370 lines
53 KiB
XML
370 lines
53 KiB
XML
<document ID-DOI="http://doi.org/10.5281/zenodo.5805296" ID-GBIF-Dataset="cf6c12db-754f-4139-acab-eb6ce69ef0a4" ID-GBIF-Taxon="191762687" ID-Zenodo-Dep="5805296" approvalRequired="4" approvalRequired_for_document="1" approvalRequired_for_matCits="1" approvalRequired_for_textStreams="2" checkinTime="1640542121772" checkinUser="donat" docAuthor="Sander, P. Martin, Griebeler, Eva Maria, Klein, Nicole, Juarbe, Jorge Velez, Wintrich, Tanja, Revell, Liam J. & Schmitz, Lars" docDate="2021" docId="03B187E33838FFA4651D4E70FADEA2AA" docLanguage="en" docName="science.abf5787.pdf" docOrigin="Science (New York, N. Y.) 374 (6575)" docSource="http://dx.doi.org/10.1126/science.abf5787" docTitle="Cymbospondylus youngorum Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz 2021, sp. nov." docType="treatment" docVersion="5" lastPageId="2" lastPageNumber="2" masterDocId="FF88FF9B3839FFA665654B42FFAEA418" masterDocTitle="Early giant reveals faster evolution of large body size in ichthyosaurs than in cetaceans" masterLastPageNumber="15" masterPageNumber="1" pageId="1" pageNumber="2" updateTime="1640549168194" updateUser="ExternalLinkService">
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<mods:mods xmlns:mods="http://www.loc.gov/mods/v3">
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<mods:titleInfo>
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<mods:title>Early giant reveals faster evolution of large body size in ichthyosaurs than in cetaceans</mods:title>
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</mods:titleInfo>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Sander, P. Martin</mods:namePart>
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</mods:name>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Griebeler, Eva Maria</mods:namePart>
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</mods:name>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Klein, Nicole</mods:namePart>
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</mods:name>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Juarbe, Jorge Velez</mods:namePart>
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</mods:name>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Wintrich, Tanja</mods:namePart>
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</mods:name>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Revell, Liam J.</mods:namePart>
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</mods:name>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Schmitz, Lars</mods:namePart>
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</mods:name>
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<mods:typeOfResource>text</mods:typeOfResource>
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<mods:relatedItem type="host">
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<mods:titleInfo>
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<mods:title>Science</mods:title>
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</mods:titleInfo>
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<mods:part>
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<mods:date>2021</mods:date>
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||
<mods:detail type="series">
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<mods:title>New York, N. Y.</mods:title>
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</mods:detail>
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<mods:detail type="pubDate">
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<mods:number>2021-12-24</mods:number>
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</mods:detail>
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<mods:detail type="volume">
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<mods:number>374</mods:number>
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</mods:detail>
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<mods:detail type="issue">
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<mods:number>6575</mods:number>
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</mods:detail>
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<mods:extent unit="page">
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<mods:start>1</mods:start>
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<mods:end>15</mods:end>
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</mods:extent>
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</mods:part>
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</mods:relatedItem>
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<mods:location>
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<mods:url>http://dx.doi.org/10.1126/science.abf5787</mods:url>
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</mods:location>
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<mods:classification>journal article</mods:classification>
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<mods:identifier type="DOI">10.1126/science.abf5787</mods:identifier>
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<mods:identifier type="GBIF-Dataset">cf6c12db-754f-4139-acab-eb6ce69ef0a4</mods:identifier>
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<mods:identifier type="Zenodo-Dep">5805321</mods:identifier>
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</mods:mods>
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<treatment ID-DOI="http://doi.org/10.5281/zenodo.5805296" ID-GBIF-Taxon="191762687" ID-Zenodo-Dep="5805296" LSID="urn:lsid:plazi:treatment:03B187E33838FFA4651D4E70FADEA2AA" httpUri="http://treatment.plazi.org/id/03B187E33838FFA4651D4E70FADEA2AA" lastPageId="2" lastPageNumber="2" pageId="1" pageNumber="2">
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<subSubSection box="[120,474,1330,1351]" pageId="1" pageNumber="2" type="nomenclature">
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<paragraph blockId="1.[98,536,1330,1379]" box="[120,474,1330,1351]" pageId="1" pageNumber="2">
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<taxonomicName authority="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz, 2021" authorityName="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz" authorityYear="2021" box="[120,397,1330,1351]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="species" species="youngorum" status="sp. nov.">
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<emphasis box="[120,397,1330,1351]" italics="true" pageId="1" pageNumber="2">Cymbospondylus youngorum</emphasis>
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</taxonomicName>
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<taxonomicNameLabel box="[403,474,1331,1351]" pageId="1" pageNumber="2" rank="species">sp. nov.</taxonomicNameLabel>
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</paragraph>
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</subSubSection>
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<subSubSection pageId="1" pageNumber="2" type="description">
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<paragraph blockId="1.[98,536,1330,1379]" pageId="1" pageNumber="2">
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(
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<figureCitation box="[484,536,1331,1351]" captionStart="Fig" captionStartId="2.[98,127,144,164]" captionTargetBox="[420,1483,134,1460]" captionTargetId="figure-515@2.[417,1487,132,1462]" captionTargetPageId="2" captionText="Fig. 2. Skull of the holotype of C. youngorum sp. nov. LACM DI 157871. (A) Skull in right dorso- lateral view. (B) Skull sutures. (C) Skull in left ventrolateral view. (D) Skull sutures. (E) Snout in left ventrolateral view. (F) Middle part of dentary tooth row in right dorsolateral view. Note the bone of attachment. (G to K) Right humerus in proximal (G), dorsal (H), posterior (I), ventral (J), and anterior view (K). a, angular; ar, articular; at, anterior terrace; d, dentary; en, external nares; f, frontal; j, jugal; l, lacrimal; lte, lower temporal embayment; mx, maxilla; n, nasal; o, orbita; pa, parietal; pf, parietal foramen; pmx, premaxilla; po, postorbital; pra, prearticular; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sc, scleral ring; sq, squamosal; st, supratemporal; uto, upper temporal opening; v, cervical vertebra." figureDoi="http://doi.org/10.5281/zenodo.5805327" httpUri="https://zenodo.org/record/5805327/files/figure.png" pageId="1" pageNumber="2">Fig. 2</figureCitation>
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and figs. S1 to S5)
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</paragraph>
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</subSubSection>
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<subSubSection pageId="1" pageNumber="2" type="etymology">
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<paragraph blockId="1.[98,536,1407,1490]" box="[98,190,1407,1427]" pageId="1" pageNumber="2">
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<heading bold="true" box="[98,190,1407,1427]" fontSize="8" level="3" pageId="1" pageNumber="2" reason="6">
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<emphasis bold="true" box="[98,190,1407,1427]" italics="true" pageId="1" pageNumber="2">Etymology</emphasis>
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</heading>
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</paragraph>
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<paragraph blockId="1.[98,536,1407,1490]" pageId="1" pageNumber="2">The species is named in honor of Tom and Bonda Young.</paragraph>
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</subSubSection>
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<subSubSection pageId="1" pageNumber="2" type="materials_examined">
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<paragraph blockId="1.[98,536,1519,1909]" lastBlockId="1.[573,1011,132,543]" pageId="1" pageNumber="2">
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<materialsCitation ID-GBIF-Occurrence="3422312301" collectionCode="LACM" country="United States of America" elevation="1676" location="Anisian age Fossil Hill Member of the Favret Formation at Favret Canyon, Augusta Mountains, Pershing County" pageId="1" pageNumber="2" specimenCode="LACM DI 157871" specimenCount="2" stateProvince="Nevada" type="holotype" typeStatus="holotype">
