Gorgonops
 | This article includes a list ofgeneral references,butit lacks sufficient correspondinginline citations.(September 2022) |
| Gorgonops Temporal range:Lopingian(Wuchiapingian),
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| G. whaitsiskull (specimen 5537) | |
Scientific classification
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Synapsida |
| Clade: | Therapsida |
| Clade: | †Gorgonopsia |
| Family: | †Gorgonopsidae |
| Subfamily: | †Gorgonopsinae |
| Genus: | †Gorgonops Owen, 1876 |
| Type species | |
| †Gorgonops torvus Owen, 1876
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| Species | |
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Gorgonops(fromGreek:Γοργών'Gorgon' andὤψ'eye, face', literally 'Gorgoneye' or 'Gorgon face') is anextinctgenusofgorgonopsiantherapsid,of which it is thetype genus.Gorgonopslived during theLate Permian(Wuchiapingian), about 260–254 million years ago in what is nowSouth Africa.
History of discovery
[edit]Theholotypeof thetype species,Gorgonops torvus,was one of the firsttherapsidsdiscovered. It was described byRichard Owen,who also coined the name "Dinosauria" on the basis of the first knowndinosaurfossils.[1]G. torvuswas also used as the type for thefamilyGorgonopsidae, which was described byRichard Lydekkerin 1890.[2]Five years later, in 1895,Harry Govier Seeleyused this genus to establish the larger clade of Gorgonopsia.[3]In later years, a large number of furtherspeciesandgenerawere designated, though many of these were later determined to be synonyms.
Gorgonopsis known from theTropidostomaand most of theCistecephalusAssemblage Zones.[4]
Description
[edit]
Gorgonopswas a medium-sized gorgonopsian, with a skull length of 22–35 centimetres (8.7–13.8 in), depending on the species. They ranged from 1.2–2 metres (3.9–6.6 ft) long from nose to tail.Gorgonopswould have been one of the key predators across southern Africa during theLate Permian.Because thecanineswere so large, they would have had little trouble in penetrating the tough hides of some of the herbivores of the time, particularlypareiasaurssuch asPareiasaurus.Aside from the teeth, one of the key predatory advantages thatGorgonopshad over prey was itssemi-erect gait,compared to the sprawling gait exhibited by most prey animals of the time. Aside from allowing for more energy efficient locomotion, this allowedGorgonopsto travel at relatively high speeds.
Skull
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Relative to body size,Gorgonopshad a deep skull with a triangular profile when viewed from above. Perhaps the most distinctive features were two enlarged canine teeth that were so big (12 centimetres (4.7 in) long) they almost protruded beyond the lower jaw. To help protect these teeth, the lower jaws grew in such a shape so that the anterior (front) portion was thicker than the posterior (rear) portion. This form would have protected the enlarged canine teeth from accidental damage, and was similar in bone function to the flanges of bone ofsabre-toothed catsin theCenozoic.
Species
[edit]Gorgonops torvus(Owen, 1876)
[edit]
The type species. The holotype is an incomplete and flattened skull, allegedly found at Mildenhall's farm (Xlu Xlu), on the Queen's Road south ofFort Beaufort,in the Eastern Cape of South Africa. A number of other specimens have been found since, all from theTropidostomaand/orCistecephalusAssemblage Zone(s). This was a medium-sized therapsid, with a skull about 22 cm in length. It is distinguished from other species by a longer snout, and other details of the bones of the skull. Originally considered rather simple, it is actually (according to Sigogneau-Russell) a rather specialised member of the group.[5]
Gorgonops whaitsi(Broom, 1912)
[edit]
Larger thanG. torvus,with the rear of the skull wider, and other details of proportion. Originally the type species ofScymnognathus.Despite being known from a large number of specimens from theKarooBasin, Beaufort West (Tropidostoma/CistecephalusAssemblage Zone), the species remains poorly known. Watson andRomerplacedGorgonopsandScymnognathusin two different families, while Sigogneau-Russell placed the two species in the same genus, and considersG. whaitsia more primitive (less derived) form.[5] Synonyms:Scymnognathus whaitsi(Broom, 1912)
Gorgonops longifrons(Haughton, 1915)
[edit]A large specimen known from an incomplete and flattened skull about 35 centimetres (14 in) long. Orbit larger and snout longer thanG. whaitsi,from which it may have descended.Beaufort West,Tropidostoma/CistecephalusAssemblage Zone. Synonyms:Gorgonognathus longifrons(Haughton, 1915)
Gorgonops? eupachygnathus(Watson, 1921)
[edit]A flattened, incomplete, medium-sized skull, probably a juvenile of eitherG. torvusorG. whaitsi Synonyms:Leptotrachelus eupachygnathus(Watson, 1921);Leptotracheliscops eupachygnathus(Watson, 1921)
Gorgonops? dixeyi(Haughton, 1926)
[edit]A large, incomplete and flattened skull, fromChiweta Beds,Nyassaland.Placement uncertain. Probably LowCistecephalusAssemblage Zone equivalent (= middle of theWuchiapingianStage).[6] Synonyms:Chiwetasaurus dixeyi(Haughton, 1926)
Gorgonops? kaiseri(Broili & Schroeder, 1934)
[edit]A large (about 35 centimetres (14 in) long), incomplete skull, with a high snout and narrower in the rear than other species, from the "HighTapinocephaluszone "(earlier than the other species, most probablyPristerognathusAssemblage Zone) Synonyms:Pachyrhinos kaiseri(Broili & Schroeder, 1934)
Classification
[edit]Below is acladogramfrom Gebauer's 2007 phylogenetic analysis.[7]
See also
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References
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- ^Owen, R.(1986).Descriptive and illustrated catalogue of the fossil Reptilia of South Africa in the collection of the British museum.British Museum (Natural History). pp. 27–29.
- ^Lydekker, R.(1890).Catalogue of the fossil Reptilia and Amphibia in the British Museum (Natural history) Part IV.British Museum (Natural History). p. 111.
- ^Seeley, H. G.(1895)."Researches on the structure, organization, and classification of the fossil reptilia.—Part IX. section 1. On the Therosuchia".Annals and Magazine of Natural History.13(6): 375.doi:10.1080/00222939408677718.
- ^Smith, R.H.M.; Keyser, A.W. (1995). "Biostratigraphy of the Tropidostoma Assemblage Zone".Geological Survey of South Africa.1:18–22.
- ^abSigogneau-Russell, D. (1989). "Theriodontia I". In H.-D., Sues (ed.).Encyclopedia of Paleoherpetology.Gustav-Fischer-Verlag.ISBN978-3-89937-033-1.
- ^Jacobs, L.L.; Winkler, D.A.; Newman, K.D.; Gomani, E.M.; Deino, A. (2005)."Therapsids from the Permian Chiweta Beds and the age of the Karoo Supergroup in Malawi".Palaeontologia Electronia.8(1): 28A.
- ^Gebauer, E.V.I. (2007).Phylogeny and evolution of the Gorgonopsia with a special reference to the skull and skeleton of GPIT/RE/7113 ('Aelurognathus?' parringtoni)(PDF)(Ph.D. thesis). Tübingen: Eberhard-Karls Universität Tübingen. pp. 1–316.
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