Cynognathus
| Cynognathus crateronotus | ||||||||||||
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Fossilized skull of a Cynognathus crateronotus |
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| Temporal occurrence | ||||||||||||
| Lower to Middle Triassic | ||||||||||||
| 245 to 242 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Cynognathus crateronotus | ||||||||||||
| Seeley , 1895 |
Cynognathus ("dog's jaw") is a genus of extinct therapsids (formerly known as " mammal-like reptiles"). The animals of this genus livedon Gondwana between 245 and 237 million years ago during the Lower and Middle Triassic . The only species of Cynognathus described is Cynognathus crateronotus .
features
Cynognathus was a large carnivore with a massive body. With a skull length of 30 to 40 cm, it was one of the largest predators of the Triassic . The strong occipital region suggests strong neck muscles. The muzzle was long, behind the large canine teeth it narrowed a little. The molars were laterally flattened and roughly serrated. There was no precise occlusion between the teeth of the upper and lower jaw .
The dental , the only bone of the lower jaw in mammals , was already very much enlarged in relation to the other lower jaw bones of the original synapsids . The other lower jaw bones ( Articulare , Praearticulare, Surangulare and Angulare) formed a rod-shaped element that was embedded in a groove on the inside of the dentary. The temporomandibular joint was still formed by quadratum and articulare.
The synapside skull window was small. Its limiting bones were very strong compared to thrinaxodon , so they formed a broad base for strong jaw muscles.
Finds
Cynognathus fossils have been found in South Africa , especially the Karoo , in Lesotho , Argentina , China and the Antarctic .
literature
- Thomas S. Kemp: The Origin & Evolution of Mammals. Oxford University Press, Oxford 2005. ISBN 0-19-850761-5 .
- Robert L. Carroll : Paleontology and Evolution of the Vertebrates. Thieme, Stuttgart et al. 1993, ISBN 3-13-774401-6 .
