437 lines
72 KiB
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437 lines
72 KiB
XML
<document id="739C670FE11508B4F0439A98FEA90783" ID-CLB-Dataset="37247" ID-DOI="10.1038/nature21072" ID-GBIF-Dataset="257ab49f-21bc-482c-8878-c0ffdd07d08e" ID-Zenodo-Dep="265124" IM.bibliography_requiresApprovalFor="plazi" IM.illustrations_requiresApprovalFor="plazi" IM.metadata_requiresApprovalFor="plazi" IM.taxonomicNames_requiresApprovalFor="plazi" checkinTime="1485851541590" checkinUser="plazi" docAuthor="Jian Han, Simon Conway Morris, Qiang Ou, Degan Shu & Hai Huang" docDate="2017" docId="E11D50529B47FFE6F5D8F9385A7FFC03" docLanguage="en" docName="nature21072.good.pdf.imf" docOrigin="Nature 541" docStyle="DocumentStyle{}" docTitle="Saccorhytus coronarius Han, Shu, Ou and Conway Morris 2017, gen et sp. nov" docType="treatment" docVersion="14" lastPageNumber="1" masterDocId="1D24282A9B47FFE5F56CFFEE5841FFA4" masterDocTitle="Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China)" masterLastPageNumber="5" masterPageNumber="1" pageNumber="1" updateTime="1698436530091" updateUser="ExternalLinkService">
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<mods:mods id="83F45458CB430DA95DB9F0329781253D" xmlns:mods="http://www.loc.gov/mods/v3">
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<mods:titleInfo id="7D25E64E7A76EB5232381CC2B093D7E8">
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<mods:title id="124F7E3323777364B365EE53B6DE77E7">Meiofaunal deuterostomes from the basal Cambrian of Shaanxi (China)</mods:title>
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</mods:titleInfo>
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<mods:name id="9DE32110E0681AB29E98A7C28172476D" type="personal">
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<mods:role id="9AB62746D22094C7E6E03E62ED5B1DEC">
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<mods:roleTerm id="D4DF44639CE93F06217BFF3DED75D22B">Author</mods:roleTerm>
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</mods:role>
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<mods:namePart id="59D87EC2C244E6ED6D65E226AA0ACE49">Jian Han</mods:namePart>
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</mods:name>
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<mods:name id="EB8A55C20FCA9054E2C5ABFD2664A61E" type="personal">
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<mods:role id="BE41A49D9969E1B89F4D04CBC4B05DB4">
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<mods:roleTerm id="95ABC72D7B74C60554DCD1ACEAD34AD6">Author</mods:roleTerm>
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</mods:role>
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<mods:namePart id="E9662523EF53A45ED7FF75ABFD1521F1">Simon Conway Morris</mods:namePart>
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</mods:name>
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<mods:name id="95C18F7D13D547CB8C1317F5DDC5CBB6" type="personal">
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<mods:role id="C1A9CB46285D31E3B326B11623331641">
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<mods:roleTerm id="0EF33BEAE0749CD297E56C253FAA31C4">Author</mods:roleTerm>
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</mods:role>
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<mods:namePart id="DE70DEA1E37FE24D4027DC05E9452DDA">Qiang Ou</mods:namePart>
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</mods:name>
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<mods:name id="6D86AFC8829F564FD6EDA03429C45A17" type="personal">
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<mods:role id="D73522262CF2E5C244E057BFA0C2817C">
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<mods:roleTerm id="8ECB877030C7F2607EA72C50ACF175CE">Author</mods:roleTerm>
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</mods:role>
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<mods:namePart id="BE9E288CE67AF66FE8A7D27E63374514">Degan Shu</mods:namePart>
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</mods:name>
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<mods:name id="119E536877FC7438CFF297CC74D7C0A1" type="personal">
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<mods:role id="D297D36816549640608FF9F96804B27B">
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<mods:roleTerm id="F86120B5948AAEAEB1534E92D0783B07">Author</mods:roleTerm>
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</mods:role>
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<mods:namePart id="AA7411FE0DCB757575F134EF8803563F">Hai Huang</mods:namePart>
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</mods:name>
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<mods:typeOfResource id="0581036872C27E13A805E7FF412274E9">text</mods:typeOfResource>
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<mods:title id="D10E6AA6A4D747E6AAF30F29435E3405">Nature</mods:title>
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<mods:part id="294FB322FB098AC5796324ECB0D21075">
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<mods:date id="04CA3CD918545DF2A128A40CAEF67909">2017</mods:date>
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<mods:detail id="ECC5AD363A9F53659C1BA69A62162BCB" type="volume">
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<mods:number id="A4C81E93BDDE33F4F6EAAB5FAEBBA295">541</mods:number>
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<mods:start id="6BC5655881F36746EA3D192705961192">1</mods:start>
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<mods:end id="3F816DDD8A3C2A735F48E74F040397A4">5</mods:end>
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<mods:classification id="50F83EFE6BFE5C5D542F1D92A96FAA19">journal article</mods:classification>
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<mods:identifier id="C71F01F96758C370B50E52ACC4AF0C7A" type="CLB-Dataset">37247</mods:identifier>
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<mods:identifier id="244B7A6E0664EF28E3401B2BA40BBAC8" type="DOI">10.1038/nature21072</mods:identifier>
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<mods:identifier id="9FBEE72D986365C1F29EDD50589F74BD" type="GBIF-Dataset">257ab49f-21bc-482c-8878-c0ffdd07d08e</mods:identifier>
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<mods:identifier id="F09D38122636343FF80DCBFA29D0AE35" type="Zenodo-Dep">265124</mods:identifier>
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<treatment id="E11D50529B47FFE6F5D8F9385A7FFC03" ID-DOI="http://doi.org/10.5281/zenodo.6010355" ID-GBIF-Taxon="127628074" ID-Zenodo-Dep="6010355" LSID="urn:lsid:plazi:treatment:E11D50529B47FFE6F5D8F9385A7FFC03" httpUri="http://treatment.plazi.org/id/E11D50529B47FFE6F5D8F9385A7FFC03" lastPageId="3" lastPageNumber="1" pageId="0" pageNumber="1">
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<subSubSection id="21AEB2CF9B47FFE5F5D8F9385A6AF8A3" pageId="0" pageNumber="1" type="nomenclature">
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<paragraph id="690BE1449B47FFE5F5D8F9385A6AF8A3" blockId="0.[113,787,512,1884]" pageId="0" pageNumber="1">
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<taxonomicName id="AEB49AC79B47FFE5F5D8F9385A6AF8A3" authority="Han, Shu, Ou and Conway Morris, 2017" authorityName="Han, Shu, Ou and Conway Morris" authorityYear="2017" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="0" pageNumber="1" rank="species" species="coronarius" status="gen. nov.">
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<emphasis id="5BC03D569B47FFE5F5D8F93859D0F948" box="[180,401,1750,1772]" italics="true" pageId="0" pageNumber="1">Saccorhytus coronarius</emphasis>
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<taxonomicNameLabel id="40F3802D9B47FFE5F4FAF9395A5BF948" box="[406,538,1751,1772]" pageId="0" pageNumber="1">gen et sp. nov</taxonomicNameLabel>
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. Han, Shu, Ou and Conway Morris, 2017
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</taxonomicName>
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</paragraph>
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</subSubSection>
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<subSubSection id="21AEB2CF9B47FFE5F51DF8E058A3F8F8" pageId="0" pageNumber="1" type="etymology">
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<paragraph id="690BE1449B47FFE5F51DF8E058A3F8F8" blockId="0.[113,787,512,1884]" pageId="0" pageNumber="1">
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<emphasis id="5BC03D569B47FFE5F51DF8E058A5F887" bold="true" box="[113,228,1806,1827]" pageId="0" pageNumber="1">Etymology.</emphasis>
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Generic name reference to bag-like body (L.
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<emphasis id="5BC03D569B47FFE5F7CEF8E15A9EF880" box="[674,735,1807,1828]" italics="true" pageId="0" pageNumber="1">saccus</emphasis>
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) and wrinkled preservation (Gr.
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<emphasis id="5BC03D569B47FFE5F41EF8C459E7F89B" box="[370,422,1834,1855]" italics="true" pageId="0" pageNumber="1">rhytis</emphasis>
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). Specific name in reference to crownlike mouth.
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</paragraph>
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</subSubSection>
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<subSubSection id="21AEB2CF9B47FFE5F65CFDE85BC2FD58" pageId="0" pageNumber="1" type="diagnosis">
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<paragraph id="690BE1449B47FFE5F65CFDE85BBBFD60" blockId="0.[816,1490,518,1884]" pageId="0" pageNumber="1">
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<emphasis id="5BC03D569B47FFE5F65CFDE85BDAFDB8" bold="true" box="[816,923,518,540]" pageId="0" pageNumber="1">Diagnosis.</emphasis>
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Hemi-ellipsoidal, bilaterally symmetrical body. Integument bears chevron pattern. Ventral mouth defined by two circlets of radial folds, inner circlet with associated protuberances. Aborally and dorsally up to four nodulate rugae. Eight body openings, conical, defined by radial folds. In mid-region anteriorly directed spines. Smaller pores parallel to body cones and in posterior region, possibly housed setae.
