266-2 Environmental and biological implications for the distribution of Parvancorina at Nilpena Ediacara National Park, South Australia
Session: The Neoproterozoic Earth and Life Co-evolution (Posters)
Poster Booth No.: 109
Presenting Author:
Phillip BoanAuthors:
Boan, Phillip Charles1, McCandless, Heather2, Droser, Mary L.3(1) Department of Geosciences, Virginia Tech, Blacksburg, Virginia, USA, (2) Department of Earth and Planetary Sciences, University of California, Riverside, Riverside, California, USA, (3) Department of Earth and Planetary Sciences, University of California, Riverside, Riverside, California, USA,
Abstract:
The Ediacara biota represents the earliest complex macroscopic animal communities in the fossil record, and have revealed insights into early metazoan evolution and ecology. Exceptional preservation at Nilpena Ediacara National Park (NENP) has enabled the excavation of over 40 fossiliferous bedding surfaces from the Ediacara Member of the Rawnsley Quartzite, revealing 10,000s of individual Ediacaran fossils. Parvancorina, an anchor-shaped soft-bodied organism associated with rheotaxes, is a common taxon at both NENP and the White Sea of Russia. Here we examine the spatial distributions of four Parvancorina populations (1T-A, 1T-FA, TC-MM3, and WS-PARV), on beds that vary in mat maturity, depositional environment, and preservational conditions. Results show that populations composed of smaller individuals were strongly aggregated (1T-A), while larger individuals displayed spatial randomness (1T-FA and TC-MM3). One population, located in a particularly high-energy environment (WS-PARV), exhibited a heterogeneous Poisson distribution, indicating that the population varied in density across the bed and implying an external effect on the population. Our data indicate that the spatial distribution of Parvancorina changes over their lifetime, with juveniles occurring within an aggregated spat while adults are found in random distributions. This further confirms that, at least within certain environments at NENP, there was limited competition and a relative abundance of resources for the adult Parvancorina. The variability in density of the Parvancorina population on WS-PARV suggests that their pattern was heavily influenced by biostratinomy, with strong currents likely removing large portions of the population. This current is indicated by the presence of toolmarks, otherwise highly uncommon on NENP beds, as well as stretched and twisted Dickinsonia, and pulled out fronds.
Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025
doi: 10.1130/abs/2025AM-6910
© Copyright 2025 The Geological Society of America (GSA), all rights reserved.
Environmental and biological implications for the distribution of Parvancorina at Nilpena Ediacara National Park, South Australia
Category
Topical Sessions
Description
Session Format: Poster
Presentation Date: 10/22/2025
Presentation Room: HBGCC, Hall 1
Poster Booth No.: 109
Author Availability: 9:00–11:00 a.m.
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