The Buff-bellied Fat-tailed Mouse Opossum is a small marsupial found from central Bolivia to northern Argentina in the Andes. It stores fat in its tail and is recorded in forest and seasonally dry forest.
Its tail stores fat seasonally and changes in size. The back is darker than the sides, and the underside is grayish. Females lack a pouch.
It is considered likely to be nocturnal. Daily torpor is also proposed as possible for this species because it occurs in other members of the genus.
An extinction-risk assessment has not been added yet.