“Jurassic World” featured a scene from an aquatic show similar to SeaWorld. Instead of a dolphin jumping out of the water though, a massive lizard-like creature sprung out of the water and ate a great white shark whole. Although exaggerated in the movie, this creature’s fossil was just discovered in North Dakota. When excavating a northeastern part of North Dakota, a fossil was found with a nearly complete skull, cervical spine, jaws, and many vertebrae. Analysis of this fossil was done by a Ph.D. student in comparative biology at the American Museum of Natural History’s Richard Gilder Graduate School, named Amelia Zietlow. Analysis and surface scanning of the fossil helped determine that this subject was a large aquatic lizard that lived during the late Cretaceous Period called a Mosasaur. Scientists named this species Jormungandr Walhallaensis after a Norse sea serpent called Jormungandr and a city in North Dakota close to where the fossil was found called Walhalla. This species is a mix of the Mosasaurus, which grows to be about 50 feet long and lived with the Tyrannosaurus Rex, and the Clidastes, which is a smaller and less developed version of the Mosasaurus.
Based on the analysis of the fossil, this specific Jormungandr Walhallaensis was about 24 feet long, had flippers, had a shark-like tail that is shorter than its body, and had pointed eyebrows, which were shown by the raised bones on the front of the skull. They were fully aquatic, but scientists are not fully sure how many times Mosasaurs have evolved flippers, but they estimate that they evolved them at least three times. Because of their characteristics, scientists are not sure whether the Mosasaur is more closely related to snakes or monitor lizards, which are large lizards like komodo dragons.
One question that has puzzled scientists studying Mosasaurs is how all types are related to each other. This may seem incorrect because the first Mosasaur was discovered more than 200 years ago and the word Mosasaur predates the word dinosaur. Because of this, you may assume that we have found many different species of the Mosasaur but this is not true. The discovery of the Jormungandr Walhallaensis allows scientists to see a better connection between multiple species of Mosasaur. This is done through dating the fossils and determining how it evolved compared to other species before and after it was alive. Based on analysis, it is clear that this species lived before the Mosasaurus, about 80 million years ago. Thanks to the Jormungandr Walhallaensis, we now have a better understanding of the timeline of the evolution of the Mosasaur.
