Late cretaceous non-avian dinosaurs from the James Ross Basin, Antarctica: description of new material, updated synthesis, biostratigraphy, and paleobiogeography
Matthew C. LAMANNA1*, Judd A. CASE2, Eric M. ROBERTS3, Victoria M. ARBOUR4, Ricardo C. ELY5, Steven W. SALISBURY6, Julia A. CLARKE7, D. Edward MALINZAK8, Abagael R. WEST9 & Patrick M. O’CONNOR10
1Section of Vertebrate Paleontology, Carnegie Museum of Natural History, 4400 Forbes Avenue, Pittsburgh, Pennsylvania 15213 USA;
2Department of Biology, Eastern Washington University, Science Building 258, Cheney, Washington 99004 USA;
3College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia;
4Royal British Columbia Museum, 675 Belleville Street, Victoria, British Columbia V8W 9W2 Canada;
5Department of Earth and Atmospheric Sciences, Indiana University, Geological Sciences Building, 1001 East 10th Street, Bloomington, Indiana 47401 USA;
6School of Biological Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia;
7Department of Geological Sciences, The University of Texas at Austin, 2275 Speedway Stop C9000, Austin, Texas 78712 USA;
8School of Natural Sciences, Black Hills State University, 1200 University Street, Spearfish, South Dakota 57799 USA;
9Department of Biological Sciences, University of Pittsburgh, 4249 Fifth Avenue,
Pittsburgh, Pennsylvania 15260 USA;
10Department of Biomedical Sciences, Ohio University College of Osteopathic Medicine, 119 Life Sciences Building, Athens, Ohio 45701 USA.
Received 7 March 2019; accepted 22 May 2019; published online 22 May 2019
Although the fossil record of non-avian dinosaurs from the Cretaceous of Antarctica is the poorest of any continent, fossils representing at least five major taxonomic groups (Ankylosauria, early-diverging Ornithopoda, Hadrosauridae, Titanosauria, and Theropoda) have been recovered. All come from Upper Cretaceous (Coniacian–Maastrichtian) marine and nearshore deposits belonging to the Gustav and Marambio groups of the James Ross Basin at the northern tip of the Antarctic Peninsula. The majority of these finds have come from the Campanian–Maastrichtian Snow Hill Island and López de Bertodano formations of James Ross and Vega islands.
Given the rarity of Antarctic Cretaceous non-avian dinosaurs, discoveries of any fossils of these archosaurs, no matter how meager, are of significance. Here we describe fragmentary new ornithischian (ankylosaur and ornithopod) material from the upper Campanian–lower Maastrichtian Cape Lamb Member of the Snow Hill Island Formation and the Maastrichtian Sandwich Bluff Member of the López de Bertodano Formation. One of these specimens is considered to probably pertain to the holotypic individual of the early-diverging ornithopod Morrosaurus antarcticus. We also provide an up-to-date synthesis of the Late Cretaceous non-avian dinosaur record of the James Ross Basin and analyze the biostratigraphic occurrences of the various finds, demonstrating that most (including all named taxa and all reasonably complete skeletons discovered to date) occur within a relatively condensed temporal interval of the late Campanian to early Maastrichtian. Most or all James Ross Basin dinosaurs share close affinities with penecontemporaneous taxa from Patagonia, indicating that at least some continental vertebrates could disperse between southern South America and Antarctica during the final stages of the Mesozoic.
Dinosauria, Antarctica, Cretaceous, James Ross Basin, biostratigraphy, paleobiogeography
Lamanna M C, Case J A, Roberts E M, et al. Late cretaceous non-avian dinosaurs from the James Ross Basin, Antarctica: description of new material, updated synthesis, biostratigraphy, and paleobiogeography. Adv Polar Sci, 2019, 30(3): **-**, doi: 10.13679/j.advps.2019.0007