Птеридиниум: ископаемый эдиакарского периода.

Ediacaran fossil
Automatic taxobox
| fossil range = Ediacaran,
| image = Pteridinium simplex. jpg
| image caption = Fossil of Pteridinium simplex at the Senckenberg Museum, Frankfurt. | taxon = Pteridinium
| authority = Gürich, 1930
| synonyms = *Onegia Keller et al. 1974
| synonyms ref =
| subdivision ranks = Species
| subdivision =
P. simplex Gürich, 1930 (type species)
P. carolinaensis St. Jean, 1973
| subdivision ref =

Fossils are common in late Precambrian deposits in South Australia, South Africa, Namibia, and the White Sea region of Russia. It has also been found in North Carolina and is reported from California and the Northwest Territories of Canada.

Pteridium simplex was originally described by Georg Gürich 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 Geology Department as Cambrian trilobites, and were classified as "Paradoxides carolinaensis", until they were discovered to be a species of Pteridinium. It was originally thought that Pteridinium might be a primitive Cnidarian, but it appears that it is, at best, only very distantly related to any known cnidarian. Its relation to other known Ediacaran biota is not clear. There are no identified related forms, although there is some vague resemblance to other Ediacaran forms such as Dickinsonia and Spriggina that share some of its enigmatic characteristics, such as the "staggered" or glide symmetry of its units, or triradial symmetry otherwise only seen in trilobozoans like Tribrachidium. Pteridinium has no known descendants.