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The Ediacaran period is a geological period of the Neoproterozoic era that spans 96 million years from the end of the Cryogenian period at 635 Mya, to the beginning of the Cambrian period at 538.8 Mya. It is the last period of the Proterozoic eon as well as the last of the so-called "Precambrian supereon", before the beginning of the subsequent Cambrian period marks the start of the Phanerozoic eon where recognizable fossil evidence of life becomes common.
Pteridinium is an erniettomorph found in a number of Precambrian deposits worldwide. It is a member of the Ediacaran biota.
Dickinsonia is a genus of extinct organism, most likely an animal, that lived during the late Ediacaran period in what is now Australia, China, Russia and Ukraine. It is one of the best known members of the Ediacaran biota. The individual Dickinsonia typically resembles a bilaterally symmetrical ribbed oval. Its affinities are presently unknown; its mode of growth has been considered consistent with a stem-group bilaterian affinity, though various other affinities have been proposed. The discovery of cholesterol molecules in fossils of Dickinsonia lends support to the idea that Dickinsonia was an animal, though these results have been questioned.
Ausia fenestrata is a curious Ediacaran period fossil represented by only one specimen 5 cm long from the Nama Group, a Vendian to Cambrian group of stratigraphic sequences deposited in the Nama foreland basin in central and southern Namibia. It has similarity to Burykhia from Ediacaran (Vendian) siliciclastic sediments exposed on the Syuzma River of Arkhangelsk Oblast, northwest Russia. This fossil is of the form of an elongate bag-like sandstone cast tapering to a cone on one end. The surface of the fossil is covered with oval depressions ("windows") regularly spaced over the surface in the manner of concentric/parallel rows. The taxonomic identity of Ausia is unresolved.
Kimberella is an extinct genus of bilaterian known only from rocks of the Ediacaran period. The slug-like organism fed by scratching the microbial surface on which it dwelt in a manner similar to the gastropods, although its affinity with this group is contentious.
Tribrachidium heraldicum is a tri-radially symmetric fossil animal that lived in the late Ediacaran (Vendian) seas. In life, it was hemispherical in form. T. heraldicum is the best known member of the extinct group Trilobozoa.
Spriggina is a genus of early bilaterian animals whose relationship to living animals is unclear. Fossils of Spriggina are known from the late Ediacaran period in what is now South Australia. Spriggina floundersi is the official fossil emblem of South Australia; it has been found nowhere else.
Yorgia waggoneri is a discoid Ediacaran organism. It has a low, segmented body consisting of a short wide "head", no appendages, and a long body region, reaching a maximum length of 25 cm (9.8 in). It is classified within the extinct animal phylum Proarticulata.
Cephalonega stepanovi is a fossil organism from Ediacaran deposits of the Arkhangelsk Region, Russia. It was described by Mikhail A. Fedonkin in 1976
Trilobozoa is a phylum of extinct, sessile animals that were originally classified into the Cnidaria. The basic body plan of trilobozoans is often a tri-radial or radial sphere-shaped form with lobes radiating from its centre. Fossils of trilobozoans are restricted to marine strata of the Late Ediacaran period.
Praecambridium sigillum is an extinct organism that superficially resembles a segmented trilobite-like arthropod. It was originally described as being a trilobite-like arthropod, though the majority of experts now place it within the Proarticulata as a close relative of the much larger Yorgia. It is from the Late Ediacaran deposit of Ediacara Hills, Australia, about 555 million years ago. On average, P. sigillum had at least 5 pairs of segments, with each unit becoming progressively larger as they approach the cephalon-like head.
Ovatoscutum concentricum is one of many enigmatic organisms known from the Ediacaran deposits of the Flinders Ranges, Australia, and the White Sea area in Russia, dating around 555 Ma.
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.
Proarticulata is a proposed phylum of extinct, bilaterally symmetrical animals known from fossils found in the Ediacaran (Vendian) marine deposits, and dates to approximately 567 to 550 million years ago. The name comes from the Greek προ = "before" and Articulata, i.e. prior to animals with true segmentation such as annelids and arthropods. This phylum was established by Mikhail A. Fedonkin in 1985 for such animals as Dickinsonia, Vendia, Cephalonega, Praecambridium and currently many other Proarticulata are described.
Vendiamorpha is a class of extinct animals within the Ediacaran phylum Proarticulata.
Vaveliksia is an extinct genus of Ediacaran Sponge-like organism with a long, tubular-shaped body and a attachment disk similar to that of Petalonamids. The Vaveliksia genus contained two species, Vaveliksia velikanovi as well as Vaveliksia vana. The two species vary in appearance to one another, with V. velikanovi having a more tubular-shaped, sack-like morphology with a crown of wrinkles on top of one of its ends as well as possessing a much more disk-like holdfast with V. vana having an appearance more similar to that of a Poriferan, with V. vana having a much more dome-shaped holdfast and a capsule-like body with no crown of wrinkles unlike V. velikanovi.
Archaeaspinus fedonkini is an extinct proarticulatan organism from the Late Precambrian (Ediacaran) period.
Cephalozoa are an extinct class of primitive segmented marine organisms within the Phylum Proarticulata from the Ediacaran period. They possessed bilateral symmetry and were characterized by a thin, rounded body.
Podolimirus is an extinct monotypic genus of unclassified proarticulates. It presents a single species, Podolimirus mirus. It was found in strata of the late Ediacaran, at the beginning of the Cambrian. It is one of the last proarticulates. The first fossils of this genus and species were found in the Ukraine along the Dneister River close by to the deposits in the Vendian Sequence in 1983.
References
- 1 2 3 4 Fedonkin, M. A. (1979). "Paleoichnology of Precambrian and Early Cambrian". In Sokolov, B. S. (ed.). Paleontology of Precambrian and Early Cambrian (in Russian). Leningrad: USSR Academy of Sciences. pp. 183–192.
- 1 2 Palij, P. M.; Posti, E.; Fedonkin, M. A. (2009). "Soft-bodied metazoa and trace fossils of Vendian and Lower Cambrian". In Keller, B. M.; Rozanov, A. Y. (eds.). Upper Precambrian and Cambrian Paleontology of East-European Platform (in Russian). Moscow: Russian Academy of Sciences. pp. 49–82.
- 1 2 Fedonkin, M. A. (2007). The rise of animals : evolution and diversification of the kingdom animalia. James G. Gehling, Kathleen Grey, Guy M. Narbonne, and Patricia Vickers-Rich. Baltimore, Md.: Johns Hopkins University Press. ISBN 9780801886799. OCLC 85162342.
- 1 2 Grazhdankin, Dima (2004). "Patterns of distribution in the Ediacaran biotas: facies versus biogeography and evolution". Paleobiology. 30 (2): 203–221. doi:10.1666/0094-8373(2004)030<0203:podite>2.0.co;2.
- ↑ Fedonkin, M. A.; Vickers-Rich, P.; Swalla, B. J.; Trusler, P.; Hall, M. (2012). "A new metazoan from the Vendian of the White Sea, Russia, with possible affinities to the ascidians". Paleontological Journal. 46 (1): 1–11. doi:10.1134/s0031030112010042. ISSN 0031-0301.
- ↑ Moitra, A. K.; Kumar, P. A.; Das Sarma, D. A. (2000). "A review of chronological status of Chuaria-Tawuia assemblage: A case study of Bhim Basin, India". Geological Survey of India. 55: 163–168.