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C. crateronotus | ||||||||||||||
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Cynognathus was a metre-long predator of the Lower Triassic. It was one of the more mammal-like of the ‘mammal-like reptiles’; a member of a grouping called Eucynodontia.
Cynognathus had a more or less worldwide distribution. Fossils have so far been recovered from South Africa, South America, China and Antarctica. This genus has been given a lot of different names over the years.
Genus: Cynognathus Seeley HG, 1895
'dog jaw'
Aka: Cistecynodon Brink & Kitching, 1953; Cynidiognathus Haughton, 1922; Cynogomphius Broom, 1932; ?Karoomys Broom, 1903b; Lycaenognathus Broom, 1925; Lycochampsa Broom, 1915b; Lycognathus Broom, 1913b; Nythosaurus Broom, 1912a
Remarks: According to the records of the Peabody Museum, Yale University, Richard Owen apparently used the name Nythosaurus in 1876. This usage seems to be unconnected with Cynognathus.
Cynognathus is presently the only recognized member of a family called Cynognathidae. Opinions vary as to whether all remains belong to the same species.
Species: Cynognathus crateronotus Seeley HG, 1895?
Aka: Cistecynodon parvus Brink & Kitching, 1953; Cynidiognathus broomi Haughton, 1922; Cynidiognathus longiceps Haughton, 1922; Cynidiognathus merenskyi Broli & Schröder, 1935b; Cynognathus beeryi Seeley, 1895b; Cynognathus minor Bonaparte, 1967a; Cynognathus platyceps Seeley, 1895b; Cynogomphius berryi Broom, 1932; ?Karoomys browni Broom, 1903b; Lycaenognathus kannemeyerz Broom, 1931; Lycaenognathus platyceps Broom, 1925; Lycochampsa ferox Broom, 1915b; Lycognathus ferox Broom, 1913a; Nythosaurus browni Broom, 1912a
Zoological Nomenclature!: Whilst having 15 names for one Mesozoic creature might be regarded as excessive, it's by no means a record. The dinosaur, Plateosaurus engelhardti, has been named well over 20 times.
Karoomys, Cistecynodon and Nythosaurus are based on tiny juveniles, whilst Lycognathus cucullatus seems to be a snake from the Mediterranean Balearic Islands, although confirmation is elusive.
Place: Karoo & Puesto Viejo Formation & Fremouw Formation &
Country: South Africa/Lesotho & Argentina & Antarctica & China
Age: Spathian, Lower Triassic - Anisian, Middle Triassic
Remarks: The lower jaw of this meat-eater was dominated by one bone known as the dentary, which was equipped with different kinds of teeth. This feature explains the origin of the name. Furthermore, the differentiated teeth show this animal could effectively process its food before swallowing. The presence of a secondary palate in the mouth indicates that Cynognathus would have been able to breathe and swallow simultaneously. The lack of ribs in the stomach region suggests the presence of an efficient diaphragm; an important muscle for mammalian breathing. Pits and canals on the bone of the snout indicate concentrations of nerves and blood cells. In mammals, such structures allow hairs to be used as sensory organs, (whiskers).
These are all seen as indications that Cynognathus was an endothermic animal; a ‘warm blooded’ creature with a relatively high metabolic rate, which needed to be able to process food and oxygen quickly.
Reference: Seeley (1895), Researches on the structure, organization and classification of the fossil Reptilia. Part IX, section 1. On the Therosuchia. Phil. Transactions of the Roy. Soc. of London, series B 185 (21), p.987-1018.