 However , the first description of a Dimetrodon fossil came a year earlier , when Cope named the species Clepsydrops limbatus from the Red Beds of Texas . ( The name Clepsydrops was first coined by Cope in 1875 for <unk> remains from Vermilion County , Illinois , and was later employed for many <unk> specimens from Texas ; many new species of sphenacodontids from Texas were assigned to either Clepsydrops or Dimetrodon in the late nineteenth and early twentieth centuries . ) C. limbatus was reclassified as a species of Dimetrodon in 1940 , meaning that Cope 's 1877 paper was the first record of Dimetrodon . 
