Cynognathus
Cynognathus | |
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Fossil skull of Cynognathus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Synapsida |
Clade: | Therapsida
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Clade: | Cynodontia
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Clade: | †Cynognathia |
Family: | †Cynognathidae Seeley, 1895 |
Genus: | †Cynognathus Seeley, 1895 |
Type species | |
†Cynognathus crateronotus Seeley, 1895
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Cynognathus is an extinct
Description
Cynognathus was a heavily built animal, and measured around 1.2 metres (3 ft 11 in)[1] in snout-to-vent body length and up to 2 metres (6 ft 7 in) in total length.[2] It had a particularly large head, up to 40 centimetres (1 ft) in length, with wide jaws and sharp teeth. Its hindlimbs were placed directly beneath the body, but the forelimbs sprawled outwards in a more reptilian fashion.[3] This form of double (erect/sprawling) gait is also found in some primitive mammals alive today.[4]
Possible
Discovery and naming
During 1888 and 1889, the British paleontologist
Fossil material probably belonging to the genus has been given several different names over the years. Generic synonyms include Cynidiognathus, Cynogomphius, Karoomys, Lycaenognathus, Lycochampsa and Lycognathus. Opinions vary as to whether all remains belong to the same species. The genus Karoomys is known only from a tiny juvenile. Species-level synonyms of Cynognathus crateronotus include Cynidiognathus broomi, Cynidiognathus longiceps, Cynidiognathus merenskyi, Cynognathus berryi, Cynognathus minor, Cynognathus platyceps, Cynogomphius berryi, Karoomys browni, Lycaenognathus platyceps, Lycochampsa ferox, Lycognathus ferox, and Nythosaurus browni.
Distribution
Fossils have been found in the Karoo, the Puesto Viejo Formation, Fremouw Formation, in South Africa/Lesotho, Argentina and Antarctica.
Cynognathus lived between the Anisian and the Ladinian (Middle Triassic).[8]
This genus forms a Cynognathus Assemblage Zone in the Beaufort Group of the Karoo Supergroup.[9][10][11]
Classification
Seeley in 1894/1895 placed Cynognathus in a separate family Cynognathidae, within the Cynodontia. Cynognathus is presently the only recognized member of the family Cynognathidae. Later a clade Cynognathia was named after the genus, within the Eucynodontia.
Cynognathus crateronotus in a cladogram after Stefanello et al. (2023):[12]
Cynognathia |
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Paleobiology
The
The possible lack of belly ribs, in the stomach region, suggests the presence of an efficient
See also
- Cynognathia
- Evolution of mammals
- Paleoworld- Featured in the episode "Tail Of A Sail".
- Thrinaxodon
- Tritylodontids
References
- ^ Jones & Bartlett Learning, Strickberger's Evolution, 2008
- ISSN 0031-0182.
- ISBN 978-1-84028-152-1.
- .
- ^ Wynd, B.M.; Peecock, B.R.; Whitney, M.R. & Sidor, C.A. 2018. "The first occurrence of Cynognathus crateronotus (Cynodontia: Cynognathia) in Tanzania and Zambia, with implications for the age and biostratigraphic correlation of Triassic strata in southern Pangea". pp. 228–239 in: C.A. Sidor and S.J. Nesbitt (eds.), Vertebrate and Climatic Evolution in the Triassic Rift Basins of Tanzania and Zambia. Society of Vertebrate Paleontology Memoir 17. Journal of Vertebrate Paleontology 37(6, Supplement)
- ^ H.G. Seeley. 1894. "Researches on the Structure, Organization, and Classification of the Fossil Reptilia. Part IX, Section 5. Abstract. On New Cynodontia". Philosophical Transactions of the Royal Society of London B 56: 291-294
- ^ H.G. Seeley. 1895. "Researches on the Structure, Organization, and Classification of the Fossil Reptilia. Part IX, Section 5. On the Skeleton in New Cynodontia from the Karroo Rocks". Philosophical Transactions of the Royal Society of London B 186: 59-148
- ISBN 9781118786352.
- ^ A threefold subdivision of the Cynognathus Assemblage Zone (Beaufort Group, South-Africa) and its paleogeographic implications. PJ Hancox, MA Shishkin, BS Rubidge, JW Kitching, South African Journal of Science, 1995
- ^ Vertebrate burrow complexes from the Early Triassic Cynognathus Zone (Driekoppen Formation, Beaufort Group) of the Karoo Basin, South AfricaGH Groenewald, J Welman, JA MacEachern - Palaios, 2001
- ^ Stratigraphic and sedimentological investigation of the contact between the Lystrosaurus and the Cynognathus assemblage zones (Beaufort group: Karoo supergroup). J Neveling - Bulletin of the Council for Geoscience, 2004
- .
Further reading
- Seeley (1895), "Researches on the structure, organization, and classification of the fossil Reptilia. Part IX., Section 5. On the skeleton in new Cynodontia from the Karroo rocks". Phil. Transactions of the Roy. Soc. of London, series B 186, p. 59–148.