New Tertiary koala (Marsupialia, Phascolarctidae) from Riversleigh, Australia, with a revision of phascolarctid phylogenetics, paleoecology, and paleobiodiversity

ABSTRACT

Here we describe the most plesiomorphic koala yet known. Priscakoala lucyturnbullae, gen. et sp. nov., is the fourth and largest koala species described from Miocene deposits in the Riversleigh World Heritage area, northern Australia. It is known from a maxilla with M1–3 and isolated M2, M3 or M4 and m1. Relationships within the diprotodontian suborder Vombatiformes are clarified using cranial and dental characters based on a data set compiled from new and more complete cranial materials for each of the respective vombatiform families. Monophyly of Phascolarctidae is supported by the development of a protostylid and metastylid on m1. Priscakoala lucyturnbullae is the most plesiomorphic phascolarctid. Inclusion in the analysis of the enigmatic Pliocene genus Koobor, currently classified as Vombatiformes incertae sedis, indicates phascolarctomorphian affinities for the genus.

ACKNOWLEDGMENTS

Support for Riversleigh research has been provided by the Australian Research Council (DP043262, DP1094569, LP0453664, LP0989969, LP100200486), Xstrata Community Partnership Program North Queensland, Queensland Parks and Wildlife Service, Environment Australia, the Queensland and Australian Museums, University of New South Wales, P. Creaser and the CREATE Fund at the University of New South Wales, Outback at Isa, Mount Isa City Council, and the Waanyi people of northwestern Queensland. Vital assistance in the field has come from many hundreds of volunteers as well as staff and postgraduate students of the University of New South Wales. Skilled preparation of material described in this paper has been carried out by A. Gillespie. We thank H. Godthelp for constructive criticism of an earlier draft of this paper, and two anonymous reviewers for their thoughtful comments.

Handling editor: Blaire Van Valkenburgh