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A polar dinosaur-track assemblage from the Eumeralla Formation (Albian), Victoria, Australia

2011; Taylor & Francis; Volume: 36; Issue: 2 Linguagem: Inglês

10.1080/03115518.2011.597564

1752-0754

Anthony J. Martin, Thomas H. Rich, Michael A Hall, Patricia Vickers-Rich, Gonzalo M. Vazquez‐Prokopec,

Coronary Artery Anomalies

Abstract Martin, A.J., Rich, T.H., Hall, M., Vickers-Rich, P. & Vazquez-Prokopec, G., June 2012. A polar dinosaur-track assemblage from the Eumeralla Formation (Albian), Victoria, Australia. Alcheringa 36, 171–188. ISSN 0311-5518. The Eumeralla Formation (Aptian–Albian) of the Otway Group in Victoria, Australia, has yielded a significant amount of dinosaur skeletal material since the late 1970s, which, when combined with finds from the Wonthaggi Formation (Aptian) of the upper Strzelecki Group, constitute the best-documented polar-dinosaur assemblage in the Southern Hemisphere. In contrast, dinosaur tracks have barely augmented this body fossil record; up to now, only one ornithopod track had been documented in any detail from the Otway Group. In this study, we report a new find of at least 24 dinosaur tracks preserved on two ripple-bedded sandstone blocks of the Eumeralla Formation, discovered at Milanesia Beach, Victoria. This dinosaur-track assemblage is the best in terms of numbers and quality found thus far in formerly polar environments of the Southern Hemisphere. One block includes the first known dinosaur trackway from the Cretaceous of Victoria, consisting of three consecutive footprints made by a small theropod. The assemblage indicates three differently sized theropods, thus providing new insights on dinosaur diversity and activity not indicated previously by body fossils in the Eumeralla Formation. Tracks are preserved in fluvial floodplain deposits and were possibly imprinted on emergent floodplain surfaces following seasonal flooding during a polar summer. The abundant tracks at this site suggest more such finds are likely in floodplain deposits of the Otway Group, although behavioural and preservational conditions unique to polar environments may have limited their formation. Anthony J. Martin and Gonzalo Vazquez-Prokopec [geoam@learnlink.emory.edu, gmvazqu@emory.edu] Department of Environmental Studies, Emory University, Atlanta, GA 30322, USA; Thomas H. Rich [trich@museum.vic.gov.au] Museum Victoria, Melbourne, Victoria, Australia; Michael Hall, Patricia Vickers-Rich and secondary address of Anthony J. Martin [mike.hall@monash.edu, pat.rich@monash.edu] School of Geosciences, Monash University, Clayton, Victoria 3800, Australia. Received 15.4.2011; revised 6.6.2011; accepted 14.6.2011. Key words: Otway BasinCretaceoustrackwayfootprintspolar faunatheropodsornithopods Acknowledgements Greg Denney is heartily thanked for discovering Block B with its dinosaur tracks, his local knowledge of coastal Victoria, and his expert guidance on various excursions with two of us (AJM and THR) along the rugged Victoria coast. Similarly, Deb Moore provided helpful logistical and moral support for those of us who conducted fieldwork in the area during June 2010. Museum Victoria graciously provided partial travel funding for AJM, and a field vehicle (with fuel) for AJM and THR during their fieldwork in the area. The Emory University Faculty Travel Fund granted the remaining travel funding for AJM, for which he is extremely grateful. David Pickering (Museum Victoria) assisted two of us (THR and PVR) with follow-up fieldwork at the site and recovery of the blocks, which are now at Museum Victoria. Ruth Schowalter and Naomi Hall are much appreciated for their spousal support of AJM and MH, respectively. Ms Schowalter accompanied three of us (AJM, THR, MH) to the site and assisted in some rugged field reconnaissance of the probable stratigraphic source of the track-bearing blocks, all while her husband (AJM) remained safely sedentary studying the tracks. The manuscript was improved considerably through the detailed and helpful reviews of Anthony (Tony) Fiorillo (Museum of Nature & Science, Dallas), Martin Lockley (University of Colorado-Denver), and Steve McLouglin (editor of Alcheringa). The Victoria Park Service is thanked for providing PVR with a collecting permit (No. 10004616) for fossils found in the area. Peter Burns (National Parks, Apollo Bay) is especially appreciated for giving advice on responsible processes and procedures for our study, respecting this beautiful area of Australia.