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<emphasis id="5BC03D569B47FFE5F65CFD405BD4FD67" bold="true" box="[816,917,686,707]" pageId="0" pageNumber="1">Holotype.</emphasis>
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XX45-20.
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</paragraph>
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<paragraph id="690BE1449B47FFE5F65CFD245BC2FD58" blockId="0.[816,1490,518,1884]" pageId="0" pageNumber="1">
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<emphasis id="5BC03D569B47FFE5F65CFD245B8FFD44" bold="true" box="[816,974,714,736]" pageId="0" pageNumber="1">Other material.</emphasis>
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XX25-62 and another 43 specimens (Supplementary Table 1).
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</paragraph>
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</subSubSection>
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<subSubSection id="21AEB2CF9B47FFE5F65CFCEC5BB9FCC8" pageId="0" pageNumber="1" type="materials_examined">
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<paragraph id="690BE1449B47FFE5F65CFCEC5B32FC90" blockId="0.[816,1490,518,1884]" pageId="0" pageNumber="1">
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<emphasis id="5BC03D569B47FFE5F65CFCEC5BCFFCBC" bold="true" box="[816,910,770,792]" pageId="0" pageNumber="1">Locality.</emphasis>
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Zhangjiagou section, Hexi, Xixiang County, Shaanxi, China.
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</paragraph>
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<paragraph id="690BE1449B47FFE5F65CFCD45BB9FCC8" blockId="0.[816,1490,518,1884]" pageId="0" pageNumber="1">
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<emphasis id="5BC03D569B47FFE5F65CFCD45B89FCF4" bold="true" box="[816,968,826,848]" pageId="0" pageNumber="1">Stratigraphy.</emphasis>
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Kuanchuanpu Formation, Fortunian Stage of Terreneuvian Series.
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</paragraph>
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</subSubSection>
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<subSubSection id="21AEB2CF9B47FFE4F62BFC9C5934F8DF" lastPageId="1" pageId="0" pageNumber="1" type="description">
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<paragraph id="690BE1449B47FFE5F62BFC9C5B83FB04" blockId="0.[816,1490,518,1884]" pageId="0" pageNumber="1">
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Forty-five phosphatized specimens are available (
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<figureCitation id="F18FFDC19B47FFE5F071FC9C5D14FC23" box="[1309,1365,882,904]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="0" pageNumber="1">Figs 1</figureCitation>
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,
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<figureCitation id="F18FFDC19B47FFE5F033FC9C5D2AFC23" box="[1375,1387,882,903]" captionStart="Figure 2" captionStartId="2.[113,175,898,917]" captionTargetId="figure@2.[668,848,382,637]" captionTargetPageId="2" captionText="Figure 2 | Saccorhytus coronarius gen. et sp. nov. a – c XX 45 - 1. a, Left side. b, Detail of mouth with nodular rugae and oral protrusions in a. c, Circular pores on the dorsal side of b. d, e, XX 36 - 22. d, Right view. Nodular rugae visible on ventral posterior part of the body, and body cones with radial ribs (Rr). e, Detail of mouth with radial folds and oral" httpUri="https://zenodo.org/record/265392/files/figure.png" pageId="0" pageNumber="1">2</figureCitation>
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, Extended Data
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<figureCitation id="F18FFDC19B47FFE5F60AFC605BE1FC00" box="[870,928,910,932]" captionStart="Figure 2" captionStartId="2.[113,175,898,917]" captionTargetId="figure@2.[668,848,382,637]" captionTargetPageId="2" captionText="Figure 2 | Saccorhytus coronarius gen. et sp. nov. a – c XX 45 - 1. a, Left side. b, Detail of mouth with nodular rugae and oral protrusions in a. c, Circular pores on the dorsal side of b. d, e, XX 36 - 22. d, Right view. Nodular rugae visible on ventral posterior part of the body, and body cones with radial ribs (Rr). e, Detail of mouth with radial folds and oral" httpUri="https://zenodo.org/record/265392/files/figure.png" pageId="0" pageNumber="1">Figs 2</figureCitation>
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–6 and Supplementary Table 1). As with similar material from this horizon
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<bibRefCitation id="0D259CB59B47FFE5F6B1FC4A5BACFC12" author="Dong, X. - P." box="[989,1005,932,950]" journalOrPublisher="Proc. R. Soc. Lond. B" pageId="0" pageNumber="1" pagination="20130071" part="280" refString="14. Dong, X. - P. et al. Embryos, polyps and medusae of the Early Cambrian scyphozoan Olivooides. Proc. R. Soc. Lond. B 280, 20130071 (2013)." title="et al. Embryos, polyps and medusae of the Early Cambrian scyphozoan Olivooides" type="journal article" year="2013">14</bibRefCitation>
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–
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<bibRefCitation id="0D259CB59B47FFE5F69BFC4A5C46FC12" author="Liu, Y. & Xiao, S. & Shao, T. & Broce, J. & Zhang, H." box="[1015,1031,932,950]" journalOrPublisher="Evol. Dev." pageId="0" pageNumber="1" pagination="155 - 165" part="16" refString="16. Liu, Y., Xiao, S., Shao, T., Broce, J. & Zhang, H. The oldest known priapulid-like scalidophoran animal and its implications for the early evolution of cycloneuralians and ecdysozoans. Evol. Dev. 16, 155 - 165 (2014)." title="The oldest known priapulid-like scalidophoran animal and its implications for the early evolution of cycloneuralians and ecdysozoans" type="journal article" year="2014">16</bibRefCitation>
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and co-eval deposits
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<bibRefCitation id="0D259CB59B47FFE5F1BFFC4A5CA5FC12" author="Zhang, H." box="[1235,1252,932,950]" journalOrPublisher="Sci. Rep." pageId="0" pageNumber="1" pagination="16521" part="5" refString="17. Zhang, H. et al. Armored kinorhynch-like scalidophoran animals from the early Cambrian. Sci. Rep. 5, 16521 (2015)." title="et al. Armored kinorhynch-like scalidophoran animals from the early Cambrian" type="journal article" year="2015">17</bibRefCitation>
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, the phosphatic composition of the specimens is evidently the result of very early diagenesis. Extensive folding suggests that in life the integument was thin, flexible and only slightly sclerotized. The integument consists of two layers (Extended Data
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<figureCitation id="F18FFDC19B47FFE5F6BEFBF45C4CFB94" box="[978,1037,1050,1072]" captionStart="Figure 2" captionStartId="2.[113,175,898,917]" captionTargetId="figure@2.[668,848,382,637]" captionTargetPageId="2" captionText="Figure 2 | Saccorhytus coronarius gen. et sp. nov. a – c XX 45 - 1. a, Left side. b, Detail of mouth with nodular rugae and oral protrusions in a. c, Circular pores on the dorsal side of b. d, e, XX 36 - 22. d, Right view. Nodular rugae visible on ventral posterior part of the body, and body cones with radial ribs (Rr). e, Detail of mouth with radial folds and oral" httpUri="https://zenodo.org/record/265392/files/figure.png" pageId="0" pageNumber="1">Figs 2</figureCitation>
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b, c, h, 3c, g, 5k, 6c, d), and frequently exhibits a fine-scale, densely spaced chevron-like folding on both external and internal surfaces (
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<figureCitation id="F18FFDC19B47FFE5F178FBBC5C0BFBCC" box="[1044,1098,1106,1128]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="0" pageNumber="1">Fig. 1</figureCitation>
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b, Extended Data
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<figureCitation id="F18FFDC19B47FFE5F06FFBBC5D7EFBCC" box="[1283,1343,1106,1128]" captionStart="Figure 2" captionStartId="2.[113,175,898,917]" captionTargetId="figure@2.[668,848,382,637]" captionTargetPageId="2" captionText="Figure 2 | Saccorhytus coronarius gen. et sp. nov. a – c XX 45 - 1. a, Left side. b, Detail of mouth with nodular rugae and oral protrusions in a. c, Circular pores on the dorsal side of b. d, e, XX 36 - 22. d, Right view. Nodular rugae visible on ventral posterior part of the body, and body cones with radial ribs (Rr). e, Detail of mouth with radial folds and oral" httpUri="https://zenodo.org/record/265392/files/figure.png" pageId="0" pageNumber="1">Figs 2</figureCitation>
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f–i, 3h, 4g and Supplementary Table 1). If original, this suggests that the integument was bi-layered.
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</paragraph>
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<paragraph id="690BE1449B47FFE5F62BFB485D85FA1C" blockId="0.[816,1490,518,1884]" pageId="0" pageNumber="1">
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The body is hemi-ellipsoidal, with a maximum length of 1,300μm, width 800μm and height 900μm (Extended Data Fig. 7). Most material is crushed but several specimens (
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<figureCitation id="F18FFDC19B47FFE5F1F0FB305C95FB57" box="[1180,1236,1246,1268]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="0" pageNumber="1">Fig. 1</figureCitation>
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g, h and Extended Data Figs 5g, h, 6a) confirm original bilateral symmetry. Otherwise, body orientations depend principally on identification of the mouth, and presumably the more dorsal and posterior location of the body cones and possibly sensory pores. Post-mortem deformation makes the precise dispositions of other structures more difficult to interpret. The most parsimonious conclusion, however, is that these features were also arranged bilaterally (
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<figureCitation id="F18FFDC19B47FFE5F14AFA4C5C18FA13" box="[1062,1113,1442,1464]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="0" pageNumber="1">Fig. 1</figureCitation>
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g, h and Extended Data Figs 4f, h 6a).
