Corythosaurus
| Corythosaurus | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Skeletal reconstruction of Corythosaurus at the Royal Ontario Museum . |
||||||||||||
| Temporal occurrence | ||||||||||||
| Upper Cretaceous (Middle to Upper Campanium ) | ||||||||||||
| 80.6 to 72 million years | ||||||||||||
| Locations | ||||||||||||
|
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Corythosaurus | ||||||||||||
| Brown , 1914 | ||||||||||||
| Art | ||||||||||||
|
||||||||||||
Corythosaurus is a genus of ornithopod dinosaur from the group of Hadrosauridae thatlived in North Americaduring the Upper Cretaceous (Middle to Upper Campanium ). Like all hadrosaurids, these herbivores could move both legged and four-legged, had the characteristic toothless “duck bill” and had molars in their jaws.
Corythosaurus is characterized by a tall, upward-facing crescent-shaped bone crest that sat on top of the skull and reached its highest point above the eyes. The majority of Corythosaurus -Fossilien comes from the Dinosaur Provincial Park in Alberta ( Canada ) - here numerous complete skeletons of different ages and at least 22 articulated skulls were found. In at least two specimens, the skin, covered with polygonal, non-overlapping scales, has been preserved in places.
Within the Hadrosauridae, Corythosaurus is counted among the Lambeosaurinae , which have various head crests, in contrast to the combless Hadrosaurinae . The only currently recognized species is Corythosaurus casuarius .
features
Corythosaurus reached a length of about 10 meters and an estimated weight of 3 to 3.8 tons. The skull is relatively short and reaches a length of 81 cm and a height of 71 cm in the holotype specimen. The bone ridge has a complex internal structure and houses the nasal passages that wind in a tortuous arc through the ridge before opening into the throat. The front section of the ridge is formed by the paired intermaxillary bone ( premaxillary), the rear section by the paired nasal bone (nasal). In contrast to related genera, the nasal bone was forked and contributed significantly more to the formation of the outer surface of the ridge.
The head comb varies in size and shape between individuals. Adult skulls can be ascribed to two different morphotypes (types of shape): the first type shows a larger crest with a slightly convex posterior edge, while the second type shows a smaller crest with a caudal indentation of the nasal bone. In the past, these differences were used to distinguish between different species; Today, many researchers assume that it is a gender dimorphism . The first type may originate from male individuals, while the second type originates from female individuals. Skulls that completely lack the crest were once assigned to a separate genus (" Tetragonosaurus "). However, Dodson (1975) recognized that these combless skulls were juveniles of the comb-bearing genera Corythosaurus , Lambeosaurus and Hypacrosaurus that were less than half the size of adult animals.
The remaining skeleton (postcranium) adjoining the skull differs only slightly from related species and is practically indistinguishable from that of the closely related Lambeosaurus . The spine is made up of 15 cervical vertebrae, 19 vertebrae, 8 sacral vertebrae and 75 caudal vertebrae.
History of discovery and naming
First skeletons of Corythosaurus discovered Barnum Brown , a famous paleontologist from the American Museum of Natural History , in what is now Dinosaur Provincial Park ( Dinosaur Provincial Park ) in Alberta . Brown was made aware of this find area by a farmer in 1909. By 1915 he was able to recover numerous skeletons, including complete specimens of Corythosaurus , Prosaurolophus , Centrosaurus , Gorgosaurus and Struthiomimus . Today the Dinosaur Provincial Park is one of the richest and most species-rich dinosaur sites in the world. Hadrosaurids are represented in the park with eight species, with Corythosaurus casuarius being the most common.
In 1914 Brown published the first description of Corythosaurus , based on an almost complete skeleton ( holotype , specimen number AMNH 5240) including remains of skin, only missing the front legs and the last caudal vertebrae. The name Corythosaurus ( gr. Koryth- (korys) - "helmet", gr. Sauros - "lizard") means something like "helmet lizard" and points to the distinctive head crest, which, according to Brown, the helmets of the ancient Corinthians and the Cassowary's head comb resembles. The second part of the species name, casuarius , refers to the cassowary ( Casuarius ).
Systematics
Internal system
In the past, more than six different species were distinguished at times, including Corythosaurus casaurius , Corythosaurus bicristatus , Corythosaurus brevicristatus , Corythosaurus excavatus , Corythosaurus frontalis and Corythosaurus intermedius . These types were distinguished from one another based on the size and shape of the head comb. As Dodson (1975) showed, the differences were likely to be ontogenic (developmental), gender, or individual variations. Today only the type species is generally recognized, Corythosaurus casuarius .
External system
Corythosaurus is a member of the Lambeosaurinae , a group within the Hadrosauridae . The Lambeosaurinae is divided into two clades by many researchers: The Parasaurolophini contain Parasaurolophus and Charonosaurus , while the Corythosaurini contain Lambeosaurus , Hypacrosaurus and Corythosaurus . Many researchers also see olorotitan as a representative of the Corythosaurini and close relatives of Corythosaurus ; However, a more recent study comes to the conclusion that Olorotitan was more original and must be classified outside of the two clades at the base of the Lambeosaurinae. Board Surman (1989) has been suggested that Corythosaurus with Hypacrosaurus could have been identical. If this is the case, the name Hypacrosaurus would have priority and the name Corythosaurus would be invalid.
