This fossil is a vertebra of Mosasaurus hoffmanni, one of the largest mosasaurs to ever exist. (Photo: James Starnes)
Scientists say a giant “sea dragon” spine found on a Mississippi riverbank may belong to the largest mosasaur ever discovered in the state.
Researchers have found only one vertebra of the creature and are unsure of its exact size, but it is believed to have been at least 30 feet (9 meters) long, the Hattiesburg American reports.
Mosasaurs, or “sea dragons,” dominated the oceans when dinosaurs ruled the land during the late Cretaceous Period (145 to 66 million years ago). The newly discovered fossil belongs to Mosasaurus hoffmanni, which is considered one of the largest — if not the largest — mosasaur species.
James Starnes, a geologist with the Mississippi Department of Environmental Quality, spotted the fossil protruding from a creek bed south of Starkville on April 15 and told Live Science in an email. Fellow geologist Jonathan Leard then carefully removed it from the sediment.
“I knew right away what it was, but I was completely blown away by the size of it,” Starnes said. “The feeling of finding a fossil, even as a professional, never ceases to be exciting. But when you find something you’ve never seen before, the excitement can be overwhelming.”
Mosasaurs were a diverse group of marine reptiles. Researchers are still working to determine the size of the largest mosasaur species, but they likely reached a maximum length of about 50 feet (15 m). One of the largest recorded specimens is a skull belonging to M. hoffmanni, and it is estimated to have been about 56 feet (17 m) long, according to a 2014 study published in the journal Proceedings of the Zoological Institute of the Russian Academy of Sciences.
The newly discovered vertebral fossil measures more than 7 inches (18 centimeters) across at its widest point. Starnes and his colleagues compared the fossil to the largest mosasaur remains housed at the Mississippi Museum of Natural Sciences, which include jaws, parts of a skull, and a tooth. Starnes noted that the jaws and skull appeared to belong to a smaller specimen than the one represented by the new vertebra, but the tooth looked like it belonged to an individual comparable in size to the new specimen. In other words, the new fossil likely belonged to a mosasaur that was larger than or the same size as the largest in the state museum. Starnes noted that it could be the largest ever found in the state.
“It's probably the biggest,” Starnes said. “The lumbar vertebra we found is a good indicator of the relative size of the animal. It's the largest vertebra I've ever encountered.”
M. hoffmanni was an apex predator that hunted its prey with large jaws and cone-shaped teeth. Large mosasaurs likely ate whatever they could catch, including fish, sharks, seabirds, and even other mosasaurs—researchers have found mosasaur remains in the fossilized stomachs of other mosasaurs. The huge mosasaur that left this vertebra probably had plenty of food in what is now Mississippi, which was a very different ecosystem by the end of the Cretaceous.
“At the time, the Mississippi was completely covered by a warm, shallow tropical sea that was teeming with life, including a wide variety of sharks, fish, sea lizards and ammonites,” Starnes said. “Pterosaurs and even some birds flew overhead, while a variety of herbivorous and carnivorous dinosaurs of varying sizes and species roamed the shorelines and forests along the coastal estuaries.”
Sourse: www.livescience.com
