Urrayira whitei gen. et sp. nov.: a dasyuromorphian (Mammalia: Marsupialia) with incipient zalambdodonty from the Middle Pleistocene of Queensland, Australia

Abstract

Urrayira whitei gen. et sp. nov. is described based on dental remains from middle Pleistocene cave sites at Mount Etna, Queensland. Its higher-level systematic affinities are unclear but it appears to be a dasyuromorphian. It is unusual in having a specialized reduced dentition characterized by reduction of the stylar cusps, protocone and talonid, resulting in an incipiently zalambdodont morphology that emphasizes the shearing crests. In addition, only two upper premolars are present, and we assume that it is P3 that has been suppressed, as has occurred multiple times within Dasyuridae. Maximum parsimony and undated Bayesian analyses of a 174 morphological character matrix intended to resolve relationships within Dasyuromorphia, with a molecular scaffold enforced, suggest that Urrayira is a dasyurid. In the maximum parsimony analysis, Urrayira is sister to Planigale gilesi (which also lacks P3), whereas in the undated Bayesian analysis, Urrayira resolves as part of a trichotomy at the base of Dasyuridae, together with Sminthopsinae and Dasyurinae; however, support values are generally low throughout the tree. While the majority of rainforest-adapted taxa in the Mount Etna sites became either extinct or were locally extirpated at, or soon after, 280 ka, there is no evidence that U. whitei gen. et sp. nov. even persisted until that time. Urrayira whitei was likely a rainforest-specialist, thus may have been particularly vulnerable to incipient effects of the Mid-Brunhes climatic shift towards aridity that eventually drove the disappearance of the Mount Etna rainforest and its associated fauna.

Jonathan Cramb* [[email protected]], Queensland Museum, PO Box 3300, South Brisbane BC, Queensland 4101, Australia; Scott Hocknull [[email protected]], Queensland Museum, PO Box 3300, South Brisbane BC, Queensland 4101, Australia; Robin M. D. Beck [[email protected]], School of Science, Engineering and Environment, University of Salford, Manchester M5 4WT, UK; Shimona Kealy [[email protected]], Archaeology and Natural History, College of Asia and the Pacific, The Australian National University, Canberra, ACT, 2601, Australia; Gilbert J. Price [[email protected]], School of Earth and Environmental Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia.

Key words:

• Dasyurid
• Dasyuromorphia
• rainforest
• zalambdodont

Acknowledgments

We acknowledge the Darumbal people, the Traditional Owners of the Mount Etna fossil sites, and pay respect to their Elders past and present. Particular thanks go to Nhaya Nicky Hatfield and LeLarnie Hatfield for sharing their language and granting permission to use the name Urrayira. We thank Cement Australia, and C. White in particular, for their proactive management of the significant fossil deposits discovered at Mt. Etna Mine, that subsequently became part of the Mt. Etna Caves National Park, protected from loss for generations to come. Special thanks to M. Archer, whose decades of work has inspired, mentored and supported all of the authors of this paper. We also thank: the Sands family for vital guidance and assistance in the field; G. E. Webb and A.M. Baker for comments on this manuscript; K. Spring and P. Wilson for collection management services; H. Janetzki and W. Goulding for access to comparative specimens, and the volunteers at QM Geosciences for assistance with specimen preparation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplemental material

Supplemental data for this article is available online at https://doi.org/10.1080/03115518.2023.2169351.

Additional information

Funding

Research was funded by Australian Research Council grant ARC LP0453664 and ARC LP0989969.