The Waggoner Ranch Formation in northern Texas preserves a significant fossil record from the Permian Period, spanning the Artinskian to Kungurian stages of the early to middle Permian. It has yielded fossils of several kinds of early tetrapods, including synapsids, temnospondyls, reptiles, and amphibians. Identified remains include Diadectes sideropelicus, other Diadectes material, and Diplocaulus. Together, these discoveries make the formation an important part of Texas’s broader Permian record and help illuminate the history of terrestrial vertebrate life before the rise of the dinosaurs.