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The Udurchukan Formation is a geological formation located in Amur Region, Far East Russia. Based on palynomorphs such as Wodehouseia spinata the Udurchukan is considered of Maastrichtian age of the Late Cretaceous, during the Cretaceous Period.

Udurchukan Formation
Stratigraphic range: Maastrichtian
~70–66 Ma
TypeGeological formation
Unit ofTsagayan Group
UnderliesBureya Formation
OverliesKundur Formation
Thickness11 metres (40 ft) exposed at Kundur locality
PrimaryConglomerate, mudstone, diamictite
Coordinates49°30′N 129°30′E / 49.5°N 129.5°E / 49.5; 129.5Coordinates: 49°30′N 129°30′E / 49.5°N 129.5°E / 49.5; 129.5
Approximate paleocoordinates51°24′N 115°48′E / 51.4°N 115.8°E / 51.4; 115.8
RegionAmur Oblast
Country Russia
ExtentZeya-Bureya Basin
Udurchukan Formation is located in Russia
Udurchukan Formation
Udurchukan Formation (Russia)


Fossil recordEdit

Inasmuch as Wodehouseia spinata and Aquillapollenites subtilis are known in the Americas only from the Late Maastrichtian, the presence of these palynomorphs in the Udurchukan caused Godefroit to consider the unit and its lambeosaur dominated fauna to be coeval with the Lance Formation and Hell Creek Formation. However, research in the Songliao Basin indicates Wodehouseia spinata is also known from the early (albeit not basal) and middle Maastrichtian of Asia.

The latest view, appearing in the paper on comparative osteology of Edmontosaurus and Shantungosaurus, is that one Udurchukan Formation locality, Kundur, is late−early Maastrichtian; and the other, Blagoveschensk, is early−late Maastrichtian. The Udurchukan Formation now appears somewhat older than the Lance and Hell Creek, albeit not by much.


Dinosaurs reported from the Udurchukan Formation
Genus Species Location Stratigraphic position Material Notes Images
Amurosaurus A. riabinini Blagoveschensk A lambeosaurine hadrosaur
Arkharavia A. heterocoelica A single tooth, proximal tail vertebrae The holotype belongs to a sauropod, but the other remains probably belong to an indeterminate hadrosaur.[1]
Kerberosaurus K. manakini Blagoveschensk A saurolophine hadrosaur
Kundurosaurus K. nagornyi Kundur A saurolophine hadrosaur; possible synonymous with Kerberosaurus
Olorotitan O. arharensis Kundur A hadrosaur

Other fossilsEdit

See alsoEdit


  1. ^ Mannion, Philip D.; Upchurch, Paul; Barnes, Rosie N.; Mateus, Octávio (2013). "Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms". Zoological Journal of the Linnean Society. 168: 98. doi:10.1111/zoj.12029.


  • Y. A. Popov. 1971. Historical development of the infraorder Nepomorpha (Heteroptera). Akademiya Nauk SSSR, Trudy Paleontologicheskogo Instituta 129:1-228