Early Cretaceous polar biotas of Victoria, southeastern Australia—an overview of research to date

Abstract

Poropat, S.F., Martin, S.K., Tosolini, A.-M.P., Wagstaff, B.E, Bean, L.B., Kear, B.P., Vickers-Rich, P. & Rich, T.H., May 2018. Early Cretaceous polar biotas of Victoria, southeastern Australia—an overview of research to date. Alcheringa 42, 158–230. ISSN 0311-5518.

Although Cretaceous fossils (coal excluded) from Victoria, Australia, were first reported in the 1850s, it was not until the 1950s that detailed studies of these fossils were undertaken. Numerous fossil localities have been identified in Victoria since the 1960s, including the Koonwarra Fossil Bed (Strzelecki Group) near Leongatha, the Dinosaur Cove and Eric the Red West sites (Otway Group) at Cape Otway, and the Flat Rocks site (Strzelecki Group) near Cape Paterson. Systematic exploration over the past five decades has resulted in the collection of thousands of fossils representing various plants, invertebrates and vertebrates. Some of the best-preserved and most diverse Hauterivian–Barremian floral assemblages in Australia derive from outcrops of the lower Strzelecki Group in the Gippsland Basin. The slightly younger Koonwarra Fossil Bed (Aptian) is a Konservat-Lagerstätte that also preserves abundant plants, including one of the oldest known flowers. In addition, insects, crustaceans (including the only syncaridans known from Australia between the Triassic and the present), arachnids (including Australia’s only known opilione), the stratigraphically youngest xiphosurans from Australia, bryozoans, unionoid molluscs and a rich assemblage of actinopterygian fish are known from the Koonwarra Fossil Bed. The oldest known—and only Mesozoic—fossil feathers from the Australian continent constitute the only evidence for tetrapods at Koonwarra. By contrast, the Barremian–Aptian-aged deposits at the Flat Rocks site, and the Aptian–Albian-aged strata at the Dinosaur Cove and Eric the Red West sites, are all dominated by tetrapod fossils, with actinopterygians and dipnoans relatively rare. Small ornithopod (=basal neornithischian) dinosaurs are numerically common, known from four partial skeletons and a multitude of isolated bones. Aquatic meiolaniform turtles constitute another prominent faunal element, represented by numerous isolated bones and articulated carapaces and plastrons. More than 50 specimens—mostly lower jaws—evince a high diversity of mammals, including monotremes, a multituberculate and several enigmatic ausktribosphenids. Relatively minor components of these fossil assemblages are diverse theropods (including birds), rare ankylosaurs and ceratopsians, pterosaurs, non-marine plesiosaurs and a lepidosaur. In the older strata of the upper Strzelecki Group, temnospondyl amphibians—the youngest known worldwide—are a conspicuous component of the fauna, whereas crocodylomorphs appear to be present only in up-sequence deposits of the Otway Group. Invertebrates are uncommon, although decapod crustaceans and unionoid bivalves have been described. Collectively, the Early Cretaceous biota of Victoria provides insights into a unique Mesozoic high-latitude palaeoenvironment and elucidates both palaeoclimatic and palaeobiogeographic changes throughout more than 25 million years of geological time.

Stephen F. Poropat*† [[email protected]; [email protected]], Faculty of Science, Engineering and Technology, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia; Sarah K. Martin*‡ [[email protected]; [email protected]] Geological Survey of Western Australia, 100 Plain St, East Perth, Western Australia 6004, Australia; Anne-Marie P. Tosolini [[email protected]] and Barbara E. Wagstaff [[email protected]] School of Earth Sciences, The University of Melbourne, Melbourne, Victoria 3010, Australia; Lynne B. Bean [[email protected]] Research School of Earth Sciences, Australian National University, Acton, Canberra, Australian Capital Territory 2001, Australia; Benjamin P. Kear [[email protected]] Museum of Evolution, Uppsala University, Norbyvägen 16, Uppsala SE-752 36, Sweden; Patricia Vickers-Rich§ [[email protected]; [email protected]] Faculty of Science, Engineering and Technology, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia; Thomas H. Rich [[email protected]] Museum Victoria, PO Box 666, Melbourne, Victoria 3001, Australia. *These authors contributed equally to this work. †Also affiliated with: Australian Age of Dinosaurs Museum of Natural History, Lot 1 Dinosaur Drive, PO Box 408, Winton, Queensland 4735, Australia. ‡Also affiliated with: Earth and Planetary Sciences, Western Australian Museum, Welshpool, Western Australia 6101, Australia. §Also affiliated with: School of Earth, Atmosphere and Environment, Monash University, Melbourne, Victoria 3800, Australia.

