175-12 Distribution of Kimberella quadrata from the Ediacara Member, South Australia

Session: The Neoproterozoic Earth and Life Co-evolution, Part I

Presenting Author:

Heather McCandless

Authors:

McCandless, Heather¹, Boan, Phillip Charles², Botha, Tory³, Evans, Scott⁴, Hughes, Ian⁵, Surprenant, Rachel⁶, Weyland, Walker⁷, Binnie, Mary-Anne⁸, Garcia-Bellido, Diego⁹, Faehnrich, Karol¹⁰, Droser, Mary¹¹

(1) Department of Earth and Planetary Sciences, UC Riverside, Riverside, CA, USA, (2) Virginia Tech, Blacksburg, VA, USA, (3) School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia, (4) Division of Paleontology, American Museum of Natural History, New York, New York, USA, (5) Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA, (6) Department of Earth and Planetary Sciences, Yale, New Haven, CT, USA, (7) Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA, (8) Palaeontology, South Australia Museum, Adelaide, SA, Australia, (9) School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia, (10) School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia, (11) Department of Earth and Planetary Sciences, UC Riverside, Riverside, CA, USA,

Abstract:

Kimberella quadrata, a classic member of the White Sea Assemblage of the Ediacara Biota, is best known from the eponymous deposits of the White Sea in Russia but also occurs in the Ediacara Member (Rawnsley Quartzite) across the Flinders Ranges area of South Australia. Kimberella has been proposed as a stem-group mollusk, giving it evolutionary significance in the origin and persistence of complex animal life.

Within the Ediacara Member, Kimberella occurs at multiple sites including Brachina Gorge, Bunyeroo Gorge, the Chace Range, and Nilpena Ediacara National Park (NENP) where it has been previously collected from float. At NENP, Kimberella is one of the few taxa consistently found in all three fossiliferous facies of the Ediacara Member, although it is not commonly preserved at this site compared to its abundance in White Sea deposits.

At NENP, over 350m² of fossiliferous bedding planes have been excavated from the Ediacara Member, revealing thousands of fossils preserved in situ. Of the 24 beds excavated from the most fossiliferous Oscillation Rippled Sandstone facies, a single specimen of Kimberella occurs on only one bed. Within the Planar-laminated and Rip-Up Sandstone Facies, fossil surface LV-Fun possesses over 40 specimens of Kimberella to date. Spatial point pattern analysis of these Kimberella on LV-Fun indicates that they are randomly distributed across the bed, consistent with most other motile Ediacara taxa. Taphonomic studies reveal that the degree of deformation of Kimberella specimens increases with size, both within the population preserved on LV-Fun and across collected float material.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6908

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