Geologists Stumble Upon Remains of Giant ‘Sea Monster’ in Mississippi, Likely the Largest Mosasaur Ever Identified in the State
Researchers uncovered one vertebra, and based on its size, they estimate the massive creature was at least 30 feet long when it roamed the shallow seas that covered the region roughly 66 million years ago
/https://tf-cmsv2-smithsonianmag-media.s3.amazonaws.com/accounts/headshot/SarahKuta.png)
Geologists were studying rock layers in east-central Mississippi when they spotted something unusual sticking out of the mud.
After the scientists carefully pulled the object from the sediment, they knew right away they’d found something special. It was a massive, fossilized mosasaur vertebra that measured more than seven inches across at its widest point. They were ecstatic.
“I … was completely awe-struck by its size,” James Starnes, a geologist at the Mississippi Department of Environmental Quality who first spotted the bone, tells Live Science’s Patrick Pester. “The feeling you get when you find a fossil, even as a professional, never gets old. But when you find something you have never seen before, the elation can be overwhelming.”
Starnes and his colleagues Jonathan Leard and Tim Palmer found the bone near Starkville, a small town that’s home to Mississippi State University. They were surveying the area to create a three-dimensional map of the land’s geologic layers, reports the Mississippi Clarion-Ledger’s Brian Broom.
They’d already found some treasures—including ancient seashells from when Mississippi was underwater millions of years ago—when they discovered the mosasaur fossil. They turned the bone over to the Mississippi Museum of Natural Science, and paleontologists identified it as belonging to Mosasaurus hoffmannii, which was one of the biggest mosasaur species to roam the planet.
This particular individual may represent the largest mosasaur ever discovered in Mississippi. Based on the size of its vertebra, researchers estimate the creature was at least 30 feet long.
“This was a true, true sea monster,” Starnes tells the Mississippi Clarion-Ledger. “This is bigger than most dinosaurs walking around on land.”
The gigantic mosasaur lived at the end of the Cretaceous period, around 66 million years ago. At the time, Mississippi looked very different than it does today. It was submerged under a warm, shallow sea that was brimming with now-extinct creatures, from sharks and fish to marine lizards and cephalopods with coiled shells known as ammonites.
“Pterosaurs and even some birds would have been flying overhead, while a variety of both plant and meat-eating dinosaurs of different sizes and kinds would have been walking the shorelines and through the wooded forests along the coastal estuaries,” Starnes tells Live Science.
M. hoffmannii and other mosasaurs were prowling around Mississippi’s shallow waters, too. These large, aquatic reptiles had sleek bodies, long tails, paddle-like limbs and, in some instances, sharp teeth. Some were apex predators that feasted on whatever they could get their jaws around—even other mosasaurs.
“While the dinosaurs ruled the land, these Mesozoic era oceans were likely the most dangerous of any time in the entire history of our planet,” according to a Mississippi Department of Environmental Quality post announcing the fossil find.
Mosasaurs disappeared, along with the dinosaurs, when an asteroid collided with Earth some 66 million years ago. But their fossilized remains continue to fascinate researchers in Mississippi and beyond. In 2022, researchers in northeast Mississippi unearthed a fossilized skeleton—including the skull—that had belonged to a mosasaur that lived more than 80 million years ago.
