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]

Quick Facts Scientific classification, Clades ...
Sphenacodontoids
Temporal range: Late Carboniferous-Recent, 300–0 Ma
Thumb
Fossilized skull of two sphenacodontoids: Clelandina (Therapsida, Gorgonopsidae) and a Dimetrodon (Sphenacodontidae).
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Sphenacomorpha
Clade: Sphenacodontia
Clade: Pantherapsida
Clade: Sphenacodontoidea
Marsh, 1878
Clades
Close

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

Phylogeny

Sphenacodontoidea in a cladogram modified from Huttenlocker et al. (2021):[1]

Synapsida

See also

References

Further reading

Wikiwand in your browser!

Seamless Wikipedia browsing. On steroids.

Every time you click a link to Wikipedia, Wiktionary or Wikiquote in your browser's search results, it will show the modern Wikiwand interface.

Wikiwand extension is a five stars, simple, with minimum permission required to keep your browsing private, safe and transparent.