Spriggina

{{Short description|Extinct genus of animals}} {{Use dmy dates|date=December 2024}} {{Speciesbox | fossil_range = Late Ediacaran, {{fossil_range|555}} | image = Spriggina Floundensi 4.png | image_caption = Fossil of ''S. floundersi''. Scale in millimetres | genus = Spriggina | parent_authority = Glaessner, 1958<ref name=Glaessner1958>{{Cite journal | author=Glaessner, Martin F. | year =1958 | url=http://www.samuseum.sa.gov.au/Journals/TRSSA/TRSSA_V081/TRSSA_V081_p185p188.pdf | title= New Fossils from the Base of the Cambrian in South Australia | journal = Transactions of the Royal Society of South Australia | volume = 81 | pages = 185–188 | id={{BHL page|41001421}} | archive-url=https://web.archive.org/web/20070929094012/http://www.samuseum.sa.gov.au/Journals/TRSSA/TRSSA_V081/TRSSA_V081_p185p188.pdf | archive-date=29 September 2007 }}</ref> | species = floundersi | authority = Glaessner, 1958 }} [[File:Big Spriggina floundersi.jpg|thumb|227x227px|Large landscape model of ''Spriggina floundersi'', located in Arkaroola Wilderness Sanctuary]] '''''Spriggina''''' is a genus of early animals whose relationship to living animals is unclear. Fossils of ''Spriggina'' are known from the late Ediacaran period in what is now South Australia. ''Spriggina floundersi'' is the official fossil emblem of South Australia;<ref>{{cite journal|title=FOSSIL EMBLEM OF THE STATE OF SOUTH AUSTRALIA|journal=The South Australian Government Gazette|date=16 February 2017|volume=2017|issue=8|page=509|url=http://www.governmentgazette.sa.gov.au/sites/default/files/public/documents/gazette/2017/February/2017_008.pdf|access-date=6 July 2017|publisher=Department of the Premier and Cabinet|location=Adelaide}}</ref> it has been found nowhere else.

The organism reached {{convert|3-5|cm}} in length and may have been predatory. Its bottom was covered with two rows of tough interlocking plates, while one row covered its top; its front few segments fused to form a "head."{{citation needed|date=May 2023}}

The affinity of ''Spriggina'' is unknown; it has been variously classified as an annelid worm, a rangeomorph-like frond, a variant of ''Charniodiscus'', a proarticulatan, an arthropod (perhaps related to the trilobites), or even an extinct phylum. The lack of known segmented legs or limbs, coupled with the presence of glide reflection instead of symmetric segments, suggests that an arthropod classification is unlikely despite some superficial resemblance.<ref name=Ivantsov2001>{{cite journal | author = Ivantsov A.Yu. | year = 2001| title = Vendian and Other Precambrian "Arthropods" | journal = Paleontological Journal | volume = 35 | pages = 335–343 | url = https://www.researchgate.net/publication/291816373}}</ref>

The genus ''Spriggina'' originally contained three different species—''S. floundersi'', ''S. ovata'', and ''S. borealis''—but ''S. ovata'' is now considered a junior synonym of ''Marywadea ovata'',<ref name=GlaessnerWade1966>{{cite journal|author1=Glaessner, Martin F. |author2=Wade, Mary |name-list-style=amp |year=1966 |title=The Late Precambrian Fossils from Ediacara, South Australia |journal=Palaeontology |volume=9 |issue=4 |pages=599–628 |url=http://palaeontology.palass-pubs.org/pdf/Vol%209/Pages%20599-628.pdf |url-status=usurped |archiveurl=https://web.archive.org/web/20130922230714/http://palaeontology.palass-pubs.org/pdf/Vol%209/Pages%20599-628.pdf |archivedate=22 September 2013 }}</ref><ref name="TRA">{{cite book | url=https://books.google.com/books?id=KsFFIrJ8IxEC&dq=Spriggina+Borealis&pg=PA287 | title=The Rise of Animals: Evolution and Diversification of the Kingdom Animalia | isbn=9780801886799 | last1=Fedonkin | first1=Mikhail A. | last2=Gehling | first2=James G. | last3=Grey | first3=Kathleen | last4=Narbonne | first4=Guy M. | last5=Vickers-Rich | first5=Patricia | year=2007 | publisher=JHU Press }}</ref> while the phylogenetic status of ''S. borealis'' remains{{as of?|date=May 2023}} a subject of active debate.<ref name="TRA"/>

