Tylosaurus proriger vertebra from the Campanian-Cretaceous period, found in the Ozan Marl Formation, Fannin County, Texas. This vertebra is part of a partial skeleton collected by Don Fagerstrom in the late 1990s to early 2000s. The specimen had a skull measuring 4 feet in length, making this a truly impressive mosasaur. Tylosaurus proriger was one of the largest marine predators of the Late Cretaceous, and this vertebra represents a piece of that fascinating history.