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<heading bold="true" box="[98,350,1519,1539]" fontSize="8" level="3" pageId="1" pageNumber="2" reason="6">
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<emphasis bold="true" box="[98,350,1519,1539]" italics="true" pageId="1" pageNumber="2">
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<typeStatus box="[98,177,1519,1539]" pageId="1" pageNumber="2">Holotype</typeStatus>
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and only specimen
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</emphasis>
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</heading>
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LACM DI 157871 is the holotype and, as of now, the only recognized individual. LACM DI 157871 is largely articulated and complete from the anterior of the trunk region to the skull, preserved ventral side up. The cervical column back to the middle dorsal vertebrae is present with ribs in articulation. The shoulder girdle is articulated, and the two humeri are situated close to their respective glenoid. At present, the skull (
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<figureCitation box="[271,324,1805,1825]" captionStart="Fig" captionStartId="2.[98,127,144,164]" captionTargetBox="[420,1483,134,1460]" captionTargetId="figure-515@2.[417,1487,132,1462]" captionTargetPageId="2" captionText="Fig. 2. Skull of the holotype of C. youngorum sp. nov. LACM DI 157871. (A) Skull in right dorso- lateral view. (B) Skull sutures. (C) Skull in left ventrolateral view. (D) Skull sutures. (E) Snout in left ventrolateral view. (F) Middle part of dentary tooth row in right dorsolateral view. Note the bone of attachment. (G to K) Right humerus in proximal (G), dorsal (H), posterior (I), ventral (J), and anterior view (K). a, angular; ar, articular; at, anterior terrace; d, dentary; en, external nares; f, frontal; j, jugal; l, lacrimal; lte, lower temporal embayment; mx, maxilla; n, nasal; o, orbita; pa, parietal; pf, parietal foramen; pmx, premaxilla; po, postorbital; pra, prearticular; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sc, scleral ring; sq, squamosal; st, supratemporal; uto, upper temporal opening; v, cervical vertebra." figureDoi="http://doi.org/10.5281/zenodo.5805327" httpUri="https://zenodo.org/record/5805327/files/figure.png" pageId="1" pageNumber="2">Fig. 2</figureCitation>
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, A to F; figs. S1 and S2; and table S1), the right humerus (
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<figureCitation box="[427,483,1833,1853]" captionStart="Fig" captionStartId="2.[98,127,144,164]" captionTargetBox="[420,1483,134,1460]" captionTargetId="figure-515@2.[417,1487,132,1462]" captionTargetPageId="2" captionText="Fig. 2. Skull of the holotype of C. youngorum sp. nov. LACM DI 157871. (A) Skull in right dorso- lateral view. (B) Skull sutures. (C) Skull in left ventrolateral view. (D) Skull sutures. (E) Snout in left ventrolateral view. (F) Middle part of dentary tooth row in right dorsolateral view. Note the bone of attachment. (G to K) Right humerus in proximal (G), dorsal (H), posterior (I), ventral (J), and anterior view (K). a, angular; ar, articular; at, anterior terrace; d, dentary; en, external nares; f, frontal; j, jugal; l, lacrimal; lte, lower temporal embayment; mx, maxilla; n, nasal; o, orbita; pa, parietal; pf, parietal foramen; pmx, premaxilla; po, postorbital; pra, prearticular; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sc, scleral ring; sq, squamosal; st, supratemporal; uto, upper temporal opening; v, cervical vertebra." figureDoi="http://doi.org/10.5281/zenodo.5805327" httpUri="https://zenodo.org/record/5805327/files/figure.png" pageId="1" pageNumber="2">Fig. 2</figureCitation>
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, G to K), parts of the shoulder girdle (fig. S3), and some vertebrae are prepared (fig. S3)
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<heading bold="true" box="[573,750,132,152]" fontSize="8" level="3" pageId="1" pageNumber="2" reason="6">
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<emphasis bold="true" box="[573,750,132,152]" italics="true" pageId="1" pageNumber="2">Horizon and locality</emphasis>
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</heading>
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<specimenCode box="[573,733,160,180]" pageId="1" pageNumber="2">LACM DI 157871</specimenCode>
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comes from the
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<location LSID="urn:lsid:plazi:treatment:03B187E33838FFA4651D4E70FADEA2AA:8EC7602E3838FFA766E74BE2FD2DA510" country="United States of America" name="Anisian age Fossil Hill Member of the Favret Formation at Favret Canyon, Augusta Mountains, Pershing County" pageId="1" pageNumber="2" stateProvince="Nevada">Anisian age Fossil Hill Member of the Favret Formation at Favret Canyon, Augusta Mountains, Pershing County</location>
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,
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<collectingRegion box="[651,725,244,264]" country="United States of America" name="Nevada" pageId="1" pageNumber="2">Nevada</collectingRegion>
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,
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<collectingCountry box="[733,778,244,264]" name="United States of America" pageId="1" pageNumber="2">USA</collectingCountry>
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. The
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<typeStatus box="[826,867,244,264]" pageId="1" pageNumber="2">type</typeStatus>
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locality, LACM 8025, is on the northern slope of the rear of Favret Canyon at an elevation of
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<quantity box="[882,950,299,319]" metricMagnitude="3" metricUnit="m" metricValue="1.6759999999999997" pageId="1" pageNumber="2" unit="m" value="1676.0">
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<elevation box="[882,950,299,319]" metricMagnitude="3" metricUnit="m" metricValue="1.6759999999999997" pageId="1" pageNumber="2" unit="m" value="1676.0">1676 m</elevation>
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</quantity>
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. Exact coordinates are on file at the repository. LACM DI 157871 originates from the same general level as the holotype of the macropredatory ichthyosaur
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<taxonomicName box="[696,978,410,431]" class="Reptilia" family="Merriamosauria incertae sedis" genus="Thalattoarchon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="species" species="saurophagis">
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<emphasis box="[696,978,410,431]" italics="true" pageId="1" pageNumber="2">Thalattoarchon saurophagis</emphasis>
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</taxonomicName>
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(
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<bibRefCitation author="N. B. FrObisch & J. FrObisch & P. M. Sander & L. Schmitz & O. Rieppel" box="[991,1003,410,431]" journalOrPublisher="Proc. Natl. Acad. Sci. U. S. A." pageId="1" pageNumber="2" pagination="1393 - 1397" part="110" refId="ref14457" refString="8. N. B. FrObisch, J. FrObisch, P. M. Sander, L. Schmitz, O. Rieppel, Macropredatory ichthyosaur from the Middle Triassic and the origin of modern trophic networks. Proc. Natl. Acad. Sci. U. S. A. 110, 1393 - 1397 (2013). doi: 10.1073 / pnas. 1216750110; pmid: 23297200" title="Macropredatory ichthyosaur from the Middle Triassic and the origin of modern trophic networks" type="journal article" year="2013">
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<emphasis box="[991,1003,410,431]" italics="true" pageId="1" pageNumber="2">8</emphasis>
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</bibRefCitation>
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) and the pistosaur
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<taxonomicName box="[755,1011,438,459]" class="Reptilia" family="Pistosauridae" genus="Augustasaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Sauropterygia incertae sedis" pageId="1" pageNumber="2" phylum="Chordata" rank="species" species="hagdorni">
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<emphasis box="[755,1011,438,459]" italics="true" pageId="1" pageNumber="2">Augustasaurus hagdorni</emphasis>
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</taxonomicName>
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(
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<bibRefCitation box="[581,602,466,487]" pageId="1" pageNumber="2" refId="ref14573" refString="10. See supplementary materials">
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<emphasis box="[581,602,466,487]" italics="true" pageId="1" pageNumber="2">10</emphasis>
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</bibRefCitation>
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) in the lower third of the Fossil Hill member and pertains to the middle Anisian
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<emphasis box="[940,1011,494,515]" italics="true" pageId="1" pageNumber="2">Taylori</emphasis>
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Zone (
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<bibRefCitation author="C. Monnet & H. Bucher" box="[634,655,522,543]" journalOrPublisher="Foss. Strat." pageId="1" pageNumber="2" pagination="1 - 121" part="52" refId="ref14911" refString="18. C. Monnet, H. Bucher, New middle and late Anisian (Middle Triassic) ammonoid faunas from Northwestern Nevada (USA): Taxonomy and biochronology. Foss. Strat. 52, 1 - 121 (2005)." title="New middle and late Anisian (Middle Triassic) ammonoid faunas from Northwestern Nevada (USA): Taxonomy and biochronology" type="journal article" year="2005">
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<emphasis box="[634,655,522,543]" italics="true" pageId="1" pageNumber="2">18</emphasis>
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</bibRefCitation>
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).
