{{Short description|Geologic formation in Russia}} {{Infobox rockunit | name = Udurchukan Formation | period = Maastrichtian | age = Maastrichtian<br>~{{fossil range|70|66}} | image = | imagesize = | caption = | type = Geological formation | prilithology = Conglomerate, mudstone, diamictite | otherlithology = Sandstone | unitof = Tsagayan Group | subunits = | underlies = Bureya Formation | overlies = Kundur Formation | thickness = {{Convert|11|m|ft|-1}} exposed at Kundur locality | area = | map = {{Location map+ | Russia#Russia Amur Oblast | relief = 1 | width = 250 | float = center | places = {{Location map~ | Russia#Russia Amur Oblast | lat_deg = 49.5 | lon_deg = 129.5 | mark = Lightgreen pog.svg | marksize = 12 }} }} | map_caption = | location = | coordinates = {{coord|49.5|N|129.5|E|display=inline,title}} | paleocoordinates = {{coord|51.4|N|115.8|E|display=inline}} | region = Amur Oblast | country = Russia | extent = Zeya-Bureya Basin | namedfor = <!--Usually a nearby town--> | namedby = <!--Author of defining paper--> | year_ts = <!--Year of definition--> | location_ts = <!--Place,mountain,...--> | coordinates_ts = | paleocoordinates_ts = | region_ts = <!--Region of type section--> | country_ts = <!--Country of type section--> | thickness_ts = <!--Thickness at type section--> }} 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 ==
[[File:Olorotitan, Anserimimus, and Charonosaurus.jpg |thumb|left| 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 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.
=== Dinosaurs === {{Paleobiota-key-compact}} ==== Ornithischians ==== ===== Ankylosaurs ===== {| class="wikitable" align="center" |- ! colspan="7" align="center" | '''Ankylosaurs reported from the Udurchukan Formation''' |- ! Taxon ! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |- |Nodosauridae<ref>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. </ref> | indet. | Kundur | Upper |A tooth, an incomplete tooth and an osteo dermal scute. | An indeterminate nodosauridae. |- |}
===== Hadrosaurs ===== {| class="wikitable" align="center" |- ! colspan="7" align="center" | '''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.<ref>{{cite journal |last1=Lauters |first1=Pascaline |last2=Bolotsky |first2=Yuri L. |last3=Van Itterbeeck |first3=Jimmy |last4=Godefroit |first4=Pascal |title=Taphonomy and Age Profile of a Latest Cretaceous Dinosaur Bone Bed in Far Eastern Russia |journal=PALAIOS |date=March 1, 2008 |volume=23 |issue=3 |pages=153–162 |url=https://doi.org/10.2110/palo.2006.p06-031r |access-date=1 May 2021 |publisher=SEPM Society for Sedimentary Geology|doi=10.2110/palo.2006.p06-031r |bibcode=2008Palai..23..153L |url-access=subscription }}</ref> | center|150px |- | ''Kerberosaurus'' | ''K. manakini'' | Blagoveschensk | | The caudal part of cranium consists of a braincase. | A saurolophine hadrosaur | center|frameless |- | ''Kundurosaurus'' | ''K. nagornyi'' | Kundur | | A partial, disarticulated skull. | A saurolophine hadrosaur; possibly synonymous with ''Kerberosaurus'' | center|150px |- |Hadrosaurinae |Indetermidate | | | | | |- | ''Olorotitan'' | ''O. arharensis'' | Kundur | | A nearly complete skeleton. | A hadrosaur | center|150px |- |}
