''Anfesta stankovskii'' is a tri-radially symmetrical fossil animal that lived in the late

Ediacaran The Ediacaran Period ( ) is a geological period that spans 96 million years from the end of the Cryogenian Period 635 million years ago (Mya), to the beginning of the Cambrian Period 538.8 Mya. It marks the end of the Proterozoic Eon, and th ...

(Vendian) seafloor. It is a member of the extinct group

Trilobozoa ''Trilobozoa'' (meaning "three-lobed animals") is a phylum of extinct mobile animals that were originally classified into the Cnidaria. The basic body plan of ''Trilobozoa'' is often a tri-radial or radial sphere-shaped form with lobes radiating ...

Etymology

The generic and specific names of the ''Anfesta stankovskii'' honour the

Arkhangel'sk Arkhangelsk (, ; rus, Арха́нгельск, p=ɐrˈxanɡʲɪlʲsk), also known in English as Archangel and Archangelsk, is a city and the administrative center of Arkhangelsk Oblast, Russia. It lies on both banks of the Northern Dvina near ...

geologist Anatoliy F. Stankovskii.

Occurrence

Fossils of ''Anfesta stankovskii'' are known from deposits of the Verkhovka and Yorga formations on the Karakhta River in

Onega Peninsula The Onega Peninsula is located in Arkhangelsk Oblast, Russia. It protrudes into the White Sea, with Onega Bay to the south-west, and Dvina Bay to the north-east. The length of the peninsula is about , and the width varies between and . Geog ...

and Zimnii Bereg (Winter Coast) of the

White Sea The White Sea (russian: Белое море, ''Béloye móre''; Karelian and fi, Vienanmeri, lit. Dvina Sea; yrk, Сэрако ямʼ, ''Serako yam'') is a southern inlet of the Barents Sea located on the northwest coast of Russia. It is su ...

Arkhangelsk Region Arkhangelsk Oblast (russian: Арха́нгельская о́бласть, ''Arkhangelskaya oblast'') is a federal subject of Russia (an oblast). It includes the Arctic archipelagos of Franz Josef Land and Novaya Zemlya, as well as the Solove ...

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

Description

''Anfesta'' represents a flattened, hemispherical form with three-fold symmetry. 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. The same ridges bifurcate twice near both of their ends. 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 ''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. Etymology The generic name ''Albumares'' derives from the Latin ''Mare Album'' (White ...

and Skinnera (Mostly ''Albumares''). The diameter of ''Anfesta'' is thought to , with the length of the ridges reaching up to , and with the width of them being up to .

Reconstruction and affinity

''Anfesta'' was originally described by

Mikhail Fedonkin Academician Mikhail Aleksandrovich Fedonkin (russian: Михаи́л Алекса́ндрович Федо́нкин; born June 19, 1946) is a Russian paleontologist specializing in documentation of the earliest animals' body fossils, tracks, an ...

as a free-swimming

scyphozoa The Scyphozoa are an exclusively marine class of the phylum Cnidaria, referred to as the true jellyfish (or "true jellies"). The class name Scyphozoa comes from the Greek word ''skyphos'' (), denoting a kind of drinking cup and alluding to the ...

-like

medusa In Greek mythology, Medusa (; Ancient Greek: Μέδουσα "guardian, protectress"), also called Gorgo, was one of the three monstrous Gorgons, generally described as winged human females with living venomous snakes in place of hair. Those ...

. 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. A year later, Fedonkin transferred such fossil animals as ''Anfesta'', ''

'' and ''

Tribrachidium ''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. Etymology ...

'' to the separate group

, populated by three-lobed, radially symmetric, coelenterate-grade animals that only superficially resemble cnidarians. Originally, Trilobozoa was established as a class within the phylum

Coelenterata Coelenterata is a term encompassing the animal phyla Cnidaria (coral animals, true jellies, sea anemones, sea pens, and their relatives) and Ctenophora (comb jellies). The name comes , referring to the hollow body cavity common to these two phyl ...

, but since Coelenterata was divided into separate phyla -

Cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that th ...

and

Ctenophora Ctenophora (; ctenophore ; ) comprise a phylum of marine invertebrates, commonly known as comb jellies, that inhabit sea waters worldwide. They are notable for the groups of cilia they use for swimming (commonly referred to as "combs"), an ...

- the Trilobozoa have been transferred to rank of phylum. According to the latest research, ''Anfesta'' was a soft-bodied

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

organism that temporarily attached (but did not adhere) to the substrate of its habitat (

microbial mat A microbial mat is a multi-layered sheet of microorganisms, mainly bacteria and archaea, or bacteria alone. Microbial mats grow at interfaces between different types of material, mostly on submerged or moist surfaces, but a few survive in deserts. ...

s). 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.

References

{{Taxonbar, from1=Q1953468, from2=Q21245969 Ediacaran life Trilobozoa White Sea fossils Fossil taxa described in 1984 Ediacaran Aquatic animals

Etymology

Occurrence

Description

Reconstruction and affinity

See also

References