A new Oligo–Miocene marsupial lion from Australia and revision of the family Thylacoleonidae

<p><i>Wakaleo schouteni</i> sp. nov., a dog-sized marsupial lion (Thylacoleonidae), is described from late Oligocene to early Miocene sediments of the Riversleigh World Heritage Area, Queensland, Australia. Fossils of this new species include a near-complete cranium, dentaries and postcrania. This species is the second thylacoleonid known from late Oligocene sediments. The other, <i>Priscileo pitikantensis</i> Rauscher, 1987, from the Etadunna Formation of South Australia, is known from teeth, part of a palate and postcrania. <i>Wakaleo schouteni</i> exhibits cranial and dental morphology characteristic of species of <i>Wakaleo</i> but possesses a relatively plesiomorphic upper dental formula (i.e. three premolars and four molars) within Thylacoleonidae that was formerly regarded to be diagnostic for species of the genus <i>Priscileo</i>. The holotype and humerus of <i>P. pitikantensis</i> have been compared with the new <i>Wakaleo</i> material described here and found to demonstrate conspicuous similarities in morphology of the M<sup>2</sup> and the humerus. In the absence of other generically diagnostic features, <i>Priscileo</i> is here regarded to be a junior synonym of <i>Wakaleo.</i> Smaller size and relatively minor morphological differences in the proximal humerus of <i>W. pitikantensis</i> comb. nov. distinguish it at the specific level from <i>W. schouteni</i>. Phylogenetic analysis of thylacoleonids recovers <i>Wakaleo</i> as a monophyletic clade. Both <i>Wakaleo pitikantensis</i> comb. nov. and <i>W. schouteni</i> are recovered as plesiomorphic sister taxa to other species of the genus. <i>Wakaleo pitikantensis</i> and <i>W</i>. <i>schouteni</i> extend the temporal range for this genus back into the late Oligocene. Body weight for <i>W. schouteni</i>, based on total skull length, is estimated to be ∼23 kg.</p> <p><a href="http://zoobank.org/urn:lsid:zoobank.org:pub:CA8A8EC8-4F66-4F1E-81DC-240A0C4080BE" target="_blank">http://zoobank.org/urn:lsid:zoobank.org:pub:CA8A8EC8-4F66-4F1E-81DC-240A0C4080BE</a></p>