| Gorgonopsia Temporal range: Middle - Late Permian |
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|---|---|
| Arctognathus | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Synapsida |
| Order: | Therapsida |
| Suborder: | †Gorgonopsia Seeley, 1895 |
| Family: | †Gorgonopsidae Lydekker, 1890 |
| Subfamilies | |
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Gorgonopsinae |
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Gorgonopsia ("Gorgon face") is a suborder of therapsid synapsids. Their name is a reference to the Gorgons of Greek mythology. Like other therapsids, gorgonopsians were at one time called "mammal-like reptiles". Their mammalian specializations include differentiated (heterodont) tooth shape, a fully developed temporal fenestra, pillar-like rear legs, a vaulted palate that may have facilitated breathing while holding the prey, and incipiently developed ear bones.[1] Gorgonopsians are a part of a group of therapsids called theriodonts, which includes mammals.[2] They were among the largest carnivores of the late Permian. The largest known, Inostrancevia, was the size of a large bear with a 45 cm long skull, and 12-cm long saber-like teeth (clearly an adaptation to being a carnivore). It is unknown whether they had fur, scales, or naked skin.
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Gorgonopsids (Gorgonopsia) are theriodonts, a major group of therapsids that included the ancestors of mammals. Gorgonopsians evolved in the Middle Permian, from a reptile-like therapsid that also lived in that period. The early gorgonopsians were small, being no larger than a dog. The extinction of dinocephalians (who dominated the Middle Permian world) led the gorgonopsians to be the dominant predators of the Late Permian. Some had approached the size of a rhinoceros, such as Inostrancevia, the largest of the gorgonopsians. A nearly complete fossil of Rubidgea has been found in South Africa.[3][4] The Gorgonopsia became extinct at the end of the Permian period, being the only theriodont line to be terminated by this mass extinction.
The gorgonopsians are one of the three groups of theriodonts (the other two were the therocephalians, and the cynodonts). Theriodonts are related to the herbivorous Anomodontia. Gorgonopsia includes three subfamilies, the Gorgonopsinae, Rubidgeinae and Inostranceviinae, plus a larger number of genera that have not been placed in any of these groups. A total of 25 genera and 41 species, with the genera described most completely being Dinogorgon, Inostrancevia and Rubidgea.
The most comprehensive review of the group is by Sigogneau-Russell, 1989. However, there has not been a detailed cladistic assessment of the phylogeny of these animals.