Udurchukan Formation

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
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 is located in Russia
Udurchukan Formation
Udurchukan Formation (Russia)
Udurchukan Formation is located in Amur Oblast
Udurchukan Formation
Udurchukan Formation (Amur Oblast)

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.

Fossil content

Dinosaurs of Udurchukan Formation

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 lambeosaurine 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.

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.

Dinosaurs

Ornithischians

Ankylosaurs
Anylosaurs reported from the Udurchukan Formation
Taxon Species Location Stratigraphic position Material Notes Images
Nodosauridae indet. Kundur Upper A tooth, an incomplete tooth and an osteo dermal scute. A nodosaurid ankylosaur
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 lambeosaurin lambeosaurine which was the most common dinosaur in the area, a bonebed containing many specimens was unearthed in 2008.
Kerberosaurus K. manakini Blagoveschensk The caudal part of cranium consists of a braincase. A edmontosaurin saurolophine
Kundurosaurus K. nagornyi Kundur A partial, disarticulated skull. A edmontosaurin saurolophine; possibly synonymous with Kerberosaurus manakini.
Hadrosaurinae indet. Indetermidate
Olorotitan O. arharensis Kundur A nearly complete skeleton. A lambeosaurin lambeosaurine

Sauropods

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

Theropods

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

Reptiles

Reptiles reported from the Udurchukan Formation
Taxon Species Location Stratigraphic position Material Notes Images
Amuremys A. planicostata A lindholmemydid turtle
Crocodylia indet. Indeterminate
Lindholmemydidae indet. Indeterminate
Shamosuchus S. sp.
Testudines indet. Indeterminate
Trionychidae indet. Indeterminate

Mammals

Mammals reported from the Udurchukan Formaton
Taxon Species Location Stratigraphic Position Material Notes Images
Cimolodonta indet. Indeterminate
Stygimys S. kuszmauli A eucosmodontid djadochtatherioid

Insects

Insects reported from the Udurchukan Formation
Taxon Species Location Stratigraphic position Material Notes Images
Mesosigara M. kryshtofovichi

Flora

Plants reported from the Udurchukan Formation
Taxon Species Location Stratigraphic position Material Notes Images
Cupressinoxylon C. sp.

See also

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. ↑ Bolotsky, Yu.L.; Godefroit, P. (2004). "A new hadrosaurine dinosaur from the Late Cretaceous of far Eastern Russia". Journal of Vertebrate Paleontology. 24 (2): 351–365. Bibcode:2004JVPal..24..351B. doi:10.1671/1110. S2CID 130691286.
  4. ↑ Pascal Godefroit; Yuri L. Bolotsky; Pascaline Lauters (2012). "A New Saurolophine Dinosaur from the Latest Cretaceous of Far Eastern Russia". PLOS ONE. 7 (5) e36849. Bibcode:2012PLoSO...736849G. doi:10.1371/journal.pone.0036849. PMC 3364265. PMID 22666331.
  5. ↑ Godefroit, Pascal; Bolotsky, Yuri; Alifanov, Vladimir (2003). "A remarkable hollow-crested hadrosaur from Russia: an Asian origin for lambeosaurines" (PDF). Comptes Rendus Palevol. 2 (2). Cellule MathDoc/CEDRAM: 143–151. Bibcode:2003CRPal...2..143G. doi:10.1016/s1631-0683(03)00017-4. ISSN 1631-0683.
  6. ↑ 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.
  7. ↑ 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.
  8. ↑ Averianov, A.O.; Bolotsky, YL; Bolotsky, YI (2023-03-14). "A Sauropod from the Late Cretaceous of the Amur Region". Doklady Earth Sciences. 507: S418–S419. doi:10.1134/S1028334X22601547. S2CID 257498576.
  9. 1 2 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.
  10. ↑ Yun, Changyu. "Testing the hypotheses of the origin of Tyrannosaurus rex: immigrant species, or native species?" (PDF). The Journal of Paleontological Sciences: 1–9.
  11. ↑ Averianov, A. O.; Bolotsky, Y. L.; Godefroit, P.; Bolotsky, I. Yu. (2025). "Multituberculate mammal of possible North American affinity in the Maastrichtian of the Russian Far East". Historical Biology: 1–8. doi:10.1080/08912963.2025.2557935.

Bibliography