Scelidosaurus
Scelidosaurus | ||||||||||||
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Skeleton of Scelidosaurus harrisonii |
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Temporal occurrence | ||||||||||||
Lower Jurassic ( Sinemurian ) | ||||||||||||
199.3 to 190.8 million years | ||||||||||||
Locations | ||||||||||||
Systematics | ||||||||||||
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Scientific name | ||||||||||||
Scelidosaurus | ||||||||||||
Owen , 1860 | ||||||||||||
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Scelidosaurus was a genus of pelvic dinosaur from the group of Thyreophora . They were armored, herbivorous dinosaurs that lived in the Lower Jurassic .
features
Scelidosaurus reached a length of around four meters. The hind legs were significantly longer than the front legs; however, the feet of the front limbs were the same size as those of the hind limbs. Each foot ended in four toes, with the innermost being the smallest. Presumably, this dinosaur usually moved on all fours, but could also stand up on its hind legs - for example when eating.
The armor of this animal consisted of horn scales that stretched in longitudinal rows along the back and flanks. There were smaller scales on the tail and limbs, in addition there were two conspicuous, triangular bone scales immediately behind the head. The skull was relatively elongated, the teeth were small and leaf-shaped and adapted to a herbivorous diet.
Discovery and naming
Fossil remains of Scelidosaurus were found in Dorset , England in the middle of the 19th century and first described by Richard Owen . The name means "limb lizard" and possibly alludes to the stocky legs, type species is S. harrisonii . The finds are dated to an age of around 200 to 190 million years in the Lower Jurassic ( Sinemurian ).
In Arizona ( USA ), bones were discovered in the 1980s that could also have come from Scelidosaurus ; a clear assignment is not possible due to the sparse finds.
Systematics
The systematic position of Scelidosaurus has been controversial since its discovery . It is undisputed that he belongs to the group of Thyreophora within the bird pelvic dinosaurs , which also includes stegosauria and ankylosauria , and that he is a relatively early and original representative of this group. At times it was considered a stego- or ankylosaur; today's phylogenetic studies see it as the sister group of the Eurypoda (the common taxon of stego- and ankylosaurs). A possible cladogram is:
Thyreophora |
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Together with Bienosaurus , a dinosaur known only through a lower jaw, Scelidosaurus forms the family of Scelidosauridae in some classifications. However, due to the sparse finds of Bienosaurus , this is controversial.
literature
- 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 .
- David E. Fastovsky , David B. Weishampel: The Evolution and Extinction of the Dinosaurs. 2nd edition. Cambridge University Press, Cambridge et al. 2005, ISBN 0-521-81172-4 .