| 词条 | Parvancorina |
| 释义 |
| image = Parvancorina species.png | image_caption = Schematic reconstructions of P. sagitta and P. minchami | fossil_range = Ediacaran, around {{Fossil range|558|555}} | regnum = Animalia | phylum = incertae sedis: Arthropoda? Mollusca? | genus = Parvancorina | genus_authority = Glaessner 1958 | type_species = P. minchami | type_species_authority = Glaessner 1958 | subdivision_ranks = Species | subdivision =
}} Parvancorina is a genus of shield-shaped bilaterally symmetrical fossil animal that lived in the late Ediacaran seafloor. It has some superficial similarities with the Cambrian trilobite-like arthropods. EtymologyThe generic name is derived from a crasis compound word from the Latin parva ancora (small anchor). The specific name of the type species, P. minchami, honors Mr. H. Mincham, the private collector, who in 1957 had collected and presented a number of fine specimens of Ediacaran fossils to the South Australian Museum. The specific name of P. sagitta is the Latin word sagitta (arrow), in direct reference to the arrow-like shape. OccurrenceP. minchami fossils were first discovered in the Ediacara Member of the Rawnslay Quartzite, Flinders Ranges, in South Australia.[1] This species is also known from deposits of the Verkhovka, Zimnegory and Yorga Formations in the White Sea area of the Arkhangelsk Region, Russia. Additionally, similar poorly preserved Parvancorina sp. fossils were found in Lyamtsa Formation of this Russian region.[2]P. sagitta is found in the Verkhovka formation on the Solza River, White Sea area of the Arkhangelsk Region, Russia.[2]DescriptionIt has a raised ridge down the central axis of symmetry. This ridge can be high in unflattened fossils. At the 'head' end of the ridge there are two quarter-circle-shaped raised arcs attached. In front of this are two nested semicircular lines. Teeth seem to come from the raised parts pointing into the centre spaces.{{Citation needed|date=July 2010}} These may show as raised lines. The fossils are normally about {{convert|1|cm|abbr=off}} in each of width and length, but can be up to {{convert|2|cm|abbr=off}}. AffinityIn attempting to determine its phylogenic relationships, Parvancorina has been compared with trilobite-like arthropods, such as Skania fragilis from the Burgess Shale Biota, Canada, and Primicaris larvaformis from the Chengjiang Biota, China.[3][4] However, the growth form of Parvancorina is unusual for an arthropod,[5] and its apparent sessile mode of life appears to rebut an arthropod affinity.[6] Furthermore, the strong resemblance of P. sagitta to the primitive mollusk-like bilateran Temnoxa[2] and similarities to parts of Kimberella[7] casts further doubt on an arthropod affinity. Lifestyle and habitusThe living Parvancorinas typically lived with their "heads" parallel to the current direction.[8] Overfolding of the fossils from all sides contradicts any form of stalked attachment to the sea floor.[9] See also{{Portal|Paleontology}}
References1. ^{{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 | deadurl = yes | archiveurl = https://web.archive.org/web/20070929094012/http://www.samuseum.sa.gov.au/Journals/TRSSA/TRSSA_V081/TRSSA_V081_p185p188.pdf | archivedate = 2007-09-29 | df = }} 2. ^1 {{cite journal | author = Ivantsov, A.Y. | author2 = Malakhovskaya, Y.E. | author3 = Serezhnikova, E.A. | year = 2004 | title = Some Problematic Fossils from the Vendian of the Southeastern White Sea Region | journal = Paleontological Journal | volume = 38 | issue = 1 | pages = 1–9 | url = http://www.vend.paleo.ru/pub/Ivantsov_et_al_2004_eng.pdf | deadurl = yes | archiveurl = https://web.archive.org/web/20070704183946/http://www.vend.paleo.ru/pub/Ivantsov_et_al_2004_eng.pdf | archivedate = 2007-07-04 | df = }} 3. ^{{cite journal |doi=10.1080/08912960500508689 |title=A Parvancorina-like arthropod from the Cambrian of South China |journal=Historical Biology |volume=18 |issue=1 |pages=33–45 |year=2006 |last1=Lin |first1=Jih-Pai |last2=Gon |first2=Samuel M |last3=Gehling |first3=James G |last4=Babcock |first4=Loren E |last5=Zhao |first5=Yuan-Long |last6=Zhang |first6=Xing-Liang |last7=Hu |first7=Shi-Xue |last8=Yuan |first8=Jin-Liang |last9=Yu |first9=Mei-Yi |last10=Peng |first10=Jin }} 4. ^{{cite journal | last1= Glaessner |first1=M. F. | year = 1980 | title = Parvancorina - an Arthropod from the Late Precambrian Fauna of the Ediacara Fossil Reserve | journal = Records of the South Australian Museum | volume = 13 | pages = 83–90 | url = http://www.biologiezentrum.at/pdf_frei_remote/ANNA_83_0083-0090.pdf}} 5. ^1 {{cite journal |doi=10.1134/S003103010901002X |title=Growth variability in the late Vendian problematics Parvancorina Glaessner |journal=Paleontological Journal |volume=43 |issue=1 |pages=12–8 |year=2009 |last1=Naimark |first1=E. B |last2=Ivantsov |first2=A. Yu }} 6. ^{{cite conference|year=2010|title=International Palaeontology Congress|location=London|author=Paterson, John}}{{full citation needed|date=September 2018}} 7. ^{{cite journal |doi=10.1666/13-072 |title=Patterns of Evolution of the Ediacaran Soft-Bodied Biota |journal=Journal of Paleontology |volume=88 |issue=2 |pages=269–83 |year=2015 |last1=Grazhdankin |first1=Dmitriy }} 8. ^{{cite journal |doi=10.1098/rsbl.2017.0033 |pmid=28515329 |pmc=5454237 |title=Inference of facultative mobility in the enigmatic Ediacaran organism Parvancorina |journal=Biology Letters |volume=13 |issue=5 |pages=20170033 |year=2017 |last1=Darroch |first1=Simon A. F |last2=Rahman |first2=Imran A |last3=Gibson |first3=Brandt |last4=Racicot |first4=Rachel A |last5=Laflamme |first5=Marc }} 9. ^{{cite journal |doi=10.1038/srep45539 |pmid=28358056 |pmc=5371987 |title=Rheotaxis in the Ediacaran epibenthic organism Parvancorina from South Australia |journal=Scientific Reports |volume=7 |pages=45539 |year=2017 |last1=Paterson |first1=John R |last2=Gehling |first2=James G |last3=Droser |first3=Mary L |last4=Bicknell |first4=Russell D. C |bibcode=2017NatSR...745539P }} External links
4 : Ediacaran biota|Prehistoric incertae sedis animal genera|White Sea fossils|Fossil taxa described in 1958 |
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