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</paragraph>
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<paragraph id="690BE1449B47FFE5F62BFA505DF8F974" blockId="0.[816,1490,518,1884]" pageId="0" pageNumber="1">
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The largest of the body openings (approximately 300–500 μm) is defined by a double circlet with prominent radial folds. The folds of the inner circlet are somewhat finer and this circlet also bears a series of oral protrusions, each consisting of an outer sheath and an inner peg-like structure (
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<figureCitation id="F18FFDC19B47FFE5F69AF9C05C71F9E7" box="[1014,1072,1582,1604]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="0" pageNumber="1">Figs 1</figureCitation>
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a, d, e, g–i, 2a, b, d, e and Extended Data
|
||
<figureCitation id="F18FFDC19B47FFE5F65CF9A45B2AF9FB" box="[816,875,1610,1632]" captionStart="Figure 2" captionStartId="2.[113,175,898,917]" captionTargetId="figure@2.[668,848,382,637]" captionTargetPageId="2" captionText="Figure 2 | Saccorhytus coronarius gen. et sp. nov. a – c XX 45 - 1. a, Left side. b, Detail of mouth with nodular rugae and oral protrusions in a. c, Circular pores on the dorsal side of b. d, e, XX 36 - 22. d, Right view. Nodular rugae visible on ventral posterior part of the body, and body cones with radial ribs (Rr). e, Detail of mouth with radial folds and oral" httpUri="https://zenodo.org/record/265392/files/figure.png" pageId="0" pageNumber="1">Figs 2</figureCitation>
|
||
c, 3f, 4a, c, f, 5a, c, d, g, i). This double circlet is interpreted as the oral region, while the protrusions, notably the most anterior pair (Extended Data Figs 5g, i, 6f, g), may represent sensilla. The flexibility of the oral region is evident from both its lateral compression and dorsal arching (
|
||
<figureCitation id="F18FFDC19B47FFE5F6E4F9545BFEF96B" box="[904,959,1722,1744]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="0" pageNumber="1">Figs 1</figureCitation>
|
||
a, d, e, i, 2d and Extended Data Figs 4a, e, 5a, c, d, g).
|
||
</paragraph>
|
||
<paragraph id="690BE1449B47FFE4F62BF9385A84F9E3" blockId="0.[816,1490,518,1884]" lastBlockId="1.[98,772,1109,1999]" lastPageId="1" pageId="0" pageNumber="1">
|
||
Anterior to the oral region, the dorsal integument consists of up to four rugae with a nodular appearance (
|
||
<figureCitation id="F18FFDC19B47FFE5F1CFF91C5C99F8A3" box="[1187,1240,1778,1800]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="0" pageNumber="1">Figs 1</figureCitation>
|
||
a, d, 2a, b, d and Extended Data
|
||
<figureCitation id="F18FFDC19B47FFE5F604F8E05BE4F880" box="[872,933,1806,1828]" captionStart="Figure 3" captionStartId="2.[113,175,1929,1948]" captionTargetPageId="2" captionText="Figure 3 | Reconstruction of Saccorhytus coronarius gen. et sp. nov. and the phylogeny of early deuterostomes. a, Lateral, hind and ventral views. b, The most parsimonious tree (tree length, 96; consistency index, 0.6771; retention index, 0.8394; rescaled consistency index, 0.5683) arising from a matrix of 25 taxa and 61 characteristics. The values at nodes indicate bootstrap support greater than 50 % (see Supplementary Information for details)." httpUri="https://zenodo.org/record/344618/files/figure.png" pageId="0" pageNumber="1">Figs 3</figureCitation>
|
||
d, 4a, c, 5a, f). These may be separated by intervening integument or (presumably as a result of contraction) are closely adpressed with the nodular regions interlocked. Behind the rugae, the integument grades into a zone with longitudinal folds, but the posterior body is relatively smooth. Otherwise the most prominent structures are a series of body cones (
|
||
<figureCitation id="F18FFDC19B46FFE4F40FFB6359DBFB06" box="[355,410,1165,1187]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="1">Figs 1</figureCitation>
|
||
a, d, g, i, 2a, d, f, g and Extended Data
|
||
<figureCitation id="F18FFDC19B46FFE4F50EFB4758DEFB1A" box="[98,159,1193,1215]" captionStart="Figure 2" captionStartId="2.[113,175,898,917]" captionTargetId="figure@2.[668,848,382,637]" captionTargetPageId="2" captionText="Figure 2 | Saccorhytus coronarius gen. et sp. nov. a – c XX 45 - 1. a, Left side. b, Detail of mouth with nodular rugae and oral protrusions in a. c, Circular pores on the dorsal side of b. d, e, XX 36 - 22. d, Right view. Nodular rugae visible on ventral posterior part of the body, and body cones with radial ribs (Rr). e, Detail of mouth with radial folds and oral" httpUri="https://zenodo.org/record/265392/files/figure.png" pageId="1">Figs 2</figureCitation>
|
||
a, b, d, h, 3a, c, d, g, 4b, d, f, h, 5a–c, e, g, k, 6). These vary in size (56–328 μm across), but all are formed of a series of ribs radiating from an unoccluded aperture. Up to eight body cones are visible, with the four body cones on the left and right sides extending in a more dorsal direction (
|
||
<figureCitation id="F18FFDC19B46FFE4F461FAF75903FA8A" box="[269,322,1305,1327]" captionStart="Figure 3" captionStartId="2.[113,175,1929,1948]" captionTargetPageId="2" captionText="Figure 3 | Reconstruction of Saccorhytus coronarius gen. et sp. nov. and the phylogeny of early deuterostomes. a, Lateral, hind and ventral views. b, The most parsimonious tree (tree length, 96; consistency index, 0.6771; retention index, 0.8394; rescaled consistency index, 0.5683) arising from a matrix of 25 taxa and 61 characteristics. The values at nodes indicate bootstrap support greater than 50 % (see Supplementary Information for details)." httpUri="https://zenodo.org/record/344618/files/figure.png" pageId="1">Fig. 3</figureCitation>
|
||
a). The first body cone is located immediately behind the oral region, and the body cone behind it is somewhat larger. The third body cone is the largest, and the most dorsal one is smaller. There are also two sets of small circular pores (30 μm across). One set is widely separated and runs parallel to the body cones (
|
||
<figureCitation id="F18FFDC19B46FFE4F7C7FA675A9EFA3A" box="[683,735,1417,1439]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="1">Fig. 1</figureCitation>
|
||
a, g and Extended Data Figs 4f, h, 5g). The other set is more dorsal and consists of sub-linear arrays (
|
||
<figureCitation id="F18FFDC19B46FFE4F4FDFA2F598DFA72" box="[401,460,1473,1495]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="1">Figs 1</figureCitation>
|
||
a, b, f, 2a, c, f, g and Extended Data
|
||
<figureCitation id="F18FFDC19B46FFE4F5FAFA335890FA56" box="[150,209,1501,1523]" captionStart="Figure 2" captionStartId="2.[113,175,898,917]" captionTargetId="figure@2.[668,848,382,637]" captionTargetPageId="2" captionText="Figure 2 | Saccorhytus coronarius gen. et sp. nov. a – c XX 45 - 1. a, Left side. b, Detail of mouth with nodular rugae and oral protrusions in a. c, Circular pores on the dorsal side of b. d, e, XX 36 - 22. d, Right view. Nodular rugae visible on ventral posterior part of the body, and body cones with radial ribs (Rr). e, Detail of mouth with radial folds and oral" httpUri="https://zenodo.org/record/265392/files/figure.png" pageId="1">Figs 2</figureCitation>
|
||
a, d, e, j, 3a, d, e, 4f, h, 5b, h, j). Finally there are occasional conspicuous spines, with a wide base and elongate anterior taper (
|
||
<figureCitation id="F18FFDC19B46FFE4F507F9FB58E5F98E" box="[107,164,1557,1579]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="1">Figs 1</figureCitation>
|
||
c, 2h and Extended Data
|
||
<figureCitation id="F18FFDC19B46FFE4F4C9F9FB59A1F98F" box="[421,480,1557,1579]" captionStart="Figure 3" captionStartId="2.[113,175,1929,1948]" captionTargetPageId="2" captionText="Figure 3 | Reconstruction of Saccorhytus coronarius gen. et sp. nov. and the phylogeny of early deuterostomes. a, Lateral, hind and ventral views. b, The most parsimonious tree (tree length, 96; consistency index, 0.6771; retention index, 0.8394; rescaled consistency index, 0.5683) arising from a matrix of 25 taxa and 61 characteristics. The values at nodes indicate bootstrap support greater than 50 % (see Supplementary Information for details)." httpUri="https://zenodo.org/record/344618/files/figure.png" pageId="1">Figs 3</figureCitation>
|
||
d, 5a, b, f, 6a). Strong folding makes the conclusion tentative, but no anus is evident (
|
||
<figureCitation id="F18FFDC19B46FFE4F714F9DF5AEDF9E2" box="[632,684,1585,1607]" captionStart="Figure 3" captionStartId="2.[113,175,1929,1948]" captionTargetPageId="2" captionText="Figure 3 | Reconstruction of Saccorhytus coronarius gen. et sp. nov. and the phylogeny of early deuterostomes. a, Lateral, hind and ventral views. b, The most parsimonious tree (tree length, 96; consistency index, 0.6771; retention index, 0.8394; rescaled consistency index, 0.5683) arising from a matrix of 25 taxa and 61 characteristics. The values at nodes indicate bootstrap support greater than 50 % (see Supplementary Information for details)." httpUri="https://zenodo.org/record/344618/files/figure.png" pageId="1">Fig. 3</figureCitation>
|
||
a).
