Stratigraphic chart of the lower Permian (partial)
Content updated October 16, 2005
OPHIACODON
Synapsida-Eupelycosauria-Ophiacodontidae
Above: picture of an Ophiacodon dorsal rib showing the sheet of bone between the tubercular and the capitular portions of the head. From Ryan Sandstone, Wellington Formation, near Waurika - Jefferson Co. Oklahoma. Lower Permian.