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</materialsCitation>
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</paragraph>
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</subSubSection>
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<subSubSection pageId="1" pageNumber="2" type="diagnosis">
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<paragraph blockId="1.[573,1012,571,1714]" box="[573,658,571,591]" pageId="1" pageNumber="2">
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<heading bold="true" box="[573,658,571,591]" fontSize="8" level="3" pageId="1" pageNumber="2" reason="6">
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<emphasis bold="true" box="[573,658,571,591]" italics="true" pageId="1" pageNumber="2">Diagnosis</emphasis>
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</heading>
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</paragraph>
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<paragraph blockId="1.[573,1012,571,1714]" pageId="1" pageNumber="2">
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<taxonomicName authority="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz, 2021" authorityName="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz" authorityYear="2021" box="[573,723,606,627]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="species" species="youngorum" status="sp. nov.">
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<emphasis box="[573,723,606,627]" italics="true" pageId="1" pageNumber="2">C. youngorum</emphasis>
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</taxonomicName>
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<taxonomicNameLabel box="[734,816,606,626]" pageId="1" pageNumber="2" rank="species">sp. nov.</taxonomicNameLabel>
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is diagnosed by a unique combination of the following eight characters (see data S1 for character descriptions and data S3 for a list of synapomorphies): squamosal, participates in supratemporal fenestra (character 72, state 0;
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<figureCitation box="[808,861,746,766]" captionStart="Fig" captionStartId="2.[98,127,144,164]" captionTargetBox="[420,1483,134,1460]" captionTargetId="figure-515@2.[417,1487,132,1462]" captionTargetPageId="2" captionText="Fig. 2. Skull of the holotype of C. youngorum sp. nov. LACM DI 157871. (A) Skull in right dorso- lateral view. (B) Skull sutures. (C) Skull in left ventrolateral view. (D) Skull sutures. (E) Snout in left ventrolateral view. (F) Middle part of dentary tooth row in right dorsolateral view. Note the bone of attachment. (G to K) Right humerus in proximal (G), dorsal (H), posterior (I), ventral (J), and anterior view (K). a, angular; ar, articular; at, anterior terrace; d, dentary; en, external nares; f, frontal; j, jugal; l, lacrimal; lte, lower temporal embayment; mx, maxilla; n, nasal; o, orbita; pa, parietal; pf, parietal foramen; pmx, premaxilla; po, postorbital; pra, prearticular; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sc, scleral ring; sq, squamosal; st, supratemporal; uto, upper temporal opening; v, cervical vertebra." figureDoi="http://doi.org/10.5281/zenodo.5805327" httpUri="https://zenodo.org/record/5805327/files/figure.png" pageId="1" pageNumber="2">Fig. 2</figureCitation>
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); dentary, labial shelf present (character 117, state 1; fig. S2C); angular, extent of anterior lateral exposure is extensive, at least as high and anteriorly as the surangular’ s exposure (character 120, state 1;
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<figureCitation box="[573,631,885,905]" captionStart="Fig" captionStartId="2.[98,127,144,164]" captionTargetBox="[420,1483,134,1460]" captionTargetId="figure-515@2.[417,1487,132,1462]" captionTargetPageId="2" captionText="Fig. 2. Skull of the holotype of C. youngorum sp. nov. LACM DI 157871. (A) Skull in right dorso- lateral view. (B) Skull sutures. (C) Skull in left ventrolateral view. (D) Skull sutures. (E) Snout in left ventrolateral view. (F) Middle part of dentary tooth row in right dorsolateral view. Note the bone of attachment. (G to K) Right humerus in proximal (G), dorsal (H), posterior (I), ventral (J), and anterior view (K). a, angular; ar, articular; at, anterior terrace; d, dentary; en, external nares; f, frontal; j, jugal; l, lacrimal; lte, lower temporal embayment; mx, maxilla; n, nasal; o, orbita; pa, parietal; pf, parietal foramen; pmx, premaxilla; po, postorbital; pra, prearticular; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sc, scleral ring; sq, squamosal; st, supratemporal; uto, upper temporal opening; v, cervical vertebra." figureDoi="http://doi.org/10.5281/zenodo.5805327" httpUri="https://zenodo.org/record/5805327/files/figure.png" pageId="1" pageNumber="2">Fig. 2</figureCitation>
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); angular, extent of posterior lateral exposure is extensive, with surangular exposure reduced to a thin strip on the lateral surface of the retroarticular process (character 121, state 1;
|
||
