Cookeroo, a New Genus of Fossil Kangaroo (Marsupialia, Macropodidae) from the Oligo-Miocene of Riversleigh, Northwestern Queensland, Australia

A new genus of Oligo-Miocene kangaroo (Macropodiformes), Cookeroo, and two new species, Cookeroobulwidarri and C. hortusensis, are described from the Riversleigh World Heritage Area, northern Australia. Species of Cookeroo are distinguished from other basal macropodids by possessing a unique combination of characters including an expanded masseteric canal confluent with the mandibular canal that extends to below m1, a sinuous i1 with enamel on the buccal surface only and with dorsal and ventral flanges present, a dentary with a marked inflection of the ventral border below m3, bilophodont molars, and an elongate third premolar. We assess the phylogenetic relationships of the genus using a combination of two previously published morphological matrices. Our analysis recovers Cookeroo species as early-branching members of a clade that also contains macropodines, sthenurines, and lagostrophines.