Gorgonopsia

Gorgonopsia Temporal range:
Arctognathus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Synapsida
Order:	Therapsida
Suborder:	†Gorgonopsia Seeley, 1895
Family:	†Gorgonopsidae Lydekker, 1890
Subfamilies
Gorgonopsinae Inostranceviinae Rubidgeinae

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, and ear bones. Gorgonopsians are a part of a group of therapsids called theriodonts, which includes mammals. 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.

Evolutionary history

Gorgonopsids (Gorgonopsia) are theriodonts of the therapsid order, to which cynodonts and their descendants, the mammals, belong. 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 complete fossil has been found in South Africa. The Gorgonopsia became extinct at the end of the Permian period, being the only theriodont line to be terminated by this mass extinction.

Classification

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.

Lycaenops

Gorgonops

Arctops

Inostrancevia

• Order Therapsida
• SUBORDER GORGONOPSIA
  • Family Gorgonopsidae
    • Aelurognathus
    • Aelurosaurus
    • Aloposaurus
    • Arctognathus
    • Arctops
    • Broomisaurus
    • Cephalicustroidus
    • Cerdorhinus
    • Clelandina
    • Cyonosaurus
    • Dinogorgon
    • Eoarctops
    • Galesuchus
    • Leontocephalus
    • Lycaenops
    • Paragalerhinus
    • Scylacognathus
    • Sycosaurus
    • Viatkogorgon
    • Subfamily Gorgonopsinae
      • Gorgonops
      • Sauroctonus
      • Scylacops
    • Subfamily Inostranceviinae
      • Inostrancevia
      • Pravoslavleria
    • Subfamily Rubidgeinae
      • Broomicephalus
      • Niuksenitia
      • Prorubidgea
      • Rubidgea

In popular culture

Gorgonopsids have appeared in several television programs animated by the special effects studio Framestore CFC. A gorgonopsid was featured in the third episode of the BBC program Walking With Monsters, and more recently the first and sixth episodes of the ITV series Primeval. Also they appeared on the video game Turok. They represent the ancestors of an advanced if deceased civilisation in alternate timeline Earth, depicted in 9/7/2009 Dresden Codak issue.

References

• Bakker, R.T. (1986), The Dinosaur Heresies, Kensington Publishing Corp.
• Cox, B. and Savage, R.J.G. and Gardiner, B. and Harrison, C. and Palmer, D. (1988) The Marshall illustrated encyclopedia of dinosaurs & prehistoric animals, 2nd Edition, Marshall Publishing
• Fenton, C.L. and Fenton, M.A. (1958) The Fossil Book, Doubleday Publishing
• Hore, P.M. (2005), The Dinosaur Age, Issue #18. National Dinosaur Museum
• Sigogneau-Russell, D., 1989, "Theriodontia I - Phthinosuchia, Biarmosuchia, Eotitanosuchia, Gorgonopsia" Part 17 B I, Encyclopedia of Paleoherpetology, Gustav Fischer Verlag, Stuttgart and New York
• Ward, P.D. (2004), Gorgon, Viking Penguin
• Gebauer (2007), Phylogeny and Evolution of the Gorgonopsia with a Special Reference to the Skull and Skeleton of GPIT/RE/7113 (‘Aelurognathus?’ parringtoni). Ph.D. Dissertation, Tübingen University.

See also

• Therocephalia
• Evolution of mammals