PARVANCORINA: THE NEXT GENERATION, A GROWTH MODEL OF HOW AN EDIACARAN ORGANISM LIVES LONG AND PROSPERS

Generally, the fossil record is significantly time-averaged with single bedding planes recording multiple generations of organisms; concentrating fossils from extended time intervals into a bedding plane which formed in a much shorter period of time. However, the Ediacara Member of the Rawnsley Quartzite within Nilpena Ediacara National Park of South Australia preserves discrete and fossiliferous bedding planes whose formation was facilitated by an organically-stabilized substrate. These organically bound sediments inhibited seafloor amalgamation of synlithological beds and facilitated the capture of individual “snapshots” of the Ediacaran seafloor.

This has allowed for significant excavation of hundreds of square meters of bedding planes representing non-time-averaged fossil communities. Pronounced size-distribution peaks of the Ediacaran taxon Parvancorina (n = 236), as well as others such as Tribrachidium (n = 50), across six fossil surfaces are interpreted as evidence of seasonal recruitment which enables the reconstruction of growth models and allows for direct comparison with models of growth for extant taxa.