Key words:

• Australia
• Victoria
• Cretaceous
• Dinosaur Cove
• Koonwarra
• palaeoclimate
• palaeobiogeography

Disclosure statement

BPK is Chief Editor of Alcheringa, but did not contribute to the processing or production of this manuscript at any stage. Alcheringa Associate Editor Stephen McLoughlin (Swedish Natural History Museum) alternatively undertook all editorial responsibilities, reviewer selection and decision making related to publication. All other authors declare no conflicts of interest.

Supplementary material

The supplementary material for this paper is available online at https://doi.org/10.1080/03115518.2018.1453085

Acknowledgements

This paper is dedicated to the late David Pickering who, as Collection Manager at Museums Victoria, excavated, prepared and studied Victorian Cretaceous fossils for many years. The authors would like to thank all of those involved in the Koonwarra, Dinosaur Cove and Dinosaur Dreaming projects: Koonwarra excavation leaders Jim Bowler, Jack Douglas, John Talent, Jim Warren, Mike Waldman and Andrew Drinnan; Koonwarra collectors Leon Costermans, Peter Duncan, Peter Handby, James McQueen and Fons VandenBerg; Rob Glenie, who reinvigorated the search for Cretaceous tetrapods on the Victorian coast; John Long and Tim Flannery for discovering the fossils that led to more intense prospecting along the Victorian coast; tireless Victorian coastal prospectors Mike Cleeland, Andrew Constantine, Lesley Kool, Andrew Ruffin and Nick van Klaveren; Dinosaur Cove and Dinosaur Dreaming dig leaders Lesley Kool and David Pickering; Dinosaur Dreaming dig co-ordinators Marion Anderson, Katch Bacheller, Anne Leorke, Doris Seegets-Villiers, Alan Tait, Nick van Klaveren, Wendy White and Corrie Williams; long-serving dig volunteers Gerrit Kool, Mike and Pip Cleeland, Mary Walters, Nicole and Alan Evered, Norman Gardiner, John Wilkins, Peggy Cole, Darren Bellingham, Astrid Werner, Caroline Ennis, John Swinkels, Rohan Long, Cindy Hann, Alanna Maguire, Dean Wright, Danielle Shean, Nicola Sanderson, Roger Close, Kim Douglas, Mike Greenwood, Lisa Nink and Jacqui Tumney; long-serving specimen preparators Paul Chedgey, Lesley Kool, Geoff Lawson, David Pickering and Alan Tait; and all others who have participated in the Victorian Cretaceous adventure to date. Were it not for their efforts, it would not have been worth our while to write this paper. In addition, we are grateful to the National Geographic Society and private donors for funding, Atlas Copco for equipment, Bimbi Park and Cape Otway Lighthouse for accommodation, Sue Hadden and her team at Parks Victoria for their advice and understanding in the issue of research permits over the years and to the local rangers in the Otways and Gippsland Coast for their interest and help in collecting and samples and keeping an eye on our sites and fossil finds, VicRoads for their assistance in access to sites along the South Gippsland Highway and for the drilling scheme to help understand the Koonwarra lake deposits, Sally Rogers-Davidson and Draga Gelt for assistance with graphics over the years, Joy Evans and the Denny Family for their assistance with the Otway digs, Monash University, and Museums Victoria. We would also like to warmly thank Rolf Schmidt and Tim Ziegler of Museums Victoria for facilitating access to specimens in their care; Steve Morton, Francesco Coffa, Frank Holmes, Jon Augier and Shane Ahyong for the use of their photographs in this work; Peter Trusler for the use of his stunning reconstructions; Ian Duddy for his comments on the geological setting section; and all those who assisted in providing access to literature including Bill Birch, Lydia Heap, Chris Mays, André Nel, Martin Norvick, Alan Partridge, Emiliana Sferco, Greg Smith, Jennifer Totterdell, Brittany Turner and Fons VandenBerg. Finally, the authors would like to thank Cai Chenyang, John Long and Phil Bell for their helpful and constructive reviews of the manuscript, and to Stephen McLoughlin for his editorial critique, which greatly enhanced this work. SKM publishes with the permission of the Geological Survey of Western Australia.