Three New Miocene Species of Musky Rat-Kangaroos (Hypsiprymnodontidae, Macropodoidea): Description, Phylogenetics, and Paleoecology

Three new species of the macropodoid genus Hypsiprymnodon are described from early to middle Miocene fossil deposits in the Riversleigh World Heritage Area, northwestern Queensland. A phylogenetic analysis of macropodoid relationships that includes these new taxa is presented. Monophyly of Macropodinae + Sthenurinae is recovered, as is a clade comprising macropodines, sthenurines, bulungamyines, and potoroids to the exclusion of hypsiprymnodontids and balbarids. Monophyly of Balbaridae is also supported, but hypsiprymnodontids are unresolved at the base of Macropodoidea, rather than forming a clade; this is probably because the new Hypsiprymnodon species described here are currently known from relatively incomplete material (isolated maxillae and dentaries). On the assumption that these extinct forms were ecologically similar to the living species H. moschatus (as suggested by close similarities in dental morphology), their presence in Riversleigh Faunal Zones B and C corroborates previous interpretations of a wet rainforest environment in northwestern Queensland during the early to middle Miocene of Australia.