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