Pristerognathus
| Pristerognathus | ||||||||||||
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Pristerognathus |
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| Temporal occurrence | ||||||||||||
| Wuchiapingium to Changhsingium ( Oberperm ) | ||||||||||||
| 258 to 251 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Pristerognathus | ||||||||||||
| Seeley , 1895 | ||||||||||||
Pristerognathus was a carnivorous synapsid terrestrial vertebrate from the Theriodontia family, the ancestors of mammals . He lived in Upper Perm about 255 million years ago and was first described in 1895 by Harry Govier Seeley using a piece of skull that he found in the Karoo in South Africa. After pristerognathus was pristerognathus -Assemblage zone, one of the sedimentary layers of the Beaufort group named.
features
The skull of Pristerognathus baini described by Robert Broom in 1904 had a length of more than 30 centimeters (measured on the underside from the occiput to the end of the muzzle ) and a width of 15 centimeters at the widest point between the temples . The head was built relatively low. The synapside skull window was larger than the eye socket and reached 30% of the skull length. 75 to 80% of the lower jaw was formed by the dental. The mouth was covered with simple, conical teeth, long canine teeth sat in the upper jaw. Overall, Pristerognathus was up to 2 m long.
Like the later mammals, Pristerognathus did not grow larger continuously, but grew very quickly as a young animal and then stopped growing in the early adult stage.
species
Three types of Pristerognathus have been described:
- Pristerognathus baini Broom , 1904
- Pristerognathus platyrhinus
- Pristerognathus polyodon Seeley , 1895
Systematics
The skull fragment of Pristerognathus polyodon found by Harry Govier Seeley himself in 1889 and described in 1895 indicates an even larger animal than Pristerognathus baini . The type specimen of P. polyodon , which is now kept in the British Museum , is a weathered piece of the skull, from which six upper and three lower incisors were preserved, but which does not allow precise statements about the number of molars . This is why Pristerognathus polyodon has often been referred to as the nomen dubium . According to some scientists, including Sidney Henry Haughton , the description was based on insufficient material that could not be clearly assigned to a particular taxon. However, other researchers have considered Pristerognathus polyodon and Pristerognathus baini to be the same species.
swell
literature
- Douglas Palmer: The Great Atlas of Prehistory . Ferderking & Thaler, 1999 ISBN 3-89405-438-7
Individual evidence
- ^ Gregory J. Retallack et al .: Middle-Late Permian mass extinction on land. Geological Society of America Bulletin, 118, 11/12; P. 1398–1411 November / December 2006 doi : 10.1130 / B26011.1 ( Complete PDF ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice . , engl.)
- ^ Robert Broom: On Two New Therocephalian Reptiles (Glanosuchus macrops and Pristerognathus baini). Transactions of the South African Philosophical Society, 15, pp. 85-88, 1904
- ^ Clifford A. Cuffey: Mammal-Like Reptiles. online ( Memento of the original dated February 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Thomas S. Kemp: The Origin and Evolution of Mammals. Oxford University Press, Oxford 2005, page 55 ISBN 0198507615
- ^ Sanghamitra Ray et al .: Bone Histology and Growth Patterns of Some Nonmammalian Therapsids. Journal of Vertebrate Paleontology, 24, 3, pp. 634-648, 2004 doi : 10.1671 / 0272-4634 (2004) 024 [0634: BHAGPO] 2.0.CO; 2
- ^ Pristerognathus in the Paleobiology Database (accessed May 7, 2010)