<figureCitation box="[595,649,997,1017]" captionStart="Fig" captionStartId="2.[98,127,144,164]" captionTargetBox="[420,1483,134,1460]" captionTargetId="figure-515@2.[417,1487,132,1462]" captionTargetPageId="2" captionText="Fig. 2. Skull of the holotype of C. youngorum sp. nov. LACM DI 157871. (A) Skull in right dorso- lateral view. (B) Skull sutures. (C) Skull in left ventrolateral view. (D) Skull sutures. (E) Snout in left ventrolateral view. (F) Middle part of dentary tooth row in right dorsolateral view. Note the bone of attachment. (G to K) Right humerus in proximal (G), dorsal (H), posterior (I), ventral (J), and anterior view (K). a, angular; ar, articular; at, anterior terrace; d, dentary; en, external nares; f, frontal; j, jugal; l, lacrimal; lte, lower temporal embayment; mx, maxilla; n, nasal; o, orbita; pa, parietal; pf, parietal foramen; pmx, premaxilla; po, postorbital; pra, prearticular; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sc, scleral ring; sq, squamosal; st, supratemporal; uto, upper temporal opening; v, cervical vertebra." figureDoi="http://doi.org/10.5281/zenodo.5805327" httpUri="https://zenodo.org/record/5805327/files/figure.png" pageId="1" pageNumber="2">Fig. 2</figureCitation>
|
||
); lower jaw glenoid, deeply excavated and present (character 126, state 1;
|
||
<figureCitation box="[940,999,1025,1045]" captionStart="Fig" captionStartId="2.[98,127,144,164]" captionTargetBox="[420,1483,134,1460]" captionTargetId="figure-515@2.[417,1487,132,1462]" captionTargetPageId="2" captionText="Fig. 2. Skull of the holotype of C. youngorum sp. nov. LACM DI 157871. (A) Skull in right dorso- lateral view. (B) Skull sutures. (C) Skull in left ventrolateral view. (D) Skull sutures. (E) Snout in left ventrolateral view. (F) Middle part of dentary tooth row in right dorsolateral view. Note the bone of attachment. (G to K) Right humerus in proximal (G), dorsal (H), posterior (I), ventral (J), and anterior view (K). a, angular; ar, articular; at, anterior terrace; d, dentary; en, external nares; f, frontal; j, jugal; l, lacrimal; lte, lower temporal embayment; mx, maxilla; n, nasal; o, orbita; pa, parietal; pf, parietal foramen; pmx, premaxilla; po, postorbital; pra, prearticular; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sc, scleral ring; sq, squamosal; st, supratemporal; uto, upper temporal opening; v, cervical vertebra." figureDoi="http://doi.org/10.5281/zenodo.5805327" httpUri="https://zenodo.org/record/5805327/files/figure.png" pageId="1" pageNumber="2">Fig. 2</figureCitation>
|
||
); dentition, definition of the base of the enamel layer is well defined and precise (character 147, state 1; fig. S2, E and F); humerus, anterior flange is absent (character 200, state 0;
|
||
<figureCitation box="[958,1011,1136,1156]" captionStart="Fig" captionStartId="2.[98,127,144,164]" captionTargetBox="[420,1483,134,1460]" captionTargetId="figure-515@2.[417,1487,132,1462]" captionTargetPageId="2" captionText="Fig. 2. Skull of the holotype of C. youngorum sp. nov. LACM DI 157871. (A) Skull in right dorso- lateral view. (B) Skull sutures. (C) Skull in left ventrolateral view. (D) Skull sutures. (E) Snout in left ventrolateral view. (F) Middle part of dentary tooth row in right dorsolateral view. Note the bone of attachment. (G to K) Right humerus in proximal (G), dorsal (H), posterior (I), ventral (J), and anterior view (K). a, angular; ar, articular; at, anterior terrace; d, dentary; en, external nares; f, frontal; j, jugal; l, lacrimal; lte, lower temporal embayment; mx, maxilla; n, nasal; o, orbita; pa, parietal; pf, parietal foramen; pmx, premaxilla; po, postorbital; pra, prearticular; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sc, scleral ring; sq, squamosal; st, supratemporal; uto, upper temporal opening; v, cervical vertebra." figureDoi="http://doi.org/10.5281/zenodo.5805327" httpUri="https://zenodo.org/record/5805327/files/figure.png" pageId="1" pageNumber="2">Fig. 2</figureCitation>
|
||
and fig. S6); and humerus, relative anteroposterior width in dorsal view, excluding dorsal and ventral processes, is approximately equal or the proximal end is wider than the distal end (character 206, state 1;
|
||
<figureCitation box="[804,859,1276,1296]" captionStart="Fig" captionStartId="2.[98,127,144,164]" captionTargetBox="[420,1483,134,1460]" captionTargetId="figure-515@2.[417,1487,132,1462]" captionTargetPageId="2" captionText="Fig. 2. Skull of the holotype of C. youngorum sp. nov. LACM DI 157871. (A) Skull in right dorso- lateral view. (B) Skull sutures. (C) Skull in left ventrolateral view. (D) Skull sutures. (E) Snout in left ventrolateral view. (F) Middle part of dentary tooth row in right dorsolateral view. Note the bone of attachment. (G to K) Right humerus in proximal (G), dorsal (H), posterior (I), ventral (J), and anterior view (K). a, angular; ar, articular; at, anterior terrace; d, dentary; en, external nares; f, frontal; j, jugal; l, lacrimal; lte, lower temporal embayment; mx, maxilla; n, nasal; o, orbita; pa, parietal; pf, parietal foramen; pmx, premaxilla; po, postorbital; pra, prearticular; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sc, scleral ring; sq, squamosal; st, supratemporal; uto, upper temporal opening; v, cervical vertebra." figureDoi="http://doi.org/10.5281/zenodo.5805327" httpUri="https://zenodo.org/record/5805327/files/figure.png" pageId="1" pageNumber="2">Fig. 2</figureCitation>
|
||
and fig. S6).