|
||
</paragraph>
|
||
<footnote id="0AAFFD4A9B47FFE5F51DF8635B1DF86F" pageId="0" pageNumber="1">
|
||
<paragraph id="690BE1449B47FFE5F51DF8635B1DF86F" blockId="0.[113,1473,1933,1996]" pageId="0" pageNumber="1">1State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi’an 710069, China. 2Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK. 3State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China. 4Department of Zoology, University of Kassel, Kassel 34132, Germany. 5College of Petroleum Engineering, Xi’an Shiyou University, Xi’an 710065, China.</paragraph>
|
||
</footnote>
|
||
<footnote id="0AAFFD4A9B47FFE5F167F81D5D90F7A5" box="[1035,1489,2035,2049]" pageId="0" pageNumber="1">
|
||
<paragraph id="690BE1449B47FFE5F167F81D5D90F7A5" blockId="0.[489,1489,2035,2074]" box="[1035,1489,2035,2049]" pageId="0" pageNumber="1">0 0 M O N T H 2 0 1 7 | V O L 0 0 0 | N A T U R E | 1</paragraph>
|
||
</footnote>
|
||
<caption id="3DCBB1CC9B46FFE4F50EFC815DEAFBBE" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="1" targetBox="[348,1235,146,861]" targetPageId="1">
|
||
<paragraph id="690BE1449B46FFE4F50EFC815DEAFBBE" blockId="1.[98,761,879,1076]" lastBlockId="1.[802,1457,879,1050]" pageId="1">
|
||
<emphasis id="5BC03D569B46FFE4F50EFC8158EEFC26" bold="true" box="[98,175,879,898]" pageId="1">Figure 1</emphasis>
|
||
|
|
||
<emphasis id="5BC03D569B46FFE4F5D3FC8159BAFC38" bold="true" pageId="1">
|
||
<taxonomicName id="AEB49AC79B46FFE4F5D3FC8159D6FC26" authority="Han, Shu, Ou and Conway Morris, 2017" authorityName="Han, Shu, Ou and Conway Morris" authorityYear="2017" box="[191,407,879,898]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="1" pageNumber="1" rank="species" species="coronarius" status="gen. nov.">
|
||
<emphasis id="5BC03D569B46FFE4F5D3FC8159D6FC26" bold="true" box="[191,407,879,898]" italics="true" pageId="1">Saccorhytus coronarius</emphasis>
|
||
</taxonomicName>
|
||
gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a–c
|
||
</emphasis>
|
||
, Holotype XX45-20.
|
||
<emphasis id="5BC03D569B46FFE4F50EFC4C582DFC11" bold="true" box="[98,108,930,949]" pageId="1">a</emphasis>
|
||
, Right side. The mouth (M) arched dorsally along the anterior–posterior axis.
|
||
<emphasis id="5BC03D569B46FFE4F5E3FC5258DAFC6B" bold="true" box="[143,155,956,975]" pageId="1">b</emphasis>
|
||
, Chevron pattern (Ch) on the inner surface of the integument.
|
||
<emphasis id="5BC03D569B46FFE4F50EFC3B582AFC4C" bold="true" box="[98,107,981,1000]" pageId="1">c</emphasis>
|
||
, A spine (Sp) close to the mouth.
|
||
<emphasis id="5BC03D569B46FFE4F4F6FC3B59F8FC4C" bold="true" box="[410,441,981,1000]" pageId="1">d–f</emphasis>
|
||
, XX45-56.
|
||
<emphasis id="5BC03D569B46FFE4F773FC3B5A6AFC4C" bold="true" box="[543,555,981,1000]" pageId="1">d</emphasis>
|
||
, Left side.
|
||
<emphasis id="5BC03D569B46FFE4F7E0FC3B5AD7FC4C" bold="true" box="[652,662,981,1000]" pageId="1">e</emphasis>
|
||
, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in
|
||
<emphasis id="5BC03D569B46FFE4F474FBE65965FBBF" bold="true" box="[280,292,1032,1051]" pageId="1">d</emphasis>
|
||
.
|
||
<emphasis id="5BC03D569B46FFE4F443FBE95977FBBE" bold="true" box="[303,310,1031,1050]" pageId="1">f</emphasis>
|
||
, Circular pores (Cp) on the dorsal, right side.
|
||
<emphasis id="5BC03D569B46FFE4F50EFBCF58C1FB90" bold="true" box="[98,128,1057,1076]" pageId="1">g–i</emphasis>
|
||
, XX48-64 with limited compression.
|
||
<emphasis id="5BC03D569B46FFE4F4A3FBCF599BFB90" bold="true" box="[463,474,1057,1076]" pageId="1">g</emphasis>
|
||
, Ventral view, showing body cones (Bc) bilaterally arranged around the anterior, including the mouth. Two circular pores are adjacent to the first body cones (Bc1) and a small circular pore is on the mid-ventral line of the body.
|
||
<emphasis id="5BC03D569B46FFE4F19CFC4C5CBDFC11" bold="true" box="[1264,1276,930,949]" pageId="1">h</emphasis>
|
||
, Oral protrusions lacking distal ends and appearing as a circle of pores.
|
||
<emphasis id="5BC03D569B46FFE4F06CFC555D46FC6A" bold="true" box="[1280,1287,955,974]" pageId="1">i</emphasis>
|
||
, Left view reconstructed by microcomputerized tomography
|
||
<taxonomicName id="AEB49AC79B46FFE4F184FC3B5D50FC4C" box="[1256,1297,981,1000]" class="Insecta" family="Noctuidae" genus="Data" kingdom="Animalia" order="Lepidoptera" pageId="1" phylum="Arthropoda" rank="genus">data</taxonomicName>
|
||
. Lbc1–Lbc4, left body cones; Nr, nodular rugae; Rbc1–Rbc4, right body cones; Rf, radial folds; Sc, sub-layer of cuticle; arrowed AP, anterior–posterior axis.
|
||
</paragraph>
|
||
</caption>
|
||
<paragraph id="690BE1449B46FFE4F515F9A35934F8DF" blockId="1.[98,772,1109,1999]" pageId="1">
|
||
The oral region could evidently distend, with its pleated arrangement accommodating changes in size. This, combined with dorsal arching, would allow ingestion of food particles and possibly somewhat larger prey
|
||
<bibRefCitation id="0D259CB59B46FFE4F465F975595BF909" author="Giere, O." box="[265,282,1691,1709]" journalOrPublisher="Sci. Rep." pageId="1" refString="18. Giere, O. Meiobenthology: The microscopic fauna in aquatic sediments (Springer-Verlag, 1993)." title="Meiobenthology: The microscopic fauna in aquatic sediments (Springer-Verlag, 1993)" type="book" year="2015">18</bibRefCitation>
|
||
. The size of mouth also suggests that water was swallowed, with the body cones being interpreted as exhalant structures. The dorsal extension of the body cones suggests that the corresponding oral cavity was also elongate. The more dorsal set of circular pores may represent the insertion points of setae. The other set adjacent to the body cones may have had a sensory function, although alternatively they could have released internal contents such as adhesive mucus or gametes.
