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dc.contributor.authorSmith, Martinen
dc.contributor.authorCaron, Jean-Bernarden
dc.date.accessioned2015-06-16T14:14:23Z
dc.date.available2015-06-16T14:14:23Z
dc.date.issued2015-06-16en
dc.identifier.citationNature 523, 75–78 (02 July 2015). DOI: 10.1038/nature14573
dc.identifier.issn0028-0836
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/248498
dc.description.abstractThe molecularly defined clade Ecdysozoa1 comprises the panarthropods (Euarthropoda, Onychophora and Tardigrada) and the cycloneuralian worms (Nematoda, Nematomorpha, Priapulida, Loricifera and Kinorhyncha). These disparate phyla are united by their means of moulting, but otherwise share few morphological characters—none of which has a meaningful fossilization potential. As such, the early evolutionary history of the group as a whole is largely uncharted. Here we redescribe the 508-million-year-old stem-group onychophoran Hallucigenia sparsa from the mid-Cambrian Burgess Shale. We document an elongate head with a pair of simple eyes, a terminal buccal chamber containing a radial array of sclerotized elements, and a differentiated foregut that is lined with acicular teeth. The radial elements and pharyngeal teeth resemble the sclerotized circumoral elements and pharyngeal teeth expressed in tardigrades stem-group euarthropods and cycloneuralian worms. Phylogenetic results indicate that equivalent structures characterized the ancestral panarthropod and, seemingly, the ancestral ecdysozoan, demonstrating the deep homology of panarthropod and cycloneuralian mouthparts, and providing an anatomical synapomorphy for the ecdysozoan supergroup.
dc.description.sponsorshipFunding for this research was provided by Clare College, Cambridge (MS), NSERC Discovery Grant #341944 (JBC) and the ROM DMV Acquisition and Research Fund and Endowment Fund (JBC). This is ROM Burgess Shale 210 project number 60.
dc.languageEnglishen
dc.language.isoenen
dc.publisherNature Publishing Group
dc.subjectHallucigeniaen
dc.subjectEcdysozoaen
dc.subjectPanarthropodaen
dc.subjectOnychophoraen
dc.subjectLobopodiaen
dc.subjectBurgess Shaleen
dc.subjectCambrian explosionen
dc.titleHallucigenia’s head and the pharyngeal armature of early ecdysozoansen
dc.typeArticle
dc.description.versionThis is the author accepted manuscript. The final version is available from Nature Publishing Group via http://dx.doi.org/10.1038/nature14573en
prism.endingPage78
prism.publicationDate2015en
prism.publicationNameNatureen
prism.startingPage75
prism.volume523en
dcterms.dateAccepted2015-05-18en
rioxxterms.versionofrecord10.1038/nature14573en
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2015-06-16en
dc.identifier.eissn1476-4687
rioxxterms.typeJournal Article/Reviewen
rioxxterms.freetoread.startdate2015-12-24


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