This spiny rat occurs in coastal lowlands of eastern and northeastern Rio de Janeiro State, Brazil. It is recorded in moist forests and forest patches within coastal restinga.
The back ranges from olive brown to cinnamon brown, paling at the sides, with a white belly. Tails are dark above and white below in specimens from Maricá and Morro do Itaoca, but this contrast is weaker in central-range specimens.
It preferentially uses semideciduous and evergreen moist forests. In coastal restinga, where open vegetation is common, it has been recorded only in forest patches.
An extinction-risk assessment has not been added yet.