Estemmenosuchus
| Estemmenosuchus Temporal range: Middle Permian, 267 Ma |
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| Skull of Estemmenosuchus mirabilis | |
Scientific classification  |
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Synapsida |
| Order: | Therapsida |
| Suborder: | †Dinocephalia |
| Family: | †Estemmenosuchidae |
| Genus: | †Estemmenosuchus Tchudinov, 1960 |
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Estemmenosuchus (meaning "crowned crocodile" in Greek) is a genus of large, early omnivorous therapsids that lived during the middle part of the Middle Permian, around 267 million years ago. The two species, E. uralensis and E. mirabilis, are characterised by distinctive horn-like structures, which were probably used for intra-specific display. Both species of Estemmenosuchus are from the Perm (or Cis-Urals) region of Russia. Two other estemmenosuchids, Anoplosuchus and Zopherosuchus, are now considered females of the species E. uralensis.[1]
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[edit] Description
Estemmenosuchus was a large, clumsy-looking animal, the size of an adult bull, with a sprawling posture. The skull is high and massive, and possesses several sets of large horns, somewhat similar to the antlers of a moose, growing upward and outward from the sides and top of the head.
The skull superficially resembles that of Styracocephalus, but the "horns" are formed from different bones; in Estemmenosuchus the horns are located on the frontals and protrude upward, whereas in Styracocephalus the horns are formed by the tabular and extend aft.
[edit] Species
Estemmenosuchus lived some 267 million years ago. Two species have been identified, from the Ocher in the Perm region or Russia. They differ in size, shape of the skull, and shape of the horns.
Estemmenosuchus uralensis ("Crowned Crocodile of the Ural Mountains") is the second most primitive therapsid after the Biarmosuchia. The species was found with the Biarmosuchians Eotitanosuchus olsoni and Biarmosuchus tener and with Estemmenosuchus mirabilis in channel flood deposits of the young Ural Mountains.
The species are characterised by horns which project upward and outward on the side of the head. The mouth contained large canines with small molar teeth. The animal had a sprawling posture as indicated by analysing its shoulder joints.
It has been suggested that the animal was warm blooded, as its large size (4-5 metres long) and small surface area suggests a warm-blooded mammal. But other scientist believe it was cold blooded, similar to today's reptiles. It has been also suggested that it was a carnivore, but the majority opinion at present is that Estemmenosuchus was a herbivore.
Estemmenosuchus mirabilis (Wondrous Crowned Crocodile) lived along with Estemmenosuchus uralensis, Eotitanosuchus olsoni and Biarmosuchus tener in the same habitat. The fossil material includes an exceptionally well preserved skin impression. The skin appears to be smooth and undifferentiated with no signs of either hairs or scales but with evidence of being well supplied with glands.[2]
Unlike Estemmenosuchus uralensis, which had only one horn on each side of its head, this species had 2 projecting bony knobs on each side of the cranium, one on the top pointing up looking like antlers and another pointing to the side similar to E. uralensis. Its snout is smaller and wider than its relative and looks vaguely like a modern moose. The palate teeth include six incisors, two canines and about twenty small incisor-like teeth at the rear. The lower palate contained six incisors, two canines and about thirty smaller back teeth.
There were many complete and incomplete skeletons found together.
[edit] References
- Chudinov, P. K. 1965, "New Facts about the Fauna of the Upper Permian of the USSR", Journal of Geology, 73:117-30
- King, Gillian M., "Anomodontia" Part 17 C, Encyclopedia of Paleoherpetology, Gutsav Fischer Verlag, Stuttgart and New York, 1988
- Olsen, E. C., 1962, Late Permian terrestrial vertebrates, USA and USSR Transactions of the American Philosophical Society, new series, 52:1–224
- Patricia Vickers-Rich and Thomas H. Rich, The Great Russian Dinosaurs, Guntar Graphics, 1993, p. 30
[edit] External links
- Palaeos - detailed description
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