Carboniferous synapsids

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.

Archaeothyris is an extinct genus of ophiacodontid synapsid that lived during the Late Carboniferous and is known from Nova Scotia. Dated to 306 million years ago, Archaeothyris, along with a more poorly known synapsid called Echinerpeton, are the oldest undisputed synapsids known. The name means ancient window (Greek), and refers to the opening in the skull, the temporal fenestra, which indicates this is an early synapsid. Protoclepsydrops also from Nova Scotia is slightly older but is known by very fragmentary materials. thumb|Life restoration of Archaeothyris florensis

Ophiacodon (meaning "snake tooth") is an extinct genus of synapsid belonging to the family Ophiacodontidae that lived from the Late Carboniferous to the Early Permian in North America and Europe. The genus was named along with its type species O. mirus by paleontologist Othniel Charles Marsh in 1878 and currently includes five other species. As an ophiacodontid, Ophiacodon is one of the most basal synapsids and is close to the evolutionary line leading to mammals.

270px|thumbnail|left|Restoration

left|thumb|159x159px|Life restoration Archaeovenator is an extinct genus of Late Carboniferous varanopid synapsids known from Greenwood County, Kansas of the United States. It was first named by Robert R. Reisz and David W. Dilkes in 2003 and the type species is Archaeovenator hamiltonensis. Archaeovenator hamiltonensis is known from the holotype KUVP 12483, a three-dimensionally preserved, nearly complete and articulated skeleton, including the skull, with limbs and girdles slightly separated from postcranial skeleton. It was collected in the Hamilton Quarry, from the Calhouns Shale Form

Protoclepsydrops is an extinct genus of early synapsids, found in Joggins, Nova Scotia. The name means 'first Clepsydrops', and refers to it being the predecessor of the other early synapsid Clepsydrops.

Neosaurus ('New Lizard') is an extinct genus of pelycosaur-grade synapsids from the Late Carboniferous-Early Permian of the Jura region of France. It is known only from a partial maxilla or upper jaw bone and an associated impression of the bone. The teardrop shape of the teeth in the jaw indicate that Neosaurus belongs to the family Sphenacodontidae, which includes the better-known Dimetrodon from the Southwestern United States. The maxilla was first attributed to an early diapsid reptile in 1857, and later a crocodylomorph in 1869, before finally being identified as a sphenacodont synapsid i

Clepsydrops is an extinct genus of primitive synapsids from the early Late Carboniferous that was related to Archaeothyris. The name means 'hour-glass appearance' (Greek klepsydra = "hourglass" + Greek ops = "eye, face, appearance").

Datheosaurus ("Dathe's lizard") is an extinct genus of caseasaur. It was at least in length. It lived during the Latest Carboniferous to Early Permian in Poland. It was named for Ernst Dathe (1845–1917), the German geologist who first announced the fossil find.

Ianthasaurus is an extinct genus of small edaphosaurids from the Late Carboniferous.

Stereorhachis is an extinct genus of non-mammalian synapsids from the Late Carboniferous of France. thumb|left|Restoration

Eocasea is an extinct genus of caseid synapsids from the Late Pennsylvanian of Kansas. It is known from a single type species, Eocasea martini.

Macromerion (Macro- is Greek/Latin for "large") is an extinct genus of non-mammalian synapsids, specifically Pelycosaurs, in the family Sphenacodontidae from Late Carboniferous deposits in the Czech Republic. It was named as a species of Labyrinthodon in 1875 and as its own genus in 1879.