NEW AUSTRALIAN OLIGOCENE TO MIOCENE RINGTAIL POSSUMS (PSEUDOCHEIRIDAE) AND REVISION OF THE GENUS MARLU

Abstract

: Four genera of extinct ringtail possums have been reported from Australian Oligocene to Miocene sediments since 1987. The genus Marlu was described from two species, M. kutjamarpensis and M. praecursor (Woodburne, Tedford and Archer), from the Miocene Kutjamarpu Local Fauna (Leaf Locality) and late Oligocene Wadikali Local Fauna respectively, of northern South Australia. New fossil material referable to this genus has been collected from the Leaf Locality and the Oligocene to Miocene Riversleigh World Heritage Area in northwest Queensland. Three new species, Marlu karya sp. nov. from middle Miocene Riversleigh local faunas and Marlu syke sp. nov. and Marlu ampelos sp. nov. from the Leaf Locality as well as early to middle Miocene Riversleigh local faunas are described. A revision and rediagnosis of the genus and published species are made following the re‐examination of referred material in conjunction with the new material. Marlu is characterized by simple dentition and synapomorphies with extant pseudocheirids such as a conjoined postmetacristid and preentocristid on m1 and the loss of the entostylid ridge. New material from middle Miocene Riversleigh deposits has been referred to M. kutjamarpensis, extending the known distribution and age of that species. Re‐examination of M. praecursor has revealed the presence of a small m1 entostylid ridge, contributing further to differences between M. praecursor and all other Marlu species and raising the possibility that Marlu is paraphyletic. The new material does not contradict a sister group relationship between ‘Marlu’ (excluding M. praecursor) and the Pliocene–Pleistocene genus Pseudokoala. Homology of the pseudocheirid m1 protostylid identified in species of Paljara, Pildra and Marlu with that observed in extant species is reconsidered. The ‘protostylid’ of the extinct genera is herein described as the buccal stylid.

Sexually Dimorphic Bandicoots (Marsupialia: Peramelemorphia) From the Oligo-Miocene of Australia, First Cranial Ontogeny for Fossil Bandicoots and New Species Descriptions

“…For example, molar dimensions of Neohelos tirarensis from the Kutjamarpu LF consistently group with those of N. tirarensis from Riversleigh's FZB (Black et al 2013a). In addition, a number of other Faunal Zone B taxa also occur in the Kutjamarpu LF including the casuariid Emuarius gidju, the phascolarctid Litokoala kutjamarpensis, the vombatid Rhizophascolonus crowcrofti, the thylacoleonid Wakaleo oldfieldi, the ektopodontid Ektopodon serratus, the pseudocheirid possums Paljara tirarensae, Marlu kutjamarpensis, M. ampelos, and M. syke, and the potoroid Wakiewakie lawsoni (Godthelp et al 1989;Archer et al 2006;Gillespie 2007;Louys et al 2007;Roberts et al 2008Roberts et al , 2009Travouillon et al 2011;Black et al 2013b). Specimens of M. variae from the Kutjamarpu LF are closer in size to those from Riversleigh's FZB, supporting an early Miocene in age for this central Australian assemblage.…”

Opalisation of the Great Artesian Basin (central Australia): an Australian story with a Martian twist

“…These formations include levels of pyritic laminated carbonaceous mud (Wopfner 1974;Tonui & De Caritat 2003) and host a rich fauna of fossils including gastropods, ostracods, algae, fish, reptiles, birds and mammals (e.g. Callen 1977;Woodburne et al 1993;Alley 1998;Roberts et al 2009). During the Pliocene to Quaternary, lacustrine evaporitic sediments including arenite, calcrete and gypcrete, and aeolian sediments, deposited in the Eyre Basin (Alley 1998).…”

Understanding morphological variation in the extant koala as a framework for identification of species boundaries in extinct koalas (Phascolarctidae; Marsupialia)

“…In regard to the latter, geological age is an extrinsic feature of a species and, in itself, is of no value in determining species boundaries. It is noteworthy, however, that there is no evidence of a significant difference in age; biocorrelation of Riversleigh's Faunal Zone C assemblages with the Kutjamarpu Local Fauna is well documented (e.g., Archer et al 1997;Black 1997;Murray et al 2000a;Travouillon et al 2006;Gillespie 2007;Roberts et al 2008Roberts et al , 2009 with at least seven shared taxa identified (see next section).…”