|
||
</paragraph>
|
||
</subSubSection>
|
||
<subSubSection id="21AEB2CF9B46FFE6F515F86F5A7FFC03" lastPageId="3" pageId="1" type="discussion">
|
||
<paragraph id="690BE1449B46FFE4F515F86F5CB5FA57" blockId="1.[98,772,1109,1999]" lastBlockId="1.[801,1474,1109,1999]" pageId="1">
|
||
The millimetric size of
|
||
<taxonomicName id="AEB49AC79B46FFE4F431F86F5991F832" box="[349,464,1921,1942]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="1" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B46FFE4F431F86F5991F832" box="[349,464,1921,1942]" italics="true" pageId="1">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
does not preclude a planktonic location, but its globular shape is consistent with a meiofaunal habit within what is now a phosphatic shelly limestone
|
||
<bibRefCitation id="0D259CB59B46FFE4F70CF85D5A30F861" author="Liu, Y. & Xiao, S. & Shao, T. & Broce, J. & Zhang, H." box="[608,625,1971,1989]" journalOrPublisher="Evol. Dev." pageId="1" pagination="155 - 165" part="16" refString="16. Liu, Y., Xiao, S., Shao, T., Broce, J. & Zhang, H. The oldest known priapulid-like scalidophoran animal and its implications for the early evolution of cycloneuralians and ecdysozoans. Evol. Dev. 16, 155 - 165 (2014)." title="The oldest known priapulid-like scalidophoran animal and its implications for the early evolution of cycloneuralians and ecdysozoans" type="journal article" year="2014">16</bibRefCitation>
|
||
. Although we did not find exact counterparts amongst extant meiobenthic taxa,
|
||
<taxonomicName id="AEB49AC79B46FFE4F64DFB9F5BD9FB22" box="[801,920,1137,1158]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="1" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B46FFE4F64DFB9F5BD9FB22" box="[801,920,1137,1158]" italics="true" pageId="1">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
shows a suite of features consistent with an interstitial habitat
|
||
<bibRefCitation id="0D259CB59B46FFE4F607FB695B3CFB3D" author="Giere, O." box="[875,893,1159,1177]" journalOrPublisher="Sci. Rep." pageId="1" refString="18. Giere, O. Meiobenthology: The microscopic fauna in aquatic sediments (Springer-Verlag, 1993)." title="Meiobenthology: The microscopic fauna in aquatic sediments (Springer-Verlag, 1993)" type="book" year="2015">18</bibRefCitation>
|
||
. These include a thick but flexible cuticle, suitable for mechanical protection and wriggling between sediment grains, respectively (Extended Data
|
||
<figureCitation id="F18FFDC19B46FFE4F15DFB2B5C22FB7E" box="[1073,1123,1221,1243]" captionStart="Figure 1" captionStartId="1.[98,160,879,898]" captionTargetId="figure@1.[660,954,372,613]" captionTargetPageId="1" captionText="Figure 1 | Saccorhytus coronarius gen. et sp. nov. from the Cambrian Kuanchuanpu Formation, South China. a – c, Holotype XX 45 - 20. a, Right side. The mouth (M) arched dorsally along the anterior – posterior axis. b, Chevron pattern (Ch) on the inner surface of the integument. c, A spine (Sp) close to the mouth. d – f, XX 45 - 56. d, Left side. e, Detail of the dorsally arched and folded mouth with radial folds (Rf) and oral protrusions (Op) in d. f, Circular pores (Cp) on the dorsal, right side. g – i, XX 48 - 64 with limited compression. g, Ventral view, showing body" httpUri="https://zenodo.org/record/265391/files/figure.png" pageId="1">Fig. 1</figureCitation>
|
||
c, d). The postulated setae, especially those towards the dorsal side, could perform a haptic role, including temporary attachment. Many meiofaunal taxa are progenetic and deciding whether
|
||
<taxonomicName id="AEB49AC79B46FFE4F6B5FAF75C0EFA8A" box="[985,1103,1305,1326]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="1" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B46FFE4F6B5FAF75C0EFA8A" box="[985,1103,1305,1326]" italics="true" pageId="1">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
is best interpreted as a miniaturized adult or a larval stage has important implications for both potential life cycles and phylogenetic relationships. Evidence in favour of the former includes the observation that, despite a size range of 548–1,326 μm, the morphology is effectively invariant. More notable is that most extant larvae
|
||
<bibRefCitation id="0D259CB59B46FFE4F630FA715B2DFA15" author="Young, C. M. & Sewell, M. A. & Rice, M. E." box="[860,876,1439,1457]" journalOrPublisher="Sci. Rep." pageId="1" refString="19. Young, C. M., Sewell, M. A. & Rice, M. E. (eds) Atlas of Marine Invertebrate Life (Academic, 2002)." title="Atlas of Marine Invertebrate Life (Academic, 2002)" type="book" year="2015">19</bibRefCitation>
|
||
are ciliated and, although a few groups such as the bryozoans (cyphonautes) and loriciferans have thin cuticular coverings, they are unlike the relatively massive coat of
|
||
<taxonomicName id="AEB49AC79B46FFE4F111FA335CAEFA56" box="[1149,1263,1501,1522]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="1" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B46FFE4F111FA335CAEFA56" box="[1149,1263,1501,1522]" italics="true" pageId="1">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
.
|
||
</paragraph>
|
||
<paragraph id="690BE1449B46FFE4F654FA175BAEF8AF" blockId="1.[801,1474,1109,1999]" pageId="1">
|
||
Irrespective of whether
|
||
<taxonomicName id="AEB49AC79B46FFE4F159FA175CF1F9AA" box="[1077,1200,1529,1550]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="1" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B46FFE4F159FA175CF1F9AA" box="[1077,1200,1529,1550]" italics="true" pageId="1">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
is a progenetic relative of unknown macroscopic taxa, its closest relationships appear to lie with the vetulicolians and possibly vetulocystids. Forming part of a highly disparate suite of taxa, collectively they appear to represent early deuterostomes
|
||
<bibRefCitation id="0D259CB59B46FFE4F6D9F98D5BFCF9D1" author="Shu, D. - G. & Conway Morris, S. & Zhang, Z. F. & Han, J." box="[949,957,1635,1653]" journalOrPublisher="Proc. R. Soc. Lond. B" pageId="1" pagination="165 - 174" part="277" refString="1. Shu, D. - G., Conway Morris, S., Zhang, Z. F. & Han, J. The earliest history of the deuterostomes: the importance of the Chengjiang Fossil-Lagerstatte. Proc. R. Soc. Lond. B 277, 165 - 174 (2010)." title="The earliest history of the deuterostomes: the importance of the Chengjiang Fossil-Lagerstatte" type="journal article" year="2010">1</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="0D259CB59B46FFE4F6ADF98D5B93F9D1" author="Peterson, K. J. & Eernisse, D. J." box="[961,978,1635,1653]" journalOrPublisher="Org. Divers. Evol." pageId="1" pagination="401 - 418" part="16" refString="20. Peterson, K. J. & Eernisse, D. J. The phylogeny, evolutionary developmental biology, and paleobiology of the Deuterostomia: 25 years of new techniques, new discoveries, and new ideas. Org. Divers. Evol. 16, 401 - 418 (2016)." title="The phylogeny, evolutionary developmental biology, and paleobiology of the Deuterostomia: 25 years of new techniques, new discoveries, and new ideas" type="journal article" year="2016">20</bibRefCitation>
|
||
, albeit ones not easily assigned to particular stem groups
|
||
<bibRefCitation id="0D259CB59B46FFE4F608F9915B35F935" author="Smith, A. B." box="[868,884,1663,1681]" journalOrPublisher="BMC Biol" pageId="1" pagination="79" part="10" refString="21. Smith, A. B. Cambrian problematica and the diversification of deuterostomes. BMC Biol. 10, 79 (2012)." title="Cambrian problematica and the diversification of deuterostomes" type="journal article" year="2012">21</bibRefCitation>
|
||
. Our phylogenetic analysis (
|
||
<figureCitation id="F18FFDC19B46FFE4F1E9F96B5CF8F93F" box="[1157,1209,1669,1691]" captionStart="Figure 3" captionStartId="2.[113,175,1929,1948]" captionTargetPageId="2" captionText="Figure 3 | Reconstruction of Saccorhytus coronarius gen. et sp. nov. and the phylogeny of early deuterostomes. a, Lateral, hind and ventral views. b, The most parsimonious tree (tree length, 96; consistency index, 0.6771; retention index, 0.8394; rescaled consistency index, 0.5683) arising from a matrix of 25 taxa and 61 characteristics. The values at nodes indicate bootstrap support greater than 50 % (see Supplementary Information for details)." httpUri="https://zenodo.org/record/344618/files/figure.png" pageId="1">Fig. 3</figureCitation>
|
||
b, Extended Data Fig. 8 and Supplementary Information) confirms both the monophyly of the deuterostomes
|
||
<bibRefCitation id="0D259CB59B46FFE4F6DEF9595B82F96D" author="Simakov, O." box="[946,963,1719,1737]" journalOrPublisher="Nature" pageId="1" pagination="459 - 465" part="527" refString="22. Simakov, O. et al. Hemichordate genomes and deuterostome origins. Nature 527, 459 - 465 (2015)." title="et al. Hemichordate genomes and deuterostome origins" type="journal article" year="2015">22</bibRefCitation>
|
||
and component groups including vetulicolians plus banffiids and vetulocystids, but the position of
|
||
<taxonomicName id="AEB49AC79B46FFE4F19BF9375D2DF94A" box="[1271,1388,1753,1774]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="1" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B46FFE4F19BF9375D2DF94A" box="[1271,1388,1753,1774]" italics="true" pageId="1">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
remains less well constrained.
