Tate’s oryzomys is a large rice rat known from the eastern slope of Ecuador’s Andes. Its confirmed localities are three nearby sites along the upper Río Pastaza.
It is relatively large and dark-furred, with short incisive foramina relative to the skull and long, broad toothrows.
The collection area included a mosaic of grassland-like and subtropical vegetation, cultivated land, secondary forest, and primary forest. The author suggested it might inhabit wet, cool premontane evergreen forest, but that remains a hypothesis.
An extinction-risk assessment has not been added yet.