Geologists uncover the largest mosasaur fossil in Mississippi

In Mississippi, researchers stumbled upon a significant fossil discovery while surveying land near Starkville. On April 15, 2025, geologists collected rock, sediment, and fossil samples in a creek bed, where they found a large lumbar vertebra. The vertebra was remarkably large, leading to immediate recognition of it being a mosasaur, specifically Mosasaurus hoffmannii. James Starnes, who specializes in surface geology for the Mississippi Department of Environmental Quality (MDEQ), recognized its distinct shape as non-mammalian and identified it as a sea lizard. The vertebra's size indicated that the animal likely measured between 30 and 40 feet long, although mosasaurs could grow up to 50 feet. Researchers noted that the Mosasaurus species typically had a weight of around 20,000 pounds and they are known for their hydrodynamic bodies, which helped them become fast and agile swimmers. Their jaws were particularly adapted for hunting, equipped with 60 sharp, dagger-like teeth suitable for capturing large prey. These marine reptiles thrived during the Late Cretaceous period, inhabiting ancient seas that once covered present-day Mississippi. The Mississippi region has a known history of fossil discoveries due to its geological formations. While shell fossils and Ice Age fossils from land animals are common, the discovery of mosasaurs is particularly rare, particularly a specimen of this size. These creatures were apex predators of their time, and finding such a large vertebra raised excitement among the researchers. Starnes expressed that this was the largest mosasaur fossil they had ever encountered in their geological studies. The Western Interior Sea Way during the Cretaceous period created the environment that allowed such marine reptiles to thrive. The fossil find reinforces the Mississippi Embayment's importance in understanding prehistoric marine life. Researchers hope that this discovery will lead to further studies, raising awareness and interest in the region's fossil record and geologic history. The extraordinary find not only highlights the importance of ongoing geological surveys but also enriches the narrative of ancient life in North America as they continue to uncover new perspectives and facts about life millions of years ago.