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<document id="FBC92A643BFCA31964AA2E20FD0B1096" ID-CLB-Dataset="5397" ID-DOI="10.1111/j.1096-3642.2006.00225.x" ID-GBIF-Dataset="4597f8e7-649f-4c70-bb57-a7e5fd48ada4" ID-ISSN="0024-4082" ID-Zenodo-Dep="4634739" IM.materialsCitations_approvedBy="felipe" IM.metadata_approvedBy="felipe" IM.tables_requiresApprovalFor="existingObjects,plazi" IM.taxonomicNames_approvedBy="felipe" checkinTime="1616618650987" checkinUser="carolina" docAuthor="Fröbisch, Nadia B., Sander, P. Martin &amp; Rieppel, Olivier" docDate="2006" docId="03E05931A010FFFE286D5F687A17FEBB" docLanguage="en" docName="ZoolJLinnSoc.147.515-538.pdf" docOrigin="Zoological Journal of the Linnean Society 147 (4)" docSource="https://academic.oup.com/zoolinnean/article-lookup/doi/10.1111/j.1096-3642.2006.00225.x" docStyle="DocumentStyle:0DD8C314D74634CE09062A86991413F8.2:ZoolJLinnSoc.2002-2009.journal_article" docStyleId="0DD8C314D74634CE09062A86991413F8" docStyleName="ZoolJLinnSoc.2002-2009.journal_article" docStyleVersion="2" docTitle="Cymbospondylus NICHOLLSI 2006, SP. NOV." docType="treatment" docVersion="6" lastPageNumber="535" masterDocId="FFD92149A012FFEA2B1659567E11FFEF" masterDocTitle="A new species of Cymbospondylus (Diapsida, Ichthyosauria) from the Middle Triassic of Nevada and a re-evaluation of the skull osteology of the genus" masterLastPageNumber="538" masterPageNumber="515" pageNumber="517" updateTime="1698934810354" updateUser="ExternalLinkService" zenodo-license-document="CC-BY-4.0" zenodo-license-figures="CC-BY-4.0">
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<mods:titleInfo id="E25E5908AD8D0EF0BFF7A22B063E1FAE">
<mods:title id="00ECC2806A0D32246172984C82BD7951">A new species of Cymbospondylus (Diapsida, Ichthyosauria) from the Middle Triassic of Nevada and a re-evaluation of the skull osteology of the genus</mods:title>
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<mods:namePart id="20A8B3491E41E348B26E3161C0503D3C">Fröbisch, Nadia B.</mods:namePart>
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<mods:namePart id="BD4998C73229A47C2B9ECD048A50F215">Sander, P. Martin</mods:namePart>
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<mods:namePart id="E018CA842E8DD0CE2E68E88791343FDC">Rieppel, Olivier</mods:namePart>
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<mods:title id="9C0E51FCEFB47926CCE4BB0679C796B9">Zoological Journal of the Linnean Society</mods:title>
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<mods:part id="6BF5487CF126CB3534E5C8A2C627EF44">
<mods:date id="09301671F0B4F2AC52C3EB5ABC6AEF47">2006</mods:date>
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<mods:number id="FE9CEC944C3C4B1DBD451593D7A270F3">2006-08-31</mods:number>
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<mods:detail id="082E6AA25344CF8C5958DECA3B24B17C" type="volume">
<mods:number id="0A265CDEE1F0AB6F84659C9EE3BAC6F7">147</mods:number>
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<mods:classification id="6596F3FFC512044E28E290B94C8D7D7C">journal article</mods:classification>
<mods:identifier id="919C022DB6F60FF53ED5D882DDD13E6A" type="CLB-Dataset">5397</mods:identifier>
<mods:identifier id="EE01C6508F6C7C28D93023FF8AE076E8" type="DOI">10.1111/j.1096-3642.2006.00225.x</mods:identifier>
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<treatment id="03E05931A010FFFE286D5F687A17FEBB" ID-DOI="http://doi.org/10.5281/zenodo.4634344" ID-GBIF-Taxon="183630744" ID-Zenodo-Dep="4634344" LSID="urn:lsid:plazi:treatment:03E05931A010FFFE286D5F687A17FEBB" httpUri="http://treatment.plazi.org/id/03E05931A010FFFE286D5F687A17FEBB" lastPageId="20" lastPageNumber="535" pageId="2" pageNumber="517">
<subSubSection id="C353BBACA010FFE8286D5F687B28F9B9" box="[891,1337,1598,1622]" pageId="2" pageNumber="517" type="nomenclature">
<paragraph id="8BF6E827A010FFE8286D5F687B28F9B9" blockId="2.[891,1337,1598,1622]" box="[891,1337,1598,1622]" pageId="2" pageNumber="517">
<heading id="D0BE5F4BA010FFE8286D5F687B28F9B9" box="[891,1337,1598,1622]" centered="true" fontSize="9" level="2" pageId="2" pageNumber="517" reason="5">
<taxonomicName id="4C4993A4A010FFE8286D5F687AC3F9BA" authority="NICHOLLSI" authorityName="NICHOLLSI" authorityYear="2006" box="[891,1234,1598,1622]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="2" pageNumber="517" phylum="Chordata" rank="genus" status="sp. nov.">
<emphasis id="B93D3435A010FFE8286D5F687AC3F9BA" box="[891,1234,1598,1622]" italics="true" pageId="2" pageNumber="517">CYMBOSPONDYLUS NICHOLLSI</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A20E894EA010FFE82FCC5F147B28F9B9" box="[1242,1337,1598,1622]" pageId="2" pageNumber="517" rank="species">SP. NOV.</taxonomicNameLabel>
</heading>
</paragraph>
</subSubSection>
<subSubSection id="C353BBACA010FFEE28305F317F95FD88" lastPageId="4" lastPageNumber="519" pageId="2" pageNumber="517" type="diagnosis">
<paragraph id="8BF6E827A010FFEE28305F317C92FDE3" blockId="2.[806,1422,1639,1906]" lastBlockId="4.[142,758,195,616]" lastPageId="4" lastPageNumber="519" pageId="2" pageNumber="517">
<emphasis id="B93D3435A010FFE828305F317D8CF993" box="[806,925,1639,1660]" italics="true" pageId="2" pageNumber="517">Diagnosis:</emphasis>
Medium-sized
<taxonomicName id="4C4993A4A010FFE82F745F317B33F993" authorityName="NICHOLLSI" authorityYear="2006" box="[1122,1314,1639,1660]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="2" pageNumber="517" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A010FFE82F745F317B33F993" box="[1122,1314,1639,1660]" italics="true" pageId="2" pageNumber="517">Cymbospondylus</emphasis>
</taxonomicName>
. Differs from
<taxonomicName id="4C4993A4A010FFE8287C5FD37A86F974" authorityName="Leidy" authorityYear="1868" box="[874,1175,1669,1691]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="2" pageNumber="517" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A010FFE8287C5FD37A86F974" box="[874,1175,1669,1691]" italics="true" pageId="2" pageNumber="517">Cymbospondylus petrinus</emphasis>
</taxonomicName>
in having a longer cheek region: the ratio between length posterior to nares and length of cheek region is
<quantity id="4CB145C2A010FFE82FAC5F957B19F936" box="[1210,1288,1731,1753]" metricMagnitude="-2" metricUnit="m" metricValue="4.699" pageId="2" pageNumber="517" unit="in" value="1.85">1.85 in</quantity>
<taxonomicName id="4C4993A4A010FFE82E195F957B9FF937" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1295,1422,1731,1752]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="2" pageNumber="517" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A010FFE82E195F957B9FF937" box="[1295,1422,1731,1752]" italics="true" pageId="2" pageNumber="517">C. nichollsi</emphasis>
</taxonomicName>
vs.
<quantity id="4CB145C2A010FFE8285B5FB77D8CF918" box="[845,925,1761,1783]" metricMagnitude="-2" metricUnit="m" metricValue="5.3594" pageId="2" pageNumber="517" unit="in" value="2.11">2.11 in</quantity>
<taxonomicName id="4C4993A4A010FFE828B05FB47A33F918" authorityName="Leidy" authorityYear="1868" box="[934,1058,1762,1783]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="2" pageNumber="517" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A010FFE828B05FB47A33F918" box="[934,1058,1762,1783]" italics="true" pageId="2" pageNumber="517">C. petrinus</emphasis>
</taxonomicName>
. The parietal foramen is about
<quantity id="4CB145C2A010FFE828305E567D61F8FA" box="[806,880,1792,1814]" metricMagnitude="-2" metricUnit="m" metricValue="4.5" pageId="2" pageNumber="517" unit="cm" value="4.5">4.5 cm</quantity>
posterior to the fronto-parietal suture within the parietal, but is very close to the fronto-parietal suture in
<taxonomicName id="4C4993A4A010FFE8288B5E687A09F8BC" authorityName="Leidy" authorityYear="1868" box="[925,1048,1854,1875]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="2" pageNumber="517" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A010FFE8288B5E687A09F8BC" box="[925,1048,1854,1875]" italics="true" pageId="2" pageNumber="517">C. petrinus</emphasis>
</taxonomicName>
. Autapomorphies of
<taxonomicName id="4C4993A4A010FFE82E195E687B9FF8BD" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1295,1422,1853,1875]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="2" pageNumber="517" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A010FFE82E195E687B9FF8BD" box="[1295,1422,1853,1875]" italics="true" pageId="2" pageNumber="517">C. nichollsi</emphasis>
</taxonomicName>
are: nasals have a long posterior process entering the upper temporal opening; the postorbital reaching far dorsally to the border of the temporal opening, whereas it is restricted to the medial portion of the cheek region in
<taxonomicName id="4C4993A4A016FFEE2A5C58767FD7FEDA" authorityName="Leidy" authorityYear="1868" box="[330,454,288,309]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="4" pageNumber="519" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A016FFEE2A5C58767FD7FEDA" box="[330,454,288,309]" italics="true" pageId="4" pageNumber="519">C. petrinus</emphasis>
</taxonomicName>
and
<taxonomicName id="4C4993A4A016FFEE291258767C90FEDB" authorityName="Sander" authorityYear="1989" box="[516,641,287,309]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="4" pageNumber="519" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A016FFEE291258767C90FEDB" box="[516,641,287,309]" italics="true" pageId="4" pageNumber="519">C. buchseri</emphasis>
</taxonomicName>
; the long, slender supratemporal extends beyond the back of the skull; the quadratojugal is short and restricted to the lateral side of the skull and does not make contact with the quadrate at the back of the skull; as a result, the squamosal takes part in the posterior border of the lateral embayment, in contrast to the condition seen in
<taxonomicName id="4C4993A4A016FFEE2BBB58A07F38FDE3" authorityName="Leidy" authorityYear="1868" box="[173,297,502,524]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="4" pageNumber="519" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A016FFEE2BBB58A07F38FDE3" box="[173,297,502,524]" italics="true" pageId="4" pageNumber="519">C. petrinus</emphasis>
</taxonomicName>
and most other ichthyosaurs.
</paragraph>
<caption id="DF36B8AFA011FFE92BB45E487FADF883" ID-DOI="http://doi.org/10.5281/zenodo.4634743" ID-Zenodo-Dep="4634743" httpUri="https://zenodo.org/record/4634743/files/figure.png" pageId="3" pageNumber="518" startId="3.[162,240,1822,1841]" targetBox="[179,1424,190,1790]" targetPageId="3">
<paragraph id="8BF6E827A011FFE92BB45E487FADF883" blockId="3.[162,1442,1822,1900]" pageId="3" pageNumber="518">
<emphasis id="B93D3435A011FFE92BB45E487F1BF8DE" bold="true" box="[162,266,1822,1841]" pageId="3" pageNumber="518">Figure 1.</emphasis>
Holotype of
<emphasis id="B93D3435A011FFE92A835E487D32F8DE" bold="true" box="[405,803,1822,1841]" pageId="3" pageNumber="518">
<taxonomicName id="4C4993A4A011FFE92A835E487CD5F8DE" authority="Fröbisch &amp; Sander &amp; Rieppel, 2006" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[405,708,1822,1841]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="3" pageNumber="518" phylum="Chordata" rank="species" species="nichollsi" status="sp. nov.">
<emphasis id="B93D3435A011FFE92A835E487CD5F8DE" bold="true" box="[405,708,1822,1841]" italics="true" pageId="3" pageNumber="518">Cymbospondylus nichollsi</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A20E894EA011FFE929DA5E487D32F8DE" box="[716,803,1822,1841]" pageId="3" pageNumber="518" rank="species">sp. nov.</taxonomicNameLabel>
</emphasis>
, specimen FMNH PR2251 in lateral (A), dorsal (B) and ventral (C) view. C shows the upper surface of the specimen as found in the field. Note the sharp bend in the cervical vertebral column. Scale bar = 20 cm.
</paragraph>
</caption>
<paragraph id="8BF6E827A016FFEE2BB15B437F95FD88" blockId="4.[142,758,195,616]" pageId="4" pageNumber="519">
The preserved postcranial parts are very similar to
<taxonomicName id="4C4993A4A016FFEE2B985B627F18FDA6" authorityName="Leidy" authorityYear="1868" box="[142,265,564,585]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="4" pageNumber="519" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A016FFEE2B985B627F18FDA6" box="[142,265,564,585]" italics="true" pageId="4" pageNumber="519">C. petrinus</emphasis>
</taxonomicName>
and
<taxonomicName id="4C4993A4A016FFEE2A5A5B627FD8FDA7" authorityName="Sander" authorityYear="1989" box="[332,457,563,585]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="4" pageNumber="519" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A016FFEE2A5A5B627FD8FDA7" box="[332,457,563,585]" italics="true" pageId="4" pageNumber="519">C. buchseri</emphasis>
</taxonomicName>
, but the clavicle is more robust in
<taxonomicName id="4C4993A4A016FFEE2BE95B047F6CFD88" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[255,381,594,615]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="4" pageNumber="519" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A016FFEE2BE95B047F6CFD88" box="[255,381,594,615]" italics="true" pageId="4" pageNumber="519">C. nichollsi</emphasis>
</taxonomicName>
.
</paragraph>
</subSubSection>
<subSubSection id="C353BBACA016FFEE282959927DBBFEF9" pageId="4" pageNumber="519" type="discussion">
<paragraph id="8BF6E827A016FFEE282959927DBBFEF9" blockId="4.[806,1422,195,278]" pageId="4" pageNumber="519">
<taxonomicName id="4C4993A4A016FFEE282959927DACFF37" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[831,957,195,217]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="4" pageNumber="519" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A016FFEE282959927DACFF37" box="[831,957,195,217]" italics="true" pageId="4" pageNumber="519">C. nichollsi</emphasis>
</taxonomicName>
possesses 8–10 cervical vertebrae in comparison with
<quantity id="4CB145C2A016FFEE2F1C59B47A42FF17" box="[1034,1107,226,248]" metricMagnitude="-1" metricUnit="m" metricValue="3.048" pageId="4" pageNumber="519" unit="in" value="12.0">12 in</quantity>
<taxonomicName id="4C4993A4A016FFEE2F7D59B47AF7FF17" authorityName="Leidy" authorityYear="1868" box="[1131,1254,226,248]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="4" pageNumber="519" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A016FFEE2F7D59B47AF7FF17" box="[1131,1254,226,248]" italics="true" pageId="4" pageNumber="519">C. petrinus</emphasis>
</taxonomicName>
and six in
<taxonomicName id="4C4993A4A016FFEE283058577DB2FEF9" authorityName="Sander" authorityYear="1989" box="[806,931,257,278]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="4" pageNumber="519" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A016FFEE283058577DB2FEF9" box="[806,931,257,278]" italics="true" pageId="4" pageNumber="519">C. buchseri</emphasis>
</taxonomicName>
.
</paragraph>
</subSubSection>
<subSubSection id="C353BBACA016FFEE283058797A58FD87" pageId="4" pageNumber="519" type="materials_examined">
<paragraph id="8BF6E827A016FFEE283058797D7EFE31" blockId="4.[806,1422,303,478]" pageId="4" pageNumber="519">
<materialsCitation id="3B21E27AA016FFEE283058797D7EFE31" ID-GBIF-Occurrence="3325221301" collectionCode="FMNH" pageId="4" pageNumber="519" specimenCode="PR2251" specimenCount="1" typeStatus="holotype">
<emphasis id="B93D3435A016FFEE283058797A60FEAB" box="[806,1137,303,324]" italics="true" pageId="4" pageNumber="519">
<typeStatus id="54F25685A016FFEE283058797D9BFEAB" box="[806,906,303,324]" pageId="4" pageNumber="519" type="holotype">Holotype</typeStatus>
and only specimen:
</emphasis>
Specimen
<collectionCode id="ED5870E2A016FFEE2E2B58797B9CFEAB" box="[1341,1421,303,324]" country="USA" httpUri="http://biocol.org/urn:lsid:biocol.org:col:34795" lsid="urn:lsid:biocol.org:col:34795" name="Field Museum of Natural History" pageId="4" pageNumber="519" type="Museum">FMNH</collectionCode>
<specimenCode id="DBEF405CA016FFEE2830581B7D93FE8C" box="[806,898,333,355]" collectionCode="FMNH" country="USA" httpUri="http://biocol.org/urn:lsid:biocol.org:col:34795" lsid="urn:lsid:biocol.org:col:34795" name="Field Museum of Natural History" pageId="4" pageNumber="519" type="Museum">PR2251</specimenCode>
. Anterior half of an articulated skeleton, comprising the skull without the rostrum, articulated vertebral column with neural arches and ribs, extending to the middle dorsal region, and parts of the shoulder girdle.
</materialsCitation>
</paragraph>
<paragraph id="8BF6E827A016FFEE283058A17A58FD87" blockId="4.[806,1422,502,616]" pageId="4" pageNumber="519">
<emphasis id="B93D3435A016FFEE283058A17DACFDE4" box="[806,957,502,524]" italics="true" pageId="4" pageNumber="519">Type locality:</emphasis>
Augusta Mountains, Pershing County,
<collectingRegion id="498D26C5A016FFEE28305B437D6CFDC4" box="[806,893,533,555]" country="United States of America" name="Nevada" pageId="4" pageNumber="519">Nevada</collectingRegion>
(T25N, R39E; Section 14; USGS Cain Moutain 7.5′ quadrangle, 1990 provisional edition, exact locality on file at the FMNH).
</paragraph>
</subSubSection>
<subSubSection id="C353BBACA016FFEE28305BD77ADBFD5A" pageId="4" pageNumber="519" type="distribution">
<paragraph id="8BF6E827A016FFEE28305BD77ADBFD5A" blockId="4.[806,1422,640,693]" pageId="4" pageNumber="519">
<emphasis id="B93D3435A016FFEE28305BD77A5AFD7A" box="[806,1099,640,662]" italics="true" pageId="4" pageNumber="519">Horizon and distribution:</emphasis>
Fossil Hill Member, Favret Formation, Anisian, Middle Triassic.
</paragraph>
</subSubSection>
<subSubSection id="C353BBACA016FFEE28305B9B7D8DFC93" pageId="4" pageNumber="519" type="etymology">
<paragraph id="8BF6E827A016FFEE28305B9B7D8DFC93" blockId="4.[806,1422,717,892]" pageId="4" pageNumber="519">
<emphasis id="B93D3435A016FFEE28305B9B7DB2FD0D" box="[806,931,717,738]" italics="true" pageId="4" pageNumber="519">Etymology:</emphasis>
Named in memory and honour of Dr Elizabeth L. Nicholls, curator of marine reptiles at the Royal Tyrrell Museum, Drumheller,
<collectingCountry id="F35EA8B7A016FFEE2FC25A5C7B3FFCCF" box="[1236,1326,778,800]" name="Canada" pageId="4" pageNumber="519">Canada</collectingCountry>
, for her work on Triassic ichthyosaurs, which greatly contributed to the increased knowledge and understanding of the group.
</paragraph>
</subSubSection>
<subSubSection id="C353BBACA016FFFE28605AE17A17FEBB" lastPageId="20" lastPageNumber="535" pageId="4" pageNumber="519" type="description">
<subSection id="E2C6F1CCA016FFE628605AE17EF9FE20" lastPageId="12" lastPageNumber="527" pageId="4" pageNumber="519" type="multiple">
<paragraph id="8BF6E827A016FFEE28605AE17B2FFC20" blockId="4.[886,1342,951,975]" box="[886,1342,951,975]" pageId="4" pageNumber="519">
<heading id="D0BE5F4BA016FFEE28605AE17B2FFC20" allCaps="true" box="[886,1342,951,975]" centered="true" fontSize="10" level="1" pageId="4" pageNumber="519" reason="1">MORPHOLOGICAL DESCRIPTION</heading>
</paragraph>
<paragraph id="8BF6E827A016FFEE2F225AB37A6EFC12" blockId="4.[1076,1151,997,1021]" box="[1076,1151,997,1021]" pageId="4" pageNumber="519">SKULL</paragraph>
<caption id="DF36B8AFA016FFEE2B985AA17F35FB8D" ID-DOI="http://doi.org/10.5281/zenodo.4634745" ID-Zenodo-Dep="4634745" httpUri="https://zenodo.org/record/4634745/files/figure.png" pageId="4" pageNumber="519" startId="4.[142,220,1015,1034]" targetBox="[146,754,663,982]" targetPageId="4">
<paragraph id="8BF6E827A016FFEE2B985AA17F35FB8D" blockId="4.[142,758,1015,1122]" pageId="4" pageNumber="519">
<emphasis id="B93D3435A016FFEE2B985AA17EE7FBE5" bold="true" box="[142,246,1015,1034]" pageId="4" pageNumber="519">Figure 2.</emphasis>
Right temporal opening of specimen FMNH PR2251 with the arrow indicating the bite marks on the parietal plateau. See Appendix for explanation of abbreviations.
</paragraph>
</caption>
<paragraph id="8BF6E827A016FFEF28305D587C8BFA4C" blockId="4.[806,1422,1038,1121]" lastBlockId="5.[162,778,993,1904]" lastPageId="5" lastPageNumber="520" pageId="4" pageNumber="519">
In dorsal view, the preserved skull has an overall trapezoidal shape, and quickly narrows towards the rostral region (
<figureCitation id="1372F4A2A016FFEE28D95D1D7A1EFB8E" box="[975,1039,1099,1121]" captionStart="Figure 3" captionStartId="4.[142,220,1853,1872]" captionTargetBox="[302,1262,1174,1821]" captionTargetId="figure-389@4.[302,1262,1172,1821]" captionTargetPageId="4" captionText="Figure 3. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in dorsal view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634747" httpUri="https://zenodo.org/record/4634747/files/figure.png" pageId="4" pageNumber="519">Fig. 3</figureCitation>
). The narrow end of the teardropshaped temporal opening points in posterior direction and a large and well-developed temporal terrace lies anteriorly to it. The parietal region between the temporal openings forms a parietal plateau, resulting in a clearly elevated skull roof, but it does not form a distinctive sagittal crest of the kind seen in
<taxonomicName id="4C4993A4A017FFEF29985D2C7D1BFB7F" authorityName="Leidy" authorityYear="1868" box="[654,778,1146,1168]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="5" pageNumber="520" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A017FFEF29985D2C7D1BFB7F" box="[654,778,1146,1168]" italics="true" pageId="5" pageNumber="520">C. petrinus</emphasis>
</taxonomicName>
specimen UCMP 9950. However, the second skull in the University of
<collectingRegion id="498D26C5A017FFEF2A6B5DE17FE1FB22" box="[381,496,1207,1229]" country="United States of America" name="California" pageId="5" pageNumber="520">California</collectingRegion>
collection described as
<taxonomicName id="4C4993A4A017FFEF2BB45D807F6BFB04" authority=", UCMP" authorityName="UCMP" box="[162,378,1238,1260]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="5" pageNumber="520" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A017FFEF2BB45D807F0FFB03" box="[162,286,1238,1260]" italics="true" pageId="5" pageNumber="520">C. petrinus</emphasis>
, UCMP
</taxonomicName>
9913, also shows a rather shallow and flat skull roof and lacks the high sagittal crest of the
<typeStatus id="54F25685A017FFEF2BDB5C457F20FAC6" box="[205,305,1299,1321]" pageId="5" pageNumber="520" type="holotype">holotype</typeStatus>
. This skull did not receive much attention in the literature and it will be necessary to re-investigate it to clarify whether it indicates a range of morphological variation within
<taxonomicName id="4C4993A4A017FFEF29305C267CB0FA6A" box="[550,673,1392,1413]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="5" pageNumber="520" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A017FFEF29305C267CB0FA6A" box="[550,673,1392,1413]" italics="true" pageId="5" pageNumber="520">C. petrinus</emphasis>
</taxonomicName>
or if it represents another specimen of
<taxonomicName id="4C4993A4A017FFEF29025CD87C82FA4C" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[532,659,1422,1443]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="5" pageNumber="520" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A017FFEF29025CD87C82FA4C" box="[532,659,1422,1443]" italics="true" pageId="5" pageNumber="520">C. nichollsi</emphasis>
</taxonomicName>
.
</paragraph>
<caption id="DF36B8AFA016FFEE2B985E6B7C99F881" ID-DOI="http://doi.org/10.5281/zenodo.4634747" ID-Zenodo-Dep="4634747" httpUri="https://zenodo.org/record/4634747/files/figure.png" pageId="4" pageNumber="519" startId="4.[142,220,1853,1872]" targetBox="[302,1262,1174,1821]" targetPageId="4">
<paragraph id="8BF6E827A016FFEE2B985E6B7C99F881" blockId="4.[142,1422,1853,1902]" pageId="4" pageNumber="519">
<emphasis id="B93D3435A016FFEE2B985E6B7EE7F8BF" bold="true" box="[142,246,1853,1872]" pageId="4" pageNumber="519">Figure 3.</emphasis>
Drawing of the skull of
<emphasis id="B93D3435A016FFEE2AEE5E6B7D92F8BE" bold="true" box="[504,899,1853,1873]" pageId="4" pageNumber="519">
<taxonomicName id="4C4993A4A016FFEE2AEE5E6B7D37F8BF" authority="Fröbisch &amp; Sander &amp; Rieppel, 2006" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[504,806,1853,1872]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="4" pageNumber="519" phylum="Chordata" rank="species" species="nichollsi" status="sp. nov.">
<emphasis id="B93D3435A016FFEE2AEE5E6B7D37F8BF" bold="true" box="[504,806,1853,1872]" italics="true" pageId="4" pageNumber="519">Cymbospondylus nichollsi</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A20E894EA016FFEE283B5E687D92F8BE" box="[813,899,1854,1873]" pageId="4" pageNumber="519" rank="species">sp. nov.</taxonomicNameLabel>
</emphasis>
(FMNH PR2251) in dorsal view. See Appendix for explanation of abbreviations. Scale bar = 10 cm.
</paragraph>
</caption>
<caption id="DF36B8AFA017FFEF2BB45A317C8DFC77" ID-DOI="http://doi.org/10.5281/zenodo.4634749" ID-Zenodo-Dep="4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="5" pageNumber="520" startId="5.[162,240,871,890]" targetBox="[322,1282,194,838]" targetPageId="5">
<paragraph id="8BF6E827A017FFEF2BB45A317C8DFC77" blockId="5.[162,1442,871,920]" pageId="5" pageNumber="520">
<emphasis id="B93D3435A017FFEF2BB45A317F1BFC95" bold="true" box="[162,266,871,890]" pageId="5" pageNumber="520">Figure 4.</emphasis>
Drawing of the skull of
<emphasis id="B93D3435A017FFEF291C5A317D85FC94" bold="true" box="[522,916,871,891]" pageId="5" pageNumber="520">
<taxonomicName id="4C4993A4A017FFEF291C5A317D29FC95" authority="Fröbisch &amp; Sander &amp; Rieppel, 2006" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[522,824,871,890]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="5" pageNumber="520" phylum="Chordata" rank="species" species="nichollsi" status="sp. nov.">
<emphasis id="B93D3435A017FFEF291C5A317D29FC95" bold="true" box="[522,824,871,890]" italics="true" pageId="5" pageNumber="520">Cymbospondylus nichollsi</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A20E894EA017FFEF28285A3E7D85FC94" box="[830,916,872,891]" pageId="5" pageNumber="520" rank="species">sp. nov.</taxonomicNameLabel>
</emphasis>
(FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm.
</paragraph>
</caption>
<paragraph id="8BF6E827A017FFEF2BAD5CFB7CB1F89F" blockId="5.[162,778,993,1904]" pageId="5" pageNumber="520">
The orbit of FMNH PR2251 is rather small and eggshaped with the wider, slightly angular end lying posteriorly (
<figureCitation id="1372F4A2A017FFEF2A1E5CBC7F5BF9EF" box="[264,330,1514,1536]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="5" pageNumber="520">Fig. 4</figureCitation>
). In both orbits, the sclerotic rings are still preserved, although the left eyeball is turned anteromedially so that an exact count of the sclerotic plates is not possible on this side. On the right skull side the eyeball is in natural position, and the full sclerotic ring with 14 plates is visible. The sclerotic ring is oval in shape and appears small compared with the size of the orbit, with a likewise small inner opening of the sclerotic ring (
<tableCitation id="C6CBDD9CA017FFEF2A635F897FD9F919" box="[373,456,1759,1782]" captionStart="Table 1" captionStartId="6.[142,206,196,215]" captionTargetPageId="6" captionText="Table 1. Measurements of C. nichollsi, specimen FMNH PR2251" httpUri="http://table.plazi.org/id/DF36B8AFA014FFEC2B9859927D53FF38" pageId="5" pageNumber="520" tableUuid="DF36B8AFA014FFEC2B9859927D53FF38">Table 1</tableCitation>
). The length/height ratio of the sclerotic ring is 1.55. However, even though the sclerotic plates are in articulation, some seem to be somewhat shifted from their original position, which might obscure the measured values slightly.
</paragraph>
<paragraph id="8BF6E827A017FFEF28455AB77A9EFBBC" blockId="5.[826,1442,993,1107]" pageId="5" pageNumber="520">
The postorbital region of the skull is rather long (
<tableCitation id="C6CBDD9CA017FFEF28575AA97D85FBF9" box="[833,916,1023,1046]" captionStart="Table 1" captionStartId="6.[142,206,196,215]" captionTargetPageId="6" captionText="Table 1. Measurements of C. nichollsi, specimen FMNH PR2251" httpUri="http://table.plazi.org/id/DF36B8AFA014FFEC2B9859927D53FF38" pageId="5" pageNumber="520" tableUuid="DF36B8AFA014FFEC2B9859927D53FF38">Table 1</tableCitation>
) and contains a large, rounded lateral embayment, bordered by the jugal, postorbital, quadratojugal, squamosal and quadrate.
