fossils. By revisiting known specimens and analyzing newly discovered fossils, scientists can gain a better understanding of the evolutionary puzzle surrounding the transition from land to sea among various animal groups. The comprehensive examination of Jormungandr walhallaensis, including detailed illustrations and descriptions, will serve as a valuable resource for future researchers and contribute to the ongoing study of mosasaurs.
