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Type |
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Age |
Late Cretaceous |
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Lithology |
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Named After |
Bayan Mandahu |
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Location |
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Region |
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Country |
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The Bayan Mandahu Formation is a geological unit of "redbeds" located near the village of Bayan Mandahu in Inner Mongolia, China Asia (Gobi Desert) and dates from the Late Cretaceous Period. Laid down in the early Campanian, possibly starting in the latest Santonian, it is dated somewhat uncertainly at about 84-75 mya (million years ago).
The paleoenvironment it preserves was semi-arid and characterized by alluvial (stream-deposited) and eolian (wind-deposited) sediments. The formation is known for its vertebrate fossils, most of which are preserved in unstrcutured sandstone, indicating burial by wind-blown sandstorms.[1]
Fauna[]
The fauna of the Bayan Mandahu is very similar in composition to the nearby Djadochta Formation, and the two may have been deposited at roughly the same time. These two formations share many of the same genera, but differ in the makeup of species. For example, the most common mammal in the Djadochta is Kryptobaatar dashzevegi, while in the Bayan Mandahu, it is the closely related Kryptobaatar mandahuensis. Similarly, the dinosaur fauna of the Djadochta includes Protoceratops andrewsi and Velociraptor mongoliensis, while the Bayan Mandahu contains Protoceratops hellenikorhinus and Velociraptor osmolskae.[2]
Birds and other theropods[]
| Theropod dinosaurs of the Bayan Mandahu Formation | ||||
|---|---|---|---|---|
| Taxa | Presence | Description | Images | |
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Eggs similar to those attributed to Gobipteryx minuta in the Djadochta Formation. |  Velociraptor mongoliensis | ||
| An oviraptorid similar to O. philoceratops. | ||||
| Also present in the Djadochta Formation. | A troodontid. | |||
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A tyrannosaur of uncertain classification. | |||
| Also present in the Djadochta Formation. | A dromaeosaurid. | |||
| A dromaeosaurid. | ||||
Crocodylomorphs[]
| Crocodylomorphs of the Bayan Mandahu Formation | ||||
|---|---|---|---|---|
| Taxa | Presence | Description | Images | |
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A mesoeucrocodylian. | |||
Lizards[]
| Lizards of the Bayan Mandahu Formation | ||||
|---|---|---|---|---|
| Taxa | Presence | Description | Images | |
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An agamid. | |||
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Worm lizards. | |||
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A diploglossan. | |||
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Iguanian lizards. | |||
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A monitor lizard. | |||
Mammals[]
| Mammals of the Bayan Mandahu Formation | ||||
|---|---|---|---|---|
| Taxa | Presence | Description | Images | |
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Also present in the Djadochta Formation. | A placental. | ||
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The most common mammal in this formation.[2] | A multituberculate. | ||
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Multituberculates. | |||
Ornithischian dinosaurs[]
| Ornithischian dinosaurs of the Bayan Mandahu Formation | ||||
|---|---|---|---|---|
| Taxa | Presence | Description | Images | |
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A hadrosaur of uncertain classification. |  Skull of Magnirostris dodsoni | ||
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A ceratopsian. | |||
| An ankylosaur. | ||||
| A ceratopsian. | ||||
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A giant ceratopsian. | |||
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Sauropods[]
| Sauropod dinosaurs of the Bayan Mandahu Formation | ||||
|---|---|---|---|---|
| Taxa | Presence | Description | Images | |
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A diplodocid of uncertain classification. | |||
Turtles[]
| Turtles of the Bayan Mandahu Formation | ||||
|---|---|---|---|---|
| Taxa | Presence | Description | Images | |
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A softshell turtle. | |||
See also[]
- Barun Goyot Formation
- List of fossil sites (with link directory)
- Nemegt Formation
- List of dinosaur-bearing rock formations
References[]
- ^ a b c d e f g h i j k l m n o p q r Jerzykiewicz, T.; Currie, P.J., Eberth, D.A., Johnston, P.A., Koster, E.H., and Zheng J. (1993). "Djadokhta correlative strata in Chinese Inner Mongolia: An overview of the stratigraphy, sedimentary geology, and paleontology and comparisons with the type locality in the pre-Altai Gobi.". Canadian Journal of Earth Sciences 30: 2180–2195. [printed early 1994]
- ^ a b c d e Godefroit, Pascal; Currie, Philip J.; Li Hong; Shang Chang Yong; and Dong Zhi-ming (2008). "A new species of Velociraptor (Dinosauria: Dromaeosauridae) from the Upper Cretaceous of northern China". Journal of Vertebrate Paleontology 28 (2): 432–438. doi:.