</paragraph>
<paragraph id="8BF6E827A017FFEF282C5D3D7DA1F9C1" blockId="5.[826,1442,1131,1582]" pageId="5" pageNumber="520">
<emphasis id="B93D3435A017FFEF282C5D3D7DAFFB6F" box="[826,958,1131,1152]" italics="true" pageId="5" pageNumber="520">Premaxilla:</emphasis>
Only the posteriormost part of the premaxilla is preserved, and the posterior and ventral borders of this bone are broken off on both sides of the skull (
<figureCitation id="1372F4A2A017FFEF28985D917DC1FB32" box="[910,976,1223,1245]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="5" pageNumber="520">Fig. 4</figureCitation>
). On the right side, the premaxilla reaches back to the middle of the preserved external naris, while on the left side it reaches almost as far posteriorly as the posterior edge of the external naris. In the present state of preservation, the premaxilla does not contribute to the margin of the external nares, but lies slightly dorsally to it. Nevertheless, it is likely that the broken ventral edges originally did contribute to the dorsal border of the external nares. The preserved posterior end of the external nares suggests that they were oval in shape and rostrocaudally elongated.
</paragraph>
<paragraph id="8BF6E827A017FFED282C5F107F3CFCB1" blockId="5.[826,1443,1606,1904]" lastBlockId="7.[162,778,717,862]" lastPageId="7" lastPageNumber="522" pageId="5" pageNumber="520">
<emphasis id="B93D3435A017FFEF282C5F107D88F9B4" box="[826,921,1606,1627]" italics="true" pageId="5" pageNumber="520">Maxilla:</emphasis>
The ventral and posteroventral margin of the preserved part of the external nares is formed by the maxilla, which is also truncated anteriorly by the fault plane. It has a straight, horizontal suture with the nasal, which runs from the posterior edge of the external nares posteriorly. The posterior part of the maxilla is drawn out into a short, triangular dorsal process, which makes contact with the lacrimal in a clearly visible suture, and an elongated ventral process. This process tapers posteriorly and extends back to one-third below the orbit, but is excluded from the ventral margin of the orbit by the lacrimal and the jugal. The ventralmost portion of this process is separated from the lacrimal by the slender anterior process of the jugal.
</paragraph>
<caption id="DF36B8AFA014FFEC2B9859927D53FF38" ID-Table-UUID="DF36B8AFA014FFEC2B9859927D53FF38" box="[142,834,196,215]" httpUri="http://table.plazi.org/id/DF36B8AFA014FFEC2B9859927D53FF38" pageId="6" pageNumber="521" startId="6.[142,206,196,215]" targetBox="[142,1422,254,1890]" targetIsTable="true" targetPageId="6">
<paragraph id="8BF6E827A014FFEC2B9859927D53FF38" blockId="6.[142,834,196,215]" box="[142,834,196,215]" pageId="6" pageNumber="521">
<emphasis id="B93D3435A014FFEC2B9859927EF9FF38" bold="true" box="[142,232,196,215]" pageId="6" pageNumber="521">Table 1.</emphasis>
Measurements of
<taxonomicName id="4C4993A4A014FFEC2AA459927C36FF38" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[434,551,196,215]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="6" pageNumber="521" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A014FFEC2AA459927C36FF38" box="[434,551,196,215]" italics="true" pageId="6" pageNumber="521">C. nichollsi</emphasis>
</taxonomicName>
, specimen FMNH PR2251
</paragraph>
</caption>
<paragraph id="8BF6E827A014FFEC2B9859A87AFEF88E" pageId="6" pageNumber="521">
<table id="F9491A87A01400152B9859A87B9FF88D" box="[142,1422,254,1890]" gridcols="4" gridrows="46" pageId="6" pageNumber="521">
<tr id="3579EA65A01400152B9859A87B9FFEFD" box="[142,1422,254,274]" gridrow="0" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B9859A87C3CFEFD" box="[142,557,254,274]" gridcol="0" gridrow="0" pageId="6" pageNumber="521">Measured structure</th>
<th id="76A88319A01400152FD559A87B9FFEFD" box="[1219,1422,254,274]" gridcol="3" gridrow="0" pageId="6" pageNumber="521">Value (in mm)</th>
</tr>
<tr id="3579EA65A01400152B98586F7B9FFEA3" box="[142,1422,313,332]" gridrow="1" pageId="6" pageNumber="521">
<th id="76A88319A01400152B98586F7B9FFEA3" box="[142,1422,313,332]" colspan="4" colspanRight="3" gridcol="0" gridrow="1" pageId="6" pageNumber="521">Skull</th>
</tr>
<tr id="3579EA65A01400152B9858227B9FFE68" box="[142,1422,372,391]" gridrow="2" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B9858227C3CFE68" box="[142,557,372,391]" gridcol="0" gridrow="2" pageId="6" pageNumber="521">Orbit – greatest length</th>
<td id="76A88319A01400152FD558227B9FFE68" box="[1219,1422,372,391]" gridcol="3" gridrow="2" pageId="6" pageNumber="521">200</td>
</tr>
<tr id="3579EA65A01400152B9858C77B9FFE4A" box="[142,1422,401,421]" gridrow="3" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B9858C77C3CFE4A" box="[142,557,401,421]" gridcol="0" gridrow="3" pageId="6" pageNumber="521">Orbit – greatest height</th>
<td id="76A88319A01400152FD558C77B9FFE4A" box="[1219,1422,401,421]" gridcol="3" gridrow="3" pageId="6" pageNumber="521">128</td>
</tr>
<tr id="3579EA65A01400152B9858F87B9FFE2D" box="[142,1422,430,450]" gridrow="4" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B9858F87C3CFE2D" box="[142,557,430,450]" gridcol="0" gridrow="4" pageId="6" pageNumber="521">Sclerotic ring – greatest length</th>
<td id="76A88319A01400152FD558F87B9FFE2D" box="[1219,1422,430,450]" gridcol="3" gridrow="4" pageId="6" pageNumber="521">144</td>
</tr>
<tr id="3579EA65A01400152B98589A7B9FFE30" box="[142,1422,460,479]" gridrow="5" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B98589A7C3CFE30" box="[142,557,460,479]" gridcol="0" gridrow="5" pageId="6" pageNumber="521">Sclerotic ring – greatest height</th>
<td id="76A88319A01400152FD5589A7B9FFE30" box="[1219,1422,460,479]" gridcol="3" gridrow="5" pageId="6" pageNumber="521">93</td>
</tr>
<tr id="3579EA65A01400152B9858BF7B9FFE12" box="[142,1422,489,509]" gridrow="6" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B9858BF7C3CFE12" box="[142,557,489,509]" gridcol="0" gridrow="6" pageId="6" pageNumber="521">Inner opening of sclerotic ring – length</th>
<td id="76A88319A01400152FD558BF7B9FFE12" box="[1219,1422,489,509]" gridcol="3" gridrow="6" pageId="6" pageNumber="521">59</td>
</tr>
<tr id="3579EA65A01400152B985B507B9FFDF5" box="[142,1422,518,538]" gridrow="7" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B985B507C3CFDF5" box="[142,557,518,538]" gridcol="0" gridrow="7" pageId="6" pageNumber="521">Inner opening of sclerotic ring – height</th>
<td id="76A88319A01400152FD55B507B9FFDF5" box="[1219,1422,518,538]" gridcol="3" gridrow="7" pageId="6" pageNumber="521">39</td>
</tr>
<tr id="3579EA65A01400152B985B727B9FFDD8" box="[142,1422,548,567]" gridrow="8" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985B727A88FDD8" box="[142,1177,548,567]" colspan="3" colspanRight="2" gridcol="0" gridrow="8" pageId="6" pageNumber="521">Preserved length of skull (posterior border of temporal opening – anterior end of preserved nasal)</th>
<td id="76A88319A01400152FD55B727B9FFDD8" box="[1219,1422,548,567]" gridcol="3" gridrow="8" pageId="6" pageNumber="521">515</td>
</tr>
<tr id="3579EA65A01400152B985B177B9FFDBB" box="[142,1422,577,596]" gridrow="9" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B985B177C3CFDBB" box="[142,557,577,596]" gridcol="0" gridrow="9" pageId="6" pageNumber="521">Length of cheek region</th>
<td id="76A88319A01400152FD55B177B9FFDBB" box="[1219,1422,577,596]" gridcol="3" gridrow="9" pageId="6" pageNumber="521">240</td>
</tr>
<tr id="3579EA65A01400152B985B087B9FFD9E" box="[142,1422,606,625]" gridrow="10" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B985B087C3CFD9E" box="[142,557,606,625]" gridcol="0" gridrow="10" pageId="6" pageNumber="521">Length of parietal foramen</th>
<td id="76A88319A01400152FD55B087B9FFD9E" box="[1219,1422,606,625]" gridcol="3" gridrow="10" pageId="6" pageNumber="521">25</td>
</tr>
<tr id="3579EA65A01400152B985B2A7B9FFD60" box="[142,1422,636,655]" gridrow="11" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B985B2A7C3CFD60" box="[142,557,636,655]" gridcol="0" gridrow="11" pageId="6" pageNumber="521">Width of parietal foramen</th>
<td id="76A88319A01400152FD55B2A7B9FFD60" box="[1219,1422,636,655]" gridcol="3" gridrow="11" pageId="6" pageNumber="521">24</td>
</tr>
<tr id="3579EA65A01400152B985BCF7B9FFD43" box="[142,1422,665,684]" gridrow="12" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B985BCF7C3CFD43" box="[142,557,665,684]" gridcol="0" gridrow="12" pageId="6" pageNumber="521">Preserved length of lower jaw</th>
<td id="76A88319A01400152FD55BCF7B9FFD43" box="[1219,1422,665,684]" gridcol="3" gridrow="12" pageId="6" pageNumber="521">434</td>
</tr>
<tr id="3579EA65A01400152B985BE07B9FFD26" box="[142,1422,694,713]" gridrow="13" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B985BE07C3CFD26" box="[142,557,694,713]" gridcol="0" gridrow="13" pageId="6" pageNumber="521">Postdentary length of lower jaw</th>
<td id="76A88319A01400152FD55BE07B9FFD26" box="[1219,1422,694,713]" gridcol="3" gridrow="13" pageId="6" pageNumber="521">364</td>
</tr>
<tr id="3579EA65A01400152B985B827B9FFD08" box="[142,1422,724,743]" gridrow="14" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B985B827C3CFD08" box="[142,557,724,743]" gridcol="0" gridrow="14" pageId="6" pageNumber="521">Temporal opening – greatest length</th>
<td id="76A88319A01400152FD55B827B9FFD08" box="[1219,1422,724,743]" gridcol="3" gridrow="14" pageId="6" pageNumber="521">227</td>
</tr>
<tr id="3579EA65A01400152B985BA77B9FFCEA" box="[142,1422,753,773]" gridrow="15" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B985BA77C3CFCEA" box="[142,557,753,773]" gridcol="0" gridrow="15" pageId="6" pageNumber="521">Temporal opening – greatest width</th>
<td id="76A88319A01400152FD55BA77B9FFCEA" box="[1219,1422,753,773]" gridcol="3" gridrow="15" pageId="6" pageNumber="521">119 (left side)</td>
</tr>
<tr id="3579EA65A01400152B985A587B9FFCCD" box="[142,1422,782,802]" gridrow="16" pageId="6" pageNumber="521" rowspan-0="1" rowspan-1="1" rowspan-2="1">
<td id="76A88319A01400152FD55A587B9FFCCD" box="[1219,1422,782,802]" gridcol="3" gridrow="16" pageId="6" pageNumber="521">98 (right side)</td>
</tr>
<tr id="3579EA65A01400152B985A7A7B9FFCD0" box="[142,1422,812,831]" gridrow="17" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B985A7A7C3CFCD0" box="[142,557,812,831]" gridcol="0" gridrow="17" pageId="6" pageNumber="521">Lateral embayment – greatest length</th>
<td id="76A88319A01400152FD55A7A7B9FFCD0" box="[1219,1422,812,831]" gridcol="3" gridrow="17" pageId="6" pageNumber="521">105</td>
</tr>
<tr id="3579EA65A01400152B985A1F7B9FFCB2" box="[142,1422,841,861]" gridrow="18" pageId="6" pageNumber="521" rowspan-1="1" rowspan-2="1">
<th id="76A88319A01400152B985A1F7C3CFCB2" box="[142,557,841,861]" gridcol="0" gridrow="18" pageId="6" pageNumber="521">Lateral embayment – greatest height</th>
<td id="76A88319A01400152FD55A1F7B9FFCB2" box="[1219,1422,841,861]" gridcol="3" gridrow="18" pageId="6" pageNumber="521">115</td>
</tr>
<tr id="3579EA65A01400152B985AE77B9FFC2B" box="[142,1422,945,964]" gridrow="19" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985AE77B9FFC2B" box="[142,1422,945,964]" colspan="4" colspanRight="3" gridcol="0" gridrow="19" pageId="6" pageNumber="521">Axial skeleton</th>
</tr>
<tr id="3579EA65A01400152B985ABA7B9FFC10" box="[142,1422,1004,1023]" gridrow="20" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985ABA7C3CFC10" box="[142,557,1004,1023]" gridcol="0" gridrow="20" pageId="6" pageNumber="521">Vertebrae – cervical</th>
<td id="76A88319A014001529505ABA7C9FFC10" box="[582,654,1004,1023]" gridcol="1" gridrow="20" pageId="6" pageNumber="521">Height</td>
<td id="76A88319A014001528955ABA7A88FC10" box="[899,1177,1004,1023]" gridcol="2" gridrow="20" pageId="6" pageNumber="521">Length</td>
<td id="76A88319A01400152FD55ABA7B9FFC10" box="[1219,1422,1004,1023]" gridcol="3" gridrow="20" pageId="6" pageNumber="521">Height/length ratio</td>
</tr>
<tr id="3579EA65A01400152B985D707B9FFBD5" box="[142,1422,1062,1082]" gridrow="21" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985D707C3CFBD5" box="[142,557,1062,1082]" gridcol="0" gridrow="21" pageId="6" pageNumber="521">3rd</th>
<td id="76A88319A014001529505D707C9FFBD5" box="[582,654,1062,1082]" gridcol="1" gridrow="21" pageId="6" pageNumber="521">63</td>
<td id="76A88319A014001528955D707A88FBD5" box="[899,1177,1062,1082]" gridcol="2" gridrow="21" pageId="6" pageNumber="521">37</td>
<td id="76A88319A01400152FD55D707B9FFBD5" box="[1219,1422,1062,1082]" gridcol="3" gridrow="21" pageId="6" pageNumber="521">17</td>
</tr>
<tr id="3579EA65A01400152B985D127B9FFBB8" box="[142,1422,1092,1111]" gridrow="22" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985D127C3CFBB8" box="[142,557,1092,1111]" gridcol="0" gridrow="22" pageId="6" pageNumber="521">4th</th>
<td id="76A88319A014001529505D127C9FFBB8" box="[582,654,1092,1111]" gridcol="1" gridrow="22" pageId="6" pageNumber="521">66</td>
<td id="76A88319A014001528955D127A88FBB8" box="[899,1177,1092,1111]" gridcol="2" gridrow="22" pageId="6" pageNumber="521">40</td>
<td id="76A88319A01400152FD55D127B9FFBB8" box="[1219,1422,1092,1111]" gridcol="3" gridrow="22" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985D377B9FFB9A" box="[142,1422,1121,1141]" gridrow="23" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985D377C3CFB9A" box="[142,557,1121,1141]" gridcol="0" gridrow="23" pageId="6" pageNumber="521">5th</th>
<td id="76A88319A014001529505D377C9FFB9A" box="[582,654,1121,1141]" gridcol="1" gridrow="23" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955D377A88FB9A" box="[899,1177,1121,1141]" gridcol="2" gridrow="23" pageId="6" pageNumber="521">38</td>
<td id="76A88319A01400152FD55D377B9FFB9A" box="[1219,1422,1121,1141]" gridcol="3" gridrow="23" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985D287B9FFB7D" box="[142,1422,1150,1170]" gridrow="24" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985D287C3CFB7D" box="[142,557,1150,1170]" gridcol="0" gridrow="24" pageId="6" pageNumber="521">6th</th>
<td id="76A88319A014001529505D287C9FFB7D" box="[582,654,1150,1170]" gridcol="1" gridrow="24" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955D287A88FB7D" box="[899,1177,1150,1170]" gridcol="2" gridrow="24" pageId="6" pageNumber="521">40</td>
<td id="76A88319A01400152FD55D287B9FFB7D" box="[1219,1422,1150,1170]" gridcol="3" gridrow="24" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985DCA7B9FFB40" box="[142,1422,1180,1199]" gridrow="25" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985DCA7C3CFB40" box="[142,557,1180,1199]" gridcol="0" gridrow="25" pageId="6" pageNumber="521">7th</th>
<td id="76A88319A014001529505DCA7C9FFB40" box="[582,654,1180,1199]" gridcol="1" gridrow="25" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955DCA7A88FB40" box="[899,1177,1180,1199]" gridcol="2" gridrow="25" pageId="6" pageNumber="521">40</td>
<td id="76A88319A01400152FD55DCA7B9FFB40" box="[1219,1422,1180,1199]" gridcol="3" gridrow="25" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985DEF7B9FFB22" box="[142,1422,1209,1229]" gridrow="26" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985DEF7C3CFB22" box="[142,557,1209,1229]" gridcol="0" gridrow="26" pageId="6" pageNumber="521">8th</th>
<td id="76A88319A014001529505DEF7C9FFB22" box="[582,654,1209,1229]" gridcol="1" gridrow="26" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955DEF7A88FB22" box="[899,1177,1209,1229]" gridcol="2" gridrow="26" pageId="6" pageNumber="521">38</td>
<td id="76A88319A01400152FD55DEF7B9FFB22" box="[1219,1422,1209,1229]" gridcol="3" gridrow="26" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985C777B9FFADA" box="[142,1422,1313,1333]" gridrow="27" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985C777C3CFADA" box="[142,557,1313,1333]" gridcol="0" gridrow="27" pageId="6" pageNumber="521">Vertebrae – dorsal</th>
<td id="76A88319A014001529505C777C9FFADA" box="[582,654,1313,1333]" gridcol="1" gridrow="27" pageId="6" pageNumber="521">Height</td>
<td id="76A88319A014001528955C777A88FADA" box="[899,1177,1313,1333]" gridcol="2" gridrow="27" pageId="6" pageNumber="521">Length</td>
<td id="76A88319A01400152FD55C777B9FFADA" box="[1219,1422,1313,1333]" gridcol="3" gridrow="27" pageId="6" pageNumber="521">Height/length ratio</td>
</tr>
<tr id="3579EA65A01400152B985C0A7B9FFA80" box="[142,1422,1372,1391]" gridrow="28" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985C0A7C3CFA80" box="[142,557,1372,1391]" gridcol="0" gridrow="28" pageId="6" pageNumber="521">11th</th>
<td id="76A88319A014001529505C0A7C9FFA80" box="[582,654,1372,1391]" gridcol="1" gridrow="28" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955C0A7A88FA80" box="[899,1177,1372,1391]" gridcol="2" gridrow="28" pageId="6" pageNumber="521">38</td>
<td id="76A88319A01400152FD55C0A7B9FFA80" box="[1219,1422,1372,1391]" gridcol="3" gridrow="28" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985C2F7B9FFA62" box="[142,1422,1401,1421]" gridrow="29" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985C2F7C3CFA62" box="[142,557,1401,1421]" gridcol="0" gridrow="29" pageId="6" pageNumber="521">12th</th>
<td id="76A88319A014001529505C2F7C9FFA62" box="[582,654,1401,1421]" gridcol="1" gridrow="29" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955C2F7A88FA62" box="[899,1177,1401,1421]" gridcol="2" gridrow="29" pageId="6" pageNumber="521">36</td>
<td id="76A88319A01400152FD55C2F7B9FFA62" box="[1219,1422,1401,1421]" gridcol="3" gridrow="29" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985CC07B9FFA45" box="[142,1422,1430,1450]" gridrow="30" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985CC07C3CFA45" box="[142,557,1430,1450]" gridcol="0" gridrow="30" pageId="6" pageNumber="521">13th</th>
<td id="76A88319A014001529505CC07C9FFA45" box="[582,654,1430,1450]" gridcol="1" gridrow="30" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955CC07A88FA45" box="[899,1177,1430,1450]" gridcol="2" gridrow="30" pageId="6" pageNumber="521">?</td>
<td id="76A88319A01400152FD55CC07B9FFA45" box="[1219,1422,1430,1450]" gridcol="3" gridrow="30" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985CE27B9FFA28" box="[142,1422,1460,1479]" gridrow="31" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985CE27C3CFA28" box="[142,557,1460,1479]" gridcol="0" gridrow="31" pageId="6" pageNumber="521">14th</th>
<td id="76A88319A014001529505CE27C9FFA28" box="[582,654,1460,1479]" gridcol="1" gridrow="31" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955CE27A88FA28" box="[899,1177,1460,1479]" gridcol="2" gridrow="31" pageId="6" pageNumber="521">37</td>
<td id="76A88319A01400152FD55CE27B9FFA28" box="[1219,1422,1460,1479]" gridcol="3" gridrow="31" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985C877B9FFA0A" box="[142,1422,1489,1509]" gridrow="32" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985C877C3CFA0A" box="[142,557,1489,1509]" gridcol="0" gridrow="32" pageId="6" pageNumber="521">15th</th>
<td id="76A88319A014001529505C877C9FFA0A" box="[582,654,1489,1509]" gridcol="1" gridrow="32" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955C877A88FA0A" box="[899,1177,1489,1509]" gridcol="2" gridrow="32" pageId="6" pageNumber="521">39</td>
<td id="76A88319A01400152FD55C877B9FFA0A" box="[1219,1422,1489,1509]" gridcol="3" gridrow="32" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985CB87B9FF9ED" box="[142,1422,1518,1538]" gridrow="33" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985CB87C3CF9ED" box="[142,557,1518,1538]" gridcol="0" gridrow="33" pageId="6" pageNumber="521">16th</th>
<td id="76A88319A014001529505CB87C9FF9ED" box="[582,654,1518,1538]" gridcol="1" gridrow="33" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955CB87A88F9ED" box="[899,1177,1518,1538]" gridcol="2" gridrow="33" pageId="6" pageNumber="521">37</td>
<td id="76A88319A01400152FD55CB87B9FF9ED" box="[1219,1422,1518,1538]" gridcol="3" gridrow="33" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985F5A7B9FF9F0" box="[142,1422,1548,1567]" gridrow="34" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985F5A7C3CF9F0" box="[142,557,1548,1567]" gridcol="0" gridrow="34" pageId="6" pageNumber="521">17th</th>
<td id="76A88319A014001529505F5A7C9FF9F0" box="[582,654,1548,1567]" gridcol="1" gridrow="34" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955F5A7A88F9F0" box="[899,1177,1548,1567]" gridcol="2" gridrow="34" pageId="6" pageNumber="521">41</td>
<td id="76A88319A01400152FD55F5A7B9FF9F0" box="[1219,1422,1548,1567]" gridcol="3" gridrow="34" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985F7F7B9FF9D2" box="[142,1422,1577,1597]" gridrow="35" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985F7F7C3CF9D2" box="[142,557,1577,1597]" gridcol="0" gridrow="35" pageId="6" pageNumber="521">18th</th>
<td id="76A88319A014001529505F7F7C9FF9D2" box="[582,654,1577,1597]" gridcol="1" gridrow="35" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955F7F7A88F9D2" box="[899,1177,1577,1597]" gridcol="2" gridrow="35" pageId="6" pageNumber="521">42</td>
<td id="76A88319A01400152FD55F7F7B9FF9D2" box="[1219,1422,1577,1597]" gridcol="3" gridrow="35" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985F107B9FF9B5" box="[142,1422,1606,1626]" gridrow="36" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985F107C3CF9B5" box="[142,557,1606,1626]" gridcol="0" gridrow="36" pageId="6" pageNumber="521">19th</th>
<td id="76A88319A014001529505F107C9FF9B5" box="[582,654,1606,1626]" gridcol="1" gridrow="36" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955F107A88F9B5" box="[899,1177,1606,1626]" gridcol="2" gridrow="36" pageId="6" pageNumber="521">37</td>
<td id="76A88319A01400152FD55F107B9FF9B5" box="[1219,1422,1606,1626]" gridcol="3" gridrow="36" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985F327B9FF998" box="[142,1422,1636,1655]" gridrow="37" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985F327C3CF998" box="[142,557,1636,1655]" gridcol="0" gridrow="37" pageId="6" pageNumber="521">20th</th>
<td id="76A88319A014001529505F327C9FF998" box="[582,654,1636,1655]" gridcol="1" gridrow="37" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955F327A88F998" box="[899,1177,1636,1655]" gridcol="2" gridrow="37" pageId="6" pageNumber="521">38</td>
<td id="76A88319A01400152FD55F327B9FF998" box="[1219,1422,1636,1655]" gridcol="3" gridrow="37" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985FD77B9FF97A" box="[142,1422,1665,1685]" gridrow="38" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985FD77C3CF97A" box="[142,557,1665,1685]" gridcol="0" gridrow="38" pageId="6" pageNumber="521">21st</th>
<td id="76A88319A014001529505FD77C9FF97A" box="[582,654,1665,1685]" gridcol="1" gridrow="38" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955FD77A88F97A" box="[899,1177,1665,1685]" gridcol="2" gridrow="38" pageId="6" pageNumber="521">36</td>
<td id="76A88319A01400152FD55FD77B9FF97A" box="[1219,1422,1665,1685]" gridcol="3" gridrow="38" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985FC87B9FF95D" box="[142,1422,1694,1714]" gridrow="39" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985FC87C3CF95D" box="[142,557,1694,1714]" gridcol="0" gridrow="39" pageId="6" pageNumber="521">22nd</th>
<td id="76A88319A014001529505FC87C9FF95D" box="[582,654,1694,1714]" gridcol="1" gridrow="39" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955FC87A88F95D" box="[899,1177,1694,1714]" gridcol="2" gridrow="39" pageId="6" pageNumber="521">37</td>
<td id="76A88319A01400152FD55FC87B9FF95D" box="[1219,1422,1694,1714]" gridcol="3" gridrow="39" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985FEA7B9FF920" box="[142,1422,1724,1743]" gridrow="40" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985FEA7C3CF920" box="[142,557,1724,1743]" gridcol="0" gridrow="40" pageId="6" pageNumber="521">23rd</th>
<td id="76A88319A014001529505FEA7C9FF920" box="[582,654,1724,1743]" gridcol="1" gridrow="40" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955FEA7A88F920" box="[899,1177,1724,1743]" gridcol="2" gridrow="40" pageId="6" pageNumber="521">32</td>
<td id="76A88319A01400152FD55FEA7B9FF920" box="[1219,1422,1724,1743]" gridcol="3" gridrow="40" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985F8F7B9FF902" box="[142,1422,1753,1773]" gridrow="41" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985F8F7C3CF902" box="[142,557,1753,1773]" gridcol="0" gridrow="41" pageId="6" pageNumber="521">24th</th>
<td id="76A88319A014001529505F8F7C9FF902" box="[582,654,1753,1773]" gridcol="1" gridrow="41" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955F8F7A88F902" box="[899,1177,1753,1773]" gridcol="2" gridrow="41" pageId="6" pageNumber="521">37</td>
<td id="76A88319A01400152FD55F8F7B9FF902" box="[1219,1422,1753,1773]" gridcol="3" gridrow="41" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985FA07B9FF8E5" box="[142,1422,1782,1802]" gridrow="42" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985FA07C3CF8E5" box="[142,557,1782,1802]" gridcol="0" gridrow="42" pageId="6" pageNumber="521">25th</th>
<td id="76A88319A014001529505FA07C9FF8E5" box="[582,654,1782,1802]" gridcol="1" gridrow="42" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955FA07A88F8E5" box="[899,1177,1782,1802]" gridcol="2" gridrow="42" pageId="6" pageNumber="521">37</td>
<td id="76A88319A01400152FD55FA07B9FF8E5" box="[1219,1422,1782,1802]" gridcol="3" gridrow="42" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985E427B9FF8C8" box="[142,1422,1812,1831]" gridrow="43" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985E427C3CF8C8" box="[142,557,1812,1831]" gridcol="0" gridrow="43" pageId="6" pageNumber="521">26th</th>
<td id="76A88319A014001529505E427C9FF8C8" box="[582,654,1812,1831]" gridcol="1" gridrow="43" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955E427A88F8C8" box="[899,1177,1812,1831]" gridcol="2" gridrow="43" pageId="6" pageNumber="521">39</td>
<td id="76A88319A01400152FD55E427B9FF8C8" box="[1219,1422,1812,1831]" gridcol="3" gridrow="43" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985E677B9FF8AA" box="[142,1422,1841,1861]" gridrow="44" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985E677C3CF8AA" box="[142,557,1841,1861]" gridcol="0" gridrow="44" pageId="6" pageNumber="521">27th</th>
<td id="76A88319A014001529505E677C9FF8AA" box="[582,654,1841,1861]" gridcol="1" gridrow="44" pageId="6" pageNumber="521">?</td>
<td id="76A88319A014001528955E677A88F8AA" box="[899,1177,1841,1861]" gridcol="2" gridrow="44" pageId="6" pageNumber="521">35</td>
<td id="76A88319A01400152FD55E677B9FF8AA" box="[1219,1422,1841,1861]" gridcol="3" gridrow="44" pageId="6" pageNumber="521">–</td>
</tr>
<tr id="3579EA65A01400152B985E187B9FF88D" box="[142,1422,1870,1890]" gridrow="45" pageId="6" pageNumber="521">
<th id="76A88319A01400152B985E187C3CF88D" box="[142,557,1870,1890]" gridcol="0" gridrow="45" pageId="6" pageNumber="521">28th</th>
<td id="76A88319A014001529505E187C9FF88D" box="[582,654,1870,1890]" gridcol="1" gridrow="45" pageId="6" pageNumber="521">87</td>
<td id="76A88319A014001528955E187A88F88D" box="[899,1177,1870,1890]" gridcol="2" gridrow="45" pageId="6" pageNumber="521">37</td>
<td id="76A88319A01400152FD55E187B9FF88D" box="[1219,1422,1870,1890]" gridcol="3" gridrow="45" pageId="6" pageNumber="521">2.35</td>
</tr>
</table>
</paragraph>
<caption id="DF36B8AFA015FFED2BBF59927F6AFF38" box="[169,379,196,215]" isContinuationCaption="true" pageId="7" pageNumber="522" startId="7.[169,233,196,215]" targetBox="[169,915,256,627]" targetIsTable="true" targetPageId="7">
<paragraph id="8BF6E827A015FFED2BBF59927F6AFF38" blockId="7.[169,379,196,215]" box="[169,379,196,215]" pageId="7" pageNumber="522">
<emphasis id="B93D3435A015FFED2BBF59927F12FF38" bold="true" box="[169,259,196,215]" pageId="7" pageNumber="522">Table 1.</emphasis>
Continued
</paragraph>
</caption>
<paragraph id="8BF6E827A015FFED2BBF58567D82FD9C" pageId="7" pageNumber="522">
<table id="F9491A87A01500152BBF58567D82FD9C" box="[169,915,256,627]" gridcols="2" gridrows="12" pageId="7" pageNumber="522">
<tr id="3579EA65A01500152BBF58567D82FEFC" box="[169,915,256,275]" gridrow="0" pageId="7" pageNumber="522">
<th id="76A88319A01500152BBF58567D82FEFC" box="[169,915,256,275]" colspan="2" colspanRight="1" gridcol="0" gridrow="0" pageId="7" pageNumber="522">Appendicular skeleton</th>
</tr>
<tr id="3579EA65A01500152BBF586C7D82FEA1" box="[169,915,314,334]" gridrow="1" pageId="7" pageNumber="522">
<td id="76A88319A01500152BBF586C7C5FFEA1" box="[169,590,314,334]" gridcol="0" gridrow="1" pageId="7" pageNumber="522">Coracoid foramen – greatest length</td>
<td id="76A88319A015001529E8586C7D82FEA1" box="[766,915,314,334]" gridcol="1" gridrow="1" pageId="7" pageNumber="522">22 (left side)</td>
</tr>
<tr id="3579EA65A01500152BBF580E7D82FE84" box="[169,915,344,363]" gridrow="2" pageId="7" pageNumber="522">
<td id="76A88319A01500152BBF580E7D82FE84" box="[169,915,344,363]" colspan="2" colspanRight="1" gridcol="0" gridrow="2" pageId="7" pageNumber="522">23 (right side)</td>
</tr>
<tr id="3579EA65A01500152BBF58237D82FE66" box="[169,915,373,393]" gridrow="3" pageId="7" pageNumber="522">
<td id="76A88319A01500152BBF58237C5FFE66" box="[169,590,373,393]" gridcol="0" gridrow="3" pageId="7" pageNumber="522">Coracoid foramen – greatest height</td>
<td id="76A88319A015001529E858237D82FE66" box="[766,915,373,393]" gridcol="1" gridrow="3" pageId="7" pageNumber="522">9 (left side)</td>
</tr>
<tr id="3579EA65A01500152BBF58C47D82FE49" box="[169,915,402,422]" gridrow="4" pageId="7" pageNumber="522" rowspan-0="1">
<td id="76A88319A015001529E858C47D82FE49" box="[766,915,402,422]" gridcol="1" gridrow="4" pageId="7" pageNumber="522">11 (right side)</td>
</tr>
<tr id="3579EA65A01500152BBF58E67D82FE2C" box="[169,915,432,451]" gridrow="5" pageId="7" pageNumber="522">
<td id="76A88319A01500152BBF58E67C5FFE2C" box="[169,590,432,451]" gridcol="0" gridrow="5" pageId="7" pageNumber="522">Coracoid glenoid facet – greatest length</td>
<td id="76A88319A015001529E858E67D82FE2C" box="[766,915,432,451]" gridcol="1" gridrow="5" pageId="7" pageNumber="522">86 (left side)</td>
</tr>
<tr id="3579EA65A01500152BBF589B7D82FE0F" box="[169,915,461,480]" gridrow="6" pageId="7" pageNumber="522">
<td id="76A88319A01500152BBF589B7D82FE0F" box="[169,915,461,480]" colspan="2" colspanRight="1" gridcol="0" gridrow="6" pageId="7" pageNumber="522">82 (right side)</td>
</tr>
<tr id="3579EA65A01500152BBF58BC7D82FE11" box="[169,915,490,510]" gridrow="7" pageId="7" pageNumber="522">
<td id="76A88319A01500152BBF58BC7C5FFE11" box="[169,590,490,510]" gridcol="0" gridrow="7" pageId="7" pageNumber="522">Coracoid glenoid facet – greatest height</td>
<td id="76A88319A015001529E858BC7D82FE11" box="[766,915,490,510]" gridcol="1" gridrow="7" pageId="7" pageNumber="522">49 (right side)</td>
</tr>
<tr id="3579EA65A01500152BBF5B5E7D82FDF4" box="[169,915,520,539]" gridrow="8" pageId="7" pageNumber="522">
<td id="76A88319A01500152BBF5B5E7C5FFDF4" box="[169,590,520,539]" gridcol="0" gridrow="8" pageId="7" pageNumber="522">Coracoid – mediolateral width</td>
<td id="76A88319A015001529E85B5E7D82FDF4" box="[766,915,520,539]" gridcol="1" gridrow="8" pageId="7" pageNumber="522">150</td>
</tr>
<tr id="3579EA65A01500152BBF5B737D82FDD6" box="[169,915,549,569]" gridrow="9" pageId="7" pageNumber="522">
<td id="76A88319A01500152BBF5B737C5FFDD6" box="[169,590,549,569]" gridcol="0" gridrow="9" pageId="7" pageNumber="522">Coracoid – anteroposterior length</td>
<td id="76A88319A015001529E85B737D82FDD6" box="[766,915,549,569]" gridcol="1" gridrow="9" pageId="7" pageNumber="522">210</td>
</tr>
<tr id="3579EA65A01500152BBF5B147D82FDB9" box="[169,915,578,598]" gridrow="10" pageId="7" pageNumber="522">
<td id="76A88319A01500152BBF5B147C5FFDB9" box="[169,590,578,598]" gridcol="0" gridrow="10" pageId="7" pageNumber="522">Clavicle – greatest length</td>
<td id="76A88319A015001529E85B147D82FDB9" box="[766,915,578,598]" gridcol="1" gridrow="10" pageId="7" pageNumber="522">400</td>
</tr>
<tr id="3579EA65A01500152BBF5B367D82FD9C" box="[169,915,608,627]" gridrow="11" pageId="7" pageNumber="522">
<td id="76A88319A01500152BBF5B367C5FFD9C" box="[169,590,608,627]" gridcol="0" gridrow="11" pageId="7" pageNumber="522">Clavicle – greatest height of blade</td>
<td id="76A88319A015001529E85B367D82FD9C" box="[766,915,608,627]" gridcol="1" gridrow="11" pageId="7" pageNumber="522">90 (right side)</td>
</tr>
</table>
</paragraph>
<paragraph id="8BF6E827A015FFED2BB45A207FEEFB4F" blockId="7.[162,778,886,1460]" pageId="7" pageNumber="522">
<emphasis id="B93D3435A015FFED2BB45A207F03FC64" box="[162,274,886,907]" italics="true" pageId="7" pageNumber="522">Lacrimal:</emphasis>
The lacrimal is a thick bone, the posterior margin of which makes contact with the prefrontal in a long, clearly visible suture (
<figureCitation id="1372F4A2A015FFED2AE15AE57C2BFC26" box="[503,570,947,969]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="7" pageNumber="522">Fig. 4</figureCitation>
). The ventral process of the prefrontal excludes the lacrimal from the anterior and anterodorsal margin of the orbit, but the ventral part of the lacrimal takes part in the anteroventral border of the orbit. Parallel to the suture with the ventral process of the prefrontal lies the prominent antorbital crest of the lacrimal, which has a crescent-shaped outline.
