Stratigraphic chart of the lower Permian (partial)
Content updated October 16, 2005
DIMETRODON
Synapsida-Eupelycosauria-Sphenacodontidae
Above: pictures of a sphenacodontid partial maxilla (probably of a Dimetrodon) in medial and lateral view . From Ryan Sandstone, Wellington Formation, near Waurika, Jefferson Co. Oklahoma.