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Attenborites janeae gen. et sp. nov., is a new enigmatic fossil from the Ediacara Member of the Rawnsley Quartzite, South Australia. Attenborites is a well-defined irregular oval to circular fossil preserved in negative hyporelief ranging in length from 4.5–24 mm. Preserved internal grooves and ridges, variable in number and running parallel to the long axis, typically converge towards one end of the specimen. This taxon is unlike any previously described both in terms of overall morphology and in terms of the irregular nature of the outer and inner morphology. While there are no direct morphological characters that suggest that this organism was pelagic, the nature of preservation suggests that a pelagic lifestyle should at least be considered. However, it is not possible to say whether this animal was likely a ctenophore, cnidarian or a pelagic organism of unknown affinity. [ABSTRACT FROM AUTHOR]

There are multiple tri-radially symmetric taxa among the Ediacara Biota, but the tri-radial body plan is unique to this time; taxa with threefold symmetry go extinct by the beginning of the Cambrian. Many of these taxa are included in a morphogroup referred to as Trilobozoa or Triradialomorpha. Abundant specimens of these tri-radial taxa exist at the Nilpena National Heritage Ediacara fossil site and at other sites throughout Australia. Here, we review the occurrence and diversity of tri-radial genera from the Australian Ediacaran, including Albumares, Anfesta, Coronacollina, Hallidaya, Rugoconites, Skinnera and Tribrachidium and evaluate the possibility that their shared symmetry unites them phylogenetically. We find that, with the exception of Coronacollina, these taxa are morphologically similar enough to justify considering them a clade of related organisms. The diversity and abundances of these taxa in South Australia provide a unique venue for research investigating the relationships among these Ediacaran taxa. [ABSTRACT FROM AUTHOR]

Here we describe a new fossil, Obamus coronatus gen. et sp. nov., from the Ediacara Member of the Rawnsley Quartzite. O. coronatus is preserved in negative hyporelief and is defined by an overall torus shape produced by a series of arch-shaped spiral grooves. Commonly, a circular to ovate raised inner portion is preserved. Both taphonomic and size-related morphological variability of this new taxon highlight the value of a suite of specimens in order to recognise and describe new taxa of soft-bodied organisms. The poorly preserved outer margin on O. coronatus indicates that the organism was benthic, sessile and at least partially embedded within the organic mat covering the Ediacaran seafloor. [ABSTRACT FROM AUTHOR]

We present findings from the newly discovered fossiliferous bed, TB-ARB, from the Ediacara Member exposed at the National Heritage Site, Nilpena Station, west of the Flinders Ranges, South Australia. TB-ARB contains Ediacaran fossils, some of which are rare, remarkably preserved as casts in fine-grained sandstone with little evidence for taphonomic disturbance. Here we demonstrate that, despite extraordinary preservation, ecological metrics from TB-ARB are characteristic of those found on other Ediacara Member beds and that this fossil assemblage is consistent with the previously recognised heterogeneity of the Ediacaran seafloor. This result suggests that limited taphonomic processes identified on more typical beds at Nilpena do not bias our view of Ediacaran paleoecology, but together, these beds present a complete picture of ancient animal communities. Remarkable preservation of rare Andiva ivantsovi allows investigations of morphology, growth and life habit. We identify complex growth in this organism that maximises surface area relative to volume and a morphology consistent with previously unsubstantiated claims for mobility. Features of Andiva indicate that it was likely related to two other extinct Ediacaran flat-lying, modular, mobile taxa, Dickinsonia and Yorgia, suggesting a possible eumetazoan placement for this organism. [ABSTRACT FROM AUTHOR]

Abstract: The paleoenvironmental setting in which the Ediacara Biota lived, died, and was preserved in the eponymous Ediacara Member of the Rawnsley Quartzite of South Australia is an issue of long‐standing interest and recent debate. Over the past few decades, interpretations have ranged from deep marine to shallow marine to terrestrial. One of the key features invoked by adherents of the terrestrial paleoenvironment hypothesis is the presence of iron oxide coatings, inferred to represent the upper horizons of paleosols, along fossiliferous sandstone beds of the Ediacara Member. We find that these surficial oxides are characterized by (234U/238U) values which are not in secular equilibrium, indicating extensive fluid‐rich alteration of these surfaces within the past approximately 2 million years. Specifically, the oxide coatings are characterized by (234U/238U) values >1, indicating interaction with high‐(234U/238U) fluids derived from alpha‐recoil discharge. These oxides are also characterized by light “stable” δ238/235U values, consistent with a groundwater U source. These U isotope data thus corroborate sedimentological observations that ferric oxides along fossiliferous surfaces of the Ediacara Member consist of surficial, non‐bedform‐parallel staining, and sharply irregular patches, strongly reflecting post‐depositional, late‐stage processes. Therefore, both sedimentological and geochemical evidence indicate that Ediacara iron oxides do not reflect synsedimentary ferruginization and that the presence of iron oxides cannot be used to either invoke a terrestrial paleoenvironmental setting for or reconstruct the taphonomic pathways responsible for preservation of the Ediacara Biota. These findings demonstrate that careful assessment of paleoenvironmental parameters is essential to the reconstruction of the habitat of the Ediacara Biota and the factors that led to the fossilization of these early complex ecosystems. [ABSTRACT FROM AUTHOR]