</paragraph>
<paragraph id="8BF6E827A015FFED2BAD5DFE7FCCFA5B" blockId="7.[162,778,886,1460]" pageId="7" pageNumber="522">Anteriorly, the lacrimal has two triangular processes, of which the smaller, dorsal one makes contact with the nasal and the maxilla, while the ventral one contacts only the maxilla. The posteroventral part of the lacrimal contacts the anterior process of the jugal. Apart from the posterior continuation of the horizontal suture with the nasal, which is poorly visible owing to fracturing of the bone in this area, the sutures of the lacrimal are clearly visible.</paragraph>
<paragraph id="8BF6E827A015FFED2BB45C9A7C0CF89F" blockId="7.[162,778,1484,1904]" pageId="7" pageNumber="522">
<emphasis id="B93D3435A015FFED2BB45C9A7F81FA0E" box="[162,400,1484,1505]" italics="true" pageId="7" pageNumber="522">Pre- and postfrontal:</emphasis>
Owing to some large cracks and breakage in the area dorsal to the orbit, the suture between pre- and postfrontal, as well as their suture with the nasal, is largely obscured, and thus the bones are discussed together. The narrow pre- and postfrontal extend along the entire dorsal margin of the orbit (
<figureCitation id="1372F4A2A015FFED2BBC5FD27EFDF975" box="[170,236,1668,1690]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="7" pageNumber="522">Fig. 4</figureCitation>
). There is a slightly roughened supraorbital crest along the anteromedial portion of the dorsal margin of the orbit. Anteriorly, the prefrontal has a well-defined, crescent-shaped suture with the lacrimal. The anterolateral process of the prefrontal runs parallel to the antorbital crest of the lacrimal and reaches into the orbit, excluding the lacrimal from the anterodorsal margin of the orbit.
</paragraph>
<paragraph id="8BF6E827A015FFED28455B9B7DB4FCD0" blockId="7.[826,1442,717,984]" pageId="7" pageNumber="522">The posterior boundary of the postfrontal is clearly visible as a serrated suture overlapping the postorbital, slightly posterior to the posterodorsal border of the orbit.</paragraph>
<paragraph id="8BF6E827A015FFED28455A1E7B7AFC37" blockId="7.[826,1442,717,984]" pageId="7" pageNumber="522">
The medial contact of the postfrontal with the end of the posterior process of the nasal is visible as a low, but distinctive ridge between the two bones (
<figureCitation id="1372F4A2A015FFED2E445AD37B85FC74" box="[1362,1428,901,923]" captionStart="Figure 3" captionStartId="4.[142,220,1853,1872]" captionTargetBox="[302,1262,1174,1821]" captionTargetId="figure-389@4.[302,1262,1172,1821]" captionTargetPageId="4" captionText="Figure 3. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in dorsal view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634747" httpUri="https://zenodo.org/record/4634747/files/figure.png" pageId="7" pageNumber="522">Fig. 3</figureCitation>
). Further anterior, this suture is not traceable because of the poor preservation of the bone in this area.
</paragraph>
<paragraph id="8BF6E827A015FFE2282C5D567EF7FF18" blockId="7.[826,1442,1024,1904]" lastBlockId="8.[142,757,195,247]" lastPageId="8" lastPageNumber="523" pageId="7" pageNumber="522">
<emphasis id="B93D3435A015FFED282C5D567D95FBFA" box="[826,900,1024,1045]" italics="true" pageId="7" pageNumber="522">Nasal:</emphasis>
A large portion of the dorsal skull region is built up by the large nasals, which also take part in the posterior margin of the external nares (
<figureCitation id="1372F4A2A015FFED2E265D6B7B69FBBD" box="[1328,1400,1085,1107]" captionStart="Figure 3" captionStartId="4.[142,220,1853,1872]" captionTargetBox="[302,1262,1174,1821]" captionTargetId="figure-389@4.[302,1262,1172,1821]" captionTargetPageId="4" captionText="Figure 3. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in dorsal view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634747" httpUri="https://zenodo.org/record/4634747/files/figure.png" pageId="7" pageNumber="522">Figs 3</figureCitation>
,
<figureCitation id="1372F4A2A015FFED2E935D6B7B84FBBC" box="[1413,1429,1085,1107]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="7" pageNumber="522">4</figureCitation>
). The medial suture, where the broad, anterior parts of the two nasals contact each other along the midline of the proximal rostrum, is well fused and is visible as a slight ridge. Dorsally, a clearly visible interdigitating suture with the broad anteromedial part of the frontals runs from side to side. The suture is infilled with calcite and therefore stands out as a white line against the dark brown bone material. Posterolateral to this interdigitating suture, the nasals quickly narrow to long, slender posterior processes, which extend all the way to the temporal openings. The median suture of each process runs along the lateral edge of the temporal terrace into the temporal opening, while the lateral border of the process runs from the posterior edge of the external nares in a nearly straight suture along the dorsolateral side of the skull. On the right side of the skull, the lateral contact with the maxilla and the lacrimal is clearly visible, whereas the suture with the prefrontal and the anterior part of the suture with the postfrontal are not because of fracturing of the bone in this area (
<figureCitation id="1372F4A2A015FFED28A15F977DE8F938" box="[951,1017,1729,1751]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="7" pageNumber="522">Fig. 4</figureCitation>
). Posterolaterally, the nasal process ends in a short, straight suture with the postorbital. The posterior nasal process includes a sharp ridge that borders the temporal terrace laterally. Therefore, the posterior process of the nasal takes part in the anterolateral border of the temporal opening and accounts for the lateral portion of the temporal terrace.
</paragraph>
<paragraph id="8BF6E827A01AFFE22B9858437FE7FCBC" blockId="8.[142,758,277,851]" pageId="8" pageNumber="523">
<emphasis id="B93D3435A01AFFE22B9858437EC4FEC5" box="[142,213,277,298]" italics="true" pageId="8" pageNumber="523">Jugal:</emphasis>
The jugal is a long and slender bone, which makes up the entire ventral margin of the orbit. Anteriorly, it thins and loses contact with the margin of the orbit, wedging between the posteroventral parts of the lacrimal and the maxilla, and separating the maxilla from the border of the orbit. Posteriorly, the jugal widens slightly and shows a rounded posterior process that reaches back into the anteroventral part of the lateral embayment; this process may represent the remnants of a former lower temporal bar. The contact with the postorbital at the posterodorsal end of the jugal is clearly visible. However, this probably does not represent the exact surficial contact of these two skull bones because the overlapping postorbital possesses a slightly broken ventral margin on the right side of the skull. On the left side of the skull, the postorbital region is crushed, revealing that the jugal extends dorsally beneath the postorbital up to at least two-thirds of the height of the postorbital.
</paragraph>
<paragraph id="8BF6E827A01AFFE22B985A397F9FFA9F" blockId="8.[142,758,879,1760]" pageId="8" pageNumber="523">
<emphasis id="B93D3435A01AFFE22B985A397F01FC6B" box="[142,272,879,900]" italics="true" pageId="8" pageNumber="523">Postorbital:</emphasis>
The posterior border of the orbit is almost entirely formed by the postorbital, which has an approximately rectangular shape and extends in dorsoventral direction (
<figureCitation id="1372F4A2A01AFFE22A605A9D7FA9FC0D" box="[374,440,971,994]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="8" pageNumber="523">Fig. 4</figureCitation>
). Its posteroventral margin also forms the anterior border of the lateral embayment. As described above, the overlapping suture of the postorbital with the jugal is slightly damaged, but it runs approximately from the anteromedial margin of the lateral embayment anteriorly to the posteroventral margin of the orbit. Anterodorsally, the postorbital makes contact with the postfrontal, whereas the latter overlaps the postorbital with a distinctive, serrated suture, which lies slightly posterior to the dorsal margin of the orbit. The suture with the posterior process of the nasal is only weakly visible; it runs dorsally in a straight line towards the margin of the upper temporal fenestra (
<figureCitation id="1372F4A2A01AFFE22A295C0C7F90FA9F" box="[319,385,1370,1392]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="8" pageNumber="523">Fig. 4</figureCitation>
).
</paragraph>
<paragraph id="8BF6E827A01AFFE22BB15C2F7FC4F90F" blockId="8.[142,758,879,1760]" pageId="8" pageNumber="523">The posterior boundary of the postorbital lies in the continuation of the anterior margin of the lateral embayment and is clearly observable as the postorbital clearly overlaps the quadratojugal, squamosal and supratemporal. In the dorsal portion of the postorbital in particular, a fan-shaped arrangement of growth lines is visible, indicating a centre of ossification situated close to the suture with the postfrontal. The dorsal margin of the postorbital coincides with the sharp ridge that borders the upper temporal opening, and the bone therefore contributes to the lateral margin of the temporal opening.</paragraph>
<paragraph id="8BF6E827A01AFFE22B985FAB7B9FFD4A" blockId="8.[142,758,1789,1904]" lastBlockId="8.[806,1422,195,831]" pageId="8" pageNumber="523">
<emphasis id="B93D3435A01AFFE22B985FAB7EF8F8FD" box="[142,233,1789,1810]" italics="true" pageId="8" pageNumber="523">Frontal:</emphasis>
The medial portions of the frontals form a flat area in front of the parietal plateau, from which it is separated through a distinctive, interdigitating suture (
<figureCitation id="1372F4A2A01AFFE22BFE5E0F7F39F89F" box="[232,296,1881,1904]" captionStart="Figure 3" captionStartId="4.[142,220,1853,1872]" captionTargetBox="[302,1262,1174,1821]" captionTargetId="figure-389@4.[302,1262,1172,1821]" captionTargetPageId="4" captionText="Figure 3. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in dorsal view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634747" httpUri="https://zenodo.org/record/4634747/files/figure.png" pageId="8" pageNumber="523">Fig. 3</figureCitation>
). The latter runs from side to side along the anterior end of the parietal plateau and stretches from the edges on each side of this plateau over a short distance anteriorly, approaching the interdigitating suture between frontals and nasals, before it runs as a straight suture on each side of the parietal plateau posteriorly along the midline of the temporal terraces into the temporal openings. Anteriorly, the medial, flat portion of the frontals is bordered by the interdigitating suture with the nasals. The suture continues posteriorly in a straight line, laterally paralleling the fronto-parietal suture on each side of the parietal plateau. Therefore, the frontals form slender processes posterolaterally, which lie medially to the slender posterior processes of the nasals. The frontal processes run into the sediment-filled temporal openings and contribute to the medial area of the temporal terraces.
</paragraph>
<paragraph id="8BF6E827A01AFFE228295BF87A83FCD0" blockId="8.[806,1422,195,831]" pageId="8" pageNumber="523">
The extreme posterior extension of the frontal, as well as the nasal, and the participation of these two bones in the border of the upper temporal fenestra, is a synapomorphy of
<taxonomicName id="4C4993A4A01AFFE22F175A5C7AD0FCF0" authorityName="NICHOLLSI" authorityYear="2006" box="[1025,1217,778,799]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="8" pageNumber="523" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A01AFFE22F175A5C7AD0FCF0" box="[1025,1217,778,799]" italics="true" pageId="8" pageNumber="523">Cymbospondylus</emphasis>
</taxonomicName>
and is not observable in any other diapsid clade.
</paragraph>
<paragraph id="8BF6E827A01AFFE228305A017A66FB32" blockId="8.[806,1422,855,1674]" pageId="8" pageNumber="523">
<emphasis id="B93D3435A01AFFE228305A017D96FC83" box="[806,903,855,876]" italics="true" pageId="8" pageNumber="523">Parietal:</emphasis>
The parietals are prominent bones, which form the anterior part of the skull roof. They form a conspicuous elevation in the medial part of the skull, which slopes gently in rostral direction. This elevation forms a medially flattened parietal plateau that steepens laterally and forms the anteromedial walls of the temporal openings (
<figureCitation id="1372F4A2A01AFFE22F1A5D597A5CFBCA" box="[1036,1101,1039,1061]" captionStart="Figure 3" captionStartId="4.[142,220,1853,1872]" captionTargetBox="[302,1262,1174,1821]" captionTargetId="figure-389@4.[302,1262,1172,1821]" captionTargetPageId="4" captionText="Figure 3. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in dorsal view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634747" httpUri="https://zenodo.org/record/4634747/files/figure.png" pageId="8" pageNumber="523">Fig. 3</figureCitation>
). Along the anterior border of the elevation runs the distinctive interdigitating suture with the frontal that stretches forward over a short distance from the lateral edges of the plateau. From there, the suture runs backwards along the centre of the temporal terrace into the temporal opening, where it is particularly clear.
</paragraph>
<paragraph id="8BF6E827A01AFFE228295DB37D84F965" blockId="8.[806,1422,855,1674]" pageId="8" pageNumber="523">
The parietal plateau encloses the parietal foramen, which clearly lies within the parietals, about
<quantity id="4CB145C2A01AFFE22E555C527B9FFAF5" box="[1347,1422,1284,1306]" metricMagnitude="-2" metricUnit="m" metricValue="4.5" pageId="8" pageNumber="523" unit="cm" value="4.5">4.5 cm</quantity>
posterior to the fronto-parietal suture. It is very large with a circular outline and its opening is anterodorsally orientated. Posterior to the parietal foramen are two more foramina formed by incomplete closure of the medial parietal sutures. The anterior one is quite small and round, whereas the posterior one is larger with an oval shape. Between the parietal foramen proper and the posterior of the two additional foramina, the calcite-filled suture between the two parietal bones is clearly visible. Anterior and posterior to this area, the suture between the parietals is fused and not apparent.
</paragraph>
<paragraph id="8BF6E827A01AFFE328305FF47F4FFE02" blockId="8.[806,1422,1698,1904]" lastBlockId="9.[162,778,195,493]" lastPageId="9" lastPageNumber="524" pageId="8" pageNumber="523">
<emphasis id="B93D3435A01AFFE228305FF47A85F958" box="[806,1172,1698,1719]" italics="true" pageId="8" pageNumber="523">Postparietal?, neomorphic bone?</emphasis>
Posterior to the second additional foramen, the parietal plateau widens distinctively, and medially opens into a V-shaped embayment. A short distance anterior to this embayment, an anteriorly convex suture runs along the lateral sides of the parietal plateau down into the temporal openings, with the posterior bone overlapping the parietals (
<figureCitation id="1372F4A2A01BFFE32A9559957FD5FF36" box="[387,452,195,217]" captionStart="Figure 3" captionStartId="4.[142,220,1853,1872]" captionTargetBox="[302,1262,1174,1821]" captionTargetId="figure-389@4.[302,1262,1172,1821]" captionTargetPageId="4" captionText="Figure 3. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in dorsal view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634747" httpUri="https://zenodo.org/record/4634747/files/figure.png" pageId="9" pageNumber="524">Fig. 3</figureCitation>
). The edges of this overlapping bone are broken off, but the general course of the border can be observed on both sides of the skull. Therefore, an extensive part of the posterior skull roof is formed by an additional paired skull bone posterior to the parietals. In this region, the lateral walls of the plateau slope more gently towards the temporal openings. The additional bone may be the postparietal, but the affinity and configuration of this skull bone are discussed below.
</paragraph>
<paragraph id="8BF6E827A01BFFE32BB45B5F7F22FC22" blockId="9.[162,778,521,973]" pageId="9" pageNumber="524">
<emphasis id="B93D3435A01BFFE32BB45B5F7F44FDF1" box="[162,341,521,542]" italics="true" pageId="9" pageNumber="524">Supratemporal:</emphasis>
The long and slender bone paralleling the posterolateral margin of the upper temporal opening is the supratemporal. It posteriorly tapers to a free pointed end that extends a short distance beyond the back of the skull. This feature is not an artefact of preservation and can be observed on both sides of the skull. Anteriorly, the supratemporal is overlapped by the postorbital, but it can be seen to extend beneath the thin postorbital to the posterior end of the posterior process of the nasal, where it probably makes contact with the nasal. The ventral margin of the supratemporal overlaps the squamosal with a short, straight suture, whereas further posteriorly it overlaps the lateral portion of the possible postparietal.
</paragraph>
<paragraph id="8BF6E827A01BFFE32BB45ABC7C9FF96B" blockId="9.[162,778,1002,1668]" pageId="9" pageNumber="524">
<emphasis id="B93D3435A01BFFE32BB45ABC7F39FC10" box="[162,296,1002,1023]" italics="true" pageId="9" pageNumber="524">Squamosal:</emphasis>
A broad area of the cheek region is formed by the large squamosal (
<figureCitation id="1372F4A2A01BFFE329015D5F7C4BFBF0" box="[535,602,1033,1055]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="9" pageNumber="524">Fig. 4</figureCitation>
). It is excluded anteriorly from the border of the temporal opening by the supratemporal, which it contacts dorsally in a short, straight, clearly visible suture. Posteriorly, it is excluded from the upper temporal fenestra by the wedge-shaped anterior process of the possible postparietal/neomorphic bone. The anteromedial portion of the squamosal is overlapped by the postorbital in a straight, dorsoventrally extending suture, and the squamosal surrounds the dorsal and posterior part of the overlying quadratojugal. A small bony bridge of the squamosal posterior to the quadratojugal extends anteroventrally and contributes to a short stretch of the posterior margin of the lateral embayment. As a result, the squamosal contacts the quadrate posteriorly in a straight suture running in posterodorsal– anteroventral direction. Posteriorly, the squamosal tapers to a blunt point at the posterior margin of the skull (
<figureCitation id="1372F4A2A01BFFE32BFB5F677F3EF9A8" box="[237,303,1585,1607]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="9" pageNumber="524">Fig. 4</figureCitation>
). Growth lines are clearly visible on the surface of the squamosal and run with a fan-shaped outline from the posterior point anteriorly.
</paragraph>
<paragraph id="8BF6E827A01BFFE32BB45FF77CB4F880" blockId="9.[162,778,1697,1903]" pageId="9" pageNumber="524">
<emphasis id="B93D3435A01BFFE32BB45FF77F40F959" box="[162,337,1697,1718]" italics="true" pageId="9" pageNumber="524">Quadratojugal:</emphasis>
The outline of the quadratojugal is roughly rectangular with an anteroposterior extension (
<figureCitation id="1372F4A2A01BFFE32BBC5F897EFDF91A" box="[170,236,1759,1781]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="9" pageNumber="524">Fig. 4</figureCitation>
). The bone possesses a short suture with the postorbital anteriorly and clearly overlaps the squamosal with its dorsal and posterior boundary. The ventral part of the quadratojugal forms the major part of the dorsal margin of the lateral embayment.
</paragraph>
<paragraph id="8BF6E827A01BFFE3282C59957DD2FCD0" blockId="9.[826,1442,195,953]" pageId="9" pageNumber="524">
<emphasis id="B93D3435A01BFFE3282C59957DBCFF37" box="[826,941,195,216]" italics="true" pageId="9" pageNumber="524">Quadrate:</emphasis>
At the back of the skull together with the posterolateral part of the pterygoid, the quadrate forms a broad connection between the palate and the skull roof (
<figureCitation id="1372F4A2A01BFFE328A058497A1BFEDA" box="[950,1034,287,309]" captionStart="Figure 5" captionStartId="10.[142,220,1087,1106]" captionTargetBox="[142,1422,195,1051]" captionTargetId="figure-418@10.[142,1424,193,1054]" captionTargetPageId="10" captionText="Figure 5. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in occipital view (A). Scale bar = 10 cm. B shows the detail view of the fault plane through the back of the skull. Scale bar = 3 cm. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634751" httpUri="https://zenodo.org/record/4634751/files/figure.png" pageId="9" pageNumber="524">Fig. 5A</figureCitation>
). The bones at the back of the skull are somewhat crushed, but the suture between quadrate and pterygoid is determinable in many parts, and it runs obliquely from the dorsomedial margin of the broad area at the back of the skull obliquely to the ventrolateral edge of the latter. Therefore, the quadrate forms the dorsolateral part of the back of the skull, while the pterygoid contributes to its ventromedial portion. Within the quadrate lies the large, elongate quadrate foramen, the greatest extension of which is in dorsoventral direction. The dorsal, medial and ventral part of the quadrate foramen is surrounded by the quadrate, whereas its lateral margin is probably formed by a narrow, flattened, posterior portion of the squamosal; owing to poor preservation lateral to the quadrate foramen, the sutures between the quadrate and the squamosal are not clearly identifiable.
</paragraph>
<paragraph id="8BF6E827A01BFFE328455A1E7BB3FC56" blockId="9.[826,1442,195,953]" pageId="9" pageNumber="524">
In contrast to that of
<taxonomicName id="4C4993A4A01BFFE32F5D5A1E7AD7FCB2" box="[1099,1222,840,861]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="9" pageNumber="524" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A01BFFE32F5D5A1E7AD7FCB2" box="[1099,1222,840,861]" italics="true" pageId="9" pageNumber="524">C. petrinus</emphasis>
</taxonomicName>
, the quadratojugal does not take part in the margin of the quadrate foramen; the posterior end of this bone clearly lies at the lateral side of the skull above the lateral embayment.
</paragraph>
<paragraph id="8BF6E827A01BFFE3282C5A817DCEFAD1" blockId="9.[826,1442,983,1495]" pageId="9" pageNumber="524">
<emphasis id="B93D3435A01BFFE3282C5A817B25FC03" box="[826,1332,983,1004]" italics="true" pageId="9" pageNumber="524">Cross-sectional view of the back of the skull:</emphasis>
The posterior end of the temporal opening and dorsal portion of the back of the skull can be observed in cross-section in the fault plane at the back of the skull (
<figureCitation id="1372F4A2A01BFFE32E375D657B67FBA6" box="[1313,1398,1075,1097]" captionStart="Figure 5" captionStartId="10.[142,220,1087,1106]" captionTargetBox="[142,1422,195,1051]" captionTargetId="figure-418@10.[142,1424,193,1054]" captionTargetPageId="10" captionText="Figure 5. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in occipital view (A). Scale bar = 10 cm. B shows the detail view of the fault plane through the back of the skull. Scale bar = 3 cm. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634751" httpUri="https://zenodo.org/record/4634751/files/figure.png" pageId="9" pageNumber="524">Fig. 5B</figureCitation>
). In the right dorsolateral part of this cross-sectional view, the suture between the parietal and the additional posterior skull bone (possible postparietal/neomorphic bone) is visible, with the latter distinctly overlapping the parietal. The cross-section of the parietal stretches along the right medial side of the parietal plateau almost halfway down to the temporal opening, where it pinches out.