==Description== [[File:Spriggina floundersi - MUSE.jpg|thumb|left|''S. floundersi'', life restoration at MUSE – Science Museum in Trento]] [[File:Spriggina, Ediacaran metazoan, Vendian, Ediacara Hills, south Australia - Houston Museum of Natural Science - DSC01385.JPG|thumb|left|Cast of ''S. floundersi'' at Houston Museum of Natural Science]] ''Spriggina'' grew to {{convert|3-5|cm}} in length and was approximately oblong. The organism was segmented, with no fused segments; the segments were sometimes curved.<ref name=McCall2006>{{cite journal | author = McCall | year = 2006 | doi = 10.1016/j.earscirev.2005.08.004 | title = The Vendian (Ediacaran) in the geological record: Enigmas in geology's prelude to the Cambrian explosion | journal = Earth-Science Reviews | volume = 77 | issue = 1–3 | pages = 1–229 | bibcode = 2006ESRv...77....1M }}</ref> The upper surface of the organism was covered by one row of overlapping cuticular plates, the underside with paired plates.<ref name=McCall2006/> [[File:Spriggina observed in situ at Nilpena Ediacara National Park.jpg|thumb|An example of Spriggina observed ''in situ'' at Nilpena Ediacara National Park|305x305px]] The first two segments formed a "head". The front segment had the shape of a horseshoe with a pair of depressions on its upper surface; these may have represented eyes.<ref name=McCall2006/> The second segment may have borne antennae. Subsequent segments bore annulations.<ref name=McCall2006/>

Some fossils have what may be a circular mouth at the centre of the semicircular head, although interpretation is hampered by the small size of the creature relative to the large grains of sandstones in which it is preserved.<ref name=McCall2006/> Legs are not preserved.

The symmetry observed is not exactly bilaterian<ref name=McCall2006/> but appears to be a glide reflection, where opposite segments are shifted by half an interval.<ref name=Ivantsov2001/> In some specimens the body segments tilt backwards, making roughly chevron patterns; while in others they are more or less straight. There appear to be fairly complex variations between these two extremes.{{citation needed|date=May 2023}}

==Discovery and naming== The genus was named after Reg Sprigg who discovered the fossils of the Ediacara Hills—part of the Flinders Ranges in South Australia—and was a proponent of their recognition as multicellular organisms.<ref name=Glaessner1958/> ''Spriggina floundersi'' is at present the only generally accepted species in this genus. The specific name "''floundersi''" refers to amateur South Australian fossil hunter Ben Flounders.<ref>Vickers-Rich, P. Komarower, P. ''The Rise and Fall of the Ediacaran Biota''. The Geological Society, 2007, p. 444.</ref> ''Spriggina ovata'' has now been moved into its own genus, ''Marywadea''.<ref name=Glaessner1976>{{Cite journal |author = Glaessner, Martin F. |year = 1976 |url = http://www.samuseum.sa.gov.au/Journals/TRSSA/TRSSA_v100/TRSSA_V100_p169p170.pdf |title = A new genus of late Precambrian polychaete worms from South Australia. |format = Free full text |journal = Transactions of the Royal Society of South Australia |volume = 100 |issue = 3 |pages = 169–170 |url-status = dead |archive-url = https://web.archive.org/web/20070929094103/http://www.samuseum.sa.gov.au/Journals/TRSSA/TRSSA_v100/TRSSA_V100_p169p170.pdf |archive-date = 29 September 2007 }}</ref>

''Spriggina'' is known only from beds of Ediacaran age. Fossils from the Vindhyan basin, reliably dated to around {{Ma|1650|million years old}},<ref name=Bengtson2009/> have been classified as ''Spriggina'',<ref name=De2005>{{cite journal |year = 2005 | doi = 10.1016/j.jseaes.2005.06.006 | title = Ediacara fossil assemblage in the upper Vindhyans of Central India and its significance | author = De, C | journal = Journal of Asian Earth Sciences | volume = 27 |issue = 5 | pages = 660–683 }}</ref> but in all likelihood represent microbial artifacts.<ref name=Bengtson2009>{{Cite journal |author = Bengtson, Stefan |author2 = Belivanova, Veneta |author3 = Rasmussen, Birger |author4 = Whitehouse, Martin |year = 2009 |doi = 10.1073/pnas.0812460106 |title = The controversial "Cambrian" fossils of the Vindhyan are real but more than a billion years older |journal = Proceedings of the National Academy of Sciences |volume = 106 |issue = 19 |pages = 7729–7734 |pmid = 19416859 |pmc= 2683128 |bibcode = 2009PNAS..106.7729B |doi-access = free }}</ref>

''Spriggina'' possessed a tough, though uncalcified body, evident from the fossils' preservation: always as a mould in the lower surface of the fossiliferous bed.

