The Long-haired Spiny Tree-rat is known from two sites in northern Peru’s upper montane forest. Its long coat mixes hair with thin, less prominent spines.
Compared with related forms, its spines are less prominent and are longer, thinner, and more mixed with fur. The underside is more hairy than spiny, and crown fur covers the tops of the ears.
The holotype was trapped under tree roots in heavy forest.
The upper surfaces of the forefeet and hindfeet are pale buff, and the digits are white.
The tail is brown throughout and ends in a long, well-developed hair pencil.
An extinction-risk assessment has not been added yet.