Polacanthus
| Polacanthus | ||||||||||||
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Hypothetical live reconstruction of Polacanthus foxii |
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| Temporal occurrence | ||||||||||||
| Lower Cretaceous ( Barremium to Aptium ) | ||||||||||||
| 130.7 to 112.9 million years | ||||||||||||
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| Scientific name | ||||||||||||
| Polacanthus | ||||||||||||
| Huxley , 1867 | ||||||||||||
| species | ||||||||||||
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Polacanthus is a genus of the bird pelvic dinosaur (Ornithischia) from the group of the Ankylosauria . He lived about 131 to 113 million years ago in the Lower Cretaceous in Europe.
features
Polacanthus reached a length of around 4 meters, but so far only the posterior parts of the postcranial skeleton are known, and part of a lower jaw is ascribed to it.
Like all ankylosaurs, it was protected by bone plates ( osteoderms ) on its body. The most noticeable feature was a coalesced, shield-like structure over the pelvis , but also smaller, round bone plates and bony spines were present. The exact arrangement of these structures is not known; the spines were probably attached to the animal's flanks.
He moved on all fours ( Quadrupedie ) and was stocky build with short, strong limbs. It can be assumed that Polacanthus , like all better known ankylosaurs, was a herbivore.
Discovery and naming
After Hylaeosaurus , Polacanthus was the second ankylosaur to be discovered in England in the 19th century . Fossil finds are known from Dorset , West Sussex and the Isle of Wight , the first description was the British natural scientist Thomas Henry Huxley .
The generic name is derived from the Greek words πολυ- / poly- (= "much") and ακανθα / acantha (= "sting" or "thorn"). Type species is P. foxii , in 1996 a second species was described with P. rudgwickensis , which was presumably somewhat larger and differed from P. foxii in the structure of the vertebrae and the bone plates .
Systematics
According to some researchers, Hylaeosaurus - of which mainly the front half of the body is known - is the same genus as Polacanthus , accordingly both species are sometimes included in this genus.
The systematic classification in the Ankylosauria is controversial. Polacanthus is namesake of the Polacanthidae or Polacanthinae , a group of ankylosaurs, which are sometimes incorporated into the Ankylosauridae and sometimes into the Nodosauridae ; sometimes they are run as an independent family . A precise classification is difficult due to the sparse findings, M. Vickaryous et al. (2004) therefore list Polacanthus as "Ankylosauria incertae sedis ".
literature
- Matthew K. Vickaryous, Teresa Maryańska , David B. Weishampel : Ankylosauria. In: David B. Weishampel, Peter Dodson , Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. 2004, ISBN 0-520-24209-2 , pp. 363-392.
Individual evidence
- ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, ISBN 978-0-691-13720-9 , p. 228, online .
