Ladonia, Texas 001.JPG

The bone was found in the Sulphur River in Northeast Texas, USA. Mosasaurs are an extinct group of marine reptiles, and depending on the particular species, varied from about 10 feet (3 meters) in length, up to a maximum of 57 feet (17.5 meters). These reptiles lived during the latter part of the Cretaceous period of the Mesozoic Era and spent their entire lives at sea. Mosasaurs were carnivores eating fish, sea urchins, turtles, and shellfish. Although they lived at the same time as many of the dinosaurs, and like the dinosaurs became extinct during the Cretaceous-Tertiary mass extinction, Mosasaurs were not dinosaurs, but lepidosaurs (the same taxonomic group which includes lizards, snakes and sphenodonts such as the tuatara).