''Pteridinium'' is an

erniettomorph The Erniettomorphs are a form of Ediacaran fossil consisting of rows of airbed-like tubes arranged along a midline with a glide symmetry. Representative genera include ''Ernietta'', '' Phyllozoon'', ''Pteridinium'', ''Swartpuntia''. Undisputed E ...

found in a number of

Precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of th ...

deposits worldwide. It is a member of the

Ediacaran biota The Ediacaran (; formerly Vendian) biota is a taxonomic period classification that consists of all life forms that were present on Earth during the Ediacaran Period (). These were composed of enigmatic tubular and frond-shaped, mostly sess ...

Body plan

The three-lobed body is generally flat such that only two lobes are visible. Each lobe consists of a number of parallel ribs extending back to the main axis where the three lobes come together. Even on well-preserved specimens, there is no sign of a mouth, anus, eyes, legs, antennae, or any other appendages or organs. The organism grew primarily by the addition of new units, probably at both ends, with the inflation of existing units contributing little to its growth.

Ecology

Specimens found in what is thought to be life positions indicate that the creature rested on — or possibly in — the

sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand ...

in shallow seas. No tracks are known that would seem to be consistent with a moving ''Pteridinium''. It is unclear whether it performed

photosynthesis Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in ...

, or osmotically extracted nutrients from seawater.

Occurrence

Fossils are common in late Precambrian deposits in

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest o ...

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

, and 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 s ...

region of

Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-ei ...

. It has also been found in

North Carolina North Carolina () is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. The state is the List of U.S. states and territories by area, 28th largest and List of states and territories of the United ...

and is reported from

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

and the

Northwest Territories The Northwest Territories (abbreviated ''NT'' or ''NWT''; french: Territoires du Nord-Ouest, formerly ''North-Western Territory'' and ''North-West Territories'' and namely shortened as ''Northwest Territory'') is a federal territory of Canada. ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by to ...

History

''Pteridium simplex'' was originally described by

Georg Gürich Georg Julius Ernst Gürich (25 September 1859, in Dobrodzień, German: Guttentag; Upper Silesia – 16 August 1938 in Berlin) was a German geologist, paleontologist and university teacher, who wrote on Paleozoic geological formations in PolandG� ...

in 1930 published in ''Zeitschrift der Deutschen Geologischen Gesellschaft'' vol.82 p. 637. ''Pteridium'' was already used back in 1777 by Scopoli as the generic name for bracken fern, and so it was changed to "''Pteridinium''" in 1933. Two Pteridinium specimens were found in North Carolina in 1963 by a high school student named John Brattain. After their discovery, they were misidentified by Joseph St. Jean from the

UNC UNC is a three-letter abbreviation that may refer to: Education * University of Northern California (disambiguation), which may refer to: ** University of Northern California (Santa Rosa), in Petaluma, California, United States ** University of No ...

Geology Department as

Cambrian The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago ...

trilobites Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the A ...

, and were classified as "

Paradoxides ''Paradoxides'' is a genus of large to very large trilobite found throughout the world during the Middle Cambrian period. One record-breaking specimen of ''Paradoxides davidis'', described by John William Salter in 1863, is . The cephalon was ...

carolinaensis", until they were discovered to be a subspecies of Pteridinium. It was originally thought that ''Pteridinium'' might be a primitive

Cnidarian 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 ...

, but it appears that it is, at best, only very distantly related to any known cnidarian. Its relation to other known

is not clear. There are no identified related forms, although there is some vague resemblance to other

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 t ...

forms such as ''

Dickinsonia ''Dickinsonia'' is an extinct genus of basal animal that lived during the late Ediacaran period in what is now Australia, China, Russia and Ukraine. The individual ''Dickinsonia'' typically resembles a bilaterally symmetrical ribbed oval. Its a ...

'' and ''

Spriggina ''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 fo ...

'' that share some of its enigmatic characteristics, such as the "staggered" or

glide symmetry In 2-dimensional geometry, a glide reflection (or transflection) is a symmetry operation that consists of a reflection over a line and then translation along that line, combined into a single operation. The intermediate step between reflecti ...

of its units, or triradial symmetry otherwise only seen in

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 ...

ns like ''

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. Etymol ...

''. ''Pteridinium'' has no known descendants.

References

External links

Vendian Animals: Pteridinium
at University of California Museum of Paleontology
Photograph
{{Taxonbar, from=Q680300 Ediacaran life White Sea fossils Prehistoric animal genera