The family Aplodontiidae also known as Aplodontidae, Haplodontiidae or Haploodontini is traditionally classified as the sole extant family of the suborder Protrogomorpha. It may be the sister family of the Sciurids.There are fossils from the Oligocene until Miocene in Asia, from Oligocene in Europe and from the Oligocene until nowadays in North America, where there is the only living species: the Mountain Beaver (Aplodontia rufa).