Albumares
GRI #688
Albumares belongs to an interesting group of Ediacaran fossils, characterized by a discoidal shape and tri-radial symmetry, particularly visible in the arrangement of three central depressions, which Ivantsov & Zakrevskaya (2021) interpret as internal body cavities of the original organism collapsed after burial. Radially oriented ridges and grooves branching towards the rim of the shield are distinctively preserved on the outer surface of this fossil. This unique tri-radial body plan is encountered in several Ediacaran taxa (e.g., the iconic Tribrachidium) and is not observed in other Phanerozoic or modern taxa. For this reason, some authors have suggested that it represents “a failed evolutionary experiment in animal body plans” (Hall et al., 2020). Like other taxa of the Ediacaran Biota, Albumares is preserved as convex impressions at the base of fine-grained beds. This mean that the organisms had slight relief above the seafloor when they were buried. As observed in this slab, other Ediacaran organisms can be found on the same surface in relatively close proximity with Albumares (e.g., Dickinsonia, see separate description). Albumares has been reported from Ediacaran strata of Russia (from which this sample also comes), Australia, and India (Ivantsov & Zakrevskaya, 2021; Parihar et al, 2023).
Detail, bottom left.
Detail, top center.
References:
Hall, C.M.S., Droser, M.L., Clites, E.C. and Gehling, J.G., 2020. The short-lived but successful tri-radial body plan: a view from the Ediacaran of Australia. Australian Journal of Earth Sciences, 67(6), pp.885-895. doi:10.1080/08120099.2018.1472666.
Ivantsov, A.Y. and Zakrevskaya, M.A., 2021. Trilobozoa, Precambrian tri-radial organisms. Paleontological Journal, 55, pp.727-741. doi:10.1134/S0031030121070066.
Parihar, V.S., Hukmaram, P.K. and Harsh, A., 2023. Trilobozoans (Tribrachidium & Albumares) Ediacaran organisms from Marwar Supergroup, Western India. Current Science India, 124(4), pp.485-490. doi:10.18520/cs/v124/i4/485-490.