 Fossils now attributed to Dimetrodon were first studied by American paleontologist Edward Drinker Cope in the 1870s . Cope had obtained the fossils along with those of many other Permian tetrapods ( four @-@ limbed vertebrates ) from several collectors who had been exploring a group of rocks in Texas called the Red Beds . Among these collectors were Swiss naturalist Jacob Boll , Texas geologist W. F. Cummins , and amateur paleontologist Charles Hazelius Sternberg . Most of Cope 's specimens went to the American Museum of Natural History or to the University of Chicago 's Walker Museum ( most of the Walker fossil collection is now housed in the Field Museum of Natural History ) . 