|
||
</paragraph>
|
||
<paragraph id="690BE1449B46FFE7F654F8FF5C7BFBCF" blockId="1.[801,1474,1109,1999]" lastBlockId="2.[816,1490,1053,1131]" lastPageId="2" pageId="1">
|
||
With respect to vetulicolians, similarities with
|
||
<taxonomicName id="AEB49AC79B46FFE4F06DF8FF5D35F882" box="[1281,1396,1809,1830]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="1" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B46FFE4F06DF8FF5D35F882" box="[1281,1396,1809,1830]" italics="true" pageId="1">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
include the circum-oral radial structures and the body openings, interpreted as pharyngeal gills in the former group. In forms such as
|
||
<taxonomicName id="AEB49AC79B46FFE4F043F8A75DCCF8FA" box="[1327,1421,1865,1886]" class="Vetulicolida" family="Didazoonidae" genus="Didazoon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Vetulicolata" pageId="1" phylum="Vetulicolia" rank="genus">
|
||
<emphasis id="5BC03D569B46FFE4F043F8A75DCCF8FA" box="[1327,1421,1865,1886]" italics="true" pageId="1">Didazoon</emphasis>
|
||
</taxonomicName>
|
||
<bibRefCitation id="0D259CB59B46FFE4F0E1F8AD5DDCF8F1" author="Shu, D. - G." box="[1421,1437,1859,1877]" journalOrPublisher="Nature" pageId="1" pagination="419 - 424" part="414" refString="12. Shu, D. - G. et al. Primitive deuterostomes from the Chengjiang Lagerstatte (Lower Cambrian, China). Nature 414, 419 - 424 (2001)." title="et al. Primitive deuterostomes from the Chengjiang Lagerstatte (Lower Cambrian, China)" type="journal article" year="2001">12</bibRefCitation>
|
||
the gills also have a convex exterior, although here the openings are directed posteriorly. Moreover, in
|
||
<taxonomicName id="AEB49AC79B46FFE4F17AF86F5C35F832" box="[1046,1140,1921,1942]" class="Vetulicolida" family="Didazoonidae" genus="Didazoon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Vetulicolata" pageId="1" phylum="Vetulicolia" rank="genus">
|
||
<emphasis id="5BC03D569B46FFE4F17AF86F5C35F832" box="[1046,1140,1921,1942]" italics="true" pageId="1">Didazoon</emphasis>
|
||
</taxonomicName>
|
||
the relative size of the openings in the posterior direction is similar to that seen in
|
||
<taxonomicName id="AEB49AC79B46FFE4F194F8735D2DF816" box="[1272,1388,1949,1970]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="1" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B46FFE4F194F8735D2DF816" box="[1272,1388,1949,1970]" italics="true" pageId="1">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
, notably with the third opening being conspicuously larger. In
|
||
<taxonomicName id="AEB49AC79B46FFE4F024F8575DEAF86A" box="[1352,1451,1977,1998]" class="Vetulicolida" family="Didazoonidae" genus="Didazoon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Vetulicolata" pageId="1" phylum="Vetulicolia" rank="genus">
|
||
<emphasis id="5BC03D569B46FFE4F024F8575DEAF86A" box="[1352,1451,1977,1998]" italics="true" pageId="1">Didazoon</emphasis>
|
||
</taxonomicName>
|
||
<bibRefCitation id="0D259CB59B46FFE4F0C7F85D5DFDF861" author="Shu, D. - G." box="[1451,1468,1971,1989]" journalOrPublisher="Nature" pageId="1" pagination="419 - 424" part="414" refString="12. Shu, D. - G. et al. Primitive deuterostomes from the Chengjiang Lagerstatte (Lower Cambrian, China). Nature 414, 419 - 424 (2001)." title="et al. Primitive deuterostomes from the Chengjiang Lagerstatte (Lower Cambrian, China)" type="journal article" year="2001">12</bibRefCitation>
|
||
,
|
||
<taxonomicName id="AEB49AC79B45FFE7F51DFBF05898FB97" box="[113,217,1054,1075]" class="Vetulicolida" family="Didazoonidae" genus="Pomatrum" higherTaxonomySource="GBIF" kingdom="Animalia" order="Vetulicolata" pageId="2" phylum="Vetulicolia" rank="genus">
|
||
<emphasis id="5BC03D569B45FFE7F51DFBF05898FB97" box="[113,217,1054,1075]" italics="true" pageId="2">Pomatrum</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName id="AEB49AC79B45FFE7F589FBF05903FB97" box="[229,322,1054,1075]" class="Vetulicolida" family="Didazoonidae" genus="Xidazoon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Vetulicolata" pageId="2" phylum="Vetulicolia" rank="genus">
|
||
<emphasis id="5BC03D569B45FFE7F589FBF05903FB97" box="[229,322,1054,1075]" italics="true" pageId="2">Xidazoon</emphasis>
|
||
</taxonomicName>
|
||
<bibRefCitation id="0D259CB59B45FFE7F42EFBF9590BFB8D" author="Shu, D. - G. & Conway Morris, S. & Zhang, Z. F. & Han, J." box="[322,330,1047,1065]" journalOrPublisher="Proc. R. Soc. Lond. B" pageId="2" pagination="165 - 174" part="277" refString="1. Shu, D. - G., Conway Morris, S., Zhang, Z. F. & Han, J. The earliest history of the deuterostomes: the importance of the Chengjiang Fossil-Lagerstatte. Proc. R. Soc. Lond. B 277, 165 - 174 (2010)." title="The earliest history of the deuterostomes: the importance of the Chengjiang Fossil-Lagerstatte" type="journal article" year="2010">1</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="0D259CB59B45FFE7F422FBF9591EFB8D" author="Shu, D. - G." box="[334,351,1047,1065]" journalOrPublisher="Nature" pageId="2" pagination="419 - 424" part="414" refString="12. Shu, D. - G. et al. Primitive deuterostomes from the Chengjiang Lagerstatte (Lower Cambrian, China). Nature 414, 419 - 424 (2001)." title="et al. Primitive deuterostomes from the Chengjiang Lagerstatte (Lower Cambrian, China)" type="journal article" year="2001">12</bibRefCitation>
|
||
and
|
||
<emphasis id="5BC03D569B45FFE7F4E3FBF05997FB97" box="[399,470,1054,1075]" italics="true" pageId="2">Banffia</emphasis>
|
||
<bibRefCitation id="0D259CB59B45FFE7F4BAFBF959A6FB8D" author="Caron, J. - B." box="[470,487,1047,1065]" journalOrPublisher="Trans. R. Soc. Edinb. Earth Sci" pageId="2" pagination="95 - 111" part="96" refString="23. Caron, J. - B. Banffia constricta, a putative vetulicolid from the Middle Cambrian Burgess Shale. Trans. R. Soc. Edinb. Earth Sci. 96, 95 - 111 (2005)." title="Banffia constricta, a putative vetulicolid from the Middle Cambrian Burgess Shale" type="journal article" year="2005">23</bibRefCitation>
|
||
the oral region shows variably developed pleating (Extended
|
||
<taxonomicName id="AEB49AC79B45FFE7F4C5FBD4599BFBEB" box="[425,474,1082,1103]" class="Insecta" family="Noctuidae" genus="Data" kingdom="Animalia" order="Lepidoptera" pageId="2" phylum="Arthropoda" rank="genus">Data</taxonomicName>
|
||
Fig. 9), similar to
|
||
<taxonomicName id="AEB49AC79B45FFE7F7F9FBD45B4DFBEB" box="[661,780,1082,1103]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="2" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B45FFE7F7F9FBD45B4DFBEB" box="[661,780,1082,1103]" italics="true" pageId="2">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
. Similarities to the vetulocystids
|
||
<bibRefCitation id="0D259CB59B45FFE7F4DCFBA159F9FBC5" author="Shu, D. - G. & Conway Morris, S. & Han, J. & Zhang, Z. F. & Liu, J. N." box="[432,440,1103,1121]" journalOrPublisher="Nature" pageId="2" pagination="422 - 428" part="430" refString="5. Shu, D. - G., Conway Morris, S., Han, J., Zhang, Z. F. & Liu, J. N. Ancestral echinoderms from the Chengjiang deposits of China. Nature 430, 422 - 428 (2004)." title="Ancestral echinoderms from the Chengjiang deposits of China" type="journal article" year="2004">5</bibRefCitation>
|
||
include body openings defined as truncated cones with well-developed radial ribs, albeit more numerous. The anterior body of vetulocystids is also strongly convoluted, and so reminiscent of
|
||
<taxonomicName id="AEB49AC79B45FFE7F6AEFBB85C75FBCF" box="[962,1076,1110,1131]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="2" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B45FFE7F6AEFBB85C75FBCF" box="[962,1076,1110,1131]" italics="true" pageId="2">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
.
|
||
</paragraph>
|
||
<caption id="3DCBB1CC9B45FFE7F51DFC6C5BF5FC5F" httpUri="https://zenodo.org/record/265392/files/figure.png" pageId="2" targetBox="[354,1249,146,879]" targetPageId="2">
|
||
<paragraph id="690BE1449B45FFE7F51DFC6C5BF5FC5F" blockId="2.[113,751,898,1019]" lastBlockId="2.[817,1476,898,1019]" pageId="2">
|
||
<emphasis id="5BC03D569B45FFE7F51DFC6C58FEFC31" bold="true" box="[113,191,898,917]" pageId="2">Figure 2</emphasis>
|
||
|
|
||
<emphasis id="5BC03D569B45FFE7F5A2FC6C5A16FC31" bold="true" box="[206,599,898,917]" pageId="2">
|
||
<taxonomicName id="AEB49AC79B45FFE7F5A2FC6C59E7FC31" authority="Han, Shu, Ou and Conway Morris, 2017" authorityName="Han, Shu, Ou and Conway Morris" authorityYear="2017" box="[206,422,898,917]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="2" pageNumber="1" rank="species" species="coronarius" status="gen. nov.">
|
||
<emphasis id="5BC03D569B45FFE7F5A2FC6C59E7FC31" bold="true" box="[206,422,898,917]" italics="true" pageId="2">Saccorhytus coronarius</emphasis>
|
||
</taxonomicName>
|
||
gen. et sp. nov. a–c
|
||
</emphasis>
|
||
XX45-1.
|
||
<emphasis id="5BC03D569B45FFE7F7C1FC6C5AF6FC31" bold="true" box="[685,695,898,917]" pageId="2">a</emphasis>
|
||
, Left side.