</paragraph>
<paragraph id="8BF6E827A01BFFE328455C117DFFFA38" blockId="9.[826,1442,983,1495]" pageId="9" pageNumber="524">Unfortunately, the preservation of the right ventrolateral side of the posterior skull cross-section is not sufficient to determine where the sutures between the skull bones forming the posterior skull roof and the quadratum are.</paragraph>
<paragraph id="8BF6E827A01BFFE3282C5CA37A4BF8EF" blockId="9.[826,1442,1525,1792]" pageId="9" pageNumber="524">
<emphasis id="B93D3435A01BFFE3282C5CA37D99F9E5" box="[826,904,1525,1546]" italics="true" pageId="9" pageNumber="524">Vomer:</emphasis>
At the rostral end of the palatal region of the preserved portion of the skull lie the posterior winglike processes of the vomers (
<figureCitation id="1372F4A2A01BFFE32F8F5F647ACBF9A7" box="[1177,1242,1586,1608]" captionStart="Figure 6" captionStartId="11.[162,240,894,913]" captionTargetBox="[322,1282,190,861]" captionTargetId="figure-114@11.[322,1283,189,861]" captionTargetPageId="11" captionText="Figure 6. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in ventral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634753" httpUri="https://zenodo.org/record/4634753/files/figure.png" pageId="9" pageNumber="524">Fig. 6</figureCitation>
). They possess a clearly visible suture with the palatines that stretches from the posterior edge of the wing-like processes of the vomers in a stepped manner anteriorly. The rostral continuation of the palatines as well as of the vomers is cut off by the fault plane that displaced the rostrum of the specimen.
</paragraph>
<paragraph id="8BF6E827A01BFFE0282C5E4D7CB4FAB9" blockId="9.[826,1442,1819,1902]" lastBlockId="10.[142,758,1222,1367]" lastPageId="10" lastPageNumber="525" pageId="9" pageNumber="524">
<emphasis id="B93D3435A01BFFE3282C5E4D7D8EF8DF" box="[826,927,1819,1840]" italics="true" pageId="9" pageNumber="524">Palatine:</emphasis>
The medial suture of the palatines with the pterygoids is in large part covered by the hyoid bones, but can in part be observed on the right side of the skull, in the region where the palatine expands medially. There, the suture runs anteromedially towards the posterior edge of the wing-like process of the right vomer. Posteriorly, the palatines contact the pterygoids in an indistinct, convex, rounded suture.
</paragraph>
<caption id="DF36B8AFA018FFE02B985D697FD3FB63" ID-DOI="http://doi.org/10.5281/zenodo.4634751" ID-Zenodo-Dep="4634751" httpUri="https://zenodo.org/record/4634751/files/figure.png" pageId="10" pageNumber="525" startId="10.[142,220,1087,1106]" targetBox="[142,1422,195,1051]" targetPageId="10">
<paragraph id="8BF6E827A018FFE02B985D697FD3FB63" blockId="10.[142,1422,1086,1164]" pageId="10" pageNumber="525">
<emphasis id="B93D3435A018FFE02B985D697EE7FBBD" bold="true" box="[142,246,1087,1106]" pageId="10" pageNumber="525">Figure 5.</emphasis>
Drawing of the skull of
<emphasis id="B93D3435A018FFE0291D5D687DB2FBBD" bold="true" box="[523,931,1086,1106]" pageId="10" pageNumber="525">
<taxonomicName id="4C4993A4A018FFE0291D5D687D2CFBBE" authority="Fröbisch &amp; Sander &amp; Rieppel, 2006" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[523,829,1086,1105]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="10" pageNumber="525" phylum="Chordata" rank="species" species="nichollsi" status="sp. nov.">
<emphasis id="B93D3435A018FFE0291D5D687D2CFBBE" bold="true" box="[523,829,1086,1105]" italics="true" pageId="10" pageNumber="525">Cymbospondylus nichollsi</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A20E894EA018FFE0285E5D697DB2FBBD" box="[840,931,1087,1106]" pageId="10" pageNumber="525" rank="species">sp. nov.</taxonomicNameLabel>
</emphasis>
(FMNH PR2251) in occipital view (A). Scale bar = 10 cm. B shows the detail view of the fault plane through the back of the skull. Scale bar = 3 cm. See Appendix for explanation of abbreviations.
</paragraph>
</caption>
<paragraph id="8BF6E827A018FFE02B985C397CE4F8DD" blockId="10.[142,758,1391,1903]" pageId="10" pageNumber="525">
<emphasis id="B93D3435A018FFE02B985C397F10FA6B" box="[142,257,1391,1412]" italics="true" pageId="10" pageNumber="525">Pterygoid:</emphasis>
At their anterior border, the pterygoids make contact with the posterior wing-like portions of the vomers and rapidly narrow into a pointed rostral end that wedges between the two vomers (
<figureCitation id="1372F4A2A018FFE029625C9D7CA6FA0E" box="[628,695,1483,1505]" captionStart="Figure 6" captionStartId="11.[162,240,894,913]" captionTargetBox="[322,1282,190,861]" captionTargetId="figure-114@11.[322,1283,189,861]" captionTargetPageId="11" captionText="Figure 6. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in ventral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634753" httpUri="https://zenodo.org/record/4634753/files/figure.png" pageId="10" pageNumber="525">Fig. 6</figureCitation>
). The interpterygoid vacuity, which is prominent in the posterior region of the palate, closes at this pointed end. Further posteriorly, the lateral margins of the pterygoids expand laterally in a smooth curve and make contact with the palatines, which form the lateral portions of the palate in this region. Behind the posterior end of the palatines, the pterygoids widen even more laterally to flat, smooth bone plates. Over a short distance, they cover the full width of the palate, apart from the distinctive interpterygoid vacuity that separates the two pterygoids nearly over their full length.
</paragraph>
<paragraph id="8BF6E827A018FFE02BB15E6D7AADFB14" blockId="10.[142,758,1391,1903]" lastBlockId="10.[806,1422,1222,1397]" pageId="10" pageNumber="525">
The pterygoids possess prominent posteromedial processes. These are slightly curled medially, forming channel-like bone flanges, and extend posteriorly beyond the basioccipital (
<figureCitation id="1372F4A2A018FFE02F5C5DB37A83FB14" box="[1098,1170,1253,1275]" captionStart="Figure 5" captionStartId="10.[142,220,1087,1106]" captionTargetBox="[142,1422,195,1051]" captionTargetId="figure-418@10.[142,1424,193,1054]" captionTargetPageId="10" captionText="Figure 5. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in occipital view (A). Scale bar = 10 cm. B shows the detail view of the fault plane through the back of the skull. Scale bar = 3 cm. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634751" httpUri="https://zenodo.org/record/4634751/files/figure.png" pageId="10" pageNumber="525">Figs 5</figureCitation>
,
<figureCitation id="1372F4A2A018FFE02F895DB37ABEFB14" box="[1183,1199,1253,1275]" captionStart="Figure 6" captionStartId="11.[162,240,894,913]" captionTargetBox="[322,1282,190,861]" captionTargetId="figure-114@11.[322,1283,189,861]" captionTargetPageId="11" captionText="Figure 6. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in ventral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634753" httpUri="https://zenodo.org/record/4634753/files/figure.png" pageId="10" pageNumber="525">6</figureCitation>
).
</paragraph>
<paragraph id="8BF6E827A018FFE028295C527A5FFA9A" blockId="10.[806,1422,1222,1397]" pageId="10" pageNumber="525">
In the occipital region of the skull, the pterygoids have flat, wing-like extensions, which contribute to the ventromedial area of the back of the skull and contact the quadrate (
<figureCitation id="1372F4A2A018FFE028E95C097A51FA9A" box="[1023,1088,1375,1397]" captionStart="Figure 5" captionStartId="10.[142,220,1087,1106]" captionTargetBox="[142,1422,195,1051]" captionTargetId="figure-418@10.[142,1424,193,1054]" captionTargetPageId="10" captionText="Figure 5. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in occipital view (A). Scale bar = 10 cm. B shows the detail view of the fault plane through the back of the skull. Scale bar = 3 cm. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634751" httpUri="https://zenodo.org/record/4634751/files/figure.png" pageId="10" pageNumber="525">Fig. 5</figureCitation>
).
</paragraph>
<paragraph id="8BF6E827A018FFE028305CF37DBDF95E" blockId="10.[806,1422,1445,1713]" pageId="10" pageNumber="525">
<emphasis id="B93D3435A018FFE028305CF37DD7FA55" box="[806,966,1445,1466]" italics="true" pageId="10" pageNumber="525">Basisphenoid:</emphasis>
A small portion of the basisphenoid is exposed in the V-shaped part of the interpterygoid vacuity between the two posterior processes of the pterygoids. The basisphenoid is approximately heartshaped with a pointed anterior end. The rounded posterior ends have roughened surfaces and make contact with the basioccipital. The preservation and the limits of preparation do not allow a more detailed description.
</paragraph>
<paragraph id="8BF6E827A018FFE128305F897DA0F880" blockId="10.[806,1421,1759,1904]" lastBlockId="11.[826,1442,1790,1904]" lastPageId="11" lastPageNumber="526" pageId="10" pageNumber="525">
<emphasis id="B93D3435A018FFE028305F897DAEF91B" box="[806,959,1759,1780]" italics="true" pageId="10" pageNumber="525">Basioccipital:</emphasis>
The basioccipital is observable from its ventral and its left lateral side in the interpterygoid vacuity between the two posterior processes of the pterygoids, and it is still in full articulation with the atlas (
<figureCitation id="1372F4A2A018FFE028645E0C7DA2F89F" box="[882,947,1882,1904]" captionStart="Figure 7" captionStartId="11.[162,240,1685,1704]" captionTargetBox="[323,1282,1002,1650]" captionTargetId="figure-145@11.[322,1282,1002,1652]" captionTargetPageId="11" captionText="Figure 7. Close-up view of the occipital–cervical complex of specimen FMNH PR2251 in posteroventral view. Vertebrae are observed in ventrolateral view. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634755" httpUri="https://zenodo.org/record/4634755/files/figure.png" pageId="10" pageNumber="525">Fig. 7</figureCitation>
). The massive body of the basioccipital has a circular cross-section. At its anterior margin are two ventrolaterally positioned, roughened and slightly elevated articular facets for the articulation with the roughened posterior ends of the basisphenoid. Posteriorly, the basioccipital forms a sharp margin from which its posterior surface slopes obliquely towards the anterior articulation surface of the atlas (
<figureCitation id="1372F4A2A019FFE128545E0C7D98F89F" box="[834,905,1882,1904]" captionStart="Figure 5" captionStartId="10.[142,220,1087,1106]" captionTargetBox="[142,1422,195,1051]" captionTargetId="figure-418@10.[142,1424,193,1054]" captionTargetPageId="10" captionText="Figure 5. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in occipital view (A). Scale bar = 10 cm. B shows the detail view of the fault plane through the back of the skull. Scale bar = 3 cm. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634751" httpUri="https://zenodo.org/record/4634751/files/figure.png" pageId="11" pageNumber="526">Figs 5</figureCitation>
,
<figureCitation id="1372F4A2A019FFE128835E0C7DB4F880" box="[917,933,1882,1903]" captionStart="Figure 7" captionStartId="11.[162,240,1685,1704]" captionTargetBox="[323,1282,1002,1650]" captionTargetId="figure-145@11.[322,1282,1002,1652]" captionTargetPageId="11" captionText="Figure 7. Close-up view of the occipital–cervical complex of specimen FMNH PR2251 in posteroventral view. Vertebrae are observed in ventrolateral view. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634755" httpUri="https://zenodo.org/record/4634755/files/figure.png" pageId="11" pageNumber="526">7</figureCitation>
).
</paragraph>
<caption id="DF36B8AFA019FFE12BB45A287C8DFC40" ID-DOI="http://doi.org/10.5281/zenodo.4634753" ID-Zenodo-Dep="4634753" httpUri="https://zenodo.org/record/4634753/files/figure.png" pageId="11" pageNumber="526" startId="11.[162,240,894,913]" targetBox="[322,1282,190,861]" targetPageId="11">
<paragraph id="8BF6E827A019FFE12BB45A287C8DFC40" blockId="11.[162,1442,894,943]" pageId="11" pageNumber="526">
<emphasis id="B93D3435A019FFE12BB45A287F1BFC7E" bold="true" box="[162,266,894,913]" pageId="11" pageNumber="526">Figure 6.</emphasis>
Drawing of the skull of
<emphasis id="B93D3435A019FFE1291E5A287D80FC7E" bold="true" box="[520,913,894,913]" pageId="11" pageNumber="526">
<taxonomicName id="4C4993A4A019FFE1291E5A287D24FC7E" authority="Fröbisch &amp; Sander &amp; Rieppel, 2006" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[520,821,894,913]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="11" pageNumber="526" phylum="Chordata" rank="species" species="nichollsi" status="sp. nov.">
<emphasis id="B93D3435A019FFE1291E5A287D24FC7E" bold="true" box="[520,821,894,913]" italics="true" pageId="11" pageNumber="526">Cymbospondylus nichollsi</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A20E894EA019FFE1282A5A287D80FC7E" box="[828,913,894,913]" pageId="11" pageNumber="526" rank="species">sp. nov.</taxonomicNameLabel>
</emphasis>
(FMNH PR2251) in ventral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm.
</paragraph>
</caption>
<caption id="DF36B8AFA019FFE12BB45FC37DCEF92A" ID-DOI="http://doi.org/10.5281/zenodo.4634755" ID-Zenodo-Dep="4634755" httpUri="https://zenodo.org/record/4634755/files/figure.png" pageId="11" pageNumber="526" startId="11.[162,240,1685,1704]" targetBox="[323,1282,1002,1650]" targetPageId="11">
<paragraph id="8BF6E827A019FFE12BB45FC37DCEF92A" blockId="11.[162,1442,1685,1733]" pageId="11" pageNumber="526">
<emphasis id="B93D3435A019FFE12BB45FC37F1BF947" bold="true" box="[162,266,1685,1704]" pageId="11" pageNumber="526">Figure 7.</emphasis>
Close-up view of the occipital–cervical complex of specimen FMNH PR2251 in posteroventral view. Vertebrae are observed in ventrolateral view. See Appendix for explanation of abbreviations.
</paragraph>
</caption>
<paragraph id="8BF6E827A01EFFE62BB159927F07FEF9" blockId="12.[142,758,195,463]" pageId="12" pageNumber="527">
In the middle of the ventral surface of the basioccipital, the round external carotid foramen is clearly visible (
<figureCitation id="1372F4A2A01EFFE62BDE58577F1BFEF9" box="[200,266,257,279]" captionStart="Figure 7" captionStartId="11.[162,240,1685,1704]" captionTargetBox="[323,1282,1002,1650]" captionTargetId="figure-145@11.[322,1282,1002,1652]" captionTargetPageId="11" captionText="Figure 7. Close-up view of the occipital–cervical complex of specimen FMNH PR2251 in posteroventral view. Vertebrae are observed in ventrolateral view. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634755" httpUri="https://zenodo.org/record/4634755/files/figure.png" pageId="12" pageNumber="527">Fig. 7</figureCitation>
).
</paragraph>
<paragraph id="8BF6E827A01EFFE62BB158497EF9FE20" blockId="12.[142,758,195,463]" pageId="12" pageNumber="527">On the left lateral side, the articulation of basioccipital and atlas is clearly visible. Owing to tight articulation, the actual posterior articulation facet of the basioccipital is not visible. It nevertheless is clear that the basioccipital must have a concave articulation surface.</paragraph>
</subSection>
<subSection id="E2C6F1CCA01EFFE62A685B437A14FB00" pageId="12" pageNumber="527" type="multiple">
<paragraph id="8BF6E827A01EFFE62A685B437C17FDC3" blockId="12.[382,518,533,557]" box="[382,518,533,557]" pageId="12" pageNumber="527">
<heading id="D0BE5F4BA01EFFE62A685B437C17FDC3" box="[382,518,533,557]" centered="true" fontSize="9" level="2" pageId="12" pageNumber="527" reason="5">LOWER JAW</heading>
</paragraph>
<paragraph id="8BF6E827A01EFFE62B985B687F09FCA6" blockId="12.[142,758,574,841]" pageId="12" pageNumber="527">
The lower jaw of specimen PR2251 is nicely preserved on the right side of the skull (
<figureCitation id="1372F4A2A01EFFE62AEE5B0B7C2BFD9C" box="[504,570,605,627]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="12" pageNumber="527">Fig. 4</figureCitation>
), but somewhat crushed and broken on the left side. The lower jaws are still in articulation with the skull and, like the latter, have been cut off by the fault plane at their anterior end so that the rostral portion is missing. The ventral border of the preserved lower jaw forms a distinctive arch and extends posteriorly beyond the back of the skull.
</paragraph>
<paragraph id="8BF6E827A01EFFE62B985A347EEBFB82" blockId="12.[142,758,865,1133]" pageId="12" pageNumber="527">
<emphasis id="B93D3435A01EFFE62B985A347EE1FC98" box="[142,240,866,887]" italics="true" pageId="12" pageNumber="527">Dentary:</emphasis>
The lateral face of the lower jaw is built up by the dentary, the surangular and the angular. Only the posterior portion of the dentary is preserved and overlaps the surangular with a clearly visible suture. The posterior margin of the dentary extends back to almost the middle of the orbit and has the form of a swallowtail with two distinct, pointed ends. Its ventral suture is straight and runs in anteroposterior direction.
</paragraph>
<paragraph id="8BF6E827A01EFFE62B985DD17F50FAD8" blockId="12.[142,758,1159,1641]" pageId="12" pageNumber="527">
<emphasis id="B93D3435A01EFFE62B985DD17F0BFB73" box="[142,282,1159,1180]" italics="true" pageId="12" pageNumber="527">Surangular:</emphasis>
The surangular accounts for the largest part of the lateral side of the lower jaw. Ventrally, it contacts the angular in a clearly visible suture that stretches further dorsally in the posterior portion of the lower jaw and slopes smoothly ventrally towards the rostral end.
</paragraph>
<paragraph id="8BF6E827A01EFFE62BB15C697FC2F986" blockId="12.[142,758,1159,1641]" pageId="12" pageNumber="527">
The surangular reaches into the ventral part of the lateral embayment with a horizontally flattened, shelf-like area (
<figureCitation id="1372F4A2A01EFFE62A575C2B7F95FA7C" box="[321,388,1405,1427]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="12" pageNumber="527">Fig. 4</figureCitation>
). At the posterior end of the lateral embayment it contacts the articular. The suture between these two bones forms a small crest that runs slightly obliquely in anterodorsal–posteroventral direction along the posterodorsal part of the jaw ramus. The surangular thins towards the retroarticular process of the lower jaw and contributes to just a narrow portion of the latter.
</paragraph>
<paragraph id="8BF6E827A01EFFE62B985FD27ED2F8DC" blockId="12.[142,758,1668,1905]" pageId="12" pageNumber="527">
<emphasis id="B93D3435A01EFFE62B985FD27EE3F976" box="[142,242,1668,1689]" italics="true" pageId="12" pageNumber="527">Angular:</emphasis>
The angular forms the ventral portion of the lateral side of the lower jaw and contacts the surangular in the long, sinuous suture described above. The angular wraps around the ventral part of the lower jaw and therefore also contributes to its ventromedial side.
</paragraph>
<paragraph id="8BF6E827A01EFFE62BB15E6A7A37FEDA" blockId="12.[142,758,1668,1905]" lastBlockId="12.[806,1422,195,309]" pageId="12" pageNumber="527">
Along the anteromedial half of the preserved lower jaw the angular contacts the splenial (
<figureCitation id="1372F4A2A01EFFE629585E0D7C81F89E" box="[590,656,1883,1905]" captionStart="Figure 6" captionStartId="11.[162,240,894,913]" captionTargetBox="[322,1282,190,861]" captionTargetId="figure-114@11.[322,1283,189,861]" captionTargetPageId="11" captionText="Figure 6. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in ventral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634753" httpUri="https://zenodo.org/record/4634753/files/figure.png" pageId="12" pageNumber="527">Fig. 6</figureCitation>
). On the posteromedial face of the jaw ramus, the straight suture between the angular and the prearticular is visible, shifting to a more ventral position towards the retroarticular process.
</paragraph>
<paragraph id="8BF6E827A01EFFE6283058057D6CFD73" blockId="12.[806,1423,339,668]" pageId="12" pageNumber="527">
<emphasis id="B93D3435A01EFFE6283058057D84FE87" box="[806,917,339,360]" italics="true" pageId="12" pageNumber="527">Articular:</emphasis>
The massive articular contributes to a large part of the retroarticular process at the posterodorsal and the posteromedial portion of the lower jaw. At the medial side of the retroarticular process, it forms a broad channel with steepened lateral walls, the anterior one of which has a clearly visible contact with the ventral portion of the quadrate (
<figureCitation id="1372F4A2A01EFFE62E125B5D7B57FDCE" box="[1284,1350,523,545]" captionStart="Figure 5" captionStartId="10.[142,220,1087,1106]" captionTargetBox="[142,1422,195,1051]" captionTargetId="figure-418@10.[142,1424,193,1054]" captionTargetPageId="10" captionText="Figure 5. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in occipital view (A). Scale bar = 10 cm. B shows the detail view of the fault plane through the back of the skull. Scale bar = 3 cm. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634751" httpUri="https://zenodo.org/record/4634751/files/figure.png" pageId="12" pageNumber="527">Fig. 5</figureCitation>
). Ventromedially, the articular shares a clear suture with the prearticular. The glenoid of the articular receives the bulbous anterolateral condyle of the quadrate (
<figureCitation id="1372F4A2A01EFFE628385BD37D61FD73" box="[814,880,645,668]" captionStart="Figure 4" captionStartId="5.[162,240,871,890]" captionTargetBox="[322,1282,194,838]" captionTargetId="figure-578@5.[322,1283,194,838]" captionTargetPageId="5" captionText="Figure 4. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in lateral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634749" httpUri="https://zenodo.org/record/4634749/files/figure.png" pageId="12" pageNumber="527">Fig. 4</figureCitation>
).
</paragraph>
<paragraph id="8BF6E827A01EFFE628305BEF7B26FC68" blockId="12.[806,1422,697,903]" pageId="12" pageNumber="527">
<emphasis id="B93D3435A01EFFE628305BEF7D9DFD21" box="[806,908,697,718]" italics="true" pageId="12" pageNumber="527">Splenial:</emphasis>
The splenial is a smooth, flat bone forming the anteromedial wall of the jaw ramus (
<figureCitation id="1372F4A2A01EFFE62E1D5B817B5DFD02" box="[1291,1356,727,749]" captionStart="Figure 6" captionStartId="11.[162,240,894,913]" captionTargetBox="[322,1282,190,861]" captionTargetId="figure-114@11.[322,1283,189,861]" captionTargetPageId="11" captionText="Figure 6. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in ventral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634753" httpUri="https://zenodo.org/record/4634753/files/figure.png" pageId="12" pageNumber="527">Fig. 6</figureCitation>
). The ventral and posterior edges seem to be slightly broken off, but it is unlikely that the splenial reached much further ventrally and posteriorly than preserved. It possesses the two-pronged posterior end that can be observed in many ichthyosaur groups (
<figureCitation id="1372F4A2A01EFFE62FF15A277B3BFC68" box="[1255,1322,881,903]" captionStart="Figure 6" captionStartId="11.[162,240,894,913]" captionTargetBox="[322,1282,190,861]" captionTargetId="figure-114@11.[322,1283,189,861]" captionTargetPageId="11" captionText="Figure 6. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in ventral view. See Appendix for explanation of abbreviations. Scale bar = 10 cm." figureDoi="http://doi.org/10.5281/zenodo.4634753" httpUri="https://zenodo.org/record/4634753/files/figure.png" pageId="12" pageNumber="527">Fig. 6</figureCitation>
).
</paragraph>
<paragraph id="8BF6E827A01EFFE628305AF17A14FB00" blockId="12.[806,1422,935,1263]" pageId="12" pageNumber="527">
<emphasis id="B93D3435A01EFFE628305AF17DA9FC53" box="[806,952,935,956]" italics="true" pageId="12" pageNumber="527">Prearticular:</emphasis>
Posterior to the broken edge of the splenial, the prearticular comes into view, forming the dorsomedial wall of the lower jaw (
<figureCitation id="1372F4A2A01EFFE62FB55AB27AF5FC15" box="[1187,1252,996,1018]" captionStart="Figure 5" captionStartId="10.[142,220,1087,1106]" captionTargetBox="[142,1422,195,1051]" captionTargetId="figure-418@10.[142,1424,193,1054]" captionTargetPageId="10" captionText="Figure 5. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in occipital view (A). Scale bar = 10 cm. B shows the detail view of the fault plane through the back of the skull. Scale bar = 3 cm. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634751" httpUri="https://zenodo.org/record/4634751/files/figure.png" pageId="12" pageNumber="527">Fig. 5</figureCitation>
). The anterior end of the prearticular is pointed. It widens slightly posteriorly before narrowing again in the region of the strongest ventral curvature of the lower jaw. Towards the retroarticular process, the bone significantly widens again and contacts the articular in a clearly visible suture, which lies perpendicular to the long axis of the ramus. The prearticular does not take part in the retroarticular process.
</paragraph>
</subSection>
<subSection id="E2C6F1CCA01EFFE628E65C6F7B50F9A1" pageId="12" pageNumber="527" type="multiple">
<paragraph id="8BF6E827A01EFFE628E65C6F7AD5FAA0" blockId="12.[1008,1220,1337,1361]" box="[1008,1220,1337,1361]" pageId="12" pageNumber="527">
<heading id="D0BE5F4BA01EFFE628E65C6F7AD5FAA0" box="[1008,1220,1337,1361]" centered="true" fontSize="9" level="2" pageId="12" pageNumber="527" reason="5">HYOID APPARATUS</heading>
</paragraph>
<paragraph id="8BF6E827A01EFFE628305C347B50F9A1" blockId="12.[806,1422,1377,1614]" pageId="12" pageNumber="527">
Two hyoid bones with a round to oval cross-section are preserved nearly
<emphasis id="B93D3435A01EFFE628F85CD77A29FA79" box="[1006,1080,1409,1430]" italics="true" pageId="12" pageNumber="527">in situ</emphasis>
lying on the palate. Although the anterior and posterior ends are broken off it is still visible that the bones thin towards their posterior end. In addition, the right hyoid bone seems to possess a slight undulation in its course, but it is not clear whether this is a natural feature of the bone or has resulted from deformation during fossilization.
</paragraph>
</subSection>
<subSection id="E2C6F1CCA01EFFFA28D85FCF7F27FAA7" lastPageId="16" lastPageNumber="531" pageId="12" pageNumber="527" type="multiple">
<paragraph id="8BF6E827A01EFFE628D85FCF7AF7F940" blockId="12.[974,1254,1689,1713]" box="[974,1254,1689,1713]" pageId="12" pageNumber="527">
<heading id="D0BE5F4BA01EFFE628D85FCF7AF7F940" box="[974,1254,1689,1713]" centered="true" fontSize="9" level="2" pageId="12" pageNumber="527" reason="5">POSTCRANIAL SKELETON</heading>
</paragraph>
<paragraph id="8BF6E827A01EFFE728305F977F22FF17" blockId="12.[806,1422,1729,1905]" lastBlockId="13.[162,779,195,831]" lastPageId="13" lastPageNumber="528" pageId="12" pageNumber="527">The postcranial axial skeleton is preserved to the middle dorsal region and consists of a continuous string of 28 vertebrae in articulation. Furthermore, atlas and axis each possess an intercentrum, and a number of ribs are present. The postcranial skeleton is preserved in two blocks that are separated from the skull and each other through fault planes, but can be tightly fitted together.</paragraph>
<paragraph id="8BF6E827A01FFFE72BAD58577F4AFD87" blockId="13.[162,779,195,831]" pageId="13" pageNumber="528">The oblique fault plane that runs through the back of the skull separated the major part of the cranium, together with the atlas, axis and third cervical, from the first postcranial block. The latter contains vertebrae 4–13 with neural arches and associated ribs, whereas the fault plane that separated the two postcranial blocks runs right through the 13th vertebra, separating the anterior half of the centrum and neural spine from its posterior half. Vertebrae 13–28 can be observed in the second postcranial block and are also associated with neural arches and ribs.</paragraph>
<paragraph id="8BF6E827A01FFFE72BAD5B277F9CFCD0" blockId="13.[162,779,195,831]" pageId="13" pageNumber="528">
A distinctive torsion within the vertebral column leads to tilted neural spines between the fourth and the 17th vertebrae, which in this region can be seen from their right lateral side and cover the dorsal portion of their respective centra (
<figureCitation id="1372F4A2A01FFFE7291D5BBD7C91FCEE" box="[523,640,747,769]" captionStart="Figure 1" captionStartId="3.[162,240,1822,1841]" captionTargetBox="[179,1424,190,1790]" captionTargetId="figure-80@3.[179,1427,190,1790]" captionTargetPageId="3" captionText="Figure 1. Holotype of Cymbospondylus nichollsi sp. nov., specimen FMNH PR2251 in lateral (A), dorsal (B) and ventral (C) view. C shows the upper surface of the specimen as found in the field. Note the sharp bend in the cervical vertebral column. Scale bar = 20 cm." figureDoi="http://doi.org/10.5281/zenodo.4634743" httpUri="https://zenodo.org/record/4634743/files/figure.png" pageId="13" pageNumber="528">Fig. 1A, B</figureCitation>
). Therefore, the direct articulation of the centra with the neural spines is not visible.
