Sphenacodontoidea
| Sphenacodontoids Temporal range: Late Carboniferous-Recent, 300–0 Ma |
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| Ctenospondylus | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Sphenacodontia |
| Clade: | Sphenacodontoidea |
| Clades | |
Sphenacodontoidea is a node-based clade that defined to include the most recent common ancestor of the Sphenacodontidae and the Therapsida and their descendants (including mammals). They are defined according to a number of specialised characteristics concerning proportions of the bones of the skull and the teeth.
The Sphenacodontoidea evolved from earlier Sphenacodontia such as Haptodus via a number of transitional stages of small, unspecialised pelycosaurs.
The following taxonomy follows Fröbisch et al. (2011) and Benson (2012) unless otherwise noted.
Class Synapsida
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