Pelycosaur

noun

1. Any of various extinct, chiefly carnivorous synapsids of the Carboniferous and Permian Periods, including the dimetrodon and other species with saillike structures along the back.
2. A large primitive reptile having a tall spinal sail; of the Permian or late Paleozoic in Europe and North America.
3. large primitive reptile having a tall spinal sail; of the Permian or late Paleozoic in Europe and North America