</paragraph>
<paragraph id="8BF6E827A01FFFE72BB45A307F8AFA89" blockId="13.[162,778,870,1904]" pageId="13" pageNumber="528">
<emphasis id="B93D3435A01FFFE72BB45A307F7CFC94" box="[162,365,870,891]" italics="true" pageId="13" pageNumber="528">Vertebral column:</emphasis>
<bibRefCitation id="EFD895D6A01FFFE72A925A307C5AFC93" author="Merriam JC" box="[388,587,870,892]" pageId="13" pageNumber="528" pagination="1 - 155" refId="ref16501" refString="Merriam JC. 1908. Triassic Ichthyosauria, with special reference to the American forms. Memoirs of the University of California 1: 1 - 155." type="journal article" year="1908">Merriam (1908)</bibRefCitation>
established a count of 11 cervical vertebrae for
<taxonomicName id="4C4993A4A01FFFE729085AD37C8BFC75" box="[542,666,901,922]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="13" pageNumber="528" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A01FFFE729085AD37C8BFC75" box="[542,666,901,922]" italics="true" pageId="13" pageNumber="528">C. petrinus</emphasis>
</taxonomicName>
, cervicals comprising all vertebrae anterior to the scapula and coracoid. This approach would suggest a count of eight cervical vertebrae in specimen FMNH PR2251. However, because the shoulder girdle may have shifted during fossilization, its position is not reliable for establishing the cervical count. The criterion that all vertebrae with parapophysis represent cervical vertebrae, as used by
<bibRefCitation id="EFD895D6A01FFFE72A495D2C7C1EFB7F" author="Sander PM" box="[351,527,1146,1168]" pageId="13" pageNumber="528" pagination="163 - 173" refId="ref16814" refString="Sander PM. 1989 b. The large ichthyosaur Cymbospondylus buchseri, sp. nov. from the Middle Triassic of Monte San Giorgio (Switzerland), with a survey of the genus in Europe. Journal of Vertebrate Paleontology 9: 163 - 173." type="journal article" year="1989">Sander (1989b)</bibRefCitation>
, is used here to determine the number of cervicals. Vertebrae 9 and 10 are covered by the coracoids in FMNH PR2251, but vertebra 8 still possesses a small parapophyses, whereas vertebra 11 does not. Therefore, there are at least eight and at most ten cervical vertebrae present in this specimen, in comparison with six in
<taxonomicName id="4C4993A4A01FFFE7299B5C647D1BFAA8" authorityName="Sander" authorityYear="1989" box="[653,778,1330,1351]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="13" pageNumber="528" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A01FFFE7299B5C647D1BFAA8" box="[653,778,1330,1351]" italics="true" pageId="13" pageNumber="528">C. buchseri</emphasis>
</taxonomicName>
and
<quantity id="4CB145C2A01FFFE72BC35C077F01FA88" box="[213,272,1361,1383]" metricMagnitude="-1" metricUnit="m" metricValue="3.048" pageId="13" pageNumber="528" unit="in" value="12.0">12 in</quantity>
<taxonomicName id="4C4993A4A01FFFE72A0E5C077F85FA89" box="[280,404,1361,1382]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="13" pageNumber="528" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A01FFFE72A0E5C077F85FA89" box="[280,404,1361,1382]" italics="true" pageId="13" pageNumber="528">C. petrinus</emphasis>
</taxonomicName>
.
</paragraph>
<paragraph id="8BF6E827A01FFFE72BAD5C397CCCF9D2" blockId="13.[162,778,870,1904]" pageId="13" pageNumber="528">
The atlas is still in articulation with the basioccipital, as well as with the axis, and it can be observed from its ventrolateral side. Its anterior, smooth and clearly convex surface makes contact with the oblique, roughened articular surface of the basioccipital (
<figureCitation id="1372F4A2A01FFFE72BBC5F5F7EFAF9F1" box="[170,235,1545,1567]" captionStart="Figure 7" captionStartId="11.[162,240,1685,1704]" captionTargetBox="[323,1282,1002,1650]" captionTargetId="figure-145@11.[322,1282,1002,1652]" captionTargetPageId="11" captionText="Figure 7. Close-up view of the occipital–cervical complex of specimen FMNH PR2251 in posteroventral view. Vertebrae are observed in ventrolateral view. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634755" httpUri="https://zenodo.org/record/4634755/files/figure.png" pageId="13" pageNumber="528">Fig. 7</figureCitation>
). Owing to this tight articulation, the tip of the convex anterior surface of the atlas is not visible.
</paragraph>
<paragraph id="8BF6E827A01FFFE72BAD5F107EF0F957" blockId="13.[162,778,870,1904]" pageId="13" pageNumber="528">Along the narrow lateral edge of the atlas, an oval depression with a roughened surface is visible. No rib articulation facets are present on the centrum of the atlas.</paragraph>
<paragraph id="8BF6E827A01FFFE72BAD5F977DA2FE5F" blockId="13.[162,778,870,1904]" lastBlockId="13.[826,1442,195,1904]" pageId="13" pageNumber="528">
Like the atlas, the massive centrum of the axis can be examined from its ventral and left lateral side (
<figureCitation id="1372F4A2A01FFFE72BBC5FA87EFAF8FB" box="[170,235,1790,1812]" captionStart="Figure 7" captionStartId="11.[162,240,1685,1704]" captionTargetBox="[323,1282,1002,1650]" captionTargetId="figure-145@11.[322,1282,1002,1652]" captionTargetPageId="11" captionText="Figure 7. Close-up view of the occipital–cervical complex of specimen FMNH PR2251 in posteroventral view. Vertebrae are observed in ventrolateral view. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634755" httpUri="https://zenodo.org/record/4634755/files/figure.png" pageId="13" pageNumber="528">Fig. 7</figureCitation>
). Slightly lateral from the ventral midline of the centrum are two large, oval and elevated parapophyses, which are orientated parallel to the anterior margin. More dorsally, the ventral portion of a strong diapophysis can be seen. It reaches from the anterior margin posteriorly to slightly behind the middle of the lateral side of the centrum. The dorsal continuation of the diapophysis is covered by sediment and the proximal portion of the short, double-headed first cervical rib. Along the ventral midline of the centrum of the axis, a slightly flattened and roughened area is developed.
</paragraph>
<paragraph id="8BF6E827A01FFFE7284558EF7B30FD4A" blockId="13.[826,1442,195,1904]" pageId="13" pageNumber="528">
There are two intercentra of different size preserved in specimen FMNH PR2251, one of which belongs to the atlas, the other one to the axis (
<figureCitation id="1372F4A2A01FFFE72FE158A07B2FFDE3" box="[1271,1342,502,524]" captionStart="Figure 5" captionStartId="10.[142,220,1087,1106]" captionTargetBox="[142,1422,195,1051]" captionTargetId="figure-418@10.[142,1424,193,1054]" captionTargetPageId="10" captionText="Figure 5. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in occipital view (A). Scale bar = 10 cm. B shows the detail view of the fault plane through the back of the skull. Scale bar = 3 cm. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634751" httpUri="https://zenodo.org/record/4634751/files/figure.png" pageId="13" pageNumber="528">Figs 5</figureCitation>
,
<figureCitation id="1372F4A2A01FFFE72E5958A17B4FFDE3" box="[1359,1374,503,524]" captionStart="Figure 7" captionStartId="11.[162,240,1685,1704]" captionTargetBox="[323,1282,1002,1650]" captionTargetId="figure-145@11.[322,1282,1002,1652]" captionTargetPageId="11" captionText="Figure 7. Close-up view of the occipital–cervical complex of specimen FMNH PR2251 in posteroventral view. Vertebrae are observed in ventrolateral view. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634755" httpUri="https://zenodo.org/record/4634755/files/figure.png" pageId="13" pageNumber="528">7</figureCitation>
). The anterior intercentrum is the larger one and has an elongated, oval and somewhat concave base. Its overall shape is that of a shallow cone with a medially positioned, pointed peak. It is nestled between the ventral surfaces of the basioccipital and the atlas.
</paragraph>
<paragraph id="8BF6E827A01FFFE728455BF87AFEFCD0" blockId="13.[826,1442,195,1904]" pageId="13" pageNumber="528">The second intercentrum has an approximately rhombic base and is smaller and less elongated than the anterior one. It ends in a rounded peak above the centre of the rhombic base and is wedged in between the ventral surfaces of atlas and axis.</paragraph>
<paragraph id="8BF6E827A01FFFE728455A117AB9FBFA" blockId="13.[826,1442,195,1904]" pageId="13" pageNumber="528">Slightly different from the situation in the axis, the parapophysis of the third cervical has a more anteroposterior extension along the ventrolateral portion of the centrum. It is truncated by the anterior margin and ends clearly before the posterior margin of the centrum. The third cervical also possesses a flattened and roughened ventral midline.</paragraph>
<paragraph id="8BF6E827A01FFFE728455D487A80FAE4" blockId="13.[826,1442,195,1904]" pageId="13" pageNumber="528">
On the fault plane cutting through the back of the skull, the round posterior face of the third cervical vertebra is observable,
<quantity id="4CB145C2A01FFFE72F3D5D0D7A68FB9E" box="[1067,1145,1115,1137]" metricMagnitude="-2" metricUnit="m" metricValue="6.3" pageId="13" pageNumber="528" unit="mm" value="63.0">63 mm</quantity>
in height and
<quantity id="4CB145C2A01FFFE72E275D0A7B91FB9E" box="[1329,1408,1116,1137]" metricMagnitude="-2" metricUnit="m" metricValue="3.7" pageId="13" pageNumber="528" unit="mm" value="37.0">37 mm</quantity>
in length (
<tableCitation id="C6CBDD9CA01FFFE728855D2C7DF7FB7F" box="[915,998,1146,1168]" captionStart="Table 1" captionStartId="6.[142,206,196,215]" captionTargetPageId="6" captionText="Table 1. Measurements of C. nichollsi, specimen FMNH PR2251" httpUri="http://table.plazi.org/id/DF36B8AFA014FFEC2B9859927D53FF38" pageId="13" pageNumber="528" tableUuid="DF36B8AFA014FFEC2B9859927D53FF38">Table 1</tableCitation>
). The peripheral parts of its posterior face slope slightly and evenly towards the centre, whereas the central region is infilled by calcite. However, it appears that the slope of the posterior face steepens in its central region.
</paragraph>
<paragraph id="8BF6E827A01FFFE728455C457DCAFA2C" blockId="13.[826,1442,195,1904]" pageId="13" pageNumber="528">The fourth cervical vertebra is partially covered by the left clavicle, and only its round cross-section in the fault plane as well as its ventral parts are visible. The ventral side is smooth and round and does not show the flattened and roughened area seen in axis and third cervical.</paragraph>
<paragraph id="8BF6E827A01FFFE728455C9D7DD6F89F" blockId="13.[826,1442,195,1904]" pageId="13" pageNumber="528">
Cervicals 5–8 are exposed from their ventrolateral side (
<figureCitation id="1372F4A2A01FFFE728695CBC7DAEF9EF" box="[895,959,1514,1536]" captionStart="Figure 8" captionStartId="14.[806,884,755,774]" captionTargetBox="[810,1418,190,723]" captionTargetId="figure-806@14.[810,1419,398,723]" captionTargetPageId="14" captionText="Figure 8. A, drawing of cervical vertebrae 5–8 and presacral vertebrae 26 and 27 as example for the vertebral structures in specimen FMNH PR2251. B, drawing of neural arches 9–12 of specimen FMNH PR2251. Anterior is to the right. Scale bar = 5 cm." figureDoi="http://doi.org/10.5281/zenodo.4634757" httpUri="https://zenodo.org/record/4634757/files/figure.png" pageId="13" pageNumber="528">Fig. 8</figureCitation>
). The parapophyses of these vertebrae clearly decrease in size from anterior to posterior. Parallel with this decrease in size, the parapophyses move away from the anterior margin of the centrum, which still truncates the parapophyses of the fifth and sixth cervical, but does not contact those of the following vertebrae. The fifth to eighth cervical vertebrae also have strongly developed, elongated diapophyses on the lateral side of the centra. Their ventral end points anteriorly but does not contact the anterior margin of the centrum. The diapophyses reach far dorsally and are continuous with the articulation facets of the neural arch.
</paragraph>
<paragraph id="8BF6E827A01CFFE42BB159957CABFE5F" blockId="14.[142,759,195,1904]" pageId="14" pageNumber="529">The ninth and tenth vertebrae are covered by the coracoids, and it thus remains unknown whether these two centra still possess parapophyses. However, because the parapophysis of the eighth cervical vertebra is reduced to just a small, round bump, it is likely that the ninth vertebra retains only a rudimentary parapophysis. The tenth vertebra probably does not have one at all, and therefore is the first dorsal.</paragraph>
<paragraph id="8BF6E827A01CFFE42BB158EF7F2DFD87" blockId="14.[142,759,195,1904]" pageId="14" pageNumber="529">
Dorsal vertebrae 11–18 are only observable from their ventral side, as their dorsal and most of the lateral aspect are covered by the tilted neural arches and ribs and by sediment (
<figureCitation id="1372F4A2A01CFFE42A855B437C19FDC4" box="[403,520,533,555]" captionStart="Figure 1" captionStartId="3.[162,240,1822,1841]" captionTargetBox="[179,1424,190,1790]" captionTargetId="figure-80@3.[179,1427,190,1790]" captionTargetPageId="3" captionText="Figure 1. Holotype of Cymbospondylus nichollsi sp. nov., specimen FMNH PR2251 in lateral (A), dorsal (B) and ventral (C) view. C shows the upper surface of the specimen as found in the field. Note the sharp bend in the cervical vertebral column. Scale bar = 20 cm." figureDoi="http://doi.org/10.5281/zenodo.4634743" httpUri="https://zenodo.org/record/4634743/files/figure.png" pageId="14" pageNumber="529">Fig. 1A, C</figureCitation>
). Large parts of vertebrae 11 and 12 are also covered by elements of the pectoral girdle.
</paragraph>
<paragraph id="8BF6E827A01CFFE42BB15B277C5EFCB1" blockId="14.[142,759,195,1904]" pageId="14" pageNumber="529">
However, the ventrolateral view of vertebrae 15–18 reveals prominent, elongated diapophyses, which extend ventrally along the body of the centrum and are clearly truncated by the anterior margin of the centrum. Vertebra 13 is cut off by the fault plane separating the two postcranial blocks. The cross-section thus exposed is slightly more oval in shape than that of the third cervical vertebra (
<tableCitation id="C6CBDD9CA01CFFE42AFC5A117C2EFCB1" box="[490,575,839,862]" captionStart="Table 1" captionStartId="6.[142,206,196,215]" captionTargetPageId="6" captionText="Table 1. Measurements of C. nichollsi, specimen FMNH PR2251" httpUri="http://table.plazi.org/id/DF36B8AFA014FFEC2B9859927D53FF38" pageId="14" pageNumber="529" tableUuid="DF36B8AFA014FFEC2B9859927D53FF38">Table 1</tableCitation>
).
</paragraph>
<caption id="DF36B8AFA01CFFE428305BA57A0AFC93" ID-DOI="http://doi.org/10.5281/zenodo.4634757" ID-Zenodo-Dep="4634757" httpUri="https://zenodo.org/record/4634757/files/figure.png" pageId="14" pageNumber="529" startId="14.[806,884,755,774]" targetBox="[810,1418,190,723]" targetPageId="14">
<paragraph id="8BF6E827A01CFFE428305BA57A0AFC93" blockId="14.[806,1422,755,892]" pageId="14" pageNumber="529">
<emphasis id="B93D3435A01CFFE428305BA57D9FFCE9" bold="true" box="[806,910,755,774]" pageId="14" pageNumber="529">Figure 8.</emphasis>
A, drawing of cervical vertebrae 5–8 and presacral vertebrae 26 and 27 as example for the vertebral structures in specimen FMNH PR2251. B, drawing of neural arches 9–12 of specimen FMNH PR2251. Anterior is to the right. Scale bar = 5 cm.
</paragraph>
</caption>
<paragraph id="8BF6E827A01CFFE42BB15A317FEFFB22" blockId="14.[142,759,195,1904]" pageId="14" pageNumber="529">Because only few rib parts are present in this hindmost preserved area the lateral sides of the centra can be studied in addition to their ventral sides. Although preservation is poor, the prominent elongate, anteriorly slanted diapophyses are clearly visible. Throughout the whole series of vertebrae 19–28, the diapophyses are distinctively truncated by the anterior margins of the centra and extend in a curve towards the neural arch. Although preservation is insufficient to determine this with certainty, the diapophyses seem to maintain contact with the articulation facet of the neural arch.</paragraph>
<paragraph id="8BF6E827A01CFFE42BB15D807F00F9EF" blockId="14.[142,759,195,1904]" pageId="14" pageNumber="529">
The ventral sides of vertebrae 13–28 are clearly exposed. In vertebrae 13–17, the ventral side is rounded and smooth, whereas the ventral sides of centra 18–26 are somewhat flattened. Vertebra 28, the last preserved, has a height/length ratio of 2.35 (vs. 1.70 of the third cervical) (
<tableCitation id="C6CBDD9CA01CFFE42ADF5C397C0DFA69" box="[457,540,1391,1414]" captionStart="Table 1" captionStartId="6.[142,206,196,215]" captionTargetPageId="6" captionText="Table 1. Measurements of C. nichollsi, specimen FMNH PR2251" httpUri="http://table.plazi.org/id/DF36B8AFA014FFEC2B9859927D53FF38" pageId="14" pageNumber="529" tableUuid="DF36B8AFA014FFEC2B9859927D53FF38">Table 1</tableCitation>
), and has a triangular outline. The increasingly tapered ventral parts and steeper lateral sides of vertebrae 25–28 indicate that a triangular outline of the centra is developed in this region.
</paragraph>
<paragraph id="8BF6E827A01CFFE42BB15F5F7CA2F89F" blockId="14.[142,759,195,1904]" pageId="14" pageNumber="529">Specimen FMNH PR2251 exhibits a continuous row of 26 neural arches, of which the first visible arch belongs to the third cervical vertebra and can be observed in cross-section in the posterior fault plane of the skull. The neural arches are numbered in conjunction with their respective centra. Neural arches 4–12 are flipped over and can be studied in right lateral view. From the 13th to the 20th neural arch they are rotated into a slightly more upright position, grading into a fully upright position in neural arches 20–28. Heavy weathering in this region allows little more than the general form of the neural arches to be inferred.</paragraph>
<paragraph id="8BF6E827A01CFFE428295A947A72FA2C" blockId="14.[806,1422,962,1904]" pageId="14" pageNumber="529">
Throughout the preserved vertebral column, the neural arches posses a rather uniform shape with little differences between particular regions (
<figureCitation id="1372F4A2A01CFFE42E3A5AA97B90FBF9" box="[1324,1409,1023,1046]" captionStart="Figure 8" captionStartId="14.[806,884,755,774]" captionTargetBox="[810,1418,190,723]" captionTargetId="figure-806@14.[810,1419,398,723]" captionTargetPageId="14" captionText="Figure 8. A, drawing of cervical vertebrae 5–8 and presacral vertebrae 26 and 27 as example for the vertebral structures in specimen FMNH PR2251. B, drawing of neural arches 9–12 of specimen FMNH PR2251. Anterior is to the right. Scale bar = 5 cm." figureDoi="http://doi.org/10.5281/zenodo.4634757" httpUri="https://zenodo.org/record/4634757/files/figure.png" pageId="14" pageNumber="529">Fig. 8B</figureCitation>
). The neural arches are robustly built with strong pre- and postzygapophyses that slope anteriorly at an angle of about 15°. In most areas, particularly clearly visible in neural arches 6–9, the pre- and postzygapophyses are tightly fused, as expressed in an area of rough, bulging and uneven bone between the zygapophyses (
<figureCitation id="1372F4A2A01CFFE428925D807DD5FB03" box="[900,964,1238,1260]" captionStart="Figure 8" captionStartId="14.[806,884,755,774]" captionTargetBox="[810,1418,190,723]" captionTargetId="figure-806@14.[810,1419,398,723]" captionTargetPageId="14" captionText="Figure 8. A, drawing of cervical vertebrae 5–8 and presacral vertebrae 26 and 27 as example for the vertebral structures in specimen FMNH PR2251. B, drawing of neural arches 9–12 of specimen FMNH PR2251. Anterior is to the right. Scale bar = 5 cm." figureDoi="http://doi.org/10.5281/zenodo.4634757" httpUri="https://zenodo.org/record/4634757/files/figure.png" pageId="14" pageNumber="529">Fig. 8</figureCitation>
). This fusion strongly stiffened the vertebral column in the preserved anterior dorsal area and restricted the lateral mobility of this region. However, given that specimen FMNH PR2251 is the so far only known specimen of
<taxonomicName id="4C4993A4A01CFFE42F525C077B7CFA89" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1092,1389,1361,1382]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="14" pageNumber="529" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A01CFFE42F525C077B7CFA89" box="[1092,1389,1361,1382]" italics="true" pageId="14" pageNumber="529">Cymbospondylus nichollsi</emphasis>
</taxonomicName>
, it remains unknown whether this feature is characteristic for the taxon, or a sign of age and/or a pathology of this particular specimen.
</paragraph>
<paragraph id="8BF6E827A01CFFE428295C9D7D7BF994" blockId="14.[806,1422,962,1904]" pageId="14" pageNumber="529">The ventral bases for the articulation with the centrum are expanded. In addition, a small, flattened, transverse process occurs at the base of neural arches 10–15. It represents the dorsal portion of the diapophysis that extends from the centrum onto the neural spine.</paragraph>
<paragraph id="8BF6E827A01CFFE428295FD57DCEF8FB" blockId="14.[806,1422,962,1904]" pageId="14" pageNumber="529">Owing to the preservation of the anterior vertebral column and the insufficient preservation more posteriorly, no details of the articulation between the neural arches and the centra can be described for specimen FMNH PR2251.</paragraph>
<paragraph id="8BF6E827A01CFFE528295E4B7FC3FF17" blockId="14.[806,1422,962,1904]" lastBlockId="15.[162,778,195,401]" lastPageId="15" lastPageNumber="530" pageId="14" pageNumber="529">The neural spines are fairly long and are all inclined posteriorly at an angle of about 30–35°. They have an oval cross-section with a sharp anterior edge and with a rounded posterior edge. The dorsal tip of the neural spines is slightly rounded.</paragraph>
<paragraph id="8BF6E827A01DFFE52BAD58577F5CFE7E" blockId="15.[162,778,195,401]" pageId="15" pageNumber="530">
The cross-section of the third neural arch at the posterior fault plane of the skull shows that there is a large, oval neural canal framed by the two stems of the neural arch and the dorsally flattened area of the centrum (
<figureCitation id="1372F4A2A01DFFE52BFA582D7F51FE7E" box="[236,320,379,401]" captionStart="Figure 5" captionStartId="10.[142,220,1087,1106]" captionTargetBox="[142,1422,195,1051]" captionTargetId="figure-418@10.[142,1424,193,1054]" captionTargetPageId="10" captionText="Figure 5. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in occipital view (A). Scale bar = 10 cm. B shows the detail view of the fault plane through the back of the skull. Scale bar = 3 cm. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634751" httpUri="https://zenodo.org/record/4634751/files/figure.png" pageId="15" pageNumber="530">Fig. 5B</figureCitation>
).
</paragraph>
<paragraph id="8BF6E827A01DFFE52BB458FF7EE3FDB7" blockId="15.[162,778,425,1245]" pageId="15" pageNumber="530">
<emphasis id="B93D3435A01DFFE52BB458FF7ECAFE51" box="[162,219,425,446]" italics="true" pageId="15" pageNumber="530">Ribs:</emphasis>
A number of distally incomplete ribs are preserved in specimen FMNH PR2251. The anterior twothirds of the postcranial skeleton preserve numerous proximal rib parts, which are closely associated with the vertebral column, but no direct articulation with centra.
</paragraph>
<paragraph id="8BF6E827A01DFFE52BAD5B377F13FD1D" blockId="15.[162,778,425,1245]" pageId="15" pageNumber="530">
One cervical rib with a double articulation lies laterally to the atlas and axis, suggesting that it is the first cervical rib (
<figureCitation id="1372F4A2A01DFFE52A7E5BC97FD3FD5A" box="[360,450,671,693]" captionStart="Figure 5" captionStartId="10.[142,220,1087,1106]" captionTargetBox="[142,1422,195,1051]" captionTargetId="figure-418@10.[142,1424,193,1054]" captionTargetPageId="10" captionText="Figure 5. Drawing of the skull of Cymbospondylus nichollsi sp. nov. (FMNH PR2251) in occipital view (A). Scale bar = 10 cm. B shows the detail view of the fault plane through the back of the skull. Scale bar = 3 cm. See Appendix for explanation of abbreviations." figureDoi="http://doi.org/10.5281/zenodo.4634751" httpUri="https://zenodo.org/record/4634751/files/figure.png" pageId="15" pageNumber="530">Figs 5A</figureCitation>
,
<figureCitation id="1372F4A2A01DFFE52ADB5BC97FE1FD5A" box="[461,496,671,693]" captionStart="Figure 9" captionStartId="15.[162,240,1825,1844]" captionTargetBox="[166,774,1320,1792]" captionTargetId="figure-540@15.[166,775,1319,1792]" captionTargetPageId="15" captionText="Figure 9. Drawings of ribs of specimen FMNH PR2251. A, double-headed first cervical rib. B, anterior dorsal rib. C, middle dorsal rib. Scale bar = 2 cm." figureDoi="http://doi.org/10.5281/zenodo.4634761" httpUri="https://zenodo.org/record/4634761/files/figure.png" pageId="15" pageNumber="530">9A</figureCitation>
). Although its distal end was cut off by the fault plane, not much seems to be missing.
</paragraph>
<paragraph id="8BF6E827A01DFFE52BAD5BAD7FF4FBAC" blockId="15.[162,778,425,1245]" pageId="15" pageNumber="530">
The next preserved rib head lies on the right side of the body at the level of the fifth neural arch. It is single-headed, like the heads of all following ribs. The rib heads are expanded, anteroposteriorly flattened and clearly set off from the distal rib shaft (
<figureCitation id="1372F4A2A01DFFE5294D5A237CDCFC63" box="[603,717,885,908]" captionStart="Figure 9" captionStartId="15.[162,240,1825,1844]" captionTargetBox="[166,774,1320,1792]" captionTargetId="figure-540@15.[166,775,1319,1792]" captionTargetPageId="15" captionText="Figure 9. Drawings of ribs of specimen FMNH PR2251. A, double-headed first cervical rib. B, anterior dorsal rib. C, middle dorsal rib. Scale bar = 2 cm." figureDoi="http://doi.org/10.5281/zenodo.4634761" httpUri="https://zenodo.org/record/4634761/files/figure.png" pageId="15" pageNumber="530">Fig. 9B, C</figureCitation>
). The articulation facet is elongated and has an oval outline with a narrow dorsal and a broader ventral part. Originating at the narrow portion of the articulation facet, a dorsal ridge extends along the rib shaft, resulting in grooves along its anterior and posterior side and in a figure-of-eight cross-section.
</paragraph>
<paragraph id="8BF6E827A01DFFE52BAD5D1A7FB1FB32" blockId="15.[162,778,425,1245]" pageId="15" pageNumber="530">
The transitional area between rib head and rib shaft is also the area of greatest curvature. The anterior ribs have a wider, smoother curvature than the more posterior ribs. In these, there is distinctive offset of head and shaft (
<figureCitation id="1372F4A2A01DFFE52A365D917F85FB32" box="[288,404,1223,1245]" captionStart="Figure 9" captionStartId="15.[162,240,1825,1844]" captionTargetBox="[166,774,1320,1792]" captionTargetId="figure-540@15.[166,775,1319,1792]" captionTargetPageId="15" captionText="Figure 9. Drawings of ribs of specimen FMNH PR2251. A, double-headed first cervical rib. B, anterior dorsal rib. C, middle dorsal rib. Scale bar = 2 cm." figureDoi="http://doi.org/10.5281/zenodo.4634761" httpUri="https://zenodo.org/record/4634761/files/figure.png" pageId="15" pageNumber="530">Fig. 9B, C</figureCitation>
).
</paragraph>
<paragraph id="8BF6E827A01DFFE5284559957B12FEBB" blockId="15.[826,1442,195,401]" pageId="15" pageNumber="530">
The large block with portions of ribs of the left body side between vertebrae 14 and 28 shows proximal to intermediate portions of ribs in ventral view (
<figureCitation id="1372F4A2A01DFFE52E5658577B84FEF8" box="[1344,1429,257,279]" captionStart="Figure 1" captionStartId="3.[162,240,1822,1841]" captionTargetBox="[179,1424,190,1790]" captionTargetId="figure-80@3.[179,1427,190,1790]" captionTargetPageId="3" captionText="Figure 1. Holotype of Cymbospondylus nichollsi sp. nov., specimen FMNH PR2251 in lateral (A), dorsal (B) and ventral (C) view. C shows the upper surface of the specimen as found in the field. Note the sharp bend in the cervical vertebral column. Scale bar = 20 cm." figureDoi="http://doi.org/10.5281/zenodo.4634743" httpUri="https://zenodo.org/record/4634743/files/figure.png" pageId="15" pageNumber="530">Fig. 1C</figureCitation>
). The shafts all possess the grooves described above, as well as the figure-of-eight cross-section.
</paragraph>
<paragraph id="8BF6E827A01DFFE52845580B7A00FE7E" blockId="15.[826,1442,195,401]" pageId="15" pageNumber="530">Because no rib is preserved in full, total rib length remains unknown.</paragraph>
<paragraph id="8BF6E827A01DFFE5282C58FF7ACDFE12" blockId="15.[826,1443,425,907]" pageId="15" pageNumber="530">
<emphasis id="B93D3435A01DFFE5282C58FF7A2FFE51" box="[826,1086,425,446]" italics="true" pageId="15" pageNumber="530">Appendicular skeleton:</emphasis>
Only the coracoids and clavicles as well as a possible forelimb fragment are preserved of the appendicular skeleton.
</paragraph>
<paragraph id="8BF6E827A01DFFE528455B537BB2FD3C" blockId="15.[826,1443,425,907]" pageId="15" pageNumber="530">
The left coracoid is almost completely preserved and only the tip of the blade is missing. Although it is somewhat crushed and flattened, the original form can still be clearly discerned (
<figureCitation id="1372F4A2A01DFFE52FB35B377B16FD97" box="[1189,1287,609,632]" captionStart="Figure 10" captionStartId="15.[826,904,1737,1756]" captionTargetBox="[830,1438,960,1704]" captionTargetId="figure-598@15.[830,1439,960,1422]" captionTargetPageId="15" captionText="Figure 10. Drawings of preserved shoulder girdle elements of specimen FMNH PR2251. A, left coracoid. B, right clavicle; the broken bone plate attached to the posterolateral end of the clavicle may represent a remnant of the scapula (Sc?). See Appendix for explanation of abbreviations. Scale bar = 5 cm." figureDoi="http://doi.org/10.5281/zenodo.4634759" httpUri="https://zenodo.org/record/4634759/files/figure.png" pageId="15" pageNumber="530">Fig. 10A</figureCitation>
). Half of the blade of the right coracoid is missing, but the preserved part suffered less compaction than the left coracoid and therefore shows the original form nicely.
