New specimens of caenagnathid theropods are described from the Judith River Formation (Campanian) of southern Alberta, the Hell Creek Formation (Maastrichtian) of South Dakota, and the Bissekty Formation (Turonian) of Uzbekistan. With the exception of the Hell Creek specimen, and a vertebra from Alberta, all are from the symphysial regions of the lower jaws. Caenagnathids are rare and poorly known animals, and the described fossils preserve heretofore unknown features, including vascular grooves and foramina in the symphysial region, and the pattern of overlapping sutures between jaw elements. Most of the new specimens are different from the holotype of Caenagnathus collinsi Sternberg and may represent the second described species, Caenagnathus sternbergi. The two jaws from the Bissekty Formation are the first oviraptorosaurian jaws described from Uzbekistan and represent a new genus and species anatomically closer to Caenagnathus than to central Asian forms like Oviraptor, Conchoraptor and Ingenia. There are at least five characters that distinguish caenagnathid and oviraptorid jaws, but it is concluded that the length of the symphysial region must be used with caution. Jaw anatomy supports the idea that oviraptorids were well adapted for eating eggs, although their diet was probably not restricted to one food type.

A new trionychid, Khunnuchelys gen.nov., represented by two new species, Khunnuchelys erinhotensis sp.nov. and Khunnuchelys kizylkumensis sp.nov. is described. Khunnuchelys erinhotensis is based on a large, well-preserved skull from the Iren Dabasu Formation in Inner Mongolia, and K. kizylkumensis is based on a series of partial skulls and isolated skull elements from the Dzhyrakuduk locality, Bissekty Formation, Uzbekistan. The occurrence of this trionychid in these two localities reinforces the suggestion of faunal similarity between the Iren Dabasu and Bissekty formations. Khunnuchelys is distinctive in the extensive development of the triturating surface, proportions of the skull, and features of the braincase. Conchochelys from the Paleocene of North America shares with Khunnuchelys derived features of the palate and braincase, and the two genera may be members of a monophyletic clade of trionychids. Autapomorphies of the triturating surface and associated features in Khunnuchelys are interpreted as durophagous specializations.

A lower molar of Sulestes sp., a deltatheridiid from the Coniacian of Uzbekistan, is described. The Deltatheroididae new fam. is erected. The Deltatheroididae and Deltatheridiidae are assigned to the order Deltatheroida Kielan‐Jaworowska 1982 and it is argued that the Deltatheroida are metatherians, a sister group of Marsupialia. The Deltatheroida have at least an incipient alisphenoid bulla, three premolars sharply differentiated morphologically from four molars, a very large stylar area and the protoconid higher than the metaconid. They differ from known Cretaceous marsupials in having a tendency to lose the last molar, in having a small protocone, a narrow and short talonid, and a hypoconulid and entoconid not approximated. Known deltatheroidan taxa are compared. Relationships of the Deltatheroida and Aegialodontia are discussed. The place of metatherian origin is still not known with certainty. □Mammalia, Metatheria, Deltatheroida, Marsupialia, Cretaceous, Asia, Paleobiogeography.

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