Estemmenosuchus

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Estemmenosuchus
Skull of Estemmenosuchus mirabilis

Skull of Estemmenosuchus mirabilis

Temporal occurrence
Upper Perm
255 million years
Locations
Systematics
Tetrapoda (land vertebrates)
Synapsids (Synapsida)
Therapsids (Therapsida)
Dinocephalia?
Estemmenosuchidae
Estemmenosuchus
Scientific name
Estemmenosuchus
Tchudinov , 1960

Estemmenosuchus was a genus in Upper Perm , about 255 million years ago, of living therapsids (formerly known as "mammal-like reptiles"), the fossil remains of which were found in Russia near the town of Ochor in the Perm region . Two species have been described, Estemmenosuchus uralensis , of which the skull and skeleton are known, and Estemmenosuchus mirabilis , of which the skull, lower jaw and vertebrae are known to be fossilized. Both species lived in the same region at the same time.

features

Estemmenosuchus was about the size of a hippopotamus (4–5 m long) and also the shape and probably the way of life of hippos. The skull was large and massive. The genus was named after two pairs of bony outgrowths on the skull. The name Estemmenosuchus means "crowned crocodile". A pair formed by the frontal bone , post-orbitals and post-frontals sat above the eyes, cheekbone and scaly bone formed another pair of outgrowths that sat on the side of the skull. The outgrowths were less spectacular in Estemmenosuchus uralensis than in Estemmenosuchus mirabilis . Also, E. uralensis was larger, and its skull was longer. In E. mirabilis the "horns" were turned more to the side.

The teeth of Estemmenosuchus show a herbivore. He had long, curved incisors, large, thick, triangular canine teeth, and a total of twenty very small molars that had sawn front and rear edges.

Systematics

Estemmenosuchus is usually assigned to the Dinocephalia as a basal member . However, some scientists are of the opinion that they are more developed than the Brithopodidae and are close to the Titanosuchia within the Dinocephalia . The Russian palaeontologist MF Ivakhenko, on the other hand, believes that, based on the growth form of the skull windows , Estemmenosuchus is not a dinocephalian, but rather belongs to an independently evolved line of primitive, herbivorous therapsids that he calls Rhopalodonta.

literature

  • Thomas S. Kemp: The Origin & Evolution of Mammals. Oxford University Press, Oxford 2005, ISBN 0-19-850761-5
  • Lexicon of dinosaurs and other prehistoric animals . Dorling Kindersley 2001, pp. 198, 199 - Mammals and their ancestors

Web links

Commons : Estemmenosuchus  - collection of images, videos and audio files