Ediacaria

Taxobox
color = #taxobox colour|incertae sedis
name = "Ediacaria"
fossil_range = fossil range|555|501Ediacaran - Early Cambrian

---

image_width = 250px
image_caption = "Cyclomedusa" specimens. "Ediacaria" looks essentially identical, but has no concentric rings around the central pimple.
regnum =
phylum =
classis =
ordo =
familia =
genus = "Ediacaria"
genus_authority = Sprigg, 1947
subdivision_ranks = Species
subdivision =
*"E. booleyi" Crimes, Insole & Williams, 1995
*"E. flindersi" (type)
synonyms =See text.

"Ediacaria" is a fossil genus dating to the Ediacaran Period of the Neoproterozoic Era. Unlike most Ediacaran biota which disappeared almost entirely from the fossil record at the end of the Period, "Ediacaria" fossils have been found dating from 555 to 501 million years ago, well into the Cambrian Period. "Ediacaria" consists of concentric rough circles, radial lines between the circles and a central dome, with a diameter from 1 to 70 cm.

Systematics and taxonomy

"Ediacaria" was named by Reg Sprigg in 1947, after the Ediacara Hills (from AborigineVerify source|date=July 2007 "Idiyakra" "water is present" or a mispronunciation of "Yata Takarra", "hard/stony ground" [http://aussieheritage.com.au/listings/sa/Parachilna/EdiacaraFossilSite-Nilpena/9895] ) in South Australia. Two species are recognised: "E. flindersi", described by Sprigg from the Pound Quartzite in the Ediacara Hills, and "E. booleyi", described in 1995 from a Late Cambrian deposit at Booley Bay (County Wexford), Ireland. The species were named after the Flinders Ranges and Booley Bay, respectively.

"Ediacaria" is possibly a synonym for "Aspidella terranovica" described in 1872. 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. As "Aspidella" is apparently a form taxon, "Ediacaria" may yet be valid and denote one specific genus among several that seem to make up "Aspidella". "Spriggina wadea" is quite likely a synonym of "Ediacaria" (and consequently, possibly "Aspidella"); the differences seem to be merely due to different substrate in which the animals were embedded. (Gehling "et al." 2000)

"Ediacaria" was often classified as a jellyfish (a Scyphozoan Cnidarian), and has also been interpreted in many of the categories postulated to house the Ediacaran biota. A conspicuous filamentous microstructure preserved in some pyritised specimens appears to conclusively prove that it was in fact a microbial colony, which disrupted the surrounding microbial mat to create the distinctive pattern (Grazhdankin, in press).

References

* (1995): A rigid-bodied Ediacaran biota from Upper Cambrian strata in Co. Wexford, Éire. "Geological Journal" 30(2): 89-109. doi|10.1002/gj.3350300202 (HTML abstract)
* (2000): The first named Ediacaran body fossil, "Aspidella terranovica". "Palaeontology" 43(3): 427-456. doi|10.1111/j.0031-0239.2000.00134.x [http://www.blackwell-synergy.com/doi/pdf/10.1111/j.0031-0239.2000.00134.x PDF fulltext]
* (2001): Microbial origin of some of the Ediacaran fossils. GSA Annual Meeting 2001: Paper 177-0. [http://gsa.confex.com/gsa/2001AM/finalprogram/abstract_21602.htm HTML abstract]
* (in press): Lethaia. doi|10.1111/j.1502-3931.2007.00025.x
* (2001): Paleogeographic links between Yreka Terrane (Klamath Mountains, Northern California) and Alaska's Nixon Fork and Alexander Terranes. GSA-AAPG-SPE Meeting 2006: Paper 24-6. [http://gsa.confex.com/gsa/2006CD/finalprogram/abstract_104214.htm HTML abstract]
* (1982): Cambrian Medusoids from the St. John Group, southwestern New Brunswick. "Geological Survey of Canada Current Research Part B." 82(1): 71-76.
* (1947): Early Cambrian(?) Jellyfishes from the Flinders Ranges, South Australia. "Transactions of the Royal Society of South Australia" 71: 212-224. [http://www.samuseum.sa.gov.au/Journals/TRSSA/TRSSA_v071/trssa_v071_p212p224.pdf PDF fulltext]
* (1960): "Velumbrella czarnockii" n. gen., n. sp. - Meduse du Cambrien Inferieur des Monts de Sainte-Croix. "Acta Palaeontologica Polonica" 5: 337-346.
* (2005): A Middle Cambrian age for the Ediacara-type fauna from the Booley Bay Formation, County Wexford, Ireland: new acritarch data and their implications. "In:" aut|Steemans, P. & Javaux, E. (eds.): Pre-Cambrian to Palaeozoic Palaeopalynology and Palaeobotany. "Carnets de Géologie / Notebooks on Geology" Memoir 2005/02, Abstract 11 [http://paleopolis.rediris.es/cg/CG2005_M02/CG2005_M02_Abstract11.pdf PDF fulltext]

External links

* Peripatus Home Page: [http://www.peripatus.gen.nz/Paleontology/EdiSur.html Ediacaran Survivors] . Version of 2006-MAY-10. Retrieved 2007-JUN-06.