Sphenacodontoidea
Superfamily of synapsids
From Wikipedia, the free encyclopedia
Sphenacodontoidea is a node-based clade that is defined to include the most recent common ancestor of Sphenacodontidae and Therapsida and its descendants (including mammals).[1] Sphenacodontoids are characterised by a number of synapomorphies concerning proportions of the bones of the skull and the teeth.[2][3]
| Sphenacodontoids Temporal range: Late Carboniferous-Recent, | |
|---|---|
| |
| Fossilized skull of two sphenacodontoids: Clelandina (Therapsida, Gorgonopsidae) and a Dimetrodon (Sphenacodontidae). | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Synapsida |
| Clade: | Sphenacomorpha |
| Clade: | Sphenacodontia |
| Clade: | Pantherapsida |
| Clade: | Sphenacodontoidea Marsh, 1878 |
| Clades | |
The sphenacodontoids evolved from earlier sphenacodonts such as Haptodus and Ianthodon via a number of transitional stages of small, 1-10 kg, faunivore animals.[1] The possible common ancestor of sphenacodontids and therapsids was a carnivorous synapsid that reached moderate or large size and more closely resembled the land-dominant Early Permian sphenacodontids than the small Haptodus.[2] The first predators among Sphenacodontoidea, like Shashajaia, appeared in the tropical western part of Pangea in the Late Carboniferous.[1] Later, in Permian, sphenacodontoids gave rise to the dominant terrestrial carnivores in both sphenacodontid and therapsid groups.[2]
Classification
The following taxonomy follows Fröbisch et al. (2011) and Benson (2012) unless otherwise noted.[4][5]
Class Synapsida
- Sphenacodontoidea
- Family †Sphenacodontidae
- Therapsida
Phylogeny
Sphenacodontoidea in a cladogram modified from Huttenlocker et al. (2021):[1]