</paragraph>
<paragraph id="8BF6E827A01DFFFA28455B8A7F1FFEF8" blockId="15.[826,1443,425,907]" lastBlockId="16.[142,758,195,1352]" lastPageId="16" lastPageNumber="531" pageId="15" pageNumber="530">The coracoid has a thick, eye-shaped glenoid facet with a roughened surface. The latter forms the base of a short, thickened stem, which quickly expands and thins as the bone widens towards the blade. The anterior and medial margin of the coracoid blade is strongly convex, whereas the posterior margin forms a sharp, concave curve. The medial and posterior margins meet in an elongated, pointed end that is directed posteriorly.</paragraph>
<caption id="DF36B8AFA01DFFE5282C5F9F7A3FF880" ID-DOI="http://doi.org/10.5281/zenodo.4634759" ID-Zenodo-Dep="4634759" httpUri="https://zenodo.org/record/4634759/files/figure.png" pageId="15" pageNumber="530" startId="15.[826,904,1737,1756]" targetBox="[830,1438,960,1704]" targetPageId="15">
<paragraph id="8BF6E827A01DFFE5282C5F9F7A3FF880" blockId="15.[826,1442,1737,1903]" pageId="15" pageNumber="530">
<emphasis id="B93D3435A01DFFE5282C5F9F7DBEF933" bold="true" box="[826,943,1737,1756]" pageId="15" pageNumber="530">Figure 10.</emphasis>
Drawings of preserved shoulder girdle elements of specimen FMNH PR2251. A, left coracoid. B, right clavicle; the broken bone plate attached to the posterolateral end of the clavicle may represent a remnant of the scapula (Sc?). See Appendix for explanation of abbreviations. Scale bar = 5 cm.
</paragraph>
</caption>
<caption id="DF36B8AFA01DFFE52BB45E777C09F880" ID-DOI="http://doi.org/10.5281/zenodo.4634761" ID-Zenodo-Dep="4634761" httpUri="https://zenodo.org/record/4634761/files/figure.png" pageId="15" pageNumber="530" startId="15.[162,240,1825,1844]" targetBox="[166,774,1320,1792]" targetPageId="15">
<paragraph id="8BF6E827A01DFFE52BB45E777C09F880" blockId="15.[162,778,1825,1903]" pageId="15" pageNumber="530">
<emphasis id="B93D3435A01DFFE52BB45E777F1BF8DB" bold="true" box="[162,266,1825,1844]" pageId="15" pageNumber="530">Figure 9.</emphasis>
Drawings of ribs of specimen FMNH PR2251. A, double-headed first cervical rib. B, anterior dorsal rib. C, middle dorsal rib. Scale bar = 2 cm.
</paragraph>
</caption>
<paragraph id="8BF6E827A002FFFA2BB158767F5EFE7E" blockId="16.[142,758,195,1352]" pageId="16" pageNumber="531">
A large lenticular coracoid foramen is seen anterolaterally close to the thickened area of the glenoid facet (see
<tableCitation id="C6CBDD9CA002FFFA2A11580B7F4AFE9D" box="[263,347,349,371]" captionStart="Table 1" captionStartId="6.[142,206,196,215]" captionTargetPageId="6" captionText="Table 1. Measurements of C. nichollsi, specimen FMNH PR2251" httpUri="http://table.plazi.org/id/DF36B8AFA014FFEC2B9859927D53FF38" pageId="16" pageNumber="531" tableUuid="DF36B8AFA014FFEC2B9859927D53FF38">Table 1</tableCitation>
for measurements of the shoulder girdle elements).
</paragraph>
<paragraph id="8BF6E827A002FFFA2BB158CC7CF3FC93" blockId="16.[142,758,195,1352]" pageId="16" pageNumber="531">
The left clavicle of the specimen is heavily crushed and weathered and parts are missing, but fortunately the right clavicle is almost uncrushed and completely preserved. The elongated, rounded anterior part of the clavicle is slightly twisted towards the medial body axis, and its tip consists of a conical, hat-like structure, which is set off from the slender neck of the clavicle (
<figureCitation id="1372F4A2A002FFFA2BDF5B277F3BFD68" box="[201,298,625,647]" captionStart="Figure 10" captionStartId="15.[826,904,1737,1756]" captionTargetBox="[830,1438,960,1704]" captionTargetId="figure-598@15.[830,1439,960,1422]" captionTargetPageId="15" captionText="Figure 10. Drawings of preserved shoulder girdle elements of specimen FMNH PR2251. A, left coracoid. B, right clavicle; the broken bone plate attached to the posterolateral end of the clavicle may represent a remnant of the scapula (Sc?). See Appendix for explanation of abbreviations. Scale bar = 5 cm." figureDoi="http://doi.org/10.5281/zenodo.4634759" httpUri="https://zenodo.org/record/4634759/files/figure.png" pageId="16" pageNumber="531">Fig. 10B</figureCitation>
). The conical structure is distinctively roughened with some deeper grooves running radially from the tip to its posterior edge, which might indicate that these roughened areas served as an attachment site for cartilage. The form of the thick anterior head suggests that the two clavicles did not articulate with each other in an interfingering fashion as seen in other ichthyosaurs; it is more likely that they solely articulated with a medially positioned interclavicle.
</paragraph>
<paragraph id="8BF6E827A002FFFA2BB15AD37F4BFB40" blockId="16.[142,758,195,1352]" pageId="16" pageNumber="531">
Posterolaterally, the slender neck of the clavicle widens into a thin, sail-like blade with a triangular outline that sits dorsally on the base of the clavicle. The latter is thickened and has a finished, rounded edge. Caudally, the clavicle possesses an elongated posterior process, which is more slender and slightly longer than the anterior neck of the clavicle. A fragment of a broken bony blade is still attached to this process (
<figureCitation id="1372F4A2A002FFFA2B805D2C7EE6FB7F" box="[150,247,1146,1168]" captionStart="Figure 10" captionStartId="15.[826,904,1737,1756]" captionTargetBox="[830,1438,960,1704]" captionTargetId="figure-598@15.[830,1439,960,1422]" captionTargetPageId="15" captionText="Figure 10. Drawings of preserved shoulder girdle elements of specimen FMNH PR2251. A, left coracoid. B, right clavicle; the broken bone plate attached to the posterolateral end of the clavicle may represent a remnant of the scapula (Sc?). See Appendix for explanation of abbreviations. Scale bar = 5 cm." figureDoi="http://doi.org/10.5281/zenodo.4634759" httpUri="https://zenodo.org/record/4634759/files/figure.png" pageId="16" pageNumber="531">Fig. 10B</figureCitation>
). The fragment could represent remnants of the right scapula.
</paragraph>
<paragraph id="8BF6E827A002FFFA2BB15DEE7F27FAA7" blockId="16.[142,758,195,1352]" pageId="16" pageNumber="531">
As in
<taxonomicName id="4C4993A4A002FFFA2BFB5DEE7F79FB22" box="[237,360,1208,1229]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA2BFB5DEE7F79FB22" box="[237,360,1208,1229]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
and in
<taxonomicName id="4C4993A4A002FFFA2AD05DEE7C55FB23" authorityName="Sander" authorityYear="1989" box="[454,580,1207,1229]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A002FFFA2AD05DEE7C55FB23" box="[454,580,1207,1229]" italics="true" pageId="16" pageNumber="531">C. buchseri</emphasis>
</taxonomicName>
, the interclavicle is not known in specimen FMNH PR2251. This is surprising considering the good preservation and tight articulation of the preserved shoulder girdle in this new specimen.
</paragraph>
</subSection>
<subSection id="E2C6F1CCA002FFFA2B985CC67C9CFA27" pageId="16" pageNumber="531" type="multiple">
<paragraph id="8BF6E827A002FFFA2B985CC67C9CFA27" blockId="16.[142,752,1424,1480]" pageId="16" pageNumber="531">
<heading id="D0BE5F4BA002FFFA2B985CC67C9CFA27" allCaps="true" centered="true" fontSize="10" level="1" pageId="16" pageNumber="531" reason="1">
COMPARISON OF THE THREE WELL-KNOWN
<taxonomicName id="4C4993A4A002FFFA2BE15CE77C1DFA27" authorityName="NICHOLLSI" authorityYear="2006" box="[247,524,1457,1480]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A002FFFA2BE15CE77C1DFA27" box="[247,524,1457,1480]" italics="true" pageId="16" pageNumber="531">CYMBOSPONDYLUS</emphasis>
</taxonomicName>
SPECIES
</heading>
</paragraph>
</subSection>
<subSection id="E2C6F1CCA002FFFA2A035C897A5CFDC4" pageId="16" pageNumber="531" type="multiple">
<paragraph id="8BF6E827A002FFFA2A035C897C7EFA1A" blockId="16.[277,623,1503,1527]" box="[277,623,1503,1527]" pageId="16" pageNumber="531">
<heading id="D0BE5F4BA002FFFA2A035C897C7EFA1A" box="[277,623,1503,1527]" centered="true" fontSize="9" level="2" pageId="16" pageNumber="531" reason="5">ESTIMATION OF BODY LENGTH</heading>
</paragraph>
<paragraph id="8BF6E827A002FFFA2B985F517A5CFDC4" blockId="16.[142,758,1543,1903]" lastBlockId="16.[806,1422,195,555]" pageId="16" pageNumber="531">
Specimen FMNH PR2251 is only preserved to its middle dorsal region, and therefore an estimate of total body length must depend on comparison with
<taxonomicName id="4C4993A4A002FFFA2B985F327F18F996" box="[142,265,1636,1657]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA2B985F327F18F996" box="[142,265,1636,1657]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
, which is known from more complete material (specimens UCMP 9950, UCMP 9947, etc.). Skull length posterior to the external nares in
<taxonomicName id="4C4993A4A002FFFA294B5FF77CCDF959" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[605,732,1697,1718]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A002FFFA294B5FF77CCDF959" box="[605,732,1697,1718]" italics="true" pageId="16" pageNumber="531">C. nichollsi</emphasis>
</taxonomicName>
is
<quantity id="4CB145C2A002FFFA2B985FE97EFDF93A" box="[142,236,1727,1749]" metricMagnitude="-1" metricUnit="m" metricValue="4.43" pageId="16" pageNumber="531" unit="mm" value="443.0">443 mm</quantity>
, which is 84% of the same measurement of the skull length of
<taxonomicName id="4C4993A4A002FFFA2A795F887C53F91C" authority="UCMP" authorityName="UCMP" box="[367,578,1758,1780]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA2A795F887FFBF91B" box="[367,490,1758,1780]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
UCMP
</taxonomicName>
9950 (
<tableCitation id="C6CBDD9CA002FFFA29845F887CF8F91B" box="[658,745,1758,1780]" captionStart="Table 2" captionStartId="18.[142,206,196,215]" captionTargetPageId="18" captionText="Table 2. Comparison of significant measurements of Cymbospondylus petrinus, C. buchseri, and C. nichollsi" httpUri="http://table.plazi.org/id/DF36B8AFA000FFF82B9859927B1AFF38" pageId="16" pageNumber="531" tableUuid="DF36B8AFA000FFF82B9859927B1AFF38">Table 2</tableCitation>
).
<bibRefCitation id="EFD895D6A002FFFA2B985FAB7F97F8FC" author="Merriam JC" box="[142,390,1789,1811]" pageId="16" pageNumber="531" pagination="1 - 155" refId="ref16501" refString="Merriam JC. 1908. Triassic Ichthyosauria, with special reference to the American forms. Memoirs of the University of California 1: 1 - 155." type="journal article" year="1908">Merriam (1908: 105)</bibRefCitation>
estimated the body length of UCMP 9950 + UCMP 9947 as exceeding
<quantity id="4CB145C2A002FFFA296C5E4D7CADF8DE" box="[634,700,1819,1841]" metricMagnitude="0" metricUnit="m" metricValue="9.1" pageId="16" pageNumber="531" unit="m" value="9.1">9.1 m</quantity>
. The skull of this skeleton is 13% of its whole body length. However, this specimen represents a composite skeleton of which the anterior body half belongs to individual UCMP 9950, while the caudal region and posterior limb were added from specimen UCMP 9947 (
<bibRefCitation id="EFD895D6A002FFFA2E4058577DB6FEDA" author="Merriam JC" pageId="16" pageNumber="531" pagination="1 - 155" refId="ref16501" refString="Merriam JC. 1908. Triassic Ichthyosauria, with special reference to the American forms. Memoirs of the University of California 1: 1 - 155." type="journal article" year="1908">Merriam, 1908</bibRefCitation>
). Assuming that the overall body proportions of specimen FMNH PR2251 are similar to
<taxonomicName id="4C4993A4A002FFFA2830580B7DB0FE9D" box="[806,929,349,370]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA2830580B7DB0FE9D" box="[806,929,349,370]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
, the estimated body length for
<taxonomicName id="4C4993A4A002FFFA2E19580B7B9FFE9D" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1295,1422,349,370]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A002FFFA2E19580B7B9FFE9D" box="[1295,1422,349,370]" italics="true" pageId="16" pageNumber="531">C. nichollsi</emphasis>
</taxonomicName>
is
<quantity id="4CB145C2A002FFFA2853582D7D97FE7E" box="[837,902,379,401]" metricMagnitude="0" metricUnit="m" metricValue="7.6" pageId="16" pageNumber="531" unit="m" value="7.6">7.6 m</quantity>
. It would therefore be intermediate in size between
<taxonomicName id="4C4993A4A002FFFA289A58CC7A18FE40" authorityName="Sander" authorityYear="1989" box="[908,1033,410,431]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A002FFFA289A58CC7A18FE40" box="[908,1033,410,431]" italics="true" pageId="16" pageNumber="531">C. buchseri</emphasis>
</taxonomicName>
, with an estimated body length of
<quantity id="4CB145C2A002FFFA283058EF7D40FE21" box="[806,849,441,463]" metricMagnitude="0" metricUnit="m" metricValue="5.0" pageId="16" pageNumber="531" unit="m" value="5.0">5 m</quantity>
(
<bibRefCitation id="EFD895D6A002FFFA287358EF7A1FFE20" author="Sander PM" box="[869,1038,441,463]" pageId="16" pageNumber="531" pagination="163 - 173" refId="ref16814" refString="Sander PM. 1989 b. The large ichthyosaur Cymbospondylus buchseri, sp. nov. from the Middle Triassic of Monte San Giorgio (Switzerland), with a survey of the genus in Europe. Journal of Vertebrate Paleontology 9: 163 - 173." type="journal article" year="1989">Sander, 1989b</bibRefCitation>
), and
<taxonomicName id="4C4993A4A002FFFA2F4858EF7ACBFE21" box="[1118,1242,441,462]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA2F4858EF7ACBFE21" box="[1118,1242,441,462]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
. However, this value takes neither ontogenetic nor intraspecific variation into account, and therefore can only be regarded as a very rough estimate.
</paragraph>
</subSection>
<subSection id="E2C6F1CCA002FFF928625B227C15FC93" lastPageId="19" lastPageNumber="534" pageId="16" pageNumber="531" type="multiple">
<paragraph id="8BF6E827A002FFFA28625B227B50FD64" blockId="16.[884,1345,628,652]" box="[884,1345,628,652]" pageId="16" pageNumber="531">
<heading id="D0BE5F4BA002FFFA28625B227B50FD64" box="[884,1345,628,652]" centered="true" fontSize="9" level="2" pageId="16" pageNumber="531" reason="5">COMPARISON OF THE SKULL OSTEOLOGY</heading>
</paragraph>
<paragraph id="8BF6E827A002FFFA28305BCB7A9EFC84" blockId="16.[806,1422,669,1488]" pageId="16" pageNumber="531">
<emphasis id="B93D3435A002FFFA28305BCB7A52FD5D" box="[806,1091,669,690]" italics="true" pageId="16" pageNumber="531">Shape and proportions:</emphasis>
The skull of
<taxonomicName id="4C4993A4A002FFFA2E195BCB7B9FFD5D" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1295,1422,669,690]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A002FFFA2E195BCB7B9FFD5D" box="[1295,1422,669,690]" italics="true" pageId="16" pageNumber="531">C. nichollsi</emphasis>
</taxonomicName>
seems to be less dorsoventrally flattened than that of
<taxonomicName id="4C4993A4A002FFFA28305B8C7DB0FD1F" box="[806,929,730,752]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA28305B8C7DB0FD1F" box="[806,929,730,752]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
and
<taxonomicName id="4C4993A4A002FFFA28CC5B8C7A49FD00" authorityName="Sander" authorityYear="1989" box="[986,1112,730,751]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A002FFFA28CC5B8C7A49FD00" box="[986,1112,730,751]" italics="true" pageId="16" pageNumber="531">C. buchseri</emphasis>
</taxonomicName>
, and the general shape differs particularly from that of
<taxonomicName id="4C4993A4A002FFFA2F945BAF7AEFFCE1" box="[1154,1278,761,782]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA2F945BAF7AEFFCE1" box="[1154,1278,761,782]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
. The orbital shape of
<taxonomicName id="4C4993A4A002FFFA28885A4E7A0CFCC3" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[926,1053,791,813]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A002FFFA28885A4E7A0CFCC3" box="[926,1053,791,813]" italics="true" pageId="16" pageNumber="531">C. nichollsi</emphasis>
</taxonomicName>
and
<taxonomicName id="4C4993A4A002FFFA2F7F5A4E7AF7FCC3" authorityName="Sander" authorityYear="1989" box="[1129,1254,791,813]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A002FFFA2F7F5A4E7AF7FCC3" box="[1129,1254,791,813]" italics="true" pageId="16" pageNumber="531">C. buchseri</emphasis>
</taxonomicName>
is alike and somewhat more rounded and enlarged than that of
<taxonomicName id="4C4993A4A002FFFA28305A037DB0FC85" box="[806,929,853,874]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA28305A037DB0FC85" box="[806,929,853,874]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
(
<figureCitation id="1372F4A2A002FFFA28BC5A037DE9FC85" box="[938,1016,853,875]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="16" pageNumber="531">Fig. 11</figureCitation>
;
<tableCitation id="C6CBDD9CA002FFFA2F135A037A74FC85" box="[1029,1125,853,875]" captionStart="Table 2" captionStartId="18.[142,206,196,215]" captionTargetPageId="18" captionText="Table 2. Comparison of significant measurements of Cymbospondylus petrinus, C. buchseri, and C. nichollsi" httpUri="http://table.plazi.org/id/DF36B8AFA000FFF82B9859927B1AFF38" pageId="16" pageNumber="531" tableUuid="DF36B8AFA000FFF82B9859927B1AFF38">Tables 2</tableCitation>
,
<tableCitation id="C6CBDD9CA002FFFA2F645A037A90FC84" box="[1138,1153,853,875]" captionStart="Table 3" captionStartId="20.[142,206,1571,1590]" captionTargetPageId="20" captionText="Table 3. Comparison of ratios and counts in Cymbospondylus petrinus, C. buchseri and C. nichollsi" pageId="16" pageNumber="531">3</tableCitation>
).
</paragraph>
<paragraph id="8BF6E827A002FFFA28295A257B41FA3F" blockId="16.[806,1422,669,1488]" pageId="16" pageNumber="531">
The ratio of orbit length/postorbital length, as a proxy for the relative length of the postorbital region, can only be given for
<taxonomicName id="4C4993A4A002FFFA2F035AE77A80FC29" box="[1045,1169,945,966]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA2F035AE77A80FC29" box="[1045,1169,945,966]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
(0.97) and
<taxonomicName id="4C4993A4A002FFFA2E195AE77B9FFC29" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1295,1422,945,966]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A002FFFA2E195AE77B9FFC29" box="[1295,1422,945,966]" italics="true" pageId="16" pageNumber="531">C. nichollsi</emphasis>
</taxonomicName>
(0.83), as the postorbital region of
<taxonomicName id="4C4993A4A002FFFA2FFA5A867B78FC0B" authorityName="Sander" authorityYear="1989" box="[1260,1385,975,997]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A002FFFA2FFA5A867B78FC0B" box="[1260,1385,975,997]" italics="true" pageId="16" pageNumber="531">C. buchseri</emphasis>
</taxonomicName>
is incompletely preserved.
<bibRefCitation id="EFD895D6A002FFFA2F2A5AB87AFBFBEB" author="Sander PM" box="[1084,1258,1006,1028]" pageId="16" pageNumber="531" pagination="163 - 173" refId="ref16814" refString="Sander PM. 1989 b. The large ichthyosaur Cymbospondylus buchseri, sp. nov. from the Middle Triassic of Monte San Giorgio (Switzerland), with a survey of the genus in Europe. Journal of Vertebrate Paleontology 9: 163 - 173." type="journal article" year="1989">Sander (1989b)</bibRefCitation>
suggested the ratio of the orbit length and postdentary length of the lower jaw as a measure of the postorbital length. This ratio is
<quantity id="4CB145C2A002FFFA286D5D1C7DD9FB8F" box="[891,968,1098,1120]" metricMagnitude="-2" metricUnit="m" metricValue="1.5748" pageId="16" pageNumber="531" unit="in" value="0.62">0.62 in</quantity>
<taxonomicName id="4C4993A4A002FFFA28D95D1C7A5BFB8F" box="[975,1098,1098,1120]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA28D95D1C7A5BFB8F" box="[975,1098,1098,1120]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
,
<quantity id="4CB145C2A002FFFA2F405D1C7AB2FB8F" box="[1110,1187,1098,1120]" metricMagnitude="-2" metricUnit="m" metricValue="1.9558" pageId="16" pageNumber="531" unit="in" value="0.77">0.77 in</quantity>
<taxonomicName id="4C4993A4A002FFFA2FBC5D1C7B36FBB0" authorityName="Sander" authorityYear="1989" box="[1194,1319,1098,1119]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A002FFFA2FBC5D1C7B36FBB0" box="[1194,1319,1098,1119]" italics="true" pageId="16" pageNumber="531">C. buchseri</emphasis>
</taxonomicName>
and
<quantity id="4CB145C2A002FFFA2E485D1C7D2CFB90" metricMagnitude="-2" metricUnit="m" metricValue="1.397" pageId="16" pageNumber="531" unit="in" value="0.55">0.55 in</quantity>
<taxonomicName id="4C4993A4A002FFFA285E5D3F7DD7FB91" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[840,966,1129,1150]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A002FFFA285E5D3F7DD7FB91" box="[840,966,1129,1150]" italics="true" pageId="16" pageNumber="531">C. nichollsi</emphasis>
</taxonomicName>
. However, the dentaries of
<taxonomicName id="4C4993A4A002FFFA2E075D3F7B9FFB91" authorityName="Sander" authorityYear="1989" box="[1297,1422,1129,1150]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A002FFFA2E075D3F7B9FFB91" box="[1297,1422,1129,1150]" italics="true" pageId="16" pageNumber="531">C. buchseri</emphasis>
</taxonomicName>
are shorter than those of
<taxonomicName id="4C4993A4A002FFFA2F465DDE7ADAFB72" box="[1104,1227,1160,1181]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA2F465DDE7ADAFB72" box="[1104,1227,1160,1181]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
and only extend back two-thirds below the orbit. When comparing the ratio between the skull length posterior to the nares and the length of the cheek region in
<taxonomicName id="4C4993A4A002FFFA2FDD5DB27B56FB16" box="[1227,1351,1252,1273]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA2FDD5DB27B56FB16" box="[1227,1351,1252,1273]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
(2.11) and
<taxonomicName id="4C4993A4A002FFFA284F5C547DC6FAF8" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[857,983,1282,1303]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A002FFFA284F5C547DC6FAF8" box="[857,983,1282,1303]" italics="true" pageId="16" pageNumber="531">C. nichollsi</emphasis>
</taxonomicName>
(1.85) as a measure of relative length of the cheek region, it becomes apparent that the cheek region of the new species is slightly longer than that of
<taxonomicName id="4C4993A4A002FFFA28965C087DEAFA9B" box="[896,1019,1374,1396]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA28965C087DEAFA9B" box="[896,1019,1374,1396]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
. Moreover, the jaw articulation of
<taxonomicName id="4C4993A4A002FFFA28305C2B7DB0FA7D" box="[806,929,1405,1426]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA28305C2B7DB0FA7D" box="[806,929,1405,1426]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
is drawn out far posteriorly compared with
<taxonomicName id="4C4993A4A002FFFA28305CCA7DB5FA5F" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[806,932,1435,1457]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A002FFFA28305CCA7DB5FA5F" box="[806,932,1435,1457]" italics="true" pageId="16" pageNumber="531">C. nichollsi</emphasis>
</taxonomicName>
, resulting in an anteriorly slanted occiput in this taxon (
<figureCitation id="1372F4A2A002FFFA28DF5CEC7A3BFA20" box="[969,1066,1466,1488]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="16" pageNumber="531">Fig. 11B</figureCitation>
,
<bibRefCitation id="EFD895D6A002FFFA2F215CEC7AF7FA20" author="Merriam JC" box="[1079,1254,1466,1488]" pageId="16" pageNumber="531" pagination="1 - 155" refId="ref16501" refString="Merriam JC. 1908. Triassic Ichthyosauria, with special reference to the American forms. Memoirs of the University of California 1: 1 - 155." type="journal article" year="1908">Merriam (1908</bibRefCitation>
: table 5).
</paragraph>
<paragraph id="8BF6E827A002FFFB28305CBF7FB7F938" blockId="16.[806,1422,1512,1902]" lastBlockId="17.[162,778,1637,1904]" lastPageId="17" lastPageNumber="532" pageId="16" pageNumber="531">
<emphasis id="B93D3435A002FFFA28305CBF7A75F9F3" italics="true" pageId="16" pageNumber="531">Location of the supratemporal and re-evaluation of the skull osteology of the genus:</emphasis>
New insights into the osteology of the skull of
<taxonomicName id="4C4993A4A002FFFA2F5C5F737B1BF9D5" authorityName="NICHOLLSI" authorityYear="2006" box="[1098,1290,1573,1594]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A002FFFA2F5C5F737B1BF9D5" box="[1098,1290,1573,1594]" italics="true" pageId="16" pageNumber="531">Cymbospondylus</emphasis>
</taxonomicName>
arise from comparison of the three species (
<figureCitation id="1372F4A2A002FFFA2FB55F127AE3F9B5" box="[1187,1266,1604,1626]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="16" pageNumber="531">Fig. 11</figureCitation>
). Despite the diverse interpretations of the cheek region and skull roof of
<taxonomicName id="4C4993A4A002FFFA28855FD47A1FF978" box="[915,1038,1666,1687]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="16" pageNumber="531" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A002FFFA28855FD47A1FF978" box="[915,1038,1666,1687]" italics="true" pageId="16" pageNumber="531">C. petrinus</emphasis>
</taxonomicName>
, the long and slender bone stretching along the dorsolateral portion of the cheek region has been interpreted as the postfrontal or the fused pre- and postfrontal by previous authors (
<bibRefCitation id="EFD895D6A002FFFA28385FAA7DF7F8FE" author="Merriam JC" box="[814,998,1788,1810]" pageId="16" pageNumber="531" pagination="1 - 155" refId="ref16501" refString="Merriam JC. 1908. Triassic Ichthyosauria, with special reference to the American forms. Memoirs of the University of California 1: 1 - 155." type="journal article" year="1908">Merriam, 1908</bibRefCitation>
;
<bibRefCitation id="EFD895D6A002FFFA28EB5FAB7AC7F8FD" author="von Huene F" box="[1021,1238,1788,1810]" pageId="16" pageNumber="531" pagination="1 - 68" refId="ref16155" refString="von Huene F. 1916. Beitrage zur Kenntnis der Ichthyosaurier im deutschen Muschelkalk. Palaeontographica 62: 1 - 68." type="journal article" year="1916">von Huene, 1916</bibRefCitation>
;
<bibRefCitation id="EFD895D6A002FFFA2FF85FAB7B9BF8FD" author="Romer AS" box="[1262,1418,1788,1810]" pageId="16" pageNumber="531" refId="ref16746" refString="Romer AS. 1956. Osteology of the reptiles. Chicago: The University of Chicago Press." type="book" year="1956">Romer, 1956</bibRefCitation>
;
<bibRefCitation id="EFD895D6A002FFFA28305E4D7DA2F8DF" author="Camp CL" box="[806,947,1819,1840]" pageId="16" pageNumber="531" pagination="139 - 200" refId="ref16133" refString="Camp CL. 1980. Large ichthyosaurs from the Upper Triassic of Nevada. Palaeontographica A 170: 139 - 200." type="journal article" year="1980">Camp, 1980</bibRefCitation>
;
<bibRefCitation id="EFD895D6A002FFFA28D45E4D7A4FF8DF" author="Motani R" box="[962,1118,1819,1841]" pageId="16" pageNumber="531" pagination="473 - 496" refId="ref16529" refString="Motani R. 1999. Phylogeny of the Ichthyopterygia. Journal of Vertebrate Paleontology 19: 473 - 496." type="journal article" year="1999">Motani, 1999</bibRefCitation>
;
<bibRefCitation id="EFD895D6A002FFFA2F7B5E4D7B9BF8DF" author="Maisch MW &amp; Matzke AT" box="[1133,1418,1819,1841]" pageId="16" pageNumber="531" pagination="1 - 159" refId="ref16258" refString="Maisch MW, Matzke AT. 2000. The Ichthyosauria. Stuttgarter Beitrage zur Naturkunde 298: 1 - 159." type="journal article" year="2000">Maisch &amp; Matzke, 2000</bibRefCitation>
,
<bibRefCitation id="EFD895D6A002FFFA28305E6C7D71F8BF" author="Maisch MW &amp; Matzke AT" box="[806,864,1850,1872]" pageId="16" pageNumber="531" pagination="370 - 384" refId="ref16279" refString="Maisch MW, Matzke AT. 2004. Observations on Triassic ichthyosaurs. Part XIII: New data on the cranial steology of Cymbospondylus petrinus (Leidy, 1868) from the Middle Triassic Prida Formation of Nevada. Neues Jahrbuch fur Geologie und Palaontologie, Monatshefte 2004 (6): 370 - 384." type="journal article" year="2004">2004</bibRefCitation>
). The long, splint-like bone entering the posterolateral margin of the temporal opening in
<taxonomicName id="4C4993A4A003FFFB2BB45F337F30F995" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[162,289,1637,1658]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A003FFFB2BB45F337F30F995" box="[162,289,1637,1658]" italics="true" pageId="17" pageNumber="532">C. nichollsi</emphasis>
</taxonomicName>
(here interpreted as the supratemporal) is most certainly homologous to this bone. We believe the bone in
<taxonomicName id="4C4993A4A003FFFB2A8A5FF47C06F957" box="[412,535,1698,1720]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A003FFFB2A8A5FF47C06F957" box="[412,535,1698,1720]" italics="true" pageId="17" pageNumber="532">C. petrinus</emphasis>
</taxonomicName>
is the supratemporal, not the prefrontal.
