Charonosaurus
| Charonosaurus | ||||||||||||
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Live reconstruction of Charonosaurus jiayinensis |
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| Temporal occurrence | ||||||||||||
| Upper Cretaceous (late Maastrichtian ) | ||||||||||||
| 69.9 to 66 million years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Charonosaurus | ||||||||||||
| Godefroit , Zan & Jin , 2000 | ||||||||||||
| Art | ||||||||||||
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Charonosaurus is a genus from the group of hadrosaurs that belong to the Ornithischia (bird's pelvis dinosaur). Remains of this large hadrosaurid aredatedto the late Upper Cretaceous (late Maastrichtian ) and come from the Chinese province of Heilongjiang .
Within the hadrosaurs, Charonosaurus is counted among the Lambeosaurinae and was probably most closely related to Parasaurolophus . Whether the bone crest of Charonosaurus was similar to that of Parasaurolophus can only be guessed, since it is only partially preserved in fossil form. The only known species , Charonosaurus jiayinensis , was described in 2000 .
features
Charonosaurus was a very large hadrosaurid with an estimated length of about 13 meters. The thigh bone (femur), which is often used for size comparisons, is up to 135 centimeters long and thus longer than in any other hadrosaurid except Shantungosaurus giganteus . Various common features ( synapomorphies ) with Parasaurolophus indicate a close relationship between these two genera, which are also summarized as Parasaurolophini : The paired frontal bone is heavily modified on the upper side and forms a platform around the base of a hollow bone cone support; also showing fibula (fibula) of charonosaurus an enlarged, lobe-shaped distal end and the ankle bone (talus) an equilateral apophysis . In contrast to Parasaurolophus and other hadrosaurs, for example, the relatively short parietal bone (parietal) does not show a sagittal crest. Like all hadrosaurids, Charonosaurus was able to perform grinding chewing motions with its jaw. The teeth were arranged in so-called tooth batteries, worn teeth were constantly replaced. In the lower jaw of adult specimens there were about 40 rows of teeth, each with two to three teeth, of which one or two teeth were in use at the same time. The teeth of the lower jaw were very high with crowns up to 40 millimeters high .
The ulna and radius of the forearms were very slender and elongated, while the upper arm was muscular. There is a clear protrusion on the proximal head of the shoulder blade (scapula), which marks the muscle attachment point for the triceps scapulare laterale externum . The coracoid shows itself in young animals a significant lateral projection of an attachment point for a very strong biceps muscle offered. The sacrum is made up of nine fused vertebrae.
Site, naming and history of discovery
The Charonosaurus remains come from large bonebeds (bone beds ) that have been discovered since 1975 during excavations by several Chinese institutions in the vicinity of the city of Jiayin on the Amur . The bonebeds consist of loose clusters of isolated bones from various animals; Remains of lambeosaurine dinosaurs, which make up about 90 percent of the finds, are mixed in with the bones of theropods , ankylosaurs , crocodiles, and turtles . Lambeosaurinen are represented by both adults and young animals. The long bones tend to have a certain orientation, from which it is concluded that the bones were transported and deposited fluviatil , i.e. in a river. Theropod teeth in the bonebeds indicate that the lambeosaurines were either killed by predators or that their carcasses were eaten by scavengers . The researchers assume that all lambeosaurine bones of the bonebeds belong to Charonosaurus .
The holotype material (copy number CUST J-V1251-57), a fragmentary skull was 2000 Pascal Godefroit, Shuqin Zan and Liyong Jin as charonosaurus jiayinensis described . The genus name Charonosaurus is derived from Charon , the ferryman from Greek mythology who brought the dead across the Acheron (or Styx ) river , and the ancient Greek sauros (lizard). The Artepitheth jiayinensis refers to the type locality (the locality) Jiayin .
Stratigraphically , the finds come from the Yuliangze Formation . The first finds from this formation were made in the summers of 1916 and 1917 from excavations carried out by the Russian Geological Committee. These include the bones of hadrosaurids, which Anatoly Riabinin described as Manchurosaurus amurensis . Furthermore ordered Riabinin another Fund, a very fragmentary ischial (ischium), the Hadrosauriden to and called it Saurolophus krystofovici . Both names are used today as the noun dubia .
Paleobiogeography
Pollen analyzes of the sediments of the Yuliangze Formation have shown that it belongs to the Wodehouseia spinata - Aquilapollenites subtilis - Palynozone . Since Wodehouseia spinata is regarded as an indicator for rock formations of the late Maastrichtian (about 65 million years ago), it is assumed that this dating also applies to the Yuliangze formation and thus to the Charonosaurus finds. Other similar sites in the Maastrichtian of Northeast Asia are Blagoveschensk and Kundur in the Russian Amur region - in these sites, too, lambeosaurines make up over 90 percent of the fossils found. These three sites thus document a dinosaur fauna just before the Cretaceous Tertiary mass extinction , which differed significantly from similar faunas from North America: While in North America either ceratopsians or titanosaurs dominated the fauna, lambeosaurines formed the main component of these Asian fauna. In North America, lambeosaurines were completely absent at the end of the Cretaceous. This means that different dinosaur faunas existed right before mass extinction. By studying these faunas, the researchers hope to gain further knowledge about the extinction of the non-avian dinosaurs at the end of the Cretaceous.
literature
Unless otherwise noted, all information comes from the following work:
- Pascal Godefroit, Shuqin Zan, Liyong Jin: Charonosaurus jiayinensis ng, n. Sp., A lambeosaurine dinosaur from the Late Maastrichtian of northeastern China. In: Comptes Rendus de l'Académie des Sciences. Series 2, Fascicule A: Sciences de la Terre et des Planètes. Vol. 330, No. 12, 2000, ISSN 0764-4450 , pp. 875-882, doi : 10.1016 / S1251-8050 (00) 00214-7 .
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. 309, online ( memento of the original from July 13, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. .
- ↑ Charonosaurus . In: Luis V. Rey's Art Gallery Dinosaurs and Paleontology. Retrieved September 27, 2014 .
- ^ A b David C. Evans, Robert R. Reisz, Kevin Dupuis: A juvenile Parasaurolophus braincase from Dinosaur Provincial Park, Alberta, with comments on crest ontogeny in the genus. In: Journal of Vertebrate Paleontology. Vol. 27, No. 3, 2007, ISSN 0272-4634 , pp. 642-650, doi : 10.1671 / 0272-4634 (2007) 27 [642: AJPOHB] 2.0.CO; 2 .
