Udurchukan Formation

Udurchukan Formation
Stratigraphic range: Maastrichtian
~
TypeGeological formation
Unit ofTsagayan Group
UnderliesBureya Formation
OverliesKundur Formation
Thickness11 metres (40 ft) exposed at Kundur locality
Lithology
PrimaryConglomerate, mudstone, diamictite
OtherSandstone
Location
Coordinates49°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
CountryRussia
ExtentZeya-Bureya Basin
Udurchukan Formation (Russia)

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.

Fossil record

Since 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

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Ornithischians

Ankylosaurs
Ankylosaurs reported from the Udurchukan Formation
Taxon Species Location Stratigraphic position Material Notes Images
Nodosauridae[1] indet. Kundur Upper A tooth, an incomplete tooth and an osteo dermal scute. An indeterminate nodosauridae.
Hadrosaurs
Hadrosaurs reported from the Udurchukan Formation
Taxon Species Location Stratigraphic position Material Notes Images
Amurosaurus A. riabinini Blagoveschensk A partial remnants of skull and lower jaw. A lambeosaurine hadrosaur which was the most common dinosaur in the area, a bonebed containing many specimens was unearthed in 2008.[2]
Kerberosaurus K. manakini Blagoveschensk The caudal part of cranium consists of a braincase. A saurolophine hadrosaur
Kundurosaurus K. nagornyi Kundur A partial, disarticulated skull. A saurolophine hadrosaur; possibly synonymous with Kerberosaurus
Hadrosaurinae Indetermidate
Olorotitan O. arharensis Kundur A nearly complete skeleton. A hadrosaur

Sauropods

Sauropods reported from the Udurchukan Formation
Taxon Species Location Stratigraphic position Material Notes Images
Arkharavia[3] A. heterocoelica Kundur Upper A single tooth and a proximal tail vertebrae, although some remains probably belong to a hadrosaurid. A Somphospondyli sauropod.[4]
Opisthocoelicaudiinae Indetermidate.
Titanosauria Indetermidate

Theropods

Theropods reported from the Udurchukan Formation
Taxon Species Location Stratigraphic position Material Notes Images
Albertosaurinae Indetermidate
Dromaeosaurinae Indetermidate.
Indeterminate.
Ornithomimidae[5] Indetermidate. Described as being very similar to Qiupalong[5]
Richardoestesia R. sp
Saurornitholestes S. cf. sp.
Theropoda Indeterminate
Troodon T. sp.
Tyrannosaurinae Indetermidate.

Other fossils

Reptiles
Insects
  • Mesosigara kryshtofovichi
Flora
  • Cupressinoxylon sp.

See also

  • Geology of Russia
  • Fossils of Russia

References

  1. ^ Tumanova, Tatiana & Bolotsky, Yu.L. & Alifanov, Vladimir. (2004). The first finds of armored dinosaurs in the Upper Cretaceous of Russia (Amur Region). Paleontological Journal. 38. 73-77.
  2. ^ Lauters, Pascaline; Bolotsky, Yuri L.; Van Itterbeeck, Jimmy; Godefroit, Pascal (March 1, 2008). "Taphonomy and Age Profile of a Latest Cretaceous Dinosaur Bone Bed in Far Eastern Russia". PALAIOS. 23 (3). SEPM Society for Sedimentary Geology: 153–162. Bibcode:2008Palai..23..153L. doi:10.2110/palo.2006.p06-031r. Retrieved 1 May 2021.
  3. ^ Alifanov, Vladimir & Bolotsky, Yu. (2010). Arkharavia heterocoelica gen. et sp. nov., a new sauropod dinosaur from the Upper Cretaceous of the Far East of Russia. Paleontological Journal. 44. 84-91. 10.1134/S0031030110010119.
  4. ^ 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: 98–206. doi:10.1111/zoj.12029.
  5. ^ a b Averianov, Alexander; Skutschas, Pavel; Bolotsky, Yuriy; Bolotsky, Ivan (2023-12-31). "First find of an ornithomimid theropod dinosaur in the Upper Cretaceous of the Russian Far East". Biological Communications. 68 (4). doi:10.21638/spbu03.2023.405. ISSN 2587-5779.

Bibliography

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