</paragraph>
<caption id="DF36B8AFA003FFFB2BB45C2B7D1AF9CC" ID-DOI="http://doi.org/10.5281/zenodo.4634763" ID-Zenodo-Dep="4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="17" pageNumber="532" startId="17.[162,240,1405,1424]" targetBox="[166,774,194,1373]" targetPageId="17">
<paragraph id="8BF6E827A003FFFB2BB45C2B7D1AF9CC" blockId="17.[162,779,1405,1571]" pageId="17" pageNumber="532">
<emphasis id="B93D3435A003FFFB2BB45C2B7F06FA7F" bold="true" box="[162,279,1405,1424]" pageId="17" pageNumber="532">Figure 11.</emphasis>
Comparison of the lateral views of the postrostral skull regions of
<taxonomicName id="4C4993A4A003FFFB2A645CCC7C32FA42" authorityName="NICHOLLSI" authorityYear="2006" box="[370,547,1434,1453]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A003FFFB2A645CCC7C32FA42" box="[370,547,1434,1453]" italics="true" pageId="17" pageNumber="532">Cymbospondylus</emphasis>
</taxonomicName>
. A,
<emphasis id="B93D3435A003FFFB295E5CCC7F76FA24" bold="true" pageId="17" pageNumber="532">
<taxonomicName id="4C4993A4A003FFFB295E5CCC7F19FA25" authority="Fröbisch &amp; Sander &amp; Rieppel, 2006" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="nichollsi" status="sp. nov.">
<emphasis id="B93D3435A003FFFB295E5CCC7F19FA25" bold="true" italics="true" pageId="17" pageNumber="532">Cymbospondylus nichollsi</emphasis>
</taxonomicName>
<taxonomicNameLabel id="A20E894EA003FFFB2A065CEE7F76FA24" box="[272,359,1464,1483]" pageId="17" pageNumber="532" rank="species">sp. nov.</taxonomicNameLabel>
</emphasis>
, based on the holotype FMNH PR2251. B,
<taxonomicName id="4C4993A4A003FFFB2BA95C837F21FA07" box="[191,304,1493,1512]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A003FFFB2BA95C837F21FA07" box="[191,304,1493,1512]" italics="true" pageId="17" pageNumber="532">C. petrinus</emphasis>
</taxonomicName>
, based on UCMP 9950. C,
<taxonomicName id="4C4993A4A003FFFB29585C837CD0FA07" authorityName="Sander" authorityYear="1989" box="[590,705,1493,1512]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A003FFFB29585C837CD0FA07" box="[590,705,1493,1512]" italics="true" pageId="17" pageNumber="532">C. buchseri</emphasis>
</taxonomicName>
, based on PIMUZ 4351, modified after
<bibRefCitation id="EFD895D6A003FFFB2AEB5CA47CB3F9EA" author="Sander PM" box="[509,674,1522,1541]" pageId="17" pageNumber="532" pagination="163 - 173" refId="ref16814" refString="Sander PM. 1989 b. The large ichthyosaur Cymbospondylus buchseri, sp. nov. from the Middle Triassic of Monte San Giorgio (Switzerland), with a survey of the genus in Europe. Journal of Vertebrate Paleontology 9: 163 - 173." type="journal article" year="1989">Sander (1989b)</bibRefCitation>
. B and C are based on left sides of the skulls and have been inverted.
</paragraph>
</caption>
<paragraph id="8BF6E827A003FFFB2BAD5F897AD1FF17" blockId="17.[162,778,1637,1904]" lastBlockId="17.[826,1443,195,1904]" pageId="17" pageNumber="532">
Although a clear suture between pre- and postfrontal is not visible (due to a major crack) in specimen FMNH PR2251, the bone forming the posterior dorsal border of the orbit must be interpreted as the postfrontal, based on its location. In
<taxonomicName id="4C4993A4A003FFFB29475E0C7CDFF880" authorityName="Sander" authorityYear="1989" box="[593,718,1882,1903]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A003FFFB29475E0C7CDFF880" box="[593,718,1882,1903]" italics="true" pageId="17" pageNumber="532">C. buchseri</emphasis>
</taxonomicName>
, the postfrontal can be observed in the same position and with almost identical dimensions.
</paragraph>
<paragraph id="8BF6E827A003FFFB284558577DBFFD0D" blockId="17.[826,1443,195,1904]" pageId="17" pageNumber="532">
The splint-like bone in the dorsal cheek region of
<taxonomicName id="4C4993A4A003FFFB282C58767DA8FEDB" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[826,953,287,309]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A003FFFB282C58767DA8FEDB" box="[826,953,287,309]" italics="true" pageId="17" pageNumber="532">C. nichollsi</emphasis>
</taxonomicName>
is very probably not the postfrontal because it is clearly overlapped by the postorbital, which in turn is overlapped by the bone forming the posterodorsal margin of the orbit. This then would have to be interpreted as the prefrontal. Although it can be seen that the splint-like bone extends further anteriorly beneath the postorbital, there is only a slight contact, if any, with the bone forming the posterodorsal border of the orbit. Therefore, this interpretation would result in the postfrontal having been displaced far posteriorly and not making contact with either the prefrontal or the frontal. Because this is highly unlikely, a new interpretation of the configuration of the skull bones of all three species becomes necessary.
</paragraph>
<paragraph id="8BF6E827A003FFFB28455BBD7B89FB7F" blockId="17.[826,1443,195,1904]" pageId="17" pageNumber="532">
The slender, splint-like bone can be observed in
<taxonomicName id="4C4993A4A003FFFB282C5A5C7DA7FCCF" box="[826,950,778,800]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A003FFFB282C5A5C7DA7FCCF" box="[826,950,778,800]" italics="true" pageId="17" pageNumber="532">C. petrinus</emphasis>
</taxonomicName>
,
<taxonomicName id="4C4993A4A003FFFB28D35A5C7A55FCF0" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[965,1092,778,799]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A003FFFB28D35A5C7A55FCF0" box="[965,1092,778,799]" italics="true" pageId="17" pageNumber="532">C. nichollsi</emphasis>
</taxonomicName>
and, a little wider, but in the same position in
<taxonomicName id="4C4993A4A003FFFB28EF5A7F7A66FCD1" authorityName="Sander" authorityYear="1989" box="[1017,1143,809,830]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A003FFFB28EF5A7F7A66FCD1" box="[1017,1143,809,830]" italics="true" pageId="17" pageNumber="532">C. buchseri</emphasis>
</taxonomicName>
. In
<taxonomicName id="4C4993A4A003FFFB2FB45A7F7B0EFCD1" authorityName="Sander" authorityYear="1989" box="[1186,1311,809,830]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A003FFFB2FB45A7F7B0EFCD1" box="[1186,1311,809,830]" italics="true" pageId="17" pageNumber="532">C. buchseri</emphasis>
</taxonomicName>
it had originally been described by
<bibRefCitation id="EFD895D6A003FFFB2F465A117AECFCB2" author="Sander PM" box="[1104,1277,839,861]" pageId="17" pageNumber="532" pagination="163 - 173" refId="ref16814" refString="Sander PM. 1989 b. The large ichthyosaur Cymbospondylus buchseri, sp. nov. from the Middle Triassic of Monte San Giorgio (Switzerland), with a survey of the genus in Europe. Journal of Vertebrate Paleontology 9: 163 - 173." type="journal article" year="1989">Sander (1989b)</bibRefCitation>
as squamosal, based on the suggestion of Romer and Camp (in
<bibRefCitation id="EFD895D6A003FFFB2E445A317D63FC74" author="Romer AS" pageId="17" pageNumber="532" pagination="27 - 41" refId="ref16764" refString="Romer AS. 1968. An ichthyosaur skull from the Cretaceous of Wyoming. Contributions to Geology, University of Wyoming 7: 27 - 41." type="journal article" year="1968">Romer, 1968</bibRefCitation>
) and
<bibRefCitation id="EFD895D6A003FFFB28AC5AD37A6FFC74" author="McGowan C" box="[954,1150,901,923]" pageId="17" pageNumber="532" pagination="1 - 109" refId="ref16415" refString="McGowan C. 1973. The cranial morphology of the Lower Liassic latipinnate ichthyosaurs of England. Bulletin of the British Museum (Natural History), Geology 93: 1 - 109." type="journal article" year="1973">McGowan (1973)</bibRefCitation>
that a supratemporal is absent in ichthyosaurs. This interpretation of the absence of a supratemporal was revised by
<bibRefCitation id="EFD895D6A003FFFB2E305A957DE5FC18" author="Massare JA &amp; Callaway JM" pageId="17" pageNumber="532" pagination="409 - 416" refId="ref16359" refString="Massare JA, Callaway JM. 1990. The affinities and ecology of Triassic ichthyosaurs. Geological Society of America Bulletin 102: 409 - 416." type="journal article" year="1990">Massare &amp; Callaway (1990)</bibRefCitation>
based on their study of the early ichthyosaur
<taxonomicName id="4C4993A4A003FFFB28BD5D567A15FBFA" box="[939,1028,1024,1045]" class="Reptilia" family="Grippiidae" genus="Grippia" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A003FFFB28BD5D567A15FBFA" box="[939,1028,1024,1045]" italics="true" pageId="17" pageNumber="532">Grippia</emphasis>
</taxonomicName>
. Later studies unequivocally documented the presence of a supratemporal in various ichthyosaurs (
<bibRefCitation id="EFD895D6A003FFFB28C95D6B7B34FBBC" author="Nicholls EL &amp; Brinkman DB" box="[991,1317,1085,1107]" pageId="17" pageNumber="532" pagination="521 - 535" refId="ref16577" refString="Nicholls EL, Brinkman DB. 1996. A new ichthyosaur from the Triassic Sulphur Mountain Formation of British Columbia. In: Sarjeant WAS, ed. Vertebrate fossils and the evolution of scientific concepts. Reading: Gordon and Breach Publishers, 521 - 535." type="book chapter" year="1996">Nicholls &amp; Brinkman, 1996</bibRefCitation>
;
<bibRefCitation id="EFD895D6A003FFFB2E225D6B7D62FB9E" author="Callaway JM" pageId="17" pageNumber="532" pagination="45 - 59" refId="ref16098" refString="Callaway JM. 1997. A new look at Mixosaurus. In: Callaway JM, Nicholls EL, eds. Ancient marine reptiles. San Diego: Academic Press, 45 - 59." type="book chapter" year="1997">Callaway, 1997</bibRefCitation>
;
<bibRefCitation id="EFD895D6A003FFFB28945D0D7A0CFB9E" author="Maisch MW" box="[898,1053,1115,1137]" pageId="17" pageNumber="532" pagination="111 - 127" refId="ref16229" refString="Maisch MW. 1997. A case against the diapsid origin of the Ichthyosauria. Neues Jahrbuch fur Geologie und Palaontologie. Abhandlungen 205: 111 - 127." type="journal article" year="1997">Maisch, 1997</bibRefCitation>
;
<bibRefCitation id="EFD895D6A003FFFB2F3A5D0D7B8FFB9E" author="Motani R &amp; Minoura N &amp; Ando T" box="[1068,1438,1115,1137]" pageId="17" pageNumber="532" pagination="255 - 257" refId="ref16549" refString="Motani R, Minoura N, Ando T. 1998. Ichthyosaurian relationships illuminated by new primitive skeletons from Japan. Nature 393: 255 - 257." type="journal article" year="1998">Motani, Minoura &amp; Ando, 1998</bibRefCitation>
;
<bibRefCitation id="EFD895D6A003FFFB282C5D2C7DC3FB60" author="Motani R" box="[826,978,1146,1168]" pageId="17" pageNumber="532" pagination="473 - 496" refId="ref16529" refString="Motani R. 1999. Phylogeny of the Ichthyopterygia. Journal of Vertebrate Paleontology 19: 473 - 496." type="journal article" year="1999">Motani, 1999</bibRefCitation>
;
<bibRefCitation id="EFD895D6A003FFFB28CB5D2C7B9CFB7F" author="Nicholls EL &amp; Brinkman DB &amp; Callaway JM" box="[989,1421,1146,1168]" pageId="17" pageNumber="532" pagination="1 - 22" refId="ref16625" refString="Nicholls EL, Brinkman DB, Callaway JM. 1999. New material of Phalarodon (Reptilia: Ichthyosauria) from the Triassic of British Columbia and its bearings on the interrelationships of mixosaurs. Palaeontographica A 252: 1 - 22." type="journal article" year="1999">Nicholls, Brinkman &amp; Callaway, 1999</bibRefCitation>
).
</paragraph>
<paragraph id="8BF6E827A003FFFB28455DCF7B10F89F" blockId="17.[826,1443,195,1904]" pageId="17" pageNumber="532">
Owing to its location at the posterolateral margin of the upper temporal opening, the splint-like bone is here interpreted as the supratemporal (
<figureCitation id="1372F4A2A003FFFB2E065D807B4EFB03" box="[1296,1375,1238,1260]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="17" pageNumber="532">Fig. 11</figureCitation>
). The bone shelf forming the border of the orbit in
<taxonomicName id="4C4993A4A003FFFB282C5C427DA7FAC6" box="[826,950,1300,1321]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A003FFFB282C5C427DA7FAC6" box="[826,950,1300,1321]" italics="true" pageId="17" pageNumber="532">C. petrinus</emphasis>
</taxonomicName>
consequently is formed by the pre- and postfrontal, with its posterior suture situated directly above the highest point of the orbit. The prefrontal is very small and makes contact with the postfrontal in a weakly visible suture, about halfway above the ascending anterior margin of the orbit (
<bibRefCitation id="EFD895D6A003FFFB2E1C5CFB7B8FFA2C" author="Romer AS" box="[1290,1438,1453,1475]" pageId="17" pageNumber="532" refId="ref16746" refString="Romer AS. 1956. Osteology of the reptiles. Chicago: The University of Chicago Press." type="book" year="1956">Romer, 1956</bibRefCitation>
: fig. 85a;
<bibRefCitation id="EFD895D6A003FFFB288F5C9A7A4DFA0E" author="von Huene F" box="[921,1116,1483,1505]" pageId="17" pageNumber="532" pagination="1 - 68" refId="ref16155" refString="von Huene F. 1916. Beitrage zur Kenntnis der Ichthyosaurier im deutschen Muschelkalk. Palaeontographica 62: 1 - 68." type="journal article" year="1916">von Huene, 1916</bibRefCitation>
: fig. 79; own observations on specimen UCMP 9950). In
<taxonomicName id="4C4993A4A003FFFB2F625CBC7AFEF9EF" box="[1140,1263,1514,1536]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A003FFFB2F625CBC7AFEF9EF" box="[1140,1263,1514,1536]" italics="true" pageId="17" pageNumber="532">C. petrinus</emphasis>
</taxonomicName>
, the supratemporal anteriorly makes contact with the long posterior process of the nasal as well as with the postfrontal and postorbital. In
<taxonomicName id="4C4993A4A003FFFB28F25F107A70F9B4" authorityName="Sander" authorityYear="1989" box="[996,1121,1606,1627]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A003FFFB28F25F107A70F9B4" box="[996,1121,1606,1627]" italics="true" pageId="17" pageNumber="532">C. buchseri</emphasis>
</taxonomicName>
, it additionally contacts the prefrontal; in
<taxonomicName id="4C4993A4A003FFFB28F05F337A75F995" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[998,1124,1637,1658]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A003FFFB28F05F337A75F995" box="[998,1124,1637,1658]" italics="true" pageId="17" pageNumber="532">C. nichollsi</emphasis>
</taxonomicName>
, by contrast, the anterior portion of the supratemporal is overlapped by the postorbital, which reaches far dorsally towards the border of the temporal opening. However, in
<taxonomicName id="4C4993A4A003FFFB2FE35F977B62F939" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1269,1395,1729,1750]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="17" pageNumber="532" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A003FFFB2FE35F977B62F939" box="[1269,1395,1729,1750]" italics="true" pageId="17" pageNumber="532">C. nichollsi</emphasis>
</taxonomicName>
the slender supratemporal also extends further anterior, but beneath the postorbital, towards the posterior margin of the postfrontal and the posterior process of the nasal. The supratemporal therefore has a similar extent and location in all three species.
</paragraph>
<caption id="DF36B8AFA000FFF82B9859927B1AFF38" ID-Table-UUID="DF36B8AFA000FFF82B9859927B1AFF38" box="[142,1291,196,215]" httpUri="http://table.plazi.org/id/DF36B8AFA000FFF82B9859927B1AFF38" pageId="18" pageNumber="533" startId="18.[142,206,196,215]" targetBox="[142,1423,254,655]" targetIsTable="true" targetPageId="18">
<paragraph id="8BF6E827A000FFF82B9859927B1AFF38" blockId="18.[142,1291,196,215]" box="[142,1291,196,215]" pageId="18" pageNumber="533">
<emphasis id="B93D3435A000FFF82B9859927EF9FF38" bold="true" box="[142,232,196,215]" pageId="18" pageNumber="533">Table 2.</emphasis>
Comparison of significant measurements of
<taxonomicName id="4C4993A4A000FFF829DE59927DC7FF39" box="[712,982,196,215]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF829DE59927DC7FF39" box="[712,982,196,215]" italics="true" pageId="18" pageNumber="533">Cymbospondylus petrinus</emphasis>
</taxonomicName>
,
<taxonomicName id="4C4993A4A000FFF828F359927A48FF38" authorityName="Sander" authorityYear="1989" box="[997,1113,196,215]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A000FFF828F359927A48FF38" box="[997,1113,196,215]" italics="true" pageId="18" pageNumber="533">C. buchseri</emphasis>
</taxonomicName>
, and
<taxonomicName id="4C4993A4A000FFF82F8059927B1AFF38" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1174,1291,196,215]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="nichollsi">C. nichollsi</taxonomicName>
</paragraph>
</caption>
<paragraph id="8BF6E827A000FFF8297059A97AD6FD60" pageId="18" pageNumber="533">
<table id="F9491A87A00000152B9859A87B9EFD60" box="[142,1423,254,655]" colsContinueIn="20.[142,1420,1629,1883]" gridcols="4" gridrows="13" pageId="18" pageNumber="533">
<tr id="3579EA65A00000152B9859A87B9EFEFD" box="[142,1423,254,274]" gridrow="0" pageId="18" pageNumber="533" rowspan-0="1">
<th id="76A88319A0000015297059A87D1DFEFD" box="[614,780,254,274]" gridcol="1" gridrow="0" pageId="18" pageNumber="533">
<taxonomicName id="4C4993A4A000FFF8297059A97CC8FEFE" box="[614,729,255,274]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF8297059A97CC8FEFE" box="[614,729,255,274]" italics="true" pageId="18" pageNumber="533">C. petrinus</emphasis>
</taxonomicName>
</th>
<th id="76A88319A0000015286859A87A3CFEFD" box="[894,1069,254,274]" gridcol="2" gridrow="0" pageId="18" pageNumber="533">
<taxonomicName id="4C4993A4A000FFF8286859A97DE2FEFE" authorityName="Sander" authorityYear="1989" box="[894,1011,254,274]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A000FFF8286859A97DE2FEFE" box="[894,1011,254,274]" italics="true" pageId="18" pageNumber="533">C. buchseri</emphasis>
</taxonomicName>
</th>
<th id="76A88319A00000152FB759A87B9EFEFD" box="[1185,1423,254,274]" gridcol="3" gridrow="0" pageId="18" pageNumber="533">
<taxonomicName id="4C4993A4A000FFF82FB759A97B06FEFE" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1185,1303,254,274]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A000FFF82FB759A97B06FEFE" box="[1185,1303,254,274]" italics="true" pageId="18" pageNumber="533">C. nichollsi</emphasis>
</taxonomicName>
</th>
</tr>
<tr id="3579EA65A00000152B98584A7B9EFEC0" box="[142,1423,284,303]" gridrow="1" pageId="18" pageNumber="533">
<th id="76A88319A00000152B98584A7FE3FEC0" box="[142,498,284,303]" gridcol="0" gridrow="1" pageId="18" pageNumber="533">Measurement (in mm)</th>
<td id="76A88319A00000152970584A7D1DFEC0" box="[614,780,284,303]" gridcol="1" gridrow="1" pageId="18" pageNumber="533">UCMP 9950</td>
<td id="76A88319A00000152868584A7A3CFEC0" box="[894,1069,284,303]" gridcol="2" gridrow="1" pageId="18" pageNumber="533">PIMUZ 4351</td>
<td id="76A88319A00000152FB7584A7B9EFEC0" box="[1185,1423,284,303]" gridcol="3" gridrow="1" pageId="18" pageNumber="533">FMNH PR2251</td>
</tr>
<tr id="3579EA65A00000152B9858007B9EFE86" box="[142,1423,342,361]" gridrow="2" pageId="18" pageNumber="533">
<th id="76A88319A00000152B9858007FE3FE86" box="[142,498,342,361]" gridcol="0" gridrow="2" pageId="18" pageNumber="533">Length of skull</th>
<td id="76A88319A0000015297058007D1DFE86" box="[614,780,342,361]" gridcol="1" gridrow="2" pageId="18" pageNumber="533">1166</td>
<td id="76A88319A0000015286858007A3CFE86" box="[894,1069,342,361]" gridcol="2" gridrow="2" pageId="18" pageNumber="533">680</td>
<td id="76A88319A00000152FB758007B9EFE86" box="[1185,1423,342,361]" gridcol="3" gridrow="2" pageId="18" pageNumber="533">975 (estimated)</td>
</tr>
<tr id="3579EA65A00000152B9858227B9EFE68" box="[142,1423,372,391]" gridrow="3" pageId="18" pageNumber="533" rowspan-0="1" rowspan-1="1" rowspan-2="1">
<td id="76A88319A00000152FB758227B9EFE68" box="[1185,1423,372,391]" gridcol="3" gridrow="3" pageId="18" pageNumber="533">(preserved length 515)</td>
</tr>
<tr id="3579EA65A00000152B9858C77B9EFE4A" box="[142,1423,401,421]" gridrow="4" pageId="18" pageNumber="533">
<th id="76A88319A00000152B9858C77FE3FE4A" box="[142,498,401,421]" gridcol="0" gridrow="4" pageId="18" pageNumber="533">Skull length posterior to nares</th>
<td id="76A88319A0000015297058C77D1DFE4A" box="[614,780,401,421]" gridcol="1" gridrow="4" pageId="18" pageNumber="533">530</td>
<td id="76A88319A0000015286858C77A3CFE4A" box="[894,1069,401,421]" gridcol="2" gridrow="4" pageId="18" pageNumber="533">?</td>
<td id="76A88319A00000152FB758C77B9EFE4A" box="[1185,1423,401,421]" gridcol="3" gridrow="4" pageId="18" pageNumber="533">443</td>
</tr>
<tr id="3579EA65A00000152B9858F87B9EFE2D" box="[142,1423,430,450]" gridrow="5" pageId="18" pageNumber="533">
<th id="76A88319A00000152B9858F87FE3FE2D" box="[142,498,430,450]" gridcol="0" gridrow="5" pageId="18" pageNumber="533">Length of orbit</th>
<td id="76A88319A0000015297058F87D1DFE2D" box="[614,780,430,450]" gridcol="1" gridrow="5" pageId="18" pageNumber="533">198</td>
<td id="76A88319A0000015286858F87A3CFE2D" box="[894,1069,430,450]" gridcol="2" gridrow="5" pageId="18" pageNumber="533">158</td>
<td id="76A88319A00000152FB758F87B9EFE2D" box="[1185,1423,430,450]" gridcol="3" gridrow="5" pageId="18" pageNumber="533">200</td>
</tr>
<tr id="3579EA65A00000152B98589A7B9EFE30" box="[142,1423,460,479]" gridrow="6" pageId="18" pageNumber="533">
<th id="76A88319A00000152B98589A7FE3FE30" box="[142,498,460,479]" gridcol="0" gridrow="6" pageId="18" pageNumber="533">Height of orbit</th>
<td id="76A88319A00000152970589A7D1DFE30" box="[614,780,460,479]" gridcol="1" gridrow="6" pageId="18" pageNumber="533">115</td>
<td id="76A88319A00000152868589A7A3CFE30" box="[894,1069,460,479]" gridcol="2" gridrow="6" pageId="18" pageNumber="533">100</td>
<td id="76A88319A00000152FB7589A7B9EFE30" box="[1185,1423,460,479]" gridcol="3" gridrow="6" pageId="18" pageNumber="533">128</td>
</tr>
<tr id="3579EA65A00000152B9858BF7B9EFE13" box="[142,1423,489,508]" gridrow="7" pageId="18" pageNumber="533">
<th id="76A88319A00000152B9858BF7FE3FE13" box="[142,498,489,508]" gridcol="0" gridrow="7" pageId="18" pageNumber="533">Length of cheek region</th>
<td id="76A88319A0000015297058BF7D1DFE13" box="[614,780,489,508]" gridcol="1" gridrow="7" pageId="18" pageNumber="533">251</td>
<td id="76A88319A0000015286858BF7A3CFE13" box="[894,1069,489,508]" gridcol="2" gridrow="7" pageId="18" pageNumber="533">?</td>
<td id="76A88319A00000152FB758BF7B9EFE13" box="[1185,1423,489,508]" gridcol="3" gridrow="7" pageId="18" pageNumber="533">240</td>
</tr>
<tr id="3579EA65A00000152B985B507B9EFDF5" box="[142,1423,518,538]" gridrow="8" pageId="18" pageNumber="533">
<th id="76A88319A00000152B985B507FE3FDF5" box="[142,498,518,538]" gridcol="0" gridrow="8" pageId="18" pageNumber="533">Preserved length of lower jaw</th>
<td id="76A88319A000001529705B507D1DFDF5" box="[614,780,518,538]" gridcol="1" gridrow="8" pageId="18" pageNumber="533">1180 (complete)</td>
<td id="76A88319A000001528685B507A3CFDF5" box="[894,1069,518,538]" gridcol="2" gridrow="8" pageId="18" pageNumber="533">655 (incomplete)</td>
<td id="76A88319A00000152FB75B507B9EFDF5" box="[1185,1423,518,538]" gridcol="3" gridrow="8" pageId="18" pageNumber="533">434 (incomplete)</td>
</tr>
<tr id="3579EA65A00000152B985B727B9EFDD8" box="[142,1423,548,567]" gridrow="9" pageId="18" pageNumber="533">
<th id="76A88319A00000152B985B727FE3FDD8" box="[142,498,548,567]" gridcol="0" gridrow="9" pageId="18" pageNumber="533">Postdentary length of lower jaw</th>
<td id="76A88319A000001529705B727D1DFDD8" box="[614,780,548,567]" gridcol="1" gridrow="9" pageId="18" pageNumber="533">319</td>
<td id="76A88319A000001528685B727A3CFDD8" box="[894,1069,548,567]" gridcol="2" gridrow="9" pageId="18" pageNumber="533">205</td>
<td id="76A88319A00000152FB75B727B9EFDD8" box="[1185,1423,548,567]" gridcol="3" gridrow="9" pageId="18" pageNumber="533">364</td>
</tr>
<tr id="3579EA65A00000152B985B177B9EFDBB" box="[142,1423,577,596]" gridrow="10" pageId="18" pageNumber="533">
<th id="76A88319A00000152B985B177FE3FDBB" box="[142,498,577,596]" gridcol="0" gridrow="10" pageId="18" pageNumber="533">Length of clavicle</th>
<td id="76A88319A000001529705B177D1DFDBB" box="[614,780,577,596]" gridcol="1" gridrow="10" pageId="18" pageNumber="533">428</td>
<td id="76A88319A000001528685B177A3CFDBB" box="[894,1069,577,596]" gridcol="2" gridrow="10" pageId="18" pageNumber="533">230</td>
<td id="76A88319A00000152FB75B177B9EFDBB" box="[1185,1423,577,596]" gridcol="3" gridrow="10" pageId="18" pageNumber="533">400</td>
</tr>
<tr id="3579EA65A00000152B985B087B9EFD9D" box="[142,1423,606,626]" gridrow="11" pageId="18" pageNumber="533">
<th id="76A88319A00000152B985B087FE3FD9D" box="[142,498,606,626]" gridcol="0" gridrow="11" pageId="18" pageNumber="533">Coracoid – mediolateral width</th>
<td id="76A88319A000001529705B087D1DFD9D" box="[614,780,606,626]" gridcol="1" gridrow="11" pageId="18" pageNumber="533">239</td>
<td id="76A88319A000001528685B087A3CFD9D" box="[894,1069,606,626]" gridcol="2" gridrow="11" pageId="18" pageNumber="533">?</td>
<td id="76A88319A00000152FB75B087B9EFD9D" box="[1185,1423,606,626]" gridcol="3" gridrow="11" pageId="18" pageNumber="533">150</td>
</tr>
<tr id="3579EA65A00000152B985B2A7B9EFD60" box="[142,1423,636,655]" gridrow="12" pageId="18" pageNumber="533">
<th id="76A88319A00000152B985B2A7FE3FD60" box="[142,498,636,655]" gridcol="0" gridrow="12" pageId="18" pageNumber="533">Coracoid – anteroposterior length</th>
<td id="76A88319A000001529705B2A7D1DFD60" box="[614,780,636,655]" gridcol="1" gridrow="12" pageId="18" pageNumber="533">306</td>
<td id="76A88319A000001528685B2A7A3CFD60" box="[894,1069,636,655]" gridcol="2" gridrow="12" pageId="18" pageNumber="533">?</td>
<td id="76A88319A00000152FB75B2A7B9EFD60" box="[1185,1423,636,655]" gridcol="3" gridrow="12" pageId="18" pageNumber="533">210</td>
</tr>
</table>
</paragraph>
<paragraph id="8BF6E827A000FFF82BB15BBA7F02FA0E" blockId="18.[142,758,747,1904]" pageId="18" pageNumber="533">
A suture that is particularly clearly visible in
<taxonomicName id="4C4993A4A000FFF82B985A5C7F18FCCF" box="[142,265,778,800]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF82B985A5C7F18FCCF" box="[142,265,778,800]" italics="true" pageId="18" pageNumber="533">C. petrinus</emphasis>
</taxonomicName>
specimen UCMP 9950 runs along the lateral walls of the parietal crest in dorsoventral direction into the upper temporal opening. Although the lateral walls of the parietal plateau are superficially fractured in
<taxonomicName id="4C4993A4A000FFF82A325AD37FB2FC75" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[292,419,901,922]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A000FFF82A325AD37FB2FC75" box="[292,419,901,922]" italics="true" pageId="18" pageNumber="533">C. nichollsi</emphasis>
</taxonomicName>
, an overlapping suture with somewhat broken, frayed edges can be seen on both sides of the skull in the same position as in
<taxonomicName id="4C4993A4A000FFF82B985AB77F18FC19" box="[142,265,993,1014]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF82B985AB77F18FC19" box="[142,265,993,1014]" italics="true" pageId="18" pageNumber="533">C. petrinus</emphasis>
</taxonomicName>
. This observation implies that an additional skull bone posterior to the parietals forms a large part of the back of the skull in
<taxonomicName id="4C4993A4A000FFF829385D487CFFFBDC" authorityName="NICHOLLSI" authorityYear="2006" box="[558,750,1054,1075]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A000FFF829385D487CFFFBDC" box="[558,750,1054,1075]" italics="true" pageId="18" pageNumber="533">Cymbospondylus</emphasis>
</taxonomicName>
. This skull bone extends laterally around the posterior margin of the upper temporal opening, and contributes to the posterodorsal part of the cheek region, where it is separated from the squamosal by clearly visible sutures in both
<taxonomicName id="4C4993A4A000FFF82AB85DEE7C3BFB22" box="[430,554,1208,1229]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF82AB85DEE7C3BFB22" box="[430,554,1208,1229]" italics="true" pageId="18" pageNumber="533">C. petrinus</emphasis>
</taxonomicName>
and
<taxonomicName id="4C4993A4A000FFF829665DEE7CFEFB23" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[624,751,1207,1229]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A000FFF829665DEE7CFEFB23" box="[624,751,1207,1229]" italics="true" pageId="18" pageNumber="533">C. nichollsi</emphasis>
</taxonomicName>
. This pattern can be inferred for
<taxonomicName id="4C4993A4A000FFF829025D807C83FB04" authorityName="Sander" authorityYear="1989" box="[532,658,1238,1259]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A000FFF829025D807C83FB04" box="[532,658,1238,1259]" italics="true" pageId="18" pageNumber="533">C. buchseri</emphasis>
</taxonomicName>
as well. The right medial surface of the parietal plateau is visible in
<taxonomicName id="4C4993A4A000FFF82BCA5C427C02FAC6" authority="(Sander, 1989 b)" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[220,531,1299,1321]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A000FFF82BCA5C427F48FAC7" box="[220,345,1299,1321]" italics="true" pageId="18" pageNumber="533">C. buchseri</emphasis>
(
<bibRefCitation id="EFD895D6A000FFF82A715C457C1BFAC6" author="Sander PM" box="[359,522,1299,1321]" pageId="18" pageNumber="533" pagination="163 - 173" refId="ref16814" refString="Sander PM. 1989 b. The large ichthyosaur Cymbospondylus buchseri, sp. nov. from the Middle Triassic of Monte San Giorgio (Switzerland), with a survey of the genus in Europe. Journal of Vertebrate Paleontology 9: 163 - 173." type="journal article" year="1989">Sander, 1989b</bibRefCitation>
)
</taxonomicName>
, and in its posterior region an overlapping suture of the parietal with a posteriorly attaching skull bone is visible. Because the suture is exposed from the medial side in
<taxonomicName id="4C4993A4A000FFF829645C267CFEFA6B" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[626,751,1391,1413]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A000FFF829645C267CFEFA6B" box="[626,751,1391,1413]" italics="true" pageId="18" pageNumber="533">C. buchseri</emphasis>
</taxonomicName>
, the pattern of overlap of the two skull bones in question is opposite to that seen in
<taxonomicName id="4C4993A4A000FFF829555CFB7CAEFA2D" box="[579,703,1453,1474]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF829555CFB7CAEFA2D" box="[579,703,1453,1474]" italics="true" pageId="18" pageNumber="533">C. petrinus</emphasis>
</taxonomicName>
and
<taxonomicName id="4C4993A4A000FFF82B985C9A7F1DFA0F" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[142,268,1483,1505]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A000FFF82B985C9A7F1DFA0F" box="[142,268,1483,1505]" italics="true" pageId="18" pageNumber="533">C. nichollsi</emphasis>
</taxonomicName>
.