==== Sauropods ==== {| class="wikitable" align="center" |- ! colspan="7" align="center" | '''Sauropods reported from the Udurchukan Formation''' |- ! Taxon ! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |- style="background:#E6E6E6;"| | ''Arkharavia''<ref>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. </ref> | ''A. heterocoelica'' | Kundur | Upper | A single tooth and a proximal tail vertebrae, although some remains probably belong to a hadrosaurid. | A Somphospondyli sauropod.<ref name="mannionetal">{{cite journal|doi=10.1111/zoj.12029|title=Osteology of the Late Jurassic Portuguese sauropod dinosaur ''Lusotitan atalaiensis'' (Macronaria) and the evolutionary history of basal titanosauriforms|journal=Zoological Journal of the Linnean Society|volume=168|pages=98–206|year=2013|last1=Mannion|first1=Philip D.|last2=Upchurch|first2=Paul|last3=Barnes|first3=Rosie N.|last4=Mateus|first4=Octávio|doi-access=free}}</ref> | 200px|center |- |Opisthocoelicaudiinae |Indetermidate. | | | | | |- |Titanosauria |Indetermidate | | | | | |}
==== Theropods ==== {| class="wikitable" align="center" |- ! colspan="7" align="center" | '''Theropods reported from the Udurchukan Formation''' |- ! Taxon ! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |- |Albertosaurinae | Indetermidate | | | | | |- | rowspan =2|Dromaeosaurinae | Indetermidate. | | | | rowspan = 2| | rowspan = 2| |- | Indeterminate. | | | |- |Ornithomimidae<ref name=ornithomimidaeindet>{{Cite journal |last1=Averianov |first1=Alexander |last2=Skutschas |first2=Pavel |last3=Bolotsky |first3=Yuriy |last4=Bolotsky |first4=Ivan |date=2023-12-31 |title=First find of an ornithomimid theropod dinosaur in the Upper Cretaceous of the Russian Far East |url=https://www.researchgate.net/publication/377971612 |journal=Biological Communications |volume=68 |issue=4 |doi=10.21638/spbu03.2023.405 |issn=2587-5779|doi-access=free }}</ref> | Indetermidate. | | | | Described as being very similar to ''Qiupalong''<ref name=ornithomimidaeindet /> | |- | ''Richardoestesia'' |'' R. sp'' | | | | | |- | ''Saurornitholestes'' | ''S. cf. sp.'' | | | | | |- | Theropoda | Indeterminate | | | | | |- |''Troodon'' | ''T. sp.'' | | | | | |- | Tyrannosaurinae | Indetermidate. | | | | Similar in size to ''Tyrannosaurus''<ref>{{Cite journal |last1=Yun |first1=Changyu |title=Testing the hypotheses of the origin of ''Tyrannosaurus rex'': immigrant species, or native species? |url=https://www.aaps-journal.org/pdf/JPS.C.2017.01.pdf |journal=The Journal of Paleontological Sciences |pages=1–9}}</ref> | |}
=== Reptiles === {| class="wikitable" align="center" |- ! colspan="7" align="center" | '''Reptiles reported from the Udurchukan Formation''' |- ! Taxon ! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |- | ''Amuremys'' |''A. planicostata'' | | | | | rowspan = 100| |- | Cimolodonta | indet. | | | | |- | Crocodylia | indet. | | | | |- |Lindholmemydidae | indet. | | | | |- |''Shamosuchus'' |''S. sp.'' | | | | |- | Testudines | indet. | | | | |- |Trionychidae |indet. | | | | |- |}
=== Insects === {| class="wikitable" align="center" |- ! colspan="7" align="center" | '''Plants reported from the Udurchukan Formation''' |- ! Taxon ! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |- | ''Mesosigara'' |''M. kryshtofovichi'' | | | | | |- |}
=== Flora === {| class="wikitable" align="center" |- ! colspan="7" align="center" | '''Plants reported from the Udurchukan Formation''' |- ! Taxon ! Species ! Location ! Stratigraphic position ! Material ! Notes ! Images |- style="background:#D1FFCF;" | ''Cupressinoxylon'' |''C. sp.'' | | | | | |- |}
== See also == * {{C|Geology of Russia}} * {{C|Fossils of Russia}}
== References == {{Reflist}}
=== Bibliography === * Y. A. Popov. 1971. Historical development of the infraorder Nepomorpha (Heteroptera). Akademiya Nauk SSSR, Trudy Paleontologicheskogo Instituta 129:1-228
Category:Geologic formations of Russia Category:Upper Cretaceous Series of Asia Category:Maastrichtian Stage Category:Conglomerate formations Category:Mudstone formations Category:Sandstone formations Category:Fluvial deposits Category:Paleontology in Russia Category:Geology of the Russian Far East Category:Geography of Amur Oblast Category:Cretaceous Russia