†unranked clade Sphenacodontoidea
Parent taxon: Sphenacodontia according to J. Fröbisch et al. 2011
See also Daly 1973
Sister taxa: Anningiidae, Cutleria, Haptodontinae, Homodontosauridae, Ianthodon, Palaeohatteria, Pantelosaurus, Shashajaia, Tappenosauridae
Subtaxa: Sphenacodontidae
Distribution:
• Permian of Canada (1: Prince Edward Island collection), France (1), Germany (1), the United Kingdom (1), United States (99: New Mexico, Ohio, Oklahoma, Texas, Utah)
• Carboniferous to Permian of Germany (1), United States (3: New Mexico, Utah)
• Carboniferous of the Czech Republic (1), United States (2: Illinois, New Mexico)
Total: 110 collections including 137 occurrences