|
||
<emphasis id="5BC03D569B45FFE7F5F3FC7558EAFC0A" bold="true" box="[159,171,923,942]" pageId="2">b</emphasis>
|
||
, Detail of mouth with nodular rugae and oral protrusions in
|
||
<emphasis id="5BC03D569B45FFE7F7A2FC755A99FC0A" bold="true" box="[718,728,923,942]" pageId="2">a</emphasis>
|
||
.
|
||
<emphasis id="5BC03D569B45FFE7F51DFC5B583BFC6C" bold="true" box="[113,122,949,968]" pageId="2">c</emphasis>
|
||
, Circular pores on the dorsal side of
|
||
<emphasis id="5BC03D569B45FFE7F4A9FC5B5990FC6C" bold="true" box="[453,465,949,968]" pageId="2">b</emphasis>
|
||
.
|
||
<emphasis id="5BC03D569B45FFE7F4B7FC5B59A6FC6C" bold="true" box="[475,487,949,968]" pageId="2">d</emphasis>
|
||
,
|
||
<emphasis id="5BC03D569B45FFE7F49DFC5B59BAFC6C" bold="true" box="[497,507,949,968]" pageId="2">e</emphasis>
|
||
, XX36-22.
|
||
<emphasis id="5BC03D569B45FFE7F70CFC5B5A2DFC6C" bold="true" box="[608,620,949,968]" pageId="2">d</emphasis>
|
||
, Right view. Nodular rugae visible on ventral posterior part of the body, and body cones with radial ribs (Rr).
|
||
<emphasis id="5BC03D569B45FFE7F40BFC095930FC5E" bold="true" box="[359,369,999,1018]" pageId="2">e</emphasis>
|
||
, Detail of mouth with radial folds and oral protrusions of which those on the middle line are largest.
|
||
<emphasis id="5BC03D569B45FFE7F059FC6C5D14FC31" bold="true" box="[1333,1365,898,917]" pageId="2">f–h</emphasis>
|
||
, XX34-298.
|
||
<emphasis id="5BC03D569B45FFE7F65DFC755B79FC0A" bold="true" box="[817,824,923,942]" pageId="2">f</emphasis>
|
||
,
|
||
<emphasis id="5BC03D569B45FFE7F62FFC755B0FFC0A" bold="true" box="[835,846,923,942]" pageId="2">g</emphasis>
|
||
, Right and left, respectively; four body cones with radial ribs on either side of the specimen with circular pores on the dorsal side.
|
||
<emphasis id="5BC03D569B45FFE7F02FFC5B5D0EFC6C" bold="true" box="[1347,1359,949,968]" pageId="2">h</emphasis>
|
||
, Anterior body showing spine and unidentified structure with a sub-rectangular base and pore.
|
||
</paragraph>
|
||
</caption>
|
||
<caption id="3DCBB1CC9B45FFE7F51DF8675DF3F86A" httpUri="https://zenodo.org/record/344618/files/figure.png" pageId="2" targetBox="[357,1251,1186,1876]" targetPageId="2">
|
||
<paragraph id="690BE1449B45FFE7F51DF8675DF3F86A" pageId="2">
|
||
<emphasis id="5BC03D569B45FFE7F51DF86758FEF838" bold="true" box="[113,191,1929,1948]" pageId="2">Figure 3</emphasis>
|
||
|
|
||
<emphasis id="5BC03D569B45FFE7F5A2F8675C3EF838" bold="true" box="[206,1151,1928,1948]" pageId="2">
|
||
Reconstruction of
|
||
<taxonomicName id="AEB49AC79B45FFE7F410F8665A15F838" authority="Han, Shu, Ou and Conway Morris, 2017" authorityName="Han, Shu, Ou and Conway Morris" authorityYear="2017" box="[380,596,1928,1948]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="2" pageNumber="1" rank="species" species="coronarius" status="gen. nov.">
|
||
<emphasis id="5BC03D569B45FFE7F410F8665A15F838" bold="true" box="[380,596,1928,1948]" italics="true" pageId="2">Saccorhytus coronarius</emphasis>
|
||
</taxonomicName>
|
||
gen. et sp. nov. and the phylogeny of early deuterostomes. a
|
||
</emphasis>
|
||
, Lateral, hind and ventral views.
|
||
<emphasis id="5BC03D569B45FFE7F51DF84C583CF811" bold="true" box="[113,125,1954,1973]" pageId="2">b</emphasis>
|
||
, The most parsimonious tree (tree length,96; consistency index,0.6771; retention index,0.8394; rescaled consistency index, 0.5683) arising from a matrix of 25 taxa and 61 characteristics. The values at nodes indicate bootstrap support greater than 50% (see Supplementary Information for details).
|
||
</paragraph>
|
||
</caption>
|
||
<paragraph id="690BE1449B44FFE6F515FF70595BFE0B" blockId="3.[98,772,151,935]" pageId="3">
|
||
Very few characters unite the deuterostomes
|
||
<bibRefCitation id="0D259CB59B44FFE6F72EFF795A0BFF0D" author="Gillis, J. A. & Fritzenwanker, J. H. & Lowe, C. J. A" box="[578,586,151,169]" journalOrPublisher="Proc. R. Soc. Lond. B" pageId="3" pagination="237 - 246" part="279" refString="8. Gillis, J. A., Fritzenwanker, J. H. & Lowe, C. J. A stem-deuterostome origin of the vertebrate pharyngeal transcriptional network. Proc. R. Soc. Lond. B 279, 237 - 246 (2012)." title="stem-deuterostome origin of the vertebrate pharyngeal transcriptional network" type="journal article" year="2012">8</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="0D259CB59B44FFE6F723FF795A21FF0D" author="Simakov, O." box="[591,608,151,169]" journalOrPublisher="Nature" pageId="3" pagination="459 - 465" part="527" refString="22. Simakov, O. et al. Hemichordate genomes and deuterostome origins. Nature 527, 459 - 465 (2015)." title="et al. Hemichordate genomes and deuterostome origins" type="journal article" year="2015">22</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="0D259CB59B44FFE6F709FF795A37FF0D" author="Lowe, C. J. & Clarke, D. N. & Medeiros, D. M. & Rokhsar, D. S. & Gerhart, J." box="[613,630,151,169]" journalOrPublisher="Nature" pageId="3" pagination="456 - 465" part="520" refString="24. Lowe, C. J., Clarke, D. N., Medeiros, D. M., Rokhsar, D. S. & Gerhart, J. The deuterostome context of chordate origins. Nature 520, 456 - 465 (2015)." title="The deuterostome context of chordate origins" type="journal article" year="2015">24</bibRefCitation>
|
||
, and only the pharyngeal openings are potentially fossilizable. In this context the body cones of
|
||
<taxonomicName id="AEB49AC79B44FFE6F44DFF3859DBFF4F" box="[289,410,214,235]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="3" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B44FFE6F44DFF3859DBFF4F" box="[289,410,214,235]" italics="true" pageId="3">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
are more similar to the apparently equivalent structures found in the vetulicolians and vetulocystids than they are to the pharyngeal structures of other deuterostomes
|
||
<bibRefCitation id="0D259CB59B44FFE6F7AAFEE95A8FFEBD" author="Shu, D. - G. & Conway Morris, S. & Zhang, Z. F. & Han, J." box="[710,718,263,281]" journalOrPublisher="Proc. R. Soc. Lond. B" pageId="3" pagination="165 - 174" part="277" refString="1. Shu, D. - G., Conway Morris, S., Zhang, Z. F. & Han, J. The earliest history of the deuterostomes: the importance of the Chengjiang Fossil-Lagerstatte. Proc. R. Soc. Lond. B 277, 165 - 174 (2010)." title="The earliest history of the deuterostomes: the importance of the Chengjiang Fossil-Lagerstatte" type="journal article" year="2010">1</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="0D259CB59B44FFE6F7BFFEE95A9AFEBD" author="Nanglu, K. & Caron, J. - B. & Conway Morris, S. & Cameron, C. B." box="[723,731,263,281]" journalOrPublisher="BMC Biol" pageId="3" pagination="56" part="14" refString="3. Nanglu, K., Caron, J. - B., Conway Morris, S. & Cameron, C. B. Cambrian suspension-feeding tubicolous hemichordates. BMC Biol. 14, 56 (2016)." title="Cambrian suspension-feeding tubicolous hemichordates" type="journal article" year="2016">3</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="0D259CB59B44FFE6F78CFEE95AA9FEBD" author="Shu, D." box="[736,744,263,281]" journalOrPublisher="Science" pageId="3" pagination="1380 - 1384" part="299" refString="7. Shu, D. et al. A new species of yunnanozoan with implications for deuterostome evolution. Science 299, 1380 - 1384 (2003)." title="et al. A new species of yunnanozoan with implications for deuterostome evolution" type="journal article" year="2003">7</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="0D259CB59B44FFE6F780FEE95ABCFEBD" author="Conway Morris, S. & Caron, J. - B. A" box="[748,765,263,281]" journalOrPublisher="Nature" pageId="3" pagination="419 - 422" part="512" refString="11. Conway Morris, S. & Caron, J. - B. A primitive fish from the Cambrian of North America. Nature 512, 419 - 422 (2014)." title="primitive fish from the Cambrian of North America" type="journal article" year="2014">11</bibRefCitation>
|
||
. Early deuterostomes have a through gut, so the apparent absence of an anus in
|
||
<taxonomicName id="AEB49AC79B44FFE6F5BEFEA85908FEFF" box="[210,329,326,347]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="3" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B44FFE6F5BEFEA85908FEFF" box="[210,329,326,347]" italics="true" pageId="3">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
could be secondary, as in brachiopods and ophiuroids. It remains possible, however, that this feature was inherited from more primitive bilaterians
|
||
<bibRefCitation id="0D259CB59B44FFE6F4CDFE9959F3FE2D" author="Hejnol, A. & Martin-Duran, J." box="[417,434,375,393]" journalOrPublisher="Zool. Anz." pageId="3" pagination="61 - 74" part="256" refString="25. Hejnol, A. & Martin-Duran, J. Getting to the bottom of anal evolution. Zool. Anz. 256, 61 - 74 (2015)." title="Getting to the bottom of anal evolution" type="journal article" year="2015">25</bibRefCitation>
|
||
, possibly linked to the acoels and xenoturbellids
|
||
<bibRefCitation id="0D259CB59B44FFE6F583FE7D58BEFE01" author="Lowe, C. J. & Clarke, D. N. & Medeiros, D. M. & Rokhsar, D. S. & Gerhart, J." box="[239,255,403,421]" journalOrPublisher="Nature" pageId="3" pagination="456 - 465" part="520" refString="24. Lowe, C. J., Clarke, D. N., Medeiros, D. M., Rokhsar, D. S. & Gerhart, J. The deuterostome context of chordate origins. Nature 520, 456 - 465 (2015)." title="The deuterostome context of chordate origins" type="journal article" year="2015">24</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="0D259CB59B44FFE6F46FFE7D5952FE01" author="Hejnol, A. & Pang, K." box="[259,275,403,421]" journalOrPublisher="Curr. Opin. Genet. Dev." pageId="3" pagination="48 - 54" part="39" refString="26. Hejnol, A. & Pang, K. Xenacoelomorpha's significance for understanding bilaterian evolution. Curr. Opin. Genet. Dev. 39, 48 - 54 (2016)." title="Xenacoelomorpha's significance for understanding bilaterian evolution" type="journal article" year="2016">26</bibRefCitation>
|
||
.
