Linheraptor
| Linheraptor | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Live reconstruction of Linheraptor exquisitus . |
||||||||||
| Temporal occurrence | ||||||||||
| Upper Cretaceous ( Campanium ) | ||||||||||
| 83.6 to 72 million years | ||||||||||
| Locations | ||||||||||
| Systematics | ||||||||||
|
||||||||||
| Scientific name | ||||||||||
| Linheraptor | ||||||||||
| Xu et al. , 2010 | ||||||||||
| Art | ||||||||||
|
Linheraptor was a genus of small carnivorous dinosaurs belonging to the Dromaeosauridae group . So far, a single, very well-preserved and almost complete skeleton is known, which comes from the Wulansuhai Formation in Chinese Inner Mongolia and is around 83.6 to 72 million years old ( Campanium ). This genus wasscientifically described in 2010 with the only species Linheraptor exquisitus .
features
Linheraptor is estimated to be 1.8 meters long, making it similar in size to Velociraptor . The trunk is estimated to be 36.5 cm in length, from the first vertebra to the acetabulum (pelvic socket). The skeleton is believed to have come from an adult, suggesting fusions of the vertebrae and the tibiotarsus (lower leg). The skull was 22.5 cm long and appears to be narrower than that of the closely related Tsaagan - but this difference could have been due to deformation of the skull. Various Velociraptor skulls show considerable variations in skull proportions. The teeth are poorly preserved, which is why the number of teeth cannot be precisely determined. However, one half of the lower jaw (dental) had about 15 teeth, as many as in Tsaagan and Velociraptor . As with Tsaagan and many basal dromaeosaurids, the front sides of the teeth were unsawed.
The S-shaped neck consisted of 10 cervical vertebrae. As with most other dromaeosaurids, the tail had strongly elongated vertebral processes (post- and prezygapophyses and chevron bones ). The upper arm bone (humerus) makes up less than 70% of the length of the thigh bone (femur). As with all dromaeosaurids, the second toe had a characteristic enlarged sickle claw.
Linheraptor was probably more closely related to Tsaagan than to other dromaeosaurids. Tsaagan is only known for one skull and the eight front cervical vertebrae. Both genera have some features in common that other dromaeosaurids lack: For example, the maxillary window is significantly enlarged and similar in size to the nostrils; In addition, the zygomatic bone (Jugale) and the scaly bone (Squamosum) touch so that the postorbital is excluded from the infratemporal window. Other features differentiate Linheraptor from Tsaagan : For example, the axis , the second cervical vertebra, showed a large pneumatic opening (foramen) on the lateral surface of the vertebral body ; similar to Mahakala , Velociraptor and Deinonychus . In tsaagan this feature is missing. Another example is the significantly deeper rear end of the lower jaw of Linheraptor , which causes the glenoid pit (fossa glenoidalis) to be level with the row of teeth.
Systematics
The description suggests that Linheraptor, together with the closely related Tsaagan, formed a separate group of late Cretaceous, Asian dromaeosaurids. Both genera were more basal than Velociraptor and phylogenetically probably stood between basal and more advanced dromaeosaurids.
Find and naming
The skeleton was discovered in 2008 during an expedition in Inner Mongolia in Bayan Mandahu in the Linhe district , and the site became known as The Gate locality . The expedition was a joint expedition of two Chinese institutes, the Institute of Vertebrate Paleontology & Paleoanthropology and the Long Hao Institute of Geology and Paleontology , and aimed to improve the understanding of the dinosaur fauna of the Upper Cretaceous in Inner Mongolia. Jonah Choiniere, a student at George Washington University ( Washington, DC ), discovered the first bone in the skeleton: the tip of a claw protruding from a wind-eroded cliff of red sandstone.
The rocks of the site belong stratigraphically to the Wulansuhai Formation , the Chinese equivalent of the Mongolian Djadochta Formation . Four other dromaeosaurid species have already been recovered from the Djadochta formation: Velociraptor mongoliensis , Velociraptor osmolskae , Tsaagan mangas and Mahakala omnogovae . Thus Linheraptor is already the fifth dromaeosaurid of this fauna.
The find ( holotype , copy number IVPP V 16923) is an almost complete skeleton found in an anatomical network. It was scientifically described by Xu Xing and colleagues in 2010 . The name Linheraptor points to the site in the municipality of Linhe ; raptor means something like "predator" and underlines the status of a predator . The epithet exquisitus indicates the exceptionally good degree of conservation of the skeleton.
supporting documents
literature
- Xing Xu , Jonah N. Choiniere, Michael Pittman, Qingwei Tan, Dong Xiao, Zhiquan Li, Lin Tan, James M. Clark , Mark A. Norell , David WE Hone, Corwin Sullivan: A new dromaeosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Wulansuhai Formation of Inner Mongolia, China. In: Zootaxa . Vol. 2403, 2010, pp. 1–9, PDF - limited preview with images , PDF, full text, without images .
Individual evidence
- ↑ Mark A. Norell, James M. Clark, Alan H. Turner, Peter J. Makovicky , Rinchen Barsbold , Timothy Rowe : A new dromaeosaurid theropod from Ukhaa Tolgod (Ömnögov, Mongolia) . (= American Museum Novitates. No. 3545, ISSN 0003-0082 ). American Museum of Natural History, New York NY 2006, (PDF; 10.2 MB).
- ↑ New Dinosaur: "Exquisite" Raptor Found. In: National Geographic - Daily News. Retrieved May 29, 2010 .