| Anfesta stankovskii Temporal range: Ediacaran, around | |
|---|---|
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | † Trilobozoa |
| Family: | † Albumaresidae |
| Genus: | † Anfesta Fedonkin, 1984 |
| Species: | †A. stankovskii |
| Binomial name | |
| †Anfesta stankovskii Fedonkin, 1984 | |
Anfesta stankovskii is a tri-radially symmetrical fossil animal that lived in the late Ediacaran (Vendian) seafloor. It is a member of the extinct group Trilobozoa.
The generic and specific names of the Anfesta stankovskii honour the Arkhangel'sk geologist Anatoliy F. Stankovskii.
Fossils of Anfesta stankovskii are known from deposits of the Verkhovka and Yorga formations on the Karakhta River in Onega Peninsula and Zimnii Bereg (Winter Coast) of the White Sea, Arkhangelsk Region, Russia. [1] [2]
Anfesta represents a flattened, hemispherical form with three-fold symmetry. [3] At the centre of the organism, 3 elongate and sausage-like ridges radiate from the centre and are put away from each other by 120 degrees and make the animal always divisible into 3 parts and the ridges becoming rounded at both edges. [3] The same ridges bifurcate twice near both of their ends. [3] In some specimens of A. stankovskii, a large amount of furrows (originally interpreted as tentacles) appear and make Anfesta look similar in anatomy to Albumares and Skinnera (Mostly Albumares). [3] The diameter of Anfesta is thought to 18 cm (7.1 in), with the length of the ridges reaching up to 5 mm (0.20 in), and with the width of them being up to 1.3 mm (0.051 in). [3]
Anfesta was originally described by Mikhail Fedonkin as a free-swimming scyphozoa-like medusa. The branched furrows on the fossil were interpreted as imprints of a system of internal radial canals, and the three oval ridges as imprints of gonads. [1] [4]
A year later, Fedonkin transferred such fossil animals as Anfesta, Albumares and Tribrachidium to the separate group Trilobozoa, populated by three-lobed, radially symmetric, coelenterate-grade animals that only superficially resemble cnidarians. [4] [5] Originally, Trilobozoa was established as a class within the phylum Coelenterata, but since Coelenterata was divided into separate phyla - Cnidaria and Ctenophora - the Trilobozoa have been transferred to rank of phylum. [6]
According to the latest research, Anfesta was a soft-bodied benthic organism that temporarily attached (but did not adhere) to the substrate of its habitat (microbial mats). This fossil is an imprint of the upper side of the animal body, with some elements of its external and internal anatomy visible to the naked eye. The branched furrows on the fossil are imprints of radial grooves on the animal's surface, while the three central ridges 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. [3]
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. It lived during the late Ediacaran. 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.
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.
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
Vendia is a genus of oval-shaped, Ediacaran fossils ranging from 4.5 to 12.5 mm long. The body is completely segmented into isomers, which are arranged alternately in two rows longitudinal to the axis of the body. The larger isomers cover the smaller ones externally but the posterior ends of all the isomers remain free. The transverse elements decrease in size from anterior to posterior and are all inclined in the same direction.
Trilobozoa is a phylum of extinct, sessile animals that were originally classified into the Cnidaria. The basic body plan of trilobozoans is often a triradial or radial sphere-shaped form with lobes radiating from its centre. Fossils of trilobozoans are restricted to marine strata of the Late Ediacaran period.
Academician Mikhail Aleksandrovich Fedonkin is a Russian paleontologist specializing in documentation of the earliest animals' body fossils, tracks, and trails. He has also described numerous Vendian-aged fossils including Hiemalora, Cephalonega, and Nimbia occlusa.
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, near-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.
Rugoconites is a genus of Ediacaran biota found as fossils in the form of a circular or oval-like impression preserved in high relief, six or more centimeters in diameter. The fossils are surrounded by frills that have been interpreted as sets of tentacles. The bifurcating radial ribs, spreading from a central dome, serve to distinguish this genus from the sponge Palaeophragmodictya, and may represent the channels of the gastrovascular system. Fossils of Rugoconites have been interpreted as early sponges, although this is countered by Sepkoski et al. (2002), who interpreted the organism as a free-swimming jellyfish-like cnidarian; similar to Ovatoscutum. However, the fossil is consistently preserved as a neat circular form and its general morphology does not vary, therefore a benthic and perhaps slow-moving or sessile lifestyle is more likely. Ivantstov & Fedonkin (2002), suggest that Rugoconites may possess tri-radial symmetry and be a member of the Trilobozoa.
Vendiamorpha is a class of extinct animals within the Ediacaran phylum Proarticulata.
Isomer is an element of transverse body articulation of the bilateral fossil animals of the Phylum Proarticulata from the Ediacaran (Vendian) period. This term has been proposed by Andrey Yu. Ivantsov, a Russian paleontologist from the Laboratory of the Precambrian organisms, Paleontological Institute, Russian Academy of Sciences.
Veprina is a rare Ediacaran coelenterate cnidarian found on the Zimny coast of the White Sea, Russia and was first described by Mikhail Fedonkin in 1980.
Palaeoplatoda is a genus from the Ediacaran biota. It is a soft-bodied organism with a segmented body that resembles Dickinsonia, another Ediacaran organism.
Archaeaspinus fedonkini is an extinct proarticulatan organism from the Late Precambrian (Ediacaran) period.
Medvezichnus is a peculiar ichnofossil described by Mikhail A Fedonkin in 1985 in the "Systematic Description of Vendian Metazoa". The fossil of Medvezichnus pudicum is described as "a unique specimen of doubtful nature". In 'Neoproterozoic Geobiology and Paleobiology', it is stated that this form requires further documentation.
Staurinidia is a genus of Ediacaran soft-bodied organism from the deposits of the Ust'-Pinega formation. It is a monotypic genus, containing only the single species Staurinidia crucicula. The genus was first described in 1985 by Russian palaeontologist Mikhail A. Fedonkin. S. crucicula's four-fold symmetry is present as a result of four canals radiating from the middle of a small cavity in the middle of the body. Other forms with four way symmetry, mainly Medusoid forms, from the Ediacaran comprise an essential chunk of the Ediacaran diversity of symmetry; their organisations are similar to, though smaller than, those of a modern-day Scyphozoan Cnidarian.
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