A fragment of dentary with m4, showing characters of some Late Cretaceous North American marsupials, is assigned to Marsasia sp. Marsasia Nessov, 1997 from the Coniacian of Uzbekistan, represented by M. aenigma known from edentulous dentaries with inflected angular processes, was attributed by Nessov to ?Marsupialia. Marsasia sp., found in the same horizon as the type species, resembles it in size and structure of the masseteric fossa, but differs in having a less steep coronoid process. We assign Marsasia to Marsupialia on the basis of the following characters: inflected angular process, shape of the dentary similar to that in Asiatherium, postcanine dental formula, inferred from alveoli for p1-3, m1-4, and structure of m4 more similar to Cretaceous marsupials than eutherians. The phylogenetic position of Marsasia may be between the Albian Kokopellia and Campanian Asiatherium. Marsasia is tentatively referred to the order Asiadelphia, which may represent an endemic Asian marsupial clade.

Key words: Asiadelphia, Cretaceous, Marsasia, Marsupialia, paleobiogeography, Uzbekistan.

Alexander O. Averianov [sasha@AA1923.spb.edu], Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 1, 199034 Saint Petersburg, Russia. Zofia Kielan-Jaworowska [zkielan@twarda.pan.pl], Instytut Paleobiologii PAN, ul. Twarda 51/55, PL-00-818 Warszawa, Poland.