// Workers AI · dad joke modeWhat did Pteridinium say? Leaf me alone.

Pteridinium; Temporal range: Ediacaran, 558–543 Ma PreꞒ Ꞓ O S D C P T J K Pg N Tonian Cryo. Edia.
	Fossil of Pteridinium simplex at the Senckenberg Museum, Frankfurt.
Scientific classification
Kingdom:	Animalia
Phylum:	†Petalonamae
Class:	†Erniettomorpha
Genus:	†Pteridinium; Gürich, 1933
Species
	P. simplex (Gürich, 1930) (type species); P. carolinaensis (St. Jean, 1973);
Synonyms
	Pteridium Gürich, 1930; Onegia Sokolov, 1976; Archangelia Fedonkin, 1979; Inkrylovia Fedonkin, 1979;

Pteridinium is a member of the Ediacaran biota belonging to the extinct clade Erniettomorpha. It is known from Ediacaran deposits worldwide, best known from South Australia, Namibia and Russia. First described in 1930, it is one of the earliest macroscopic fossils of the Precambrian to be identified.

Description

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.^[2]

Paleoecology

Specimens found in what is thought to be life positions indicate that the creature rested on, or possibly in, the sediment in shallow seas. No tracks are known that would seem to be consistent with a moving Pteridinium. It is unclear whether it performed photosynthesis, or osmotically extracted nutrients from seawater.^[2]

Distribution

Fossils of Pteridinium are common in late Ediacaran 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.^{[citation needed]}

While many other Ediacaran biota went extinct during the boundary between the White Sea Assemblage and Nama assemblage ~548 Ma, Pteridinium had persisted in the fossil record up until near the Ediacaran-Cambrian boundary.^[3]

Discovery and history

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.^[4]

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.

Like most other Ediacaran biota, Pteridinium has no known descendant taxa, nor are there any known extant species with analogous body plans.^[3]

References

1 2 "Pteridinium". Paleobiology Database. Retrieved 23 February 2024.
1 2 Laflamme, M.; Xiao, S.; Kowalewski, M. (2009). "Osmotrophy in modular Ediacara organisms". Proceedings of the National Academy of Sciences. 106 (34): 14438–14443. Bibcode:2009PNAS..10614438L. doi:10.1073/pnas.0904836106. PMC 2732876. PMID 19706530.
1 2 A. F. Darroch, Simon; M. Gibson, Brandt; Syverson, Maggie; A. Rahman, Imran; A. Racicot, Rachel; S. Dunn, Frances; Gutarra, Susana; Schindler, Eberhard; Wehrmann, Achim; Laflamme, Marc (2022). "The life and times of Pteridinium simplex" (PDF). Paleobiology. 48 (4). Cambridge University Press: 527–556.
↑ St Jean, Joseph (1973). "A new Cambrian trilobite from the Piedmont of North Carolina" (PDF). American Journal of Science. 273-A: 196–216.

External links

Vendian Animals: Pteridinium, at University of California Museum of Paleontology
Photograph

[fossilworks-1] 1 2 "Pteridinium". Paleobiology Database. Retrieved 23 February 2024.

[Laflamme2009-2] 1 2 Laflamme, M.; Xiao, S.; Kowalewski, M. (2009). "Osmotrophy in modular Ediacara organisms". Proceedings of the National Academy of Sciences. 106 (34): 14438–14443. Bibcode:2009PNAS..10614438L. doi:10.1073/pnas.0904836106. PMC 2732876. PMID 19706530.

[:0-3] 1 2 A. F. Darroch, Simon; M. Gibson, Brandt; Syverson, Maggie; A. Rahman, Imran; A. Racicot, Rachel; S. Dunn, Frances; Gutarra, Susana; Schindler, Eberhard; Wehrmann, Achim; Laflamme, Marc (2022). "The life and times of Pteridinium simplex" (PDF). Paleobiology. 48 (4). Cambridge University Press: 527–556.

[4] St Jean, Joseph (1973). "A new Cambrian trilobite from the Piedmont of North Carolina" (PDF). American Journal of Science. 273-A: 196–216.

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