It is a marine reptile that lived during the Late Cretaceous Senonian period approximately 95 million years ago. Belonging to the Stegosauridae family of the plesiosauriformes order, it is a long necked plesiosaur with a genus name in Greek meaning 'ruler of the ocean'. Fossils are mainly found in North America, especially in the Graneros shale layers of the Midwest United States. The body length can reach 12 meters, with a very long neck and 65 vertebrae, about 6 meters in length, accounting for half of the body length. The length of the skull is 47 centimeters, the length of the teeth can reach 5 centimeters, and the length of the fin like limbs is approximately between 1.5 and 2 meters.