Stygimoloch
Stygimoloch | ||||||||||||
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Reconstruction of the skull of Stygimoloch spinifer , exhibited in the Museum für Naturkunde Berlin |
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Temporal occurrence | ||||||||||||
Upper Cretaceous (late Maastrichtian ) | ||||||||||||
69.9 to 66 million years | ||||||||||||
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Systematics | ||||||||||||
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Scientific name | ||||||||||||
Stygimoloch | ||||||||||||
Galton & Sues , 1983 |
Stygimoloch is a genus of the bird pelvic dinosaur (Ornithischia) from the group of the Pachycephalosauria . Like all representatives of this group of dinosaurs, it had a thickened skull-roof, characteristic were the long spines on the back of the head. There is only one species, Stygimoloch spinifer .
features
Stygimoloch was a medium-sized pachycephalosaur with an estimated length of 3 meters.
As with all pachycephalosaurs, the thickened roof of the skull was formed from the fused frontal and parietal bones (frontoparietals), the top of the skull was arched and very pointed like hardly any other representative of this dinosaur group. The skull was decorated with numerous small bony bumps, including on the nasal and scale bones . At the back of the head there were also two 10 cm long, backward-protruding horns next to a few smaller horns.
Paleobiology
Presumably, as with all pachycephalosaurs, the hind legs were significantly longer than the front legs and Stygimoloch moved bipedally (two-legged). Like other representatives of this group, he may have kept his spine horizontal while running and the tail stiffened by ossified tendons served as a counterweight. Its diet was likely to have consisted mainly of plant material.
The function of the thickened skull roof and the spines is discussed. As with other pachycephalosaurs, it is considered that ramming duels were carried out with the skulls, for example for the mating privilege. Kenneth Carpenter counters this by saying that due to the bulging skull, the impact area was too small for such duels. He thinks it is conceivable that the animals tried to hit the flanks of their opponent in duels. Maryańska et al. think it is conceivable that in Stygimoloch, in contrast to other pachycephalosaurs, the top of the skull and the spines were only used for display and were not used in disputes.
Discovery and naming
Fossil remains of Stygimoloch were found in the US states of North Dakota , Wyoming and Montana , they are dated in the Upper Cretaceous (late Maastrichtian ) to an age of about 69 to 66 million years.
The genus was first described in 1983 by Galton & Sues , the type species and the only known species is S. spinifer . The generic name is derived from Styx , a river of hell in Greek mythology, and Moloch , a demon in the Hebrew tradition. It was named after the Hell Creek Formation (Hell Creek = "Höllenbach") in the US states of Montana and Wyoming, from whose rock five fragmentary skulls have so far been recovered.
Systematics
The systematic position of Stygimoloch within the Pachycephalosaurier is not exactly clarified. R. Sullivan classifies it as a close relative of Pachycephalosaurus and Dracorex in the Pachycephalosaurini, a cladistic study by Maryańska et al. sees in him, however, a more primitive representative. According to recent studies, Stygimoloch could be half-grown, almost sexually mature specimens of Pachycephalosaurus .
literature
- Kenneth Carpenter : Agonistic behavior in pachycephalosaurs (Ornithischia: Dinosauria): a new look at head-butting behavior. In: Contributions to Geology. Vol. 32, No. 1, 1997, ISSN 0010-7980 , pp. 19-25, digital version (PDF; 984.18 KB) .
- Teresa Maryańska , Ralph E. Chapman, David B. Weishampel : Pachycephalosauria. 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. 464-477.
- Robert M. Sullivan: A taxonomic review of the Pachycephalosauridae (Dinosauria: Ornithischia). In: Spencer G. Lucas, Robert M. Sullivan (Eds.): Late Cretaceous Vertebrates from the Western Interior (= New Mexico Museum of Natural History and Science. Bulletin. 35, ISSN 1524-4156 ). New Mexico Museum of Natural History and Science, Albuquerque NM 2006, pp. 347–365, digital version (PDF; 4.79 MB) .
Web links
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. 244, online .
- ^ Science Daily New Analyzes Of Dinosaur Growth May Wipe Out One-Third Of Species
- ↑ scinexx the knowledge magazine One third of the dinosaur species wrong?