Olorotitan
| Olorotitan | ||||||||||||
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Skeleton of Olorotitan in the Museum of Natural Sciences in Brussels . |
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| Temporal occurrence | ||||||||||||
| Upper Cretaceous (late Maastrichtian ) | ||||||||||||
| 69.9 to 66 million years | ||||||||||||
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| Scientific name | ||||||||||||
| Olorotitan | ||||||||||||
| Godefroit , Bolotsky & Alifanov , 2003 | ||||||||||||
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Olorotitan is a genus of ornithopod dinosaur that belongs to the Lambeosaurinae , a subfamily of the Hadrosauridae . So far, an almost complete skeleton is known that comes from layers of the Upper Cretaceous (late Maastrichtian ) from the Amur region in Eastern Russia .
Like his relatives, Olorotitan had a bony outgrowth on his head. It was a herbivore that could likely walk both two-legged ( biped ) and four-legged ( quadruped ).
The only known species of this genus is Olorotitan arharensis , which was described by Godefroit, Bolotsky and Alifanov in 2003. The name Olorotitan means something like "giant swan", while the epithet arharensis refers to the site in Arhara land.
description
Olorotitan is based on an almost complete, nine to ten meter long skeleton - the best preserved lambeosaurine skeleton outside of North America. Although some skull bones (the neurocranium and the roof of the skull) are missing, the rear hatchet-shaped crest of the skull is very well preserved. This is also unusual among lambeosaurines and the most striking feature.
Another important autapomorphy is the elongated neck, which consists of 18 vertebrae - in contrast to the 15 cervical vertebrae of all other hadrosaurids. With 15 or 16 vertebrae, the sacrum ( sacrum ) also has at least three more vertebrae than that of other hadrosaurids. The proximal third of the tail (facing the body) has connections between the tips of the vertebral processes, which stiffen this tail section. However, a pathological (disease-induced) cause for this characteristic cannot be ruled out; only further findings can bring clarity.
Classification, site and paleoecology
Within the Lambeosaurinae there are two subgroups, the Parasaurolophini and the Lambeosaurini. Olorotitan is classified in the latter and is considered a sister taxon to the North American species Hypacrosaurus and Corythosaurus .
The site belonging to the Udurchukan Formation (the lower part of the Tsagayan Group ) was discovered near Kundur in 1991 and, in addition to the Olorotitan skeleton, also released the remains of turtles, crocodiles, theropods and nodosaurids . At other sites in the Amur region, especially near Jiayin and Blagoweschensk , other hadrosaurid species were found with which Olorotitan shared the habitat. These include the lambeosaurins Amurosaurus and Charonosaurus and the Hadrosaurine Kerberosaurus . Unlike in North America, where the Lambeosaurinae became rare at the end of the Maastrichtian, it was still common in Asia at the same time, which is attributed to climatic or ecological differences.
literature
- Pascal Godefroit, Yuri Bolotsky, Vladimir Alifanov: A remarkable hollow-crested hadrosaur from Russia: an Asian origin for lambeosaurines. In: Comptes Rendus Palevol. Vol. 2, No. 2, 2003, ISSN 1631-0683 , pp. 143-151, doi : 10.1016 / S1631-0683 (03) 00017-4 .
- Pascal Godefroit, Yuri L. Bolotsky, Jimmy Van Itterbeeck: The lambeosaurine dinosaur Amurosaurus riabinini, from the Maastrichtian of Far Eastern Russia. In: Acta Palaeontologica Polonica. Vol. 49, No. 4, 2004, pp. 585-618, online .
Individual evidence
- ^ Gregory S. Paul : The Princeton Field Guide To Dinosaurs. Princeton University Press, Princeton NJ et al. 2010, p. 309, ISBN 978-0-691-13720-9 , online .