Despite the Dimetrodon looking like a dinosaur, the Dimetrodon is actually a mammalian like reptile. It’s most striking feature is the sail on its back, which is made from spinal nerves coming from vertebrae. This sail’s function was thought to be for thermoregulation as proposed by Alfred Romer and Llewellyn Ivor Price by 1940. However, recent studies have disputed this after looking at models and related species. Currently, the sail is thought to be for sexual selection.Dimetrodon