Latest Miocene ostracods from the Bookpurnong Formation in the Murray Basin of southeastern Australia: shallow marine migrants into an epicontinental sea

Abstract

The uppermost Miocene Bookpurnong Formation within the Murray Basin of southeastern Australia overlies a regionally extensive subaerial unconformity formed by relatively low late Miocene eustatic sea levels, and the initial phase of the Kosciuszko Uplift tectonic event. A diverse marine fossil ostracod fauna has been recovered from the Bookpurnong Formation, and is associated with a marine transgression that flooded inland regions of southeastern Australia to form a shallow epicontinental sea. Many of the Bookpurnong Formation ostracods represent immigrant taxa, with species such as Puriana lubbockiana, evidencing a subtropical range expansion of thermophilic warm water forms into southern mid-latitudes. We attribute this to warm plumes from the East Australian Current, which would have impacted southeastern Australia at that time. In general, the Bookpurnong Formation ostracod assemblages indicate low to moderate energy shallow offshore palaeoenvironments subject to warm-temperate and subtropical conditions. One new genus and five new species are described: Fortistriginglymus gen. nov., Bradyleberis praecristatella sp. nov., Callistocythere bookpurnongensis sp. nov., Callistocythere mchenryi sp. nov., Callistocythere zigzaga sp. nov., and Parakeijia notoreticularis sp. nov.

Keywords:

• Ostracoda
• marine transgression
• taxonomy
• late Miocene
• southeast Australia

Acknowledgements

A.P.M. acknowledges funding from a Deakin University postgraduate scholarship. M.T.W. thanks staff at the Geological Survey of South Australia and NMV for access to samples and information. John Ward (Deakin University) assisted with use of SEM facilities. Comments from two anonymous reviewers and the Editorial Board of Alcheringa substantially improved the content and layout of our manuscript.

Additional information

Notes on contributors

Abbey P. McDonald

Abbey P. McDonald [[email protected]], School of Life and Environmental Sciences and Centre for Integrative Ecology, Melbourne Campus, Deakin University, Geelong, Victoria 3220, Australia.

Mark T. Warne

Mark T. Warne [[email protected]], School of Life and Environmental Sciences and Centre for Integrative Ecology, Melbourne Campus, Deakin University, Geelong, Victoria 3220, Australia, and Museums Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia.