Early Permian

Red Beds Facies

Archer County, TX, USA

55mm jaw section with 6 teeth. Extremely rare.

Synapsid, Pelycosaur

Dimetrodon is the famous sailback vertebrate of the American West.  There are actually several species ranging in size from about 5 to 13 feet in length.  The larger ones were the top land predators of their day.

Dimetrodon was not technically a reptile though it would have looked like one.  It was an early member of the synapsids, a reptile-like group that led to mammals.

Many collectors have a tooth or vertebra or claw of Dimetrodon but not that many have a jaw section with teeth.