Dimetrodon sp.
Permian
Clearfork Shale
Frederick
Oklahoma, USA.

Fossil tooth from Dimetrodon sp., a large sail backed synapsid predator that lived during the Permian Period. Despite often being mistaken for a dinosaur, Dimetrodon predates dinosaurs by tens of millions of years and is more closely related to the lineage that eventually led to mammals.
27mm tooth with serrations