Distribution and preservation of Kimberella quadrata from the Ediacara Member, South Australia

The fossil Kimberella quadrata is one of the most morphologically complex members of the soft-bodied Ediacara Biota. Kimberella and its trace fossil, Kimberichnus teruzzii, are largely known from the White Sea region of Russia, where Kimberella occurs abundantly. Kimberella occurs rarely in the Flinders Ranges area of South Australia, previously identified almost exclusively from float material. Here, we leverage previously collected specimens and 51 body fossils recently uncovered on a single bedding surface at Nilpena Ediacara National Park to examine Kimberella and Kimberichnus from the Ediacara Member of South Australia. We find that body and trace fossils are widely distributed both geographically and across a variety of shallow water facies throughout the Ediacara Member. Geometric morphometrics indicate that Kimberella grew allometrically, becoming more oblong as overall size increased. Larger specimens are also preserved with reduced vertical relief compared to smaller ones, demonstrating preferential deformation of larger Kimberella during burial. We find similarities between the distribution, morphology, and deformation patterns of Kimberella specimens from Russia and South Australia. These data thus affirm that despite the palaeogeographic distance between these regions, both populations of Kimberella likely represent the same species. All data are consistent with a Lophotrochozoan affinity for Kimberella and the possibility of this taxon representing a stem-group mollusc.Heather K. McCandless* [[email protected]] Department of Earth and Planetary Sciences, University of California, Riverside, 900 University Ave, Riverside, CA 92521, USA; Tory L. Botha [[email protected]] School of Biological Sciences, Adelaide University, Adelaide, South Australia 5005, Australia; Phillip C. Boan [[email protected]] Department of Geosciences, Virginia Tech, 926 West Campus Drive Blacksburg, VA 24061, USA; Scott D. Evans [[email protected]] Department of Invertebrate Palaeontology, American Museum of Natural History, 200 Central Park West, New York, NY 10024, USA; Ian V. Hughes [[email protected]] Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St, Cambridge, MA 02138, USA; Diego C. García-Bellido [[email protected]] School of Biological Sciences, Adelaide University, Adelaide, South Australia 5005, Australia; South Australian Museum, Adelaide, South Australia 5000, Australia; Walker C. Weyland [[email protected]] Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St, Cambridge, MA 02138, USA; Rachel L. Surprenant [[email protected]] Department of Physical Sciences, San Diego City College, 1313 Park Boulevard, San Diego, CA 92101-4787, USA; Mary-Anne N. Binnie [[email protected]] South Australian Museum, Adelaide, South Australia 5000, Australia; Karol Faehnrich [[email protected]] School of Biological Sciences, Adelaide University, Adelaide, South Australia 5005, Australia; Mary L. Droser [[email protected]] Department of Earth and Planetary Sciences, University of California, Riverside, 900 University Ave, Riverside, CA 92521, USA.