|
||
</paragraph>
|
||
<paragraph blockId="1.[573,1012,571,1714]" pageId="1" pageNumber="2">
|
||
The new taxon is characterized by the following autapomorphies: a thick base of bone of attachment of the teeth (
|
||
<figureCitation box="[830,883,1359,1379]" captionStart="Fig" captionStartId="2.[98,127,144,164]" captionTargetBox="[420,1483,134,1460]" captionTargetId="figure-515@2.[417,1487,132,1462]" captionTargetPageId="2" captionText="Fig. 2. Skull of the holotype of C. youngorum sp. nov. LACM DI 157871. (A) Skull in right dorso- lateral view. (B) Skull sutures. (C) Skull in left ventrolateral view. (D) Skull sutures. (E) Snout in left ventrolateral view. (F) Middle part of dentary tooth row in right dorsolateral view. Note the bone of attachment. (G to K) Right humerus in proximal (G), dorsal (H), posterior (I), ventral (J), and anterior view (K). a, angular; ar, articular; at, anterior terrace; d, dentary; en, external nares; f, frontal; j, jugal; l, lacrimal; lte, lower temporal embayment; mx, maxilla; n, nasal; o, orbita; pa, parietal; pf, parietal foramen; pmx, premaxilla; po, postorbital; pra, prearticular; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sc, scleral ring; sq, squamosal; st, supratemporal; uto, upper temporal opening; v, cervical vertebra." figureDoi="http://doi.org/10.5281/zenodo.5805327" httpUri="https://zenodo.org/record/5805327/files/figure.png" pageId="1" pageNumber="2">Fig. 2</figureCitation>
|
||
and fig. S2, C and E), the distinctive shape of the scapula with a very large and wide dorsal blade and a narrow ventral part (figs. S3 and S6), the distinctive humerus morphology with a wider proximal than distal end, and a triangular proximal head and triangular shaft cross section (
|
||
<figureCitation box="[957,1011,1527,1547]" captionStart="Fig" captionStartId="2.[98,127,144,164]" captionTargetBox="[420,1483,134,1460]" captionTargetId="figure-515@2.[417,1487,132,1462]" captionTargetPageId="2" captionText="Fig. 2. Skull of the holotype of C. youngorum sp. nov. LACM DI 157871. (A) Skull in right dorso- lateral view. (B) Skull sutures. (C) Skull in left ventrolateral view. (D) Skull sutures. (E) Snout in left ventrolateral view. (F) Middle part of dentary tooth row in right dorsolateral view. Note the bone of attachment. (G to K) Right humerus in proximal (G), dorsal (H), posterior (I), ventral (J), and anterior view (K). a, angular; ar, articular; at, anterior terrace; d, dentary; en, external nares; f, frontal; j, jugal; l, lacrimal; lte, lower temporal embayment; mx, maxilla; n, nasal; o, orbita; pa, parietal; pf, parietal foramen; pmx, premaxilla; po, postorbital; pra, prearticular; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sc, scleral ring; sq, squamosal; st, supratemporal; uto, upper temporal opening; v, cervical vertebra." figureDoi="http://doi.org/10.5281/zenodo.5805327" httpUri="https://zenodo.org/record/5805327/files/figure.png" pageId="1" pageNumber="2">Fig. 2</figureCitation>
|
||
and fig. S6). Note that these autapomorphies were not added as characters to our character matrix. A differential diagnosis and detailed anatomical descriptions (figs. S2 and S3) and comparisons (figs. S4 to S6 and tables S2 and S3) are provided in the supplementary materials (
|
||
<bibRefCitation box="[953,973,1693,1714]" pageId="1" pageNumber="2" refId="ref14573" refString="10. See supplementary materials">
|
||
<emphasis box="[953,973,1693,1714]" italics="true" pageId="1" pageNumber="2">10</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
</subSubSection>
|
||
<subSubSection pageId="1" pageNumber="2" type="discussion">
|
||
<paragraph blockId="1.[573,1011,1742,1909]" box="[573,764,1742,1762]" pageId="1" pageNumber="2">
|
||
<heading bold="true" box="[573,764,1742,1762]" fontSize="8" level="3" pageId="1" pageNumber="2" reason="6">
|
||
<emphasis bold="true" box="[573,764,1742,1762]" italics="true" pageId="1" pageNumber="2">Phylogenetic position</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph blockId="1.[573,1011,1742,1909]" lastBlockId="1.[1048,1487,132,1045]" pageId="1" pageNumber="2">
|
||
Phylogenetic analyses (
|
||
<bibRefCitation box="[797,818,1777,1798]" pageId="1" pageNumber="2" refId="ref14573" refString="10. See supplementary materials">
|
||
<emphasis box="[797,818,1777,1798]" italics="true" pageId="1" pageNumber="2">10</emphasis>
|
||
</bibRefCitation>
|
||
) (table S4) indicate that
|
||
<taxonomicName authority="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz, 2021" authorityName="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz" authorityYear="2021" box="[618,757,1805,1826]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="species" species="youngorum" status="sp. nov.">
|
||
<emphasis box="[618,757,1805,1826]" italics="true" pageId="1" pageNumber="2">C. youngorum</emphasis>
|
||
</taxonomicName>
|
||
<taxonomicNameLabel box="[761,836,1806,1826]" pageId="1" pageNumber="2" rank="species">sp. nov.</taxonomicNameLabel>
|
||
is nested within a clade of closely related
|
||
<taxonomicName box="[784,1010,1833,1854]" pageId="1" pageNumber="2">
|
||
<emphasis box="[784,941,1833,1854]" italics="true" pageId="1" pageNumber="2">Cymbospondylus</emphasis>
|
||
species
|
||
</taxonomicName>
|
||
that account for much of the lineage diversity and morphological disparity of large-bodied Early and Middle Triassic ichthyosaurs (
|
||
<figureCitation box="[1432,1486,132,152]" captionStart="Fig" captionStartId="3.[98,127,1260,1280]" captionTargetBox="[130,1456,141,1231]" captionTargetId="figure-425@3.[130,1456,134,1239]" captionTargetPageId="3" captionText="Fig. 3. Time-calibrated phylogenies and body-size illustrations of Ichthyosauria and Cetacea and the relationships of the new giant ichthyosaur C. youngorum sp. nov. Ichthyosaurs originated in the late Early Triassic shortly after the end-Permian mass extinction (EPME), survived the end-Triassic mass extinction (ETME), and went extinct in the early Late Cretaceous. Lilac stratigraphic ranges denote taxa from the Fossil Hill Fauna. Cetaceans originated in the late Paleocene after the Cretaceous-Paleogene mass extinction (CPME). See (10) for sources of phylogenies and table S6 for image credits. mya, million years ago." figureDoi="http://doi.org/10.5281/zenodo.5805329" httpUri="https://zenodo.org/record/5805329/files/figure.png" pageId="1" pageNumber="2">Fig. 3</figureCitation>
|
||
and fig. S7). The close relationship of these species points to an adaptive radiation (as much as one can be recognized in the fossil record of Mesozoic reptiles). Further evidence for such a radiation is that there are no other four seemingly sympatric species of any ichthyosaur genus in the ichthyosaur record and that other finds of
|
||
<taxonomicName authorityName="Leidy" authorityYear="1868" box="[1188,1351,354,375]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1188,1351,354,375]" italics="true" pageId="1" pageNumber="2">Cymbospondylus</emphasis>
|
||
</taxonomicName>
