The Riversleigh rainforest koala (Nimiokoala greystanesi) is an extinct species of marsupial, closely related to the modern koala, that lived 10–16 million years ago in the middle Miocene of Queensland. It probably had a diet of leaves similar to that of the modern species, but whether it specialized on eucalypt leaves is unknown. It was a third of a modern koala's size, being 25–30 cm long, and the mouth protruded from the skull. To date a partial skull has been found along with several lower jaws and isolated teeth, containing in aggregate the entire dentition.