Qigu Formation
Geological formation in Xinjiang, China
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The Qigu Formation is a Late Jurassic (Oxfordian) geologic formation in the Southern Junggar Basin in China. Indeterminate Dinosaur remains are among the fossils that have been recovered from the formation, including the stegosaur ("Angustungui qiketaensis"),[1] theropod teeth and a fibula.[2] a stegosaur dorsal vertebra[3] and a Eusauropod tooth.[4] Xinjiangtitan was erroneously thought to be from this formation, but it is actually from the older Qiketai Formation, which is in a different basin.[5] The term "Qigu Formation" is also used to sediments of equivalent age in the Turpan Basin, but this might better be treated as a separate formation. It is laterally equivalent to the Shishugou Formation.
| Qigu Formation | |
|---|---|
| Stratigraphic range: Oxfordian-Early Kimmeridgian, | |
| Type | Geological formation |
| Underlies | Kalaza Formation |
| Overlies | Toutunhe Formation (Junggar) Qiketai Formation (equivalent unit in the Turpan Basin) |
| Thickness | Over 520 m (1,710 ft) |
| Lithology | |
| Primary | Siltstone, sandstone |
| Location | |
| Coordinates | 43.6°N 87.3°E |
| Approximate paleocoordinates | 42.9°N 97.5°E |
| Region | Xinjiang |
| Country | China |
| Extent | Southern Junggar Basin (blue) Turpan Basin (disputed) (cyan) |
   Qigu Formation (China)  Qigu Formation (Dzungaria) | |
Fossil content
The mass accumulation of Jurassic freshwater turtle fossils belonging to the genus Annemys, discovered in 2009 at a site nicknamed "Mesa Chelonia" in Shanshan County, Xinjiang is thought to likely belong to the Qigu Formation, though it belongs to the strata of the Turpan Basin.[6][7] Remains of indeterminate dinosaurs, including ankylosaurs, metriacanthosaurids, and dromaeosaurids are known from the formation.[8][9][10]
The remains of indeterminate rhamphorhynchid pterosaurs have been recovered from the formation. Among others, the following fossils have been found in the formation:[11]
| Crocodyliformes of the Qigu Formation | ||||||
|---|---|---|---|---|---|---|
| Taxa | Species | Material | Location | Notes | Images | |
| Nominosuchus | Indeterminate | Liuhuanggou bonebed | ||||
| Sunosuchus | Indeterminate | |||||
| Theriosuchus | Indeterminate | |||||
| Mammaliamorphs[12] of the Qigu Formation | ||||||
|---|---|---|---|---|---|---|
| Taxa | Species | Material | Location | Notes | Images | |
| Nanolestes | N. mackennai | Liuhuanggou bonebed | ||||
| Tegotherium | Indeterminate | |||||
| Dsungarodon | D. zuoi | Docodontan | ||||
| Sineleutherus | S. uyguricus | |||||
| Eutriconodonta | Indeterminate | |||||
| Stegosaur of the Qigu Formation | ||||||
|---|---|---|---|---|---|---|
| Taxa | Species | Material | Location | Notes | Images | |
| Angustungui | A. qiketaiensis | Partial skeletons | A Stegosaurid | |||