Ediacaria
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Ediacaria is a medusoid fossil from the Precambrian Era, or more precisely the Ediacaran Period. It consists of concentric rough circles, radial lines between the circles and a central domelooking vaguely like tree rings. The diameter is 1 to 70 cm. Ediacaria was named by Reg Sprigg in 1847. It was named after the Ediacaran Hills in South Australia.
Two species are E. flindersi described by Sprigg, and E. booleyi described by Crimes, Insole & Williams in 1995 from a Late Cambrian deposit. The species were named after the Flinders Ranges, and Booley Bay. Ediacaria is possibly a synomym for Aspidella terranovica described in 1872 by Billings. Although Ediacaria is one of the first described organisms from the Precambrian, Aspidella was described earlier, although its age was not understood to be Precambrian.
Ediacaria is found in the Pound Quartzite in the Ediacara Hills, and E. booleyi is from Booley Bay, Wexford Ireland. Ediacaria is also found in Klamath Mountains, northern California.
The significance of this genus is that it is a survivor, lasting into the Cambrian, across the terminal Ediacaran extinction event. Other Cambrian related forms are Velumbrella czarnocki described by Stasinska in 1960 and also documented by Pickerill in 1982.
The time period when Ediacaria existed was from 555 Mya to about 501 Mya.
It is classified as class Scyphozoa (jellyfish) from the Cnidaria, and has also been interpreted as a holdfast. It may have been an anenome attached to the sea floor with tentacles extended upwards. Other interpretations are a bacterial colony, or a fungus.
[edit] References
- Ediacaran Survivors
- Sprigg, R.C. 1947: Early Cambrian (?) Jellyfishes from the Flinders Ranges, South Australia. Trans. Roy. Soc. S. Aust. 71: 212-224.
- Crimes, T.P.; Insole, A.; Williams, B.P.J. 1995: A rigid-bodied Ediacaran biota from Upper Cambrian strata in Co. Wexford, Eire. Geological Journal 30: 89-109.
- middle Cambrian Age
- Stasinska, A. 1960: Velumbrella czarnockii n. gen., n. sp. - Meduse du Cambrien Inferieur des Monts de Sainte-Croix. Acta Palaeontologica Polonica 5: 337-346.
- Pickerill, R.K. 1982: Cambrian Medusoids from the St. John Group, southwestern New Brunswick. In Current Research, Part B. Geological Survey of Canada 82-1B: 71-76.
- MICROBIAL ORIGIN
- Yreka Terrane