==Classification== thumb|right|Digitally enhanced image of a ''Spriggina'' fossil Like many of the Ediacara biota, the relationship of ''Spriggina'' to other groups is unclear. It bears some similarity to the living polychaete worm ''Tomopteris'' and Amphinomidae,<ref name=Donovan2001>{{cite journal | author = Donovan, S. K. |author2=Lewis, D. N. | year = 2001 | title = Fossils explained 35: The Ediacaran biota | journal = Geology Today | volume = 17 | issue = 3 | pages = 115–120 | doi = 10.1046/j.0266-6979.2001.00285.x |s2cid=128395097 }}</ref> but its lack of chaetae, along with other lines of evidence, suggests that it cannot be placed in this phylum.<ref name=Merz2006>{{cite journal | author = Merz | year = 2006 | doi = 10.1093/icb/icj057 | title = Polychaete chaetae: Function, fossils, and phylogeny | journal = Integrative and Comparative Biology | volume = 46 | issue = 4 | pages = 481–96 | pmid=21672760 | doi-access = }}</ref> It was also compared to the rangeomorphs, frondose members of the Ediacara biota that may represent a separate kingdom.<ref name="Seilacher1992">{{cite journal | author = Seilacher, A. | year = 1992 | title = Vendobionta and Psammocorallia: lost constructions of Precambrian evolution | journal = Journal of the Geological Society | volume = 149 | issue = 4 | pages = 607–613 | url = http://jgs.lyellcollection.org/cgi/content/abstract/149/4/607 | doi = 10.1144/gsjgs.149.4.0607 | bibcode = 1992JGSoc.149..607S | s2cid = 128681462 | access-date = 21 June 2007 | url-access = subscription }}</ref> While its glide symmetry may suggest otherwise, some researchers like Mark McMenamin suggested ''Spriggina'' would be an arthropod; its superficial resemblance to the trilobites may suggest a close relationship to this class and even suggested to be predatory.<ref>{{Cite journal |last=McMenamin |first=Mark |date=1 January 2003 |title=Spriggina is a trilobitoid ecdysozoan |url=https://www.academia.edu/2476873 |journal=Abstracts with Programs}}</ref><ref>{{Cite book |author=McMenamin, M. A. S. |title=Predator-Prey Interactions in the Fossil Record |year=2003 |editor1=P. Kelley |chapter=Origin and early evolution of predators: The ecotone model and early evidence for macropredation |editor2=M. Kowalewski |editor3=T. Hansen}}</ref> However, later studies do not consider such Ediacaran biota like it and ''Parvancorina'' to be stem-arthropods, as they do not share compelling characters with arthropods, and there are no definite proof to make them related to arthropods or other extant bilaterians.<ref>{{Cite journal |last1=Budd |first1=Graham E. |last2=Telford |first2=Maximilian J. |date=2009 |title=The origin and evolution of arthropods |url=https://www.nature.com/articles/nature07890 |journal=Nature |language=en |volume=457 |issue=7231 |pages=812–817 |doi=10.1038/nature07890 |pmid=19212398 |bibcode=2009Natur.457..812B |issn=1476-4687|url-access=subscription }}</ref><ref>{{Cite journal |last1=Edgecombe |first1=Gregory D. |last2=Legg |first2=David A. |date=2014 |editor-last=Smith |editor-first=Andrew |title=Origins and early evolution of arthropods |url=https://onlinelibrary.wiley.com/doi/10.1111/pala.12105 |journal=Palaeontology |language=en |volume=57 |issue=3 |pages=457–468 |doi=10.1111/pala.12105 |bibcode=2014Palgy..57..457E |issn=0031-0239}}</ref><ref>{{Cite journal |last1=Budd |first1=Graham E. |last2=Jensen |first2=Sören |date=2017 |title=The origin of the animals and a 'Savannah' hypothesis for early bilaterian evolution |url=https://onlinelibrary.wiley.com/doi/full/10.1111/brv.12239 |journal=Biological Reviews |language=en |volume=92 |issue=1 |pages=446–473 |doi=10.1111/brv.12239 |pmid=26588818 |issn=1469-185X}}</ref> This similarity to trilobites could also be an example of convergent evolution.<ref name=ConwayMorris1993>{{cite journal|url=http://jan.ucc.nau.edu/~bio222-c/Reserve%20Reading/RR1/Morris_1993.pdf|title=The fossil record and the early evolution of the Metazoa|bibcode=1993Natur.361..219M|access-date=11 October 2016|archive-url=https://web.archive.org/web/20160804083105/http://jan.ucc.nau.edu/~bio222-c/Reserve%20Reading/RR1/Morris_1993.pdf|archive-date=4 August 2016|url-status=dead|last1=Conway Morris|first1=S.|journal=Nature|year=1993|volume=361|issue=6409|page=219|doi=10.1038/361219a0|s2cid=86276440}}</ref>

