Marmosa rutteri is a mouse opossum recorded in the western Amazon. Its taxonomic revision reports captures in both seasonally flooded várzea forest and unflooded forest. The coat is described as ranging from grayish olive to yellowish.
The dorsal fur ranges from grayish olive to yellowish, while the underside is yellowish. Some specimens are described as having gray areas in the ventral fur.
The revision records captures in both seasonally flooded várzea forest and unflooded terra firme forest.
An extinction-risk assessment has not been added yet.