The buff-bellied rhipidomys is a long-tailed mouse known from the eastern Andes of southeastern Peru. It has a reddish-brown back, a pale orange underside, and a tuft at the tail tip.
The back is reddish brown and the underside pale orange. Its dark tail is longer than the head and body and ends in a conspicuous hair pencil.
The rediscovered animal was a subadult male trapped at ground level at Yanacocha in May 2010. Seeds and ants were found in its stomach, but the authors said more specimens were needed to characterize its diet.
An extinction-risk assessment has not been added yet.