The Phascolarctidae (Phasco - pouch or bag, larct- from the Greek arctos meaning bear) are a family of marsupials of the order Diprotodontia, consisting of only one extant species, the koala, and six well-known fossil species, with another five less well known fossil species, and two fossil species of the genus Koobor, whose taxonomy is debatable but are placed in this group. The closest relatives of the Phascolarctidae are the wombats, which comprise the family Vombatidae. The fossil record of the family dates back to the Middle Miocene or Late Oligocene.