Sphenacodontia

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Sphenacodontia
Temporal range: Late
Ma
3D restoration of
sphenacodontid
Restoration of a pair of
therocephalian therapsid
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Sphenacomorpha
Clade: Sphenacodontia
Romer & Price, 1940
Subgroups

Sphenacodontia is a

Upper Carboniferous) epoch. From the end of the Carboniferous to the end of the Permian
, most of them remained large, with only some secondarily becoming small in size.

transitional evolutionary series from early pelycosaurs to ancestral therapsids (which in turn were the ancestors of more advanced forms and finally the mammals
). One might say that the sphenacodontians are proto-therapsids (even though there is almost a 30-million-years gap between the separation of the ancestors of therapsids from other sphenacodontians and the first appearance of therapsids in the fossil record).

Characteristics

The

caniniform) teeth; and the premaxillary
teeth being set in deep sockets. All other (sister group and more primitive) synapsid clades have teeth that are set in shallow sockets.

Classification

Pantelosaurus, from the Early Permian
Secodontosaurus, Early Permian

The following taxonomy follows Fröbisch et al. (2011), Benson (2012) and Spinder (2016) unless otherwise noted.[3][4][5]

Class Synapsida

Phylogeny

Sphenacodontia in a cladogram after Fröbisch et al., 2011:[5]

Edaphosauridae

Sphenacodontia

Haptodus garnettensis

Palaeohatteria longicaudata

Pantelosaurus saxonicus

Ianthodon schultzei

Cutleria wilmarthi

Sphenacodontoidea

Therapsida

Sphenacodontidae

Secodontosaurus obtusidens

Cryptovenator hirschbergeri

See also

References

  1. ^
    S2CID 202192911
    . Retrieved 8 October 2019.
  2. ^ a b Spindler, F.; Scott, Diane; Reisz, Robert (October 2014). "New information on the cranial and postcranial anatomy of the early synapsid Ianthodon schultzei (Sphenacomorpha: Sphenacodontia), and its evolutionary significance". Fossil Record. 18: 17–30.
  3. ^ a b Spindler, F. 2016. Morphological description and taxonomic status of Palaeohatteria and Pantelosaurus (Synapsida: Sphenacodontia). Freiberger Forschungshefte C550(23): 1–57. https://www.researchgate.net/publication/321129043_Morphological_description_and_taxonomic_status_of_Palaeohatteria_and_Pantelosaurus_Synapsida_Sphenacodontia
  4. ^
    S2CID 84706899
    .
  5. ^
    doi:10.4202/app.2010.0039
    .
  6. S2CID 214247325
    .

External links
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