What is "hyotheridium"

Hyotheridium is a possible Eutherian from the Late Cretaceous (?late Santonian–early Campanian) Djadochta Formation of Mongolia. It could be also be a Deltatheriid, although the fossil, a poorly preserved skull with the upper and lower jaws connected in a way that makes them hard to separate and to examine, makes it difficult to determine what it is.