|
||
from the late Early and early Middle Triassic are widely distributed across the Northern Hemisphere (
|
||
<bibRefCitation author="N. FrObisch & P. M. Sander & O. Rieppel" box="[1453,1473,410,431]" journalOrPublisher="Zool. J. Linn. Soc." pageId="1" pageNumber="2" pagination="515 - 538" part="147" refId="ref14777" refString="16. N. FrObisch, P. M. Sander, O. Rieppel, A new species of Cymbospondylus (Diapsida, Ichthyosauria) from the Middle Triassic of Nevada and re-evaluation of the skull osteology of the genus. Zool. J. Linn. Soc. 147, 515 - 538 (2006). doi: 10.1111 / j. 1096 - 3642.2006.00225. x" title="A new species of Cymbospondylus (Diapsida, Ichthyosauria) from the Middle Triassic of Nevada and re-evaluation of the skull osteology of the genus" type="journal article" year="2006">
|
||
<emphasis box="[1453,1473,410,431]" italics="true" pageId="1" pageNumber="2">16</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="1.[1048,1487,132,1045]" pageId="1" pageNumber="2">
|
||
Our analysis with TNT (a software for phylogenetic analysis) and its “new technology” search algorithm resulted in a tree length of 1225 steps. The four most parsimonious trees were retained (table S4), and the nearly fully resolved strict consensus of the four trees is shown in
|
||
<figureCitation box="[1148,1204,606,626]" captionStart="Fig" captionStartId="3.[98,127,1260,1280]" captionTargetBox="[130,1456,141,1231]" captionTargetId="figure-425@3.[130,1456,134,1239]" captionTargetPageId="3" captionText="Fig. 3. Time-calibrated phylogenies and body-size illustrations of Ichthyosauria and Cetacea and the relationships of the new giant ichthyosaur C. youngorum sp. nov. Ichthyosaurs originated in the late Early Triassic shortly after the end-Permian mass extinction (EPME), survived the end-Triassic mass extinction (ETME), and went extinct in the early Late Cretaceous. Lilac stratigraphic ranges denote taxa from the Fossil Hill Fauna. Cetaceans originated in the late Paleocene after the Cretaceous-Paleogene mass extinction (CPME). See (10) for sources of phylogenies and table S6 for image credits. mya, million years ago." figureDoi="http://doi.org/10.5281/zenodo.5805329" httpUri="https://zenodo.org/record/5805329/files/figure.png" pageId="1" pageNumber="2">Fig. 3</figureCitation>
|
||
and fig. S7. The consistency index of this tree is 0.259, coupled with a retention index of 0.627. The absolute Bremer support of the nodes varies from 1 to 5 (fig. S7). Additional analyses (table S4) confirmed the placement of LACM DI 157871 in a clade with other cymbospondylids, yet the position of the
|
||
<taxonomicName authorityName="Leidy" authorityYear="1868" box="[1048,1211,801,822]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1048,1211,801,822]" italics="true" pageId="1" pageNumber="2">Cymbospondylus</emphasis>
|
||
</taxonomicName>
|
||
clade varies with the selection of taxa that were included in the analyses (
|
||
<bibRefCitation box="[1056,1078,857,878]" pageId="1" pageNumber="2" refId="ref14573" refString="10. See supplementary materials">
|
||
<emphasis box="[1056,1078,857,878]" italics="true" pageId="1" pageNumber="2">10</emphasis>
|
||
</bibRefCitation>
|
||
). We note that the interrelationships of ichthyosaurs remain difficult to resolve, both in the Triassic and the Jurassic part of the tree. This uncertainty reflects the difficulty in resolving ichthyosaur interrelationships in general (
|
||
<bibRefCitation author="B. Moon" box="[1056,1077,996,1017]" journalOrPublisher="J. Syst. Palaeontology" pageId="1" pageNumber="2" pagination="129 - 155" part="17" refId="ref14956" refString="19. B. Moon, A new phylogeny of ichthyosaurs (Reptilia: Diapsida). J. Syst. Palaeontology 17, 129 - 155 (2019). doi: 10.1080 / 14772019.2017. 1394922" title="A new phylogeny of ichthyosaurs (Reptilia: Diapsida)" type="journal article" year="2019">
|
||
<emphasis box="[1056,1077,996,1017]" italics="true" pageId="1" pageNumber="2">19</emphasis>
|
||
</bibRefCitation>
|
||
) and the need for a concerted effort of redefining and rescoring characters.
|
||
</paragraph>
|
||
</subSubSection>
|
||
<subSubSection lastPageId="2" lastPageNumber="3" pageId="1" pageNumber="2" type="biology_ecology">
|
||
<paragraph blockId="1.[1048,1487,1073,1910]" box="[1048,1384,1073,1093]" pageId="1" pageNumber="2">
|
||
<emphasis bold="true" box="[1048,1384,1073,1093]" italics="true" pageId="1" pageNumber="2">Inferred diet and estimated body size</emphasis>
|
||
</paragraph>
|
||
<paragraph blockId="1.[1048,1487,1073,1910]" lastBlockId="2.[1048,1487,1526,1714]" lastPageId="2" lastPageNumber="3" pageId="1" pageNumber="2">
|
||
The conical, bluntly pointed tooth crowns of
|
||
<taxonomicName authority="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz, 2021" authorityName="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz" authorityYear="2021" box="[1048,1184,1136,1157]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="species" species="youngorum" status="sp. nov.">
|
||
<emphasis box="[1048,1184,1136,1157]" italics="true" pageId="1" pageNumber="2">C. youngorum</emphasis>
|
||
</taxonomicName>
|
||
<taxonomicNameLabel box="[1190,1262,1136,1156]" pageId="1" pageNumber="2" rank="species">sp. nov.</taxonomicNameLabel>
|
||
, in conjunction with the elongate snout, suggest a generalist diet of fish and squid (
|
||
<bibRefCitation author="J. A. Massare" box="[1149,1172,1191,1212]" journalOrPublisher="J. Vertebr. Paleontol." pageId="1" pageNumber="2" pagination="121 - 137" part="7" refId="ref14994" refString="20. J. A. Massare, Tooth morphology and prey preference of Mesozoic marine reptiles. J. Vertebr. Paleontol. 7, 121 - 137 (1987). doi: 10.1080 / 02724634.1987.10011647" title="Tooth morphology and prey preference of Mesozoic marine reptiles" type="journal article" year="1987">
|
||
<emphasis box="[1149,1172,1191,1212]" italics="true" pageId="1" pageNumber="2">20</emphasis>
|
||
</bibRefCitation>
|
||
), as inferred for most ichthyosaurs from teeth and stomach contents (
|
||
<bibRefCitation author="R. Motani" box="[1375,1395,1219,1240]" journalOrPublisher="Annu. Rev. Earth Planet. Sci. 33" pageId="1" pageNumber="2" refId="ref15032" refString="21. R. Motani, Evolution of fish-shaped reptiles (Reptilia: Ichthyopterygia) in their physical environments and constraints. Annu. Rev. Earth Planet. Sci. 33, 12.11 - 12.26 (2005)." title="Evolution of fish-shaped reptiles (Reptilia: Ichthyopterygia) in their physical environments and constraints" type="book" year="2005">
|
||
<emphasis box="[1375,1395,1219,1240]" italics="true" pageId="1" pageNumber="2">21</emphasis>
|
||
</bibRefCitation>
|
||
). Considering its size,
|
||
<taxonomicName authority="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz, 2021" authorityName="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz" authorityYear="2021" box="[1175,1310,1247,1268]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="species" species="youngorum" status="sp. nov.">