The following is a current classification example (simplified from Evans and Reisz, 2007):
| Hadrosauridae |
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
|
Individual evidence
- ↑ Victoria M. Arbor, Michael E. Burns, Robin L. Sissons: A redescription of the ankylosaurid dinosaur Dyoplosaurus acutosquameus Parks, 1924 (Ornithischia: Ankylosauria) and a revision of the genus. In: Journal of Vertebrate Paleontology. Vol. 29, No. 4, 2009, ISSN 0272-4634 , pp. 1117-1135, doi : 10.1671 / 039.029.0405 .
- ↑ a b c d e Michael J. Ryan, David C. Evans: Ornithischian Dinosaurs. In: Philip J. Currie , Eva B. Koppelhus (Eds.): Dinosaur Provincial Park. A Spectacular Ancient Ecosystem Revealed. Indiana University Press, Bloomington et al. a. 2005, ISBN 0-253-34595-2 , pp. 312-348.
- ^ A b Charles W. Gilmore : Notes on recently mounted reptile fossil skeletons in the United States National Museum (= Proceedings of the United States National Museum. Vol. 96, No. 3196, ISSN 0096-3801 ). US Government Printing Office, Washington DC 1946, pp. 195-203.
- ↑ Barnum Brown: Corythosaurus casuarius: Skeleton, musculature and epidermis. Second paper. In: Bulletin American Museum of Natural History. Vol. 35, Article 38, 1916, ISSN 0003-0090 , pp. 709-716, digital version (PDF; 9.85 MB) .
- ↑ a b c d Barnum Brown : Corythosaurus casuarius, a new crested dinosaur from the Belly River Cretaceous, with provisional classification of the family Trachodontidae. In: Bulletin American Museum of Natural History. Vol. 33, Article 35, 1914, pp. 559-564, digital version (PDF; 3.51 MB) .
- ^ Frank Seebacher: A new method to calculate allometric length-mass relationships of dinosaurs. In: Journal of Vertebrate Paleontology. Vol. 21, No. 1, 2001, pp. 51-60, doi : 10.1671 / 0272-4634 (2001) 021 [0051: ANMTCA] 2.0.CO; 2 .
- ↑ Catherine A. Forster: Hadrosauridae. In: Philip J. Currie, Kevin Padian (Eds.): Encyclopedia of dinosaurs. Academic Press, San Diego CA et al. a. 1997, ISBN 0-12-226810-5 , pp. 293-298.
- ↑ a b c Peter Dodson : Taxonomic implications of relative growth in lambeosaurine hadrosaurs. In: Systematic Zoology. Vol. 24, No. 1, 1975, ISSN 0039-7989 , pp. 37-54, doi : 10.1093 / sysbio / 24.1.37 .
- ↑ David C. Evans: Cranial anatomy and ontogeny of Hypacrosaurus altispinus, and a comparative analysis of skull growth in lambeosaurines (Ornithischia: Hadrosauridae). In: Zoological Journal of the Linnean Society. Vol. 159, No. 2, 2010, ISSN 0024-4082 , pp. 398-434, doi : 10.1111 / j.1096-3642.2009.00611.x .
- ^ A b Michael Keith Brett-Surman: A Revision of the Hadrosauridae (Reptilia: Ornithischia) And Their Evolution During the Campanian and Maastrichtian. Washington DC 1989 (Washington DC, George Washington University, dissertation, 1989), digitized version (PDF; 3.4 MB) .
- ^ Clive Coy: Dinosaur Provincial Park. In: Philip J. Currie, Kevin Padian (Eds.): Encyclopedia of dinosaurs. Academic Press, San Diego CA et al. a. 1997, ISBN 0-12-226810-5 , p. 184.
- ↑ Ben Creisler: Dinosauria Translation and Pronunciation Guide ( Memento of October 13, 2011 in the Internet Archive )
- ^ John R. Horner , David B. Weishampel , Catherine A. Forster: Hadrosauridae. In: David B. Weishampel, Peter Dodson, Halszka Osmólska (eds.): The Dinosauria . 2nd edition. University of California Press, Berkeley CA et al. a. 2004, ISBN 0-520-24209-2 , pp. 438-463.
- ^ A b c David C. Evans, Robert R. Reisz: Anatomy and Relationships of Lambeosaurus magnicristatus, a crested hadrosaurid dinosaur (Ornithischia) from the Dinosaur Park Formation, Alberta. In: Journal of Vertebrate Paleontology. Vol. 27, No. 2, 2007, pp. 373-393, doi : 10.1671 / 0272-4634 (2007) 27 [373: AAROLM] 2.0.CO; 2 .
- ^ Albert Prieto-Marquez: Global phylogeny of Hadrosauridae (Dinosauria: Ornithopoda) using parsimony and Bayesian methods. In: Zoological Journal of the Linnean Society. Vol. 159, No. 2, 2010, pp. 435-502, doi : 10.1111 / j.1096-3642.2009.00617.x .
