 The tail of Dimetrodon makes up a large portion of its total body length and includes around 50 caudal vertebrae . Tails were missing or incomplete in the first described skeletons of Dimetrodon ; the only caudal vertebrae known were the eleven closest to the hip . Since these first few caudal vertebrae narrow rapidly as they progress farther from the hip , many paleontologists in the late nineteenth and early twentieth centuries thought that Dimetrodon had a very short tail . It was not until 1927 that a largely complete tail of Dimetrodon was described . 
