These include four species of ringtail possum (Petauridae), Australia's only two tree-kangaroo species Dendrolagus lumholtzi and D. bennettianus, and the musky rat-kangaroo Hypsiprymnodon moschatus, which is the smallest and in many respects the most primitive of the macropods.    From Wordnik.com.  [Wet Tropics of Queensland World Heritage Site, Australia] Reference