Sphenacodontia
| Sphenacodonts Temporal range: Late Pennsylvanian-Recent,
| |
|---|---|
| |
| 3D restoration of Dimetrodon grandis | |
| File:Inostrancevia preys on a juvenile Scutosaurus.png | |
| Restoration of the gorgonopsid theraspid Inostrancevia feasting on the carcass of a young Scutosaurus (a pareiasaurid parareptile) | |
Scientific classification 
| |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Synapsida |
| Clade: | Sphenacomorpha |
| Clade: | Sphenacodontia Romer & Price, 1940 |
| Subgroups | |
| |
Sphenacodontia is a stem-based clade of derived synapsids. It was defined by Amson and Laurin (2011) as "the largest clade that includes Haptodus baylei, Haptodus garnettensis and Sphenacodon ferox, but not Edaphosaurus pogonias".[2] They first appear during the Late Pennsylvanian (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.
Basal Sphenacodontia constitute a 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 defining characteristics include a thickening of the maxilla visible on its internal surface, above the large front (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
The following taxonomy follows Fröbisch et al. (2011), Benson (2012) and Spinder (2016) unless otherwise noted.[1][2][3]
Class Synapsida
- Eupelycosauria
- Sphenacodontia
See also
References
- ^ 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
- ^ a b Benson, R.J. (2012). "Interrelationships of basal synapsids: cranial and postcranial morphological partitions suggest different topologies". Journal of Systematic Palaeontology. 10 (4): 601–624. doi:10.1080/14772019.2011.631042. S2CID 84706899.
- ^ Jörg Fröbisch, Rainer R. Schoch, Johannes Müller, Thomas Schindler and Dieter Schweiss (2011). "A new basal sphenacodontid synapsid from the Late Carboniferous of the Saar-Nahe Basin, Germany" (PDF). Acta Palaeontologica Polonica. 56 (1): 113–120. doi:10.4202/app.2010.0039.
{{cite journal}}: CS1 maint: uses authors parameter (link) - ^ Spindler, Frederik (2020). "The skull of Tetraceratops insignis (Synapsida, Sphenacodontia)". Palaeovertebrata. 43 (1): e1. doi:10.18563/pv.43.1.e1. S2CID 214247325.
- Laurin, M. and Reisz, R. R., 1997, Autapomorphies of the main clades of synapsids - Tree of Life Web Project
External links
| |||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||||
.jpg)
Error: "Q930410" is not a valid Wikidata entity ID.
- CS1 maint: uses authors parameter
- Articles with short description
- Articles with 'species' microformats
- Taxonbars desynced from Wikidata
- Taxonbar pages requiring a Wikidata item
- Taxonbars with invalid from parameters
- Taxonbars without secondary Wikidata taxon IDs
- Sphenacodonts
- Extant Pennsylvanian first appearances
- Taxa named by Llewellyn Ivor Price
- Taxa named by Alfred Romer