 In the first few decades of the twentieth century , American paleontologist E. C. Case authored many studies on Dimetrodon and described several new species . He received funding from the Carnegie Institution for his study of many Dimetrodon specimens in the collections of the American Museum of Natural History and several other museums . Many of these fossils had been collected by Cope but had not been thoroughly described , as Cope was known for erecting new species on the basis of only a few bone fragments . 
