Wikipedia
Ctenospondylus, ("comb vertebra") was a pelycosaur that was about 3 meters (10 feet) long. It is known only from the 'Seymouran' Land Vertebrate Faunachron, which is equivalent to the upper part of the Artinskian stage and the lowermost Kungurian stage of the Early Permian. Its fossils were found in the U.S. states of Ohio and Texas. It was a carnivore and preyed upon animals close to its size. Ctenospondylus had a long tail, short back spines, and a very deep yet narrow skull with massive jaws that had sharp teeth. Because of its large size, it was probably the apex predator in its environment, and might have competed with other predators like Dimetrodon for food. A Sphenacodontid, it was a close relative of Dimetrodon. A species has been found in Ohio, along with Dimetrodon, Edaphosaurus, Ophiacodon, and Eryops, according to the latest Fossils of Ohio book.