Öösh Formation
Geological formation in Övörkhangai, Mongolia
The Öösh Formation, also known as the Tevsh Formation, is a geological formation of Lower Cretaceous strata in Övörkhangai Province, Mongolia. Dinosaur remains are among the fossils that have been recovered from the formation. It overlies folded and metamorphosed basement strata of the Gobi region, and is capped by basalt. The succession is around 600 metres thick and consists of red claystones and sandstones, along with black thinly laminated shales. The claystones and sandstones were deposited as part of an alluvial fan system, while the shales were deposited in lakes present in the foot of the fan. Many of the fossils come from the "Cannonball beds", which comprise the lowest 60 metres of the unit and consist of green siltstone.
01Vertebrate paleofauna
Dinosaurs
| Dinosaurs of the Öösh Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Asiatosaurus | A. mongoliensis | Teeth | Indeterminate sauropod | |||
| Halszkaraptorinae indet. | ISMD-VP09, preserving a maxillary fragment, two teeth, and partial appendicular elements | Halszkaraptorine | ||||
| Prodeinodon | P. mongoliensis | Several teeth, fragmentary tibia, fragmentary fibula | Indeterminate theropod | |||
| Protiguanodon | P. mongoliensis | Reclassified as a species of Psittacosaurus, Psittacosaurus protiguanodonensis | ||||
| Psittacosaurus | P. mongoliensis | |||||
| P. protiguanodonensis | Junior synonym of P. mongoliensis | |||||
| Shanag | S. ashile | Upper and lower jaw fragment (IGM 100/1119) | A paravian, possibly a dromaeosaur | |||
Mammals
| Mammals of the Öösh Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Gobiconodon | G. hopsoni | Cannonball Member of Öösh Formation, possibly equivalent of Tevsh Formation | Two upper and lower jaws (PSS-MAE 140 (Holotype) & PSS-MAE 139) | |||
Pterosaurs
| Pterosaurs of the Öösh Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Indeterminate tapejaroid | "Single cervical vertebra (IGM 100/1321)" | |||||
Squamates
| Squamates of the Öösh Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Norellius | N. nyctisaurops | "Nearly complete skull with mandibles and partial hyoid" | Gekkonomorph | |||
Color key
|
Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited. |
Sources and credits
This article is adapted from the Wikipedia article “Öösh Formation”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- Psittacosaurus stomach stones.jpg by Ryan Somma, CC BY-SA 2.0
- Shanag skull.png by Skye McDavid, CC BY-SA 4.0
- GobiconodonDB15.jpg by DiBgd, CC BY-SA 4.0
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