|
||
<emphasis box="[1175,1310,1247,1268]" italics="true" pageId="1" pageNumber="2">C. youngorum</emphasis>
|
||
</taxonomicName>
|
||
<taxonomicNameLabel box="[1315,1387,1248,1268]" pageId="1" pageNumber="2" rank="species">sp. nov.</taxonomicNameLabel>
|
||
could also have preyed on smaller and juvenile marine reptiles (
|
||
<bibRefCitation box="[1124,1144,1303,1324]" pageId="1" pageNumber="2" refId="ref14573" refString="10. See supplementary materials">
|
||
<emphasis box="[1124,1144,1303,1324]" italics="true" pageId="1" pageNumber="2">10</emphasis>
|
||
</bibRefCitation>
|
||
). The right lower jaw of
|
||
<taxonomicName authority="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz, 2021" authorityName="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz" authorityYear="2021" box="[1358,1486,1303,1324]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="species" species="youngorum" status="sp. nov.">
|
||
<emphasis box="[1358,1486,1303,1324]" italics="true" pageId="1" pageNumber="2">C.youngorum</emphasis>
|
||
</taxonomicName>
|
||
<taxonomicNameLabel box="[1048,1121,1331,1351]" pageId="1" pageNumber="2" rank="species">sp. nov.</taxonomicNameLabel>
|
||
measures 1970 mm from the tip of the dentary to the end of the retroarticular process (table S1). At a total length of 1890 mm (table S1), the skull of LACM DI 15787 is one of the largest complete ichthyosaur skulls known. Although post-Triassic ichthyosaurs never reached the size of Triassic ones again (
|
||
<bibRefCitation author="B. C. Moon & T. L. Stubbs" box="[1463,1473,1498,1519]" journalOrPublisher="Commun. Biol." pageId="1" pageNumber="2" pagination="68" part="3" refId="ref14405" refString="7. B. C. Moon, T. L. Stubbs, Early high rates and disparity in the evolution of ichthyosaurs. Commun. Biol. 3, 68 (2020). doi: 10.1038 / s 42003 - 020 - 0779 - 6; pmid: 32054967" title="Early high rates and disparity in the evolution of ichthyosaurs" type="journal article" year="2020">
|
||
<emphasis box="[1463,1473,1498,1519]" italics="true" pageId="1" pageNumber="2">7</emphasis>
|
||
</bibRefCitation>
|
||
), there are skulls of
|
||
<taxonomicName authorityName="Lydekker" authorityYear="1889" box="[1239,1430,1526,1547]" class="Reptilia" family="Leptopterygiidae" genus="Temnodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1239,1430,1526,1547]" italics="true" pageId="1" pageNumber="2">Temnodontosaurus</emphasis>
|
||
</taxonomicName>
|
||
from the Lower Jurassic of England and Germany (
|
||
<bibRefCitation author="C. McGowan" box="[1055,1078,1582,1603]" journalOrPublisher="Can. J. Earth Sci." pageId="1" pageNumber="2" pagination="1011 - 1021" part="33" refId="ref15072" refString="22. C. McGowan, Giant ichthyosaurs of the Early Jurassic. Can. J. Earth Sci. 33, 1011 - 1021 (1996). doi: 10.1139 / e 96 - 077" title="Giant ichthyosaurs of the Early Jurassic" type="journal article" year="1996">
|
||
<emphasis box="[1055,1078,1582,1603]" italics="true" pageId="1" pageNumber="2">22</emphasis>
|
||
</bibRefCitation>
|
||
) that are the same length as that of LACM DI 15787 within the limits of preservation. However, these large ichthyosaurs probably were less than 9 m long, having proportionally larger skulls (
|
||
<bibRefCitation author="C. McGowan" box="[1117,1141,1693,1714]" journalOrPublisher="Can. J. Earth Sci." pageId="1" pageNumber="2" pagination="1011 - 1021" part="33" refId="ref15072" refString="22. C. McGowan, Giant ichthyosaurs of the Early Jurassic. Can. J. Earth Sci. 33, 1011 - 1021 (1996). doi: 10.1139 / e 96 - 077" title="Giant ichthyosaurs of the Early Jurassic" type="journal article" year="1996">
|
||
<emphasis box="[1117,1141,1693,1714]" italics="true" pageId="1" pageNumber="2">22</emphasis>
|
||
</bibRefCitation>
|
||
). Larger skulls than those of LACM DI 15787 and these largest
|
||
<taxonomicName authorityName="Lydekker" authorityYear="1889" box="[1302,1486,1721,1742]" class="Reptilia" family="Leptopterygiidae" genus="Temnodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1302,1486,1721,1742]" italics="true" pageId="1" pageNumber="2">Temnodontosaurus</emphasis>
|
||
</taxonomicName>
|
||
specimens are only known from Late Triassic ichthyosaurs, specifically
|
||
<taxonomicName authorityName="Camp" authorityYear="1976" box="[1276,1485,1777,1798]" class="Reptilia" family="Shastasauridae" genus="Shonisaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="species" species="popularis">
|
||
<emphasis box="[1276,1485,1777,1798]" italics="true" pageId="1" pageNumber="2">Shonisaurus popularis</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<emphasis box="[1090,1336,1805,1826]" italics="true" pageId="1" pageNumber="2">
|
||
Shastasaurus
|
||
<taxonomicName baseAuthorityName="Nicholls & Manabe" baseAuthorityYear="2004" box="[1221,1336,1805,1826]" class="Reptilia" family="Shastasauridae" genus="Shonisaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="1" pageNumber="2" phylum="Chordata" rank="species" species="sikanniensis">sikanniensis</taxonomicName>
|
||
</emphasis>
|
||
, with estimated skull lengths of 2750 and 3000 mm,respectively (
|
||
<bibRefCitation author="B. C. Moon & T. L. Stubbs" box="[1466,1475,1833,1854]" journalOrPublisher="Commun. Biol." pageId="1" pageNumber="2" pagination="68" part="3" refId="ref14405" refString="7. B. C. Moon, T. L. Stubbs, Early high rates and disparity in the evolution of ichthyosaurs. Commun. Biol. 3, 68 (2020). doi: 10.1038 / s 42003 - 020 - 0779 - 6; pmid: 32054967" title="Early high rates and disparity in the evolution of ichthyosaurs" type="journal article" year="2020">
|
||
<emphasis box="[1466,1475,1833,1854]" italics="true" pageId="1" pageNumber="2">7</emphasis>
|
||
</bibRefCitation>
|
||
). Humerus length is another commonly used proxy for ichthyosaurian body size [(
|
||
<bibRefCitation author="N. FrObisch & P. M. Sander & O. Rieppel" box="[1391,1411,1889,1910]" journalOrPublisher="Zool. J. Linn. Soc." pageId="1" pageNumber="2" pagination="515 - 538" part="147" refId="ref14777" refString="16. N. FrObisch, P. M. Sander, O. Rieppel, A new species of Cymbospondylus (Diapsida, Ichthyosauria) from the Middle Triassic of Nevada and re-evaluation of the skull osteology of the genus. Zool. J. Linn. Soc. 147, 515 - 538 (2006). doi: 10.1111 / j. 1096 - 3642.2006.00225. x" title="A new species of Cymbospondylus (Diapsida, Ichthyosauria) from the Middle Triassic of Nevada and re-evaluation of the skull osteology of the genus" type="journal article" year="2006">
|
||
<emphasis box="[1391,1411,1889,1910]" italics="true" pageId="1" pageNumber="2">16</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation author="N. Klein & L. Schmitz & T. Wintrich & P. M. Sander" box="[1421,1439,1889,1910]" journalOrPublisher="J. Syst. Palaeontology" pageId="1" pageNumber="2" pagination="1167 - 1191" part="18" refId="ref14847" refString="17. N. Klein, L. Schmitz, T. Wintrich, P. M. Sander, A new cymbospondylid ichthyosaur (Ichthyosauria) from the Middle Triassic (Anisian) of the Augusta Mountains, Nevada, USA. J. Syst. Palaeontology 18, 1167 - 1191 (2020). doi: 10.1080 / 14772019.2020. 1748132" title="A new cymbospondylid ichthyosaur (Ichthyosauria) from the Middle Triassic (Anisian) of the Augusta Mountains, Nevada, USA" type="journal article" year="2020">
