Sphenacodon (meaning "wedge point tooth") is an extinct genus of
synapsid that lived from about 300 to about 280 million years ago (Ma) during the Late
Carboniferous and Early
Permian periods. Like the closely related
Dimetrodon,
Sphenacodon was a carnivorous member of the
Eupelycosauria family
Sphenacodontidae. However,
Sphenacodon had a low crest along its back, formed from blade-like bones on its vertebrae (neural spines) instead of the tall dorsal sail found in
Dimetrodon. Fossils of
Sphenacodon are known from
New Mexico and the
Utah-
Arizona border region in
North America.