Albumares brunsae is a tri-radially symmetrical fossil animal that lived in the late Ediacaran seafloor. It is a member of the extinct group Trilobozoa.[1]
Etymology
The generic name Albumares derives from the Latin Mare Album (White Sea).[1] The specific name "brunsae" honors Elizabeth P. Bruns, an early 20th-century Russian geologist noted for her extensive and important research of the Upper Precambrian[a] stratigraphy of European Russia.[1]
Occurrence
Fossils of the Albumares brunsae are known from deposits on the Verkhovka formation on the Syuzma River in the Onega Peninsula of the White Sea, Arkhangelsk Region, Russia.[1][2] There are reports about Albumares sp. from the Rawnslay Quartzite, Flinders Ranges in the South Australia, but photographs or description of these fossils have not yet been published.[3]
Description
Albumares fossils are preserved as negative, low impressions on the bases of sandstone beds. The fossil exhibits circular, trefoil-like (three-lobe) form, and is covered by three dendritic-branched furrows and three oval ridges that radiate from the center. The lobes are twisted into weak spirals.[4][5][1][2][6]
The diameters of known specimens vary from 8 to 15 millimeters.[4]
Reconstruction and affinity
Albumares was originally described by Mikhail Fedonkin as a free-swimming scyphozoanjellyfish. The branched furrows on the fossil were interpreted as imprints of a system of internal radial canals and tentacles along the outer margin of the fossil, with the three oval ridges described as imprints of mouth lobes[1][2] or gonades.[6]
Later, with the discovery of the closely related Anfesta and with their seeming affinities to Tribrachidium, Fedonkin appointed these animals to the Trilobozoa, an extinct group of the tri-radially symmetrical coelenterate-like animals that only superficially resembled cnidarians.[6][7] Originally, Trilobozoa was established as a class in the phylumCoelenterata, but since Coelenterata has been divided into two separate phyla, Cnidaria and Ctenophora, Trilobozoa itself has been promoted to the rank of phylum.[8]
According to the latest research, Albumares was a soft-bodied benthic organism that temporarily attached (but did not adhere) to the substrate of its habitat (microbial mats). This fossil typically displays as an imprint of the upper side of the animal's body, and often some elements of its internal structure can be discerned. The branched furrows on the fossil are imprints of radial grooves on the surface of the animal, while the three ridges in the central part of the fossil are imprints of cavities within the body. Presumably, this system of grooves and cavities could be related to the collection and digestion of food particles.[4]
^In stratigraphy, an upper era is a more recent period than a lower era, as exemplified by the usage of era divisions such as the Upper Paleolithic period and Lower Paleolithic period(Lower paleolithic is an early phase of the paleolithic period and Upper comes much later).
^ abcKeller, B.M.; Fedonkin, M.A. (1977). "New organic fossil finds in the Precambrian Valday series along the Syuz'ma River". International Geology Review. 19 (8): 924–930. Bibcode:1977IGRv...19..924K. doi:10.1080/00206817709471091.
^ abcFedonkin, M.A. (1985). "Systematic Description of Vendian Metazoa". In Sokolov, B.S.; Iwanowski, A.B. (eds.). Vendian System: Historical–Geological and Paleontological Foundation (in Russian). Vol. 1: Paleontology. Moscow: Nauka. pp. 70–106.
^Fedonkin, M.A. (1990). "Precambrian Metazoans". In Briggs D.; Crowther P. (eds.). Palaeobiology: A Synthesis(PDF). Blackwell. pp. 17–24. Archived from the original(PDF) on 2012-01-12. Retrieved 2013-03-23.
^Runnegar, B.N.; Fedonkin, M.A. (1992). "Proterozoic Metazoan Body Fossils". In Schopf, J.W.; Klein, C. (eds.). The Proterozoic Biosphere: A Multidisciplinary Study. Cambridge University Press. p. 373. ISBN9780521366151.
