Phylogenetic implications of macropodid (Marsupialia: Macropodoidea) posteranial remains from Miocene deposits of Riversleigh, northwestern Queensland

A new sthenurine taxon, Rhizosthenurus flanneryi gen. et sp. nov. from middle late Miocene deposits of Riversleigh, northwestern Queensland, is established on the basis of material previously assigned to Bulungamayinae. Postcranial remains belonging to an indeterminate basal macropodid are described. Cladistic analysis of 50 discrete postcranial characters coded for 16 ingroup and two outgroup taxa suggests that R. flanneryi is the most plesiomorphic member of a clade containing the late Miocene macropodid Hadronomas puckridgi and crown-group sthenurines. The indeterminate basal macropodid is placed as the immediate sister taxon to the bulungamayine Ganguroo bilamina and a monophyletic clade containing macropodines and sthenurines. This arrangement supports consideration of bulungamayines as ancestral to other macropodids and suggests that macropodines and sthenurines are monophyletic. However, the possibility of a diphyletic origin for Macropodinae and Sthenurinae from within Bulungamayinae cannot be dismissed.