Microbiotheriidae is a family of australidelphian marsupials represented by only one extant species, the monito del monte, and a number of extinct species known from fossils in South America, Western Antarctica, and northeastern Australia.

Microbiotheriids were once thought to be members of the order Didelphimorphia (which contains the Virginia opossum); however, an accumulation of both anatomical and genetic evidence in recent years has led to the conclusion that microbiotheriids and other microbiotheres are not didelphids at all, but are instead most closely related to the Australasian marsupials; together, the microbiotheres and the Australian orders form the clade Australidelphia which are now thought to have first evolved in the South American region of Gondwana.

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