All known species are endemic to the Caribbean island of Hispaniola (in the present-day Dominican Republic and Haiti).

The genus name Plagiodontia means "oblique tooth", and derives from the two ancient greek words πλάγιος (plágios), meaning "placed sideways", and ὀδούς, ὀδόντος (odoús, odóntos), meaning "tooth".

[1][2] This genus contains the following three species (two of them extinct): Within Capromyidae, Plagiodontia is the deepest branching genus, belonging to the tribe Plagiodontini.

It is the sister group to the other genera Geocapromys, Mesocapromys, Mysateles and Capromys, all belonging to the tribe Capromyini.

Trinomys (Atlantic spiny rats) Clyomys Euryzygomatomys (guiaras) Carterodon (Owl's spiny rat) Plagiodontia Geocapromys Capromys (Desmarest's hutia) Mesocapromys Mysateles Data related to Plagiodontia at Wikispecies