The Vombatiformes are one of the three suborders of the large marsupial order Diprotodontia. Five of the seven known families within this suborder are extinct; only the families Phascolarctidae, with the koala, and Vombatidae, with three extant species of wombat, survive.Among the extinct families are the Diprotodontidae, which include the diprotodon, believed by many to be the inspiration for the bunyip.