|
||
<emphasis box="[1421,1439,1889,1910]" italics="true" pageId="1" pageNumber="2">17</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation author="T. M. Scheyer & C. Romano & J. Jenks & H. Bucher" box="[1449,1472,1889,1910]" journalOrPublisher="PLOS ONE" pageId="1" pageNumber="2" pagination="88987" part="9" refId="ref15109" refString="23. T. M. Scheyer, C. Romano, J. Jenks, H. Bucher, Early Triassic marine biotic recovery: The predators ' perspective. PLOS ONE 9, e 88987 (2014). doi: 10.1371 / journal. pone. 0088987; pmid: 24647136" title="Early Triassic marine biotic recovery: The predators ' perspective" type="journal article" year="2014">
|
||
<emphasis box="[1449,1472,1889,1910]" italics="true" pageId="1" pageNumber="2">23</emphasis>
|
||
</bibRefCitation>
|
||
); fig. S8A], even though it is available for fewer ichthyosaur taxa than skull length. At 453 mm, the humerus of the holotype of
|
||
<taxonomicName authority="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz, 2021" authorityName="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz" authorityYear="2021" box="[400,536,1582,1603]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="2" pageNumber="3" phylum="Chordata" rank="species" species="youngorum" status="sp. nov.">
|
||
<emphasis box="[400,536,1582,1603]" italics="true" pageId="2" pageNumber="3">C. youngorum</emphasis>
|
||
</taxonomicName>
|
||
<taxonomicNameLabel box="[98,175,1610,1630]" pageId="2" pageNumber="3" rank="species">sp. nov.</taxonomicNameLabel>
|
||
is the second largest ichthyosaurian humerus known, translating into a total length of 17.65 m (
|
||
<bibRefCitation box="[223,245,1666,1687]" pageId="2" pageNumber="3" refId="ref14573" refString="10. See supplementary materials">
|
||
<emphasis box="[223,245,1666,1687]" italics="true" pageId="2" pageNumber="3">10</emphasis>
|
||
</bibRefCitation>
|
||
). The lower 95% prediction interval of its length is 12.48 m; the upper 95% prediction interval is 24.96 m (
|
||
<bibRefCitation box="[404,425,1721,1742]" pageId="2" pageNumber="3" refId="ref14573" refString="10. See supplementary materials">
|
||
<emphasis box="[404,425,1721,1742]" italics="true" pageId="2" pageNumber="3">10</emphasis>
|
||
</bibRefCitation>
|
||
) (fig. S8A). We also estimated body mass based on a recent dataset for ichthyosaurs (
|
||
<bibRefCitation box="[336,357,1777,1798]" pageId="2" pageNumber="3" refId="ref14573" refString="10. See supplementary materials">
|
||
<emphasis box="[336,357,1777,1798]" italics="true" pageId="2" pageNumber="3">10</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation author="S. Gutarra" box="[366,389,1777,1798]" journalOrPublisher="Proc. Biol. Sci." pageId="2" pageNumber="3" pagination="20182786" part="286" refId="ref15163" refString="24. S. Gutarra et al., Effects of body plan evolution on the hydrodynamic drag and energy requirements of swimming in ichthyosaurs. Proc. Biol. Sci. 286, 20182786 (2019). doi: 10.1098 / rspb. 2018.2786; pmid: 30836867" title="Effects of body plan evolution on the hydrodynamic drag and energy requirements of swimming in ichthyosaurs" type="journal article" year="2019">
|
||
<emphasis box="[366,389,1777,1798]" italics="true" pageId="2" pageNumber="3">24</emphasis>
|
||
</bibRefCitation>
|
||
) (table S5). The regression function (fig. S8B) yielded a body mass estimate of 44,699 kg for the 17.65-msized LACM DI 15787 specimen (table S5). The lower mass based on the 95% prediction interval of both regressions is 14,712 kg (lower limit of the 95% prediction interval of body mass against length evaluated for 12.48 m); the upper mass is 135,809 kg (upper limit of the 95% prediction interval of body mass against length evaluated for 24.96 m). These body size metrics of
|
||
<taxonomicName authority="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz, 2021" authorityName="Sander & Griebeler & Klein & Juarbe & Wintrich & Revell & Schmitz" authorityYear="2021" box="[783,926,1693,1714]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="2" pageNumber="3" phylum="Chordata" rank="species" species="youngorum" status="sp. nov.">
|
||
<emphasis box="[783,926,1693,1714]" italics="true" pageId="2" pageNumber="3">C. youngorum</emphasis>
|
||
</taxonomicName>
|
||
<taxonomicNameLabel box="[934,1012,1694,1714]" pageId="2" pageNumber="3" rank="species">sp. nov.</taxonomicNameLabel>
|
||
result in one of the highest length and mass estimates for any ichthyosaur and the largest taxon of the Middle Triassic: Based on length and scaled-up mass data in Gutarra
|
||
<emphasis box="[917,958,1805,1826]" italics="true" pageId="2" pageNumber="3">et al</emphasis>
|
||
. (
|
||
<bibRefCitation author="S. Gutarra" box="[975,999,1805,1826]" journalOrPublisher="Proc. Biol. Sci." pageId="2" pageNumber="3" pagination="20182786" part="286" refId="ref15163" refString="24. S. Gutarra et al., Effects of body plan evolution on the hydrodynamic drag and energy requirements of swimming in ichthyosaurs. Proc. Biol. Sci. 286, 20182786 (2019). doi: 10.1098 / rspb. 2018.2786; pmid: 30836867" title="Effects of body plan evolution on the hydrodynamic drag and energy requirements of swimming in ichthyosaurs" type="journal article" year="2019">
|
||
<emphasis box="[975,999,1805,1826]" italics="true" pageId="2" pageNumber="3">24</emphasis>
|
||
</bibRefCitation>
|
||
),
|
||
<taxonomicName authorityName="Camp" authorityYear="1976" box="[573,694,1833,1854]" class="Reptilia" family="Shastasauridae" genus="Shonisaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="2" pageNumber="3" phylum="Chordata" rank="species" species="popularis">
|
||
<emphasis box="[573,694,1833,1854]" italics="true" pageId="2" pageNumber="3">S. popularis</emphasis>
|
||
</taxonomicName>
|
||
from the late Carnian (about 230 Ma ago) was 13.5 m long and had a mass of 21,651 kg, whereas the middle Norian (about 212 Ma ago)
|
||
<taxonomicName baseAuthorityName="Nicholls & Manabe" baseAuthorityYear="2004" box="[1180,1331,1526,1547]" class="Reptilia" family="Shastasauridae" genus="Shonisaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="2" pageNumber="3" phylum="Chordata" rank="species" species="sikanniensis">
|
||
<emphasis box="[1180,1331,1526,1547]" italics="true" pageId="2" pageNumber="3">S. sikanniensis</emphasis>
|
||
</taxonomicName>
|
||
was 21 m long and had an estimated body mass of 81,497 kg. Taken together, these length and mass estimates place ichthyosaurs in the range of body sizes of living cetaceans, but it appears that ichthyosaurs reached their largest sizes much earlier in clade history than whales.
|
||
</paragraph>
|
||
</subSubSection>
|
||
</treatment>
|
||
</document> |