|
||
</paragraph>
|
||
<paragraph id="690BE1449B44FFE6F515FE585A7FFC03" blockId="3.[98,772,151,935]" pageId="3">
|
||
We draw two main conclusions. First, some of the earliest deuterostomes were meiofaunal, and this finding complements proposals that such animals were benthic worms
|
||
<bibRefCitation id="0D259CB59B44FFE6F706FE095A3DFE5D" author="Brown, F. D. & Prendergast, A. & Swalla, B. J." box="[618,636,487,505]" journalOrPublisher="Genesis" pageId="3" pagination="605 - 613" part="46" refString="27. Brown, F. D., Prendergast, A. & Swalla, B. J. Man is but a worm: chordate origins. Genesis 46, 605 - 613 (2008)." title="Man is but a worm: chordate origins" type="journal article" year="2008">27</bibRefCitation>
|
||
. In contrast, however, to the suggestions that early deuterostomes possessed an indirect life cycle with a feeding larva
|
||
<bibRefCitation id="0D259CB59B44FFE6F4B2FDF159AEFD95" author="Lowe, C. J. & Clarke, D. N. & Medeiros, D. M. & Rokhsar, D. S. & Gerhart, J." box="[478,495,543,561]" journalOrPublisher="Nature" pageId="3" pagination="456 - 465" part="520" refString="24. Lowe, C. J., Clarke, D. N., Medeiros, D. M., Rokhsar, D. S. & Gerhart, J. The deuterostome context of chordate origins. Nature 520, 456 - 465 (2015)." title="The deuterostome context of chordate origins" type="journal article" year="2015">24</bibRefCitation>
|
||
, the biology of
|
||
<taxonomicName id="AEB49AC79B44FFE6F7E1FDC85B42FD9F" box="[653,771,550,571]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="3" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B44FFE6F7E1FDC85B42FD9F" box="[653,771,550,571]" italics="true" pageId="3">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
seems more consistent with direct development
|
||
<bibRefCitation id="0D259CB59B44FFE6F75DFDD55A00FDE9" author="Sly, B. J. & Snoke, M. S. & Raff, R. A." box="[561,577,571,589]" journalOrPublisher="Int. J. Dev. Biol." pageId="3" pagination="623 - 632" part="47" refString="28. Sly, B. J., Snoke, M. S. & Raff, R. A. Who came first-larvae or adults? origins of bilaterian metazoan larvae. Int. J. Dev. Biol. 47, 623 - 632 (2003)." title="Who came first-larvae or adults? origins of bilaterian metazoan larvae" type="journal article" year="2003">28</bibRefCitation>
|
||
. Previous work had emphasized the possible importance of the first stages of metazoan evolution occurring in a meiofaunal context
|
||
<bibRefCitation id="0D259CB59B44FFE6F75AFD9D5A09FD21" author="Boaden, P." box="[566,584,627,645]" journalOrPublisher="Zool. J. Linn. Soc." pageId="3" pagination="217 - 227" part="96" refString="29. Boaden, P. Meiofauna and the origins of the Metazoa. Zool. J. Linn. Soc. 96, 217 - 227 (1989)." title="Meiofauna and the origins of the Metazoa" type="journal article" year="1989">29</bibRefCitation>
|
||
. The discrepancy between the known fossil record of early metazoans and their estimated times of divergence
|
||
<bibRefCitation id="0D259CB59B44FFE6F44CFD455970FD19" author="Erwin, D. H." box="[288,305,683,701]" journalOrPublisher="Science" pageId="3" pagination="1091 - 1097" part="334" refString="30. Erwin, D. H. et al. The Cambrian conundrum: early divergence and later ecological success in the early history of animals. Science 334, 1091 - 1097 (2011)." title="et al. The Cambrian conundrum: early divergence and later ecological success in the early history of animals" type="journal article" year="2011">30</bibRefCitation>
|
||
as based on molecular clocks suggests that such miniaturized forms could slip through the nets of most fossilization pathways and so help to explain this cryptic history
|
||
<bibRefCitation id="0D259CB59B44FFE6F727FD0D5A12FD51" author="Wray, G. A." box="[587,595,739,757]" journalOrPublisher="Phil. Trans. R. Soc. Lond. B" pageId="3" pagination="20150046" part="370" refString="9. Wray, G. A. Molecular clocks and the early evolution of metazoan nervous systems. Phil. Trans. R. Soc. Lond. B 370, 20150046 (2015)." title="Molecular clocks and the early evolution of metazoan nervous systems" type="journal article" year="2015">9</bibRefCitation>
|
||
. Second, the body cone openings of
|
||
<taxonomicName id="AEB49AC79B44FFE6F463FCE859C3FCBF" box="[271,386,774,795]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="3" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B44FFE6F463FCE859C3FCBF" box="[271,386,774,795]" italics="true" pageId="3">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
are consistent with deuterostome body openings being very primitive
|
||
<bibRefCitation id="0D259CB59B44FFE6F4E7FCF559D2FC89" author="Gillis, J. A. & Fritzenwanker, J. H. & Lowe, C. J. A" box="[395,403,795,813]" journalOrPublisher="Proc. R. Soc. Lond. B" pageId="3" pagination="237 - 246" part="279" refString="8. Gillis, J. A., Fritzenwanker, J. H. & Lowe, C. J. A stem-deuterostome origin of the vertebrate pharyngeal transcriptional network. Proc. R. Soc. Lond. B 279, 237 - 246 (2012)." title="stem-deuterostome origin of the vertebrate pharyngeal transcriptional network" type="journal article" year="2012">8</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="0D259CB59B44FFE6F4FBFCF559E9FC89" author="Lowe, C. J. & Clarke, D. N. & Medeiros, D. M. & Rokhsar, D. S. & Gerhart, J." box="[407,424,795,813]" journalOrPublisher="Nature" pageId="3" pagination="456 - 465" part="520" refString="24. Lowe, C. J., Clarke, D. N., Medeiros, D. M., Rokhsar, D. S. & Gerhart, J. The deuterostome context of chordate origins. Nature 520, 456 - 465 (2015)." title="The deuterostome context of chordate origins" type="journal article" year="2015">24</bibRefCitation>
|
||
. In
|
||
<taxonomicName id="AEB49AC79B44FFE6F4A2FCCC5A00FC93" box="[462,577,802,823]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="3" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B44FFE6F4A2FCCC5A00FC93" box="[462,577,802,823]" italics="true" pageId="3">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
, however, diffusion across the body surface would have met any respiratory needs, suggesting that a transformation to specifically pharyngeal gills was linked to an increase in body size. If
|
||
<taxonomicName id="AEB49AC79B44FFE6F409FC985996FC2F" box="[357,471,886,907]" class="Vetulicolida" family="Saccorhytidae" genus="Saccorhytus" kingdom="Animalia" pageId="3" pageNumber="1" rank="genus" status="gen. nov.">
|
||
<emphasis id="5BC03D569B44FFE6F409FC985996FC2F" box="[357,471,886,907]" italics="true" pageId="3">Saccorhytus</emphasis>
|
||
</taxonomicName>
|
||
lacked an anus, body openings may have originated to dispose of waste material.
|
||
</paragraph>
|
||
</subSubSection>
|
||
</treatment>
|
||
</document> |