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.Weishampel, David B; et al. (2004). "Dinosaur distribution (Early Cretaceous, Asia)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 563-570. . 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.
Vertebrate 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 elementsHalszkaraptorine 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 tapejaroidAndres, B. and Norell, M.A. 2005. The first record of a pterosaur from the Early Cretaceous strata of Öösh (Övörkhangai; Mongolia). American Museum Novitates 3472: 1–6. "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
See also List of dinosaur-bearing rock formations
References