==Affinity== At first, ''Spriggina'' was thought to resemble a polychaete worm such as ''Nereis'', but a close look at the segmentation reveals that the segments do not match across the midline, just as in ''Dickinsonia''. In 1989 Seilacher turned the interpretation upside-down, suggesting that ''Spriggina'' could be another type of sea-pen, and that the ‘head’ was actually a holdfast.<ref> {{cite book |author1=Selden, P.A. |author2=Nudds, J.A. |year=2012 |edition=2nd |title=Evolution of Fossil Ecosystems |publisher=Academic Press |pages=15–18 |isbn=978-0-12-404629-0 |doi=10.1016/C2012-0-01282-3 |url=https://repository.naturalis.nl/pub/214351 }}</ref><ref> {{cite book |author1=Seilacher, A. |author1-link=Adolf Seilacher |author2=Gishlick, A. |year=2014 |title=Morphodynamics |publisher=CRC Press |page=137 |isbn=9780429170416 |doi=10.1201/b17557 |url=https://books.google.com/books?id=tpTaBAAAQBAJ }} </ref>

A relationship with arthropods has also been suggested because of superficial similarities with the Cambrian trilobite, but the lack of limbs<ref name=Ivantsov2001/> and exoskeleton casts profound doubt on an arthropod affinity.<ref>{{cite journal |author=Seilacher, A. |author-link=Adolf Seilacher |year=1989 |title=Vendozoa: organismic construction in the Proterozoic biosphere |journal=Lethaia |volume=22 |issue=3 |pages=229–239 |doi=10.1111/j.1502-3931.1989.tb01332.x |doi-access=free |bibcode=1989Letha..22..229S }}</ref> Furthermore, the broad pleural lobes of trilobites served primarily as a rigid hood under which the legs could process the sediment for food.<ref>{{cite journal |author=Seilacher, A. |author-link=Adolf Seilacher |year=1985 |title=Trilobite palaeobiology and substrate relationships |journal=Transactions of the Royal Society of Edinburgh |volume=76 |issue=2–3 |pages=231–237 |doi=10.1017/S0263593300010464 |bibcode=1985EESTR..76..231S }}</ref>

==South Australia’s fossil emblem== In 14 February 2017 the ''Spriggina'' was adopted as South Australia’s fossil emblem, due the fact it hasn’t been found anywhere else. The uniqueness of this Ediacaran fossil has led it to become the official fossil emblem of South Australia, the 550-million-year-old fossil was chosen for best representing the state’s geological and scientific prowess.<ref>{{cite news | last=Gage | first=Nicola | date=14 February 2017 | title=Reg Sprigg honoured with South Australia's first fossil emblem, the Spriggina | url = https://www.abc.net.au/news/2017-02-15/reg-sprigg-recognised-honoured-with-sa-fossil-emblem-spriggina/8271586 | access-date = 4 December 2024}}</ref> More than 3500 South Australians cast their vote for a fossil to become the state’s new emblem in an online poll.<ref> {{cite news | last = Gailberger | first = Jade | date = 14 February 2017 | title = Spriggina chosen as South Australia's fossil emblem | url = https://www.adelaidenow.com.au/news/south-australia/spriggina-chosen-as-south-australias-fossil-emblem/news-story/b15c8d115af55caef859e16568e37282 | work = | location = | access-date = 4 December 2024 }}</ref>

==See also== {{Portal|Paleontology}}

* ''Yorgia'' * ''Dickinsonia'' * List of Ediacaran genera

==References== {{Reflist|2}}

==External links== *[http://images.google.ca/images?hl=en&q=Spriggina&btnG=Google+Search&sa=N&tab=wi Google Image Search]: ''Spriggina'' *[https://ediacarafoundation.org/ediacaran-fossils/ Ediacara Foundation]: ''Ediacaran Fossils''

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Category:Sprigginidae †Spriggina Category:Emblems of South Australia