Chuanjiesaurus
| Chuanjiesaurus | ||||||||||
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Skeleton cast in the Chinese Science and Technology Museum in Beijing . |
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| Temporal occurrence | ||||||||||
| formerly Middle Jurassic | ||||||||||
| approx. 174.1 to 170.3 million years | ||||||||||
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| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Chuanjiesaurus | ||||||||||
| Fang et al. , 2000 | ||||||||||
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Chuanjiesaurus is a genus of sauropod dinosaur from the Central Jurassic of China . So far, a single find is known that consists of two fragmentary skeletons lying next to each other. Both skeletons are only partially cut out of the rock and, protected from the weather by a roof, were left at their place of discovery, which is now part of the dinosaur theme park “World Dinosaur Valley”. Chuanjiesaurus is one of the Mamenchisauridae , a group of early sauropods that has so far only been identified from China. Chuanjiesaurus was named in 2000, the name refers to the village of Chuanjie , where the fossils were discovered. The only species is Chuanjiesaurus anaensis .
features
Chuanjiesaurus possibly reached a length of around 25 meters, making it one of the largest early sauropods. As with other Mamenchisaurids, its blueprint was characterized by a long tail and an extremely long neck. Although only the anterior and middle sections of the neck have survived - other Mamenchisaurids had 18 to 19 cervical vertebrae, more than other sauropods. The cervical vertebrae were also elongated - the vertebral body of the eleventh cervical vertebra, the longest adequately preserved vertebra, measures 67.7 centimeters in length - the height of this vertebral body is only 22.0 centimeters. In addition to the elongated neck, Chuanjiesaurus showed other similarities with other Mamenchisaurids: The sacrum consisted of four sacral vertebrae; In addition, the dorsal vertebrae were only weakly pneumatized (with air-filled chambers left out), while the anterior caudal vertebrae were procoel - concave on the front and convex on the rear . Chuanjiesaurus differs from all other Mamenchisaurids by a number of unique features , which are mainly found on the vertebrae, but also on the limbs.
Systematics
A phylogenetic analysis by Sekiya (2011) comes to the conclusion that Chuanjiesaurus can be classified together with Mamenchisaurus , Tienshanosaurus and Yuanmousaurus within a monophyletic group - the Mamenchisauridae. According to this analysis, it is unclear whether Omeisaurus is to be classified within this group or whether it is the sister taxon of this group. The relationships within the Mamenchisauridae can hardly be dissolved. The Mamenchisauridae form a group that is to be classified within the Eusauropoda , but outside of the Neosauropoda , which includes all later sauropods.
Paleohabitat
The fossils come from the Chuanjie Formation , a series of rocks that has only been formally independent since 2000 and before that comprised the lowest section of the "Upper Lufeng Formation". The formation is dated to the early Middle Jurassic . Their palaeohabitat has been little explored, but recent studies report that the climate at the time of the deposition was warm, humid to semi-arid .
Find and research history
The first fossils were discovered in 1995 by Tao Wang of the Lufeng Dinosaur Museum in Chuanjie Village, Lufeng County, Yunnan Province, China . The site, which consists of dark red, massive siltstones , is a bonebed , which, in addition to the two Chuanjiesaurus skeletons, contains the remains of two other large sauropods. However, these skeletons are much worse preserved; whether they are also Chuanjiesaurus cannot be determined. In addition to the sauropod fossils, the site also contains the remains of the theropod Shidaisaurus and four turtles. The sauropod fossils were only partially cut out of the rock and left in situ at their place of discovery; In the first few years after it was uncovered, a small house was used to protect it from the weather. Today the site is part of the World Dinosaur Valley , which opened in 2008, and is the largest dinosaur theme park in China.
The fossils are assigned to two specimens. The holotype specimen consists of a series of caudal vertebrae, parts of the shoulder girdle and the forelegs as well as parts of the pelvis and the hind limbs. The second specimen, meanwhile, consists of vertebrae (11 cervical vertebrae, 6 posterior vertebrae, 4 sacral vertebrae, 25 caudal vertebrae and chevron bones ), parts of the arms and pelvis, and a femur.
Chuanjiesaurus was scientifically described for the first time in 2000 by researchers around Xiaosi Fang . This publication, written in Chinese , is, however, very short; the description was declared to be inadequate by various commentators. In 2011 an extensive new description by Toru Sekiya followed.
Individual evidence
- ^ A b c Paul Upchurch , Paul M. Barrett , Peter Dodson : Sauropoda. 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. 259-324, here pp. 261, 299.
- ↑ a b X. Fang, Pang, J., Y. Zhang, Pan, X. Wang, Li, Cheng: Lower, Middle, and Upper Jurassic divisions of the Lufeng region of Yunnan province. In: Proceedings of the Third National Stratigraphical Conference of China. Geological Publishing House, Peking 2000, pp. 208-214, (In Chinese language and writing).
- ↑ a b c d e f g Toru Sekiya: Re-examination of Chuanjiesaurus anaensis (Dinosauria: Sauropoda) from the Middle Jurassic Chuanjie Formation, Lufeng County, Yunnan Province, Southwest China. In: Memoir of the Fukui Prefectural Dinosaur Museum. No. 10, 2011, ISSN 1347-5622 , pp. 1–54, digital version (PDF; 9.26 MB) .
- ↑ Thomas R. Holtz Jr .: Supplementary Information. to: Thomas R. Holtz Jr .: Dinosaurs. The most complete, up-to-date Encyclopedia for Dinosaur Lovers of all ages. Random House, New York NY 2007, ISBN 978-0-375-82419-7 , p. 28, online (PDF; 184.08 kB) .
- ^ Dinosaur Valley Opened in Yunnan Province. In: crienglish.com. September 21, 2008, accessed August 13, 2014 .
