New materials of Dimetrodon teutonis (Synapsida: Sphenacodontidae) from the Lower Permian of Germany

Abstract

Additional specimens of the sphenacodontid synapsid Dimetrodon teutonis, including a maxilla, dorsal vertebrae, scapulocoracoids, a humerus, and partial, articulated hindlimbs that consist of the epipodials, tarsi, and incomplete digits, not only expand significantly its known anatomy, but also confirm its recognition as a new species of Dimitrodon. The new materials, like the holotype, are from the Lower Permian Tambach Formation, lowermost formation of the Upper Rotliegend Group or Series, of the Bromacker quarry locality in the midregion of the Thuringian Forest near Gotha, central Germany, and represent the only record of the genus outside of North America. The original estimated weight of 14 kg for the holotype of D. teutonis, calculated on the basis of centra size, is revised to 24 kg for the larger, more fully mature, newly discovered specimens. This is still significantly less than the calculated maximum of nearly 37 kg for the smallest, previously recognized species, D. natalis. Linear measurements of appendicular elements also indicate a substantial size difference between the two species.