''Ediacaria'' is a ''nomen dubium''

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

dating to the

Ediacaran The Ediacaran ( ) is a geological period of the Neoproterozoic geologic era, Era that spans 96 million years from the end of the Cryogenian Period at 635 Million years ago, Mya to the beginning of the Cambrian Period at 538.8 Mya. It is the last ...

Period of the

Neoproterozoic The Neoproterozoic Era is the last of the three geologic eras of the Proterozoic geologic eon, eon, spanning from 1 billion to 538.8 million years ago, and is the last era of the Precambrian "supereon". It is preceded by the Mesoproterozoic era an ...

Era. Unlike most

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 enigmatic tubular and frond-shaped, mostly sessile, organis ...

, which disappeared almost entirely from the fossil record at the end of the Period, ''Ediacaria'' fossils have been found dating from the Baikalian age (850–650 Ma) of the Upper Riphean to 501

million years ago Million years ago, abbreviated as Mya, Myr (megayear) or Ma (megaannum), is a unit of time equal to (i.e. years), or approximately 31.6 teraseconds. Usage Myr is in common use in fields such as Earth science and cosmology. Myr is also used w ...

, well into the

Cambrian The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordov ...

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 Ediacara Hills ( ), also known as Ediacaran Hills, are a range of low hills in the northern part of the Flinders Ranges of South Australia, around north of the state capital of Adelaide city centre, Adelaide. They are within the Nilpena Ediaca ...

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...

. Two species are recognised: ''E. flindersi'', described by Sprigg from the Pound

Quartzite Quartzite is a hard, non- foliated metamorphic rock that was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tecton ...

in the Ediacara Hills, and ''E. booleyi'', described in 1995 from a

Late Cambrian The Furongian is the fourth and final Epoch (geology), epoch and Series (stratigraphy), series of the Cambrian. It lasted from to million years ago. It succeeds the Miaolingian series of the Cambrian and precedes the Lower Ordovician Tremadocia ...

deposit at Booley Bay (

County Wexford County Wexford () is a Counties of Ireland, county in Republic of Ireland, Ireland. It is in the Provinces of Ireland, province of Leinster and is part of the Southern Region, Ireland, Southern Region. Named after the town of Wexford, it was ba ...

Ireland Ireland (, ; ; Ulster Scots dialect, Ulster-Scots: ) is an island in the North Atlantic Ocean, in Northwestern Europe. Geopolitically, the island is divided between the Republic of Ireland (officially Names of the Irish state, named Irelan ...

. The species were named after the

Flinders Ranges The Flinders Ranges are the largest mountain ranges in South Australia, which starts about north of Adelaide. The ranges stretch for over from Port Pirie to Lake Callabonna. The Adnyamathanha people are the Aboriginal group who have inhab ...

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 Form classification is the classification of organisms based on their morphology (biology), morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncer ...

, ''Ediacaria'' may yet be valid and denote one specific genus among several that seem to make up ''Aspidella''. '' Spriggia 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

Cnidaria Cnidaria ( ) is a phylum under kingdom Animalia containing over 11,000 species of aquatic invertebrates found both in fresh water, freshwater and marine environments (predominantly the latter), including jellyfish, hydroid (zoology), hydroids, ...

n), and has also been interpreted in many of the categories postulated to house the

. A conspicuous filamentous microstructure preserved in some pyritised specimens suggests that it may have been a microbial colony, which disrupted the surrounding

microbial mat A microbial mat is a multi-layered sheet or biofilm of microbial colonies, composed of mainly bacteria and/or archaea. Microbial mats grow at interfaces between different types of material, mostly on submerged or moist surfaces, but a few surviv ...

to create the distinctive pattern (Grazhdankin, 2007).

References

Notes

* (1995): A rigid-bodied Ediacaran biota from Upper Cambrian strata in Co. Wexford, Éire. ''Geological Journal'' 30(2): 89-109. (HTML abstract) * (2000): The first named Ediacaran body fossil, ''Aspidella terranovica''. ''Palaeontology'' 43(3): 427-456. PDF fulltext
* (2001): Microbial origin of some of the Ediacaran fossils. GSA Annual Meeting 2001: Paper 177-0
HTML abstract
* (2007): Lethaia. * (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
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
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:'' (eds.): Pre-Cambrian to Palaeozoic Palaeopalynology and Palaeobotany. '' Carnets de Géologie / Notebooks on Geology'', Memoir 2005/02, Abstract 1
PDF fulltext

External links

* Peripatus Home Page

Version of 2006-MAY-10. Retrieved 2007-JUN-06. {{Taxonbar, from=Q5337989 Ediacaran life Cambrian life Fossils of Australia Scyphozoa Fossil taxa described in 1947

Systematics and taxonomy

See also

References

Notes

External links