</paragraph>
<paragraph id="8BF6E827A000FFF82BB15CBC7FDAF976" blockId="18.[142,758,747,1904]" pageId="18" pageNumber="533">
The small strip of bone extending along the dorsal margin of the supratemporal in
<taxonomicName id="4C4993A4A000FFF8291D5F5F7C99F9F1" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[523,648,1545,1566]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A000FFF8291D5F5F7C99F9F1" box="[523,648,1545,1566]" italics="true" pageId="18" pageNumber="533">C. buchseri</emphasis>
</taxonomicName>
(
<figureCitation id="1372F4A2A000FFF8298F5F5F7CF6F9F0" box="[665,743,1545,1567]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="18" pageNumber="533">Fig. 11</figureCitation>
), interpreted as a possible posterolateral process of the frontal by
<bibRefCitation id="EFD895D6A000FFF82A135F107FA4F9B3" author="Sander PM" box="[261,437,1606,1628]" pageId="18" pageNumber="533" pagination="163 - 173" refId="ref16814" refString="Sander PM. 1989 b. The large ichthyosaur Cymbospondylus buchseri, sp. nov. from the Middle Triassic of Monte San Giorgio (Switzerland), with a survey of the genus in Europe. Journal of Vertebrate Paleontology 9: 163 - 173." type="journal article" year="1989">Sander (1989b)</bibRefCitation>
, could represent the anterolateral process of the additional skull bone as in
<taxonomicName id="4C4993A4A000FFF82B985FD27F18F976" box="[142,265,1668,1689]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF82B985FD27F18F976" box="[142,265,1668,1689]" italics="true" pageId="18" pageNumber="533">C. petrinus</emphasis>
</taxonomicName>
and
<taxonomicName id="4C4993A4A000FFF82A535FD27FD5F977" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[325,452,1667,1689]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A000FFF82A535FD27FD5F977" box="[325,452,1667,1689]" italics="true" pageId="18" pageNumber="533">C. nichollsi</emphasis>
</taxonomicName>
.
</paragraph>
<paragraph id="8BF6E827A000FFF82BB15FF47C65F89F" blockId="18.[142,758,747,1904]" pageId="18" pageNumber="533">
What is the homology of the additional skull bone in
<taxonomicName id="4C4993A4A000FFF82B985F977F5FF939" authority="One" authorityName="NICHOLLSI" authorityYear="2006" box="[142,334,1729,1750]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A000FFF82B985F977F5FF939" box="[142,334,1729,1750]" italics="true" pageId="18" pageNumber="533">Cymbospondylus</emphasis>
</taxonomicName>
? One possibility is that it represents a neomorphic structure unique to the genus. Another interpretation, avoiding the assumption of a neomorphic bone, is its identification as the postparietal, which in primitive diapsids is located posterior to the parietal and medial to the supratemporal.
</paragraph>
<paragraph id="8BF6E827A000FFF828295BBD7B98FCD0" blockId="18.[806,1422,747,1383]" pageId="18" pageNumber="533">
The presence of an unpaired postparietal bone positioned at the dorsal edge of the occipital plane has recently been suggested by
<bibRefCitation id="EFD895D6A000FFF82F735A7F7B94FCD0" author="Maisch MW &amp; Matzke AT" box="[1125,1413,809,831]" pageId="18" pageNumber="533" pagination="370 - 384" refId="ref16279" refString="Maisch MW, Matzke AT. 2004. Observations on Triassic ichthyosaurs. Part XIII: New data on the cranial steology of Cymbospondylus petrinus (Leidy, 1868) from the Middle Triassic Prida Formation of Nevada. Neues Jahrbuch fur Geologie und Palaontologie, Monatshefte 2004 (6): 370 - 384." type="journal article" year="2004">Maisch &amp; Matzke (2004)</bibRefCitation>
.
</paragraph>
<paragraph id="8BF6E827A000FFF828295A117B4EFBBC" blockId="18.[806,1422,747,1383]" pageId="18" pageNumber="533">
The presence of a separate bone in this area in
<taxonomicName id="4C4993A4A000FFF828305A307DB0FC93" box="[806,929,870,892]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF828305A307DB0FC93" box="[806,929,870,892]" italics="true" pageId="18" pageNumber="533">C. petrinus</emphasis>
</taxonomicName>
was not identified during our observations of specimens in the collection of the Paleontological Museum in Berkeley in 2002 and can therefore not be corroborated here. The paired bone discussed in this paper as a possible postparietal or neomorphic element is a different one from that identified as postparietal by
<bibRefCitation id="EFD895D6A000FFF8288F5D487AD6FBDB" author="Maisch MW &amp; Matzke AT" box="[921,1223,1054,1076]" pageId="18" pageNumber="533" pagination="370 - 384" refId="ref16279" refString="Maisch MW, Matzke AT. 2004. Observations on Triassic ichthyosaurs. Part XIII: New data on the cranial steology of Cymbospondylus petrinus (Leidy, 1868) from the Middle Triassic Prida Formation of Nevada. Neues Jahrbuch fur Geologie und Palaontologie, Monatshefte 2004 (6): 370 - 384." type="journal article" year="2004">Maisch &amp; Matzke (2004)</bibRefCitation>
, and is situated posterodorsally, forming the posterior skull table.
</paragraph>
<paragraph id="8BF6E827A000FFF828295D0A7AC1FA89" blockId="18.[806,1422,747,1383]" pageId="18" pageNumber="533">
However, the find of the new species of
<taxonomicName id="4C4993A4A000FFF82E215D0D7D89FB60" authorityName="NICHOLLSI" authorityYear="2006" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A000FFF82E215D0D7D89FB60" italics="true" pageId="18" pageNumber="533">Cymbospondylus</emphasis>
</taxonomicName>
described here as well as the recent different interpretations of the osteology of the skull of this taxon (
<bibRefCitation id="EFD895D6A000FFF8286A5DE17AC5FB22" author="Maisch MW &amp; Matzke AT" box="[892,1236,1207,1229]" pageId="18" pageNumber="533" pagination="1 - 159" refId="ref16258" refString="Maisch MW, Matzke AT. 2000. The Ichthyosauria. Stuttgarter Beitrage zur Naturkunde 298: 1 - 159." type="journal article" year="2000">Maisch &amp; Matzke, 2000: 64</bibRefCitation>
,
<bibRefCitation id="EFD895D6A000FFF82FF15DEE7B31FB22" author="Maisch MW &amp; Matzke AT" box="[1255,1312,1208,1229]" pageId="18" pageNumber="533" pagination="370 - 384" refId="ref16279" refString="Maisch MW, Matzke AT. 2004. Observations on Triassic ichthyosaurs. Part XIII: New data on the cranial steology of Cymbospondylus petrinus (Leidy, 1868) from the Middle Triassic Prida Formation of Nevada. Neues Jahrbuch fur Geologie und Palaontologie, Monatshefte 2004 (6): 370 - 384." type="journal article" year="2004">2004</bibRefCitation>
;
<bibRefCitation id="EFD895D6A000FFF82E255DE17D4FFB03" author="Stocker NB" pageId="18" pageNumber="533" pagination="53" refId="ref17060" refString="Stocker NB. 2003. A new species of Cymbospondylus (Reptilia, Ichthyosauria) from the Middle Triassic of Nevada and its implications for the skull osteology of this genus. Journal of Vertebrate Paleontology 23 (3) (Suppl.): 53 A." type="journal article" year="2003">Stöcker, 2003</bibRefCitation>
) clearly underline the peculiarity of the genus. Further preparation of the best-known specimen of
<taxonomicName id="4C4993A4A000FFF828305C427DEDFAC6" authority=", UCMP" authorityName="UCMP" box="[806,1020,1300,1321]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF828305C427DB0FAC6" box="[806,929,1300,1321]" italics="true" pageId="18" pageNumber="533">C. petrinus</emphasis>
, UCMP
</taxonomicName>
9950, and further finds will be necessary for a better understanding of this taxon and the final resolution of its skull osteology.
</paragraph>
<paragraph id="8BF6E827A000FFF828305CD87B15F8FB" blockId="18.[806,1422,1422,1904]" pageId="18" pageNumber="533">
<emphasis id="B93D3435A000FFF828305CD87B45FA4B" box="[806,1364,1422,1444]" italics="true" pageId="18" pageNumber="533">Comparison of cheek region and occipital region:</emphasis>
The posterior cheek region, consisting of the quadratojugal and squamosal, is missing in
<taxonomicName id="4C4993A4A000FFF82F995C9A7B1DFA0F" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[1167,1292,1483,1505]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A000FFF82F995C9A7B1DFA0F" box="[1167,1292,1483,1505]" italics="true" pageId="18" pageNumber="533">C. buchseri</emphasis>
</taxonomicName>
(
<figureCitation id="1372F4A2A000FFF82E365C9D7B90FA0D" box="[1312,1409,1483,1506]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="18" pageNumber="533">Fig. 11C</figureCitation>
), but the shape of the postorbital is similar to that of
<taxonomicName id="4C4993A4A000FFF828305F5F7DB0F9F1" box="[806,929,1545,1566]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF828305F5F7DB0F9F1" box="[806,929,1545,1566]" italics="true" pageId="18" pageNumber="533">C. petrinus</emphasis>
</taxonomicName>
. The jugal posteriorly encompasses the posteroventral portion of the postorbital in
<taxonomicName id="4C4993A4A000FFF82E045F7E7B9FF9D2" box="[1298,1422,1576,1597]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF82E045F7E7B9FF9D2" box="[1298,1422,1576,1597]" italics="true" pageId="18" pageNumber="533">C. petrinus</emphasis>
</taxonomicName>
and makes contact with the quadratojugal, a pattern that cannot be observed in the other two species. In
<taxonomicName id="4C4993A4A000FFF828305FD27DB5F977" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[806,932,1667,1689]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A000FFF828305FD27DB5F977" box="[806,932,1667,1689]" italics="true" pageId="18" pageNumber="533">C. nichollsi</emphasis>
</taxonomicName>
, the jugal shows a rounded posterior extension that reaches slightly into the lateral embayment and may represent a remnant of a lower temporal bar.
<taxonomicName id="4C4993A4A000FFF828955FB67A11F91B" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[899,1024,1759,1781]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A000FFF828955FB67A11F91B" box="[899,1024,1759,1781]" italics="true" pageId="18" pageNumber="533">C. buchseri</emphasis>
</taxonomicName>
has a smooth posterior margin of the jugal without any such protuberance.
</paragraph>
<paragraph id="8BF6E827A000FFF928295E4B7F12FF17" blockId="18.[806,1422,1422,1904]" lastBlockId="19.[162,778,195,892]" lastPageId="19" lastPageNumber="534" pageId="18" pageNumber="533">
Additionally to the frontals, the nasals enter the upper temporal fenestra in
<taxonomicName id="4C4993A4A000FFF82F765E6A7ACEF8BF" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1120,1247,1851,1873]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A000FFF82F765E6A7ACEF8BF" box="[1120,1247,1851,1873]" italics="true" pageId="18" pageNumber="533">C. nichollsi</emphasis>
</taxonomicName>
. This contrasts with the condition found in
<taxonomicName id="4C4993A4A000FFF82F7A5E0C7AF9F89F" box="[1132,1256,1882,1904]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="18" pageNumber="533" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A000FFF82F7A5E0C7AF9F89F" box="[1132,1256,1882,1904]" italics="true" pageId="18" pageNumber="533">C. petrinus</emphasis>
</taxonomicName>
in which only the frontals reach posteriorly to the upper temporal opening.
</paragraph>
<paragraph id="8BF6E827A001FFF92BAD58577C15FC93" blockId="19.[162,778,195,892]" pageId="19" pageNumber="534">
The quadratojugal of
<taxonomicName id="4C4993A4A001FFF92AAF58577C29FEF9" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[441,568,257,278]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF92AAF58577C29FEF9" box="[441,568,257,278]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
is very short and restricted to the lateral side of the skull. It does not contact the quadrate, so that a small bridge of the squamosal wedges in between the posterior end of the quadratojugal and the quadrate and contributes to the posterior border of the lateral embayment. This is also the reason why the quadratojugal does not contribute to the lateral margin of the quadrate foramen at the back of the skull. In
<taxonomicName id="4C4993A4A001FFF92AB958A07C3BFDE3" box="[431,554,502,524]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92AB958A07C3BFDE3" box="[431,554,502,524]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
, the long, slender quadratojugal extends posteriorly and clearly makes contact with the quadrate (
<figureCitation id="1372F4A2A001FFF92AE35B657C45FDA6" box="[501,596,563,585]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="19" pageNumber="534">Fig. 11B</figureCitation>
) and, together with the squamosal, contributes to the lateral border of the quadrate foramen (
<bibRefCitation id="EFD895D6A001FFF92AE35B277CBEFD69" author="Merriam JC" box="[501,687,625,647]" pageId="19" pageNumber="534" pagination="1 - 155" refId="ref16501" refString="Merriam JC. 1908. Triassic Ichthyosauria, with special reference to the American forms. Memoirs of the University of California 1: 1 - 155." type="journal article" year="1908">Merriam, 1908</bibRefCitation>
: fig. 6). Where the back of the skull is exposed, i.e. in
<taxonomicName id="4C4993A4A001FFF92BB45BF87F0FFD2B" box="[162,286,686,708]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92BB45BF87F0FFD2B" box="[162,286,686,708]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
and in
<taxonomicName id="4C4993A4A001FFF92A695BF87FECFD2C" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[383,509,686,707]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF92A695BF87FECFD2C" box="[383,509,686,707]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
, it presents very similarly in both species, although it is distinctly tilted forward in
<taxonomicName id="4C4993A4A001FFF92A215BBA7FA3FCEE" box="[311,434,748,769]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92A215BBA7FA3FCEE" box="[311,434,748,769]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
. The pterygoid has strong posterior processes and broad, wing-like portions that form the ventrolateral parts of the back of the skull. The quadrate reaches far dorsally and makes contact with the putative postparietal.
</paragraph>
</subSection>
<subSection id="E2C6F1CCA001FFF92A0E5A837B40FEF8" pageId="19" pageNumber="534" type="multiple">
<paragraph id="8BF6E827A001FFF92A0E5A837C84FC03" blockId="19.[280,661,981,1005]" box="[280,661,981,1005]" pageId="19" pageNumber="534">
<heading id="D0BE5F4BA001FFF92A0E5A837C84FC03" box="[280,661,981,1005]" centered="true" fontSize="9" level="2" pageId="19" pageNumber="534" reason="5">COMPARISON OF THE LOWER JAW</heading>
</paragraph>
<paragraph id="8BF6E827A001FFF92BB45AA87FDDFA4C" blockId="19.[162,779,1022,1903]" pageId="19" pageNumber="534">
The shape of the lower jaw of
<taxonomicName id="4C4993A4A001FFF92AE25AA87C63FBFC" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[500,626,1022,1043]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF92AE25AA87C63FBFC" box="[500,626,1022,1043]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
with its high posterior portion of the ramus resembles the lower jaws of
<taxonomicName id="4C4993A4A001FFF92A1D5D6A7F96FBBE" box="[267,391,1084,1105]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92A1D5D6A7F96FBBE" box="[267,391,1084,1105]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
and
<taxonomicName id="4C4993A4A001FFF92AC25D6A7C40FBBF" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[468,593,1083,1105]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A001FFF92AC25D6A7C40FBBF" box="[468,593,1083,1105]" italics="true" pageId="19" pageNumber="534">C. buchseri</emphasis>
</taxonomicName>
, although this upward bend is even slightly stronger in
<taxonomicName id="4C4993A4A001FFF9299A5D0C7D1BFB80" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[652,778,1114,1135]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF9299A5D0C7D1BFB80" box="[652,778,1114,1135]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
and the posterior region of the jaw is more massive. However, the pattern of bones building up the lower jaw differs in a number of respects (
<figureCitation id="1372F4A2A001FFF929625DE07CD3FB23" box="[628,706,1206,1228]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="19" pageNumber="534">Fig. 11</figureCitation>
). The dentary is clearly shorter in
<taxonomicName id="4C4993A4A001FFF9290A5D837C8AFB05" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[540,667,1237,1258]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF9290A5D837C8AFB05" box="[540,667,1237,1258]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
than in
<taxonomicName id="4C4993A4A001FFF92BB45DA27F0FFAE6" box="[162,286,1268,1289]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92BB45DA27F0FFAE6" box="[162,286,1268,1289]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
and reaches back only two-thirds below the orbit, whereas it reaches to the posterior edge of the orbit in
<taxonomicName id="4C4993A4A001FFF92A265C677FBDFAA9" box="[304,428,1329,1350]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92A265C677FBDFAA9" box="[304,428,1329,1350]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
. The dentary of
<taxonomicName id="4C4993A4A001FFF929665C677CFFFAA9" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[624,750,1329,1350]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A001FFF929665C677CFFFAA9" box="[624,750,1329,1350]" italics="true" pageId="19" pageNumber="534">C. buchseri</emphasis>
</taxonomicName>
is as short as in
<taxonomicName id="4C4993A4A001FFF92A505C067FD5FA8B" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[326,452,1359,1381]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF92A505C067FD5FA8B" box="[326,452,1359,1381]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
, but as in
<taxonomicName id="4C4993A4A001FFF929295C067CAAFA8A" box="[575,699,1360,1381]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF929295C067CAAFA8A" box="[575,699,1360,1381]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
it posteriorly tapers to a point instead of ending in a notched posterior margin.
</paragraph>
<paragraph id="8BF6E827A001FFF92BAD5CFD7F17F9D3" blockId="19.[162,779,1022,1903]" pageId="19" pageNumber="534">
The angular forms almost half of the lateral wall of the ramus in
<taxonomicName id="4C4993A4A001FFF92A5A5C9C7FDAFA30" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[332,459,1482,1503]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF92A5A5C9C7FDAFA30" box="[332,459,1482,1503]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
, but contributes only to a small portion of the ventrolateral wall in
<taxonomicName id="4C4993A4A001FFF929985CBF7D1BFA11" box="[654,778,1513,1534]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF929985CBF7D1BFA11" box="[654,778,1513,1534]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
and, as far as can be determined, in
<taxonomicName id="4C4993A4A001FFF9299B5F5E7D1BF9F3" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[653,778,1543,1565]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A001FFF9299B5F5E7D1BF9F3" box="[653,778,1543,1565]" italics="true" pageId="19" pageNumber="534">C. buchseri</emphasis>
</taxonomicName>
(
<figureCitation id="1372F4A2A001FFF92BBC5F707EE8F9D3" box="[170,249,1574,1596]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="19" pageNumber="534">Fig. 11</figureCitation>
).
</paragraph>
<paragraph id="8BF6E827A001FFF92BAD5F137FD4F881" blockId="19.[162,779,1022,1903]" pageId="19" pageNumber="534">
The jaw articulation is drawn far posteriorly in
<taxonomicName id="4C4993A4A001FFF92BB45F327F0FF996" box="[162,286,1636,1657]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92BB45F327F0FF996" box="[162,286,1636,1657]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
, resulting in the slanted occipital region, and lies far posteriorly to the posterior edge of the parietal crest (
<figureCitation id="1372F4A2A001FFF92A5D5FF77FBCF958" box="[331,429,1697,1719]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="19" pageNumber="534">Fig. 11B</figureCitation>
). In
<taxonomicName id="4C4993A4A001FFF92AF55FF77C70F959" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[483,609,1697,1718]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF92AF55FF77C70F959" box="[483,609,1697,1718]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
, the jaw articulation lies anterior to the posterior edge of the parietal region and has a broad contact between articular and quadrate (
<figureCitation id="1372F4A2A001FFF92A5D5FAB7FBDF8FC" box="[331,428,1789,1811]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="19" pageNumber="534">Fig. 11A</figureCitation>
). The articulation of lower jaw and skull is incompletely preserved in
<taxonomicName id="4C4993A4A001FFF9294C5E4A7CC6F8DF" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[602,727,1819,1841]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A001FFF9294C5E4A7CC6F8DF" box="[602,727,1819,1841]" italics="true" pageId="19" pageNumber="534">C. buchseri</emphasis>
</taxonomicName>
, but the position of the quadrate indicates a similar configuration as in
<taxonomicName id="4C4993A4A001FFF92A565E0F7FAFF881" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[320,446,1881,1902]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF92A565E0F7FAFF881" box="[320,446,1881,1902]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
.
</paragraph>
<paragraph id="8BF6E827A001FFF9284559957B40FEF8" blockId="19.[826,1441,195,279]" pageId="19" pageNumber="534">
All three
<taxonomicName id="4C4993A4A001FFF928A859957A6FFF37" authorityName="NICHOLLSI" authorityYear="2006" box="[958,1150,195,216]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A001FFF928A859957A6FFF37" box="[958,1150,195,216]" italics="true" pageId="19" pageNumber="534">Cymbospondylus</emphasis>
</taxonomicName>
species possess a shelf in the angular bone of the lower jaw that forms the ventral border of the lateral embayment (
<figureCitation id="1372F4A2A001FFF92FE258577B52FEF8" box="[1268,1347,257,279]" captionStart="Figure 11" captionStartId="17.[162,240,1405,1424]" captionTargetBox="[166,774,194,1373]" captionTargetId="figure-637@17.[166,775,194,1373]" captionTargetPageId="17" captionText="Figure 11. Comparison of the lateral views of the postrostral skull regions of Cymbospondylus. A, Cymbospondylus nichollsi sp. nov., based on the holotype FMNH PR2251. B, C. petrinus, based on UCMP 9950. C, C. buchseri, based on PIMUZ 4351, modified after Sander (1989b). B and C are based on left sides of the skulls and have been inverted." figureDoi="http://doi.org/10.5281/zenodo.4634763" httpUri="https://zenodo.org/record/4634763/files/figure.png" pageId="19" pageNumber="534">Fig. 11</figureCitation>
).
</paragraph>
</subSection>
<subSection id="E2C6F1CCA001FFFE287158077A17FEBB" lastPageId="20" lastPageNumber="535" pageId="19" pageNumber="534" type="multiple">
<paragraph id="8BF6E827A001FFF9287158077B64FE88" blockId="19.[871,1397,337,361]" box="[871,1397,337,361]" pageId="19" pageNumber="534">
<heading id="D0BE5F4BA001FFF9287158077B64FE88" box="[871,1397,337,361]" centered="true" fontSize="9" level="2" pageId="19" pageNumber="534" reason="5">COMPARISON OF THE POSTCRANIAL SKELETON</heading>
</paragraph>
<paragraph id="8BF6E827A001FFF9282C582F7A6FFC96" blockId="19.[826,1443,377,1902]" pageId="19" pageNumber="534">
<emphasis id="B93D3435A001FFF9282C582F7A7FFE61" box="[826,1134,377,398]" italics="true" pageId="19" pageNumber="534">Vertebral column and ribs:</emphasis>
Comparison of the postcranial features of the three species strengthens the affinity of specimen FMNH PR2251 with the genus
<taxonomicName id="4C4993A4A001FFF9282C58837DEBFE05" authorityName="NICHOLLSI" authorityYear="2006" box="[826,1018,469,490]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A001FFF9282C58837DEBFE05" box="[826,1018,469,490]" italics="true" pageId="19" pageNumber="534">Cymbospondylus</emphasis>
</taxonomicName>
and its close relationship with the two recognized species,
<taxonomicName id="4C4993A4A001FFF92F4A58A27AC6FDE5" box="[1116,1239,500,522]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92F4A58A27AC6FDE5" box="[1116,1239,500,522]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
and
<taxonomicName id="4C4993A4A001FFF92E0858A27B8AFDE6" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[1310,1435,500,521]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A001FFF92E0858A27B8AFDE6" box="[1310,1435,500,521]" italics="true" pageId="19" pageNumber="534">C. buchseri</emphasis>
</taxonomicName>
. The occipital–cervical complex is unknown in
<taxonomicName id="4C4993A4A001FFF9282C5B647DA9FDA9" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[826,952,561,583]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A001FFF9282C5B647DA9FDA9" box="[826,952,561,583]" italics="true" pageId="19" pageNumber="534">C. buchseri</emphasis>
</taxonomicName>
, but is well known in
<taxonomicName id="4C4993A4A001FFF92FFD5B647B77FDA8" box="[1259,1382,562,583]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92FFD5B647B77FDA8" box="[1259,1382,562,583]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
and
<emphasis id="B93D3435A001FFF9282C5B067DD1FD8A" box="[826,960,592,613]" italics="true" pageId="19" pageNumber="534">
<taxonomicName id="4C4993A4A001FFF9282C5B067DADFD8A" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[826,956,592,613]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">C. nichollsi</taxonomicName>
.
</emphasis>
The ventrolateral side of the atlas in
<taxonomicName id="4C4993A4A001FFF9282C5B397DA8FD6B" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[826,953,623,644]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF9282C5B397DA8FD6B" box="[826,953,623,644]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
is identical to that of
<taxonomicName id="4C4993A4A001FFF92FF25B397B4EFD6B" box="[1252,1375,623,644]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92FF25B397B4EFD6B" box="[1252,1375,623,644]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
with smooth, rounded edges and a strongly convex anterior surface that articulates with the concave surface of the basioccipital. Laterally, the atlas shows an elongated, smooth impression surface, which is also clearly developed in
<taxonomicName id="4C4993A4A001FFF92F325A5E7A8EFCF1" box="[1060,1183,776,798]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92F325A5E7A8EFCF1" box="[1060,1183,776,798]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
. The axis also shows a very similar form in both species, with strongly developed diapophyses and anteriorly and posteriorly bulging margins of the centrum.
</paragraph>
<paragraph id="8BF6E827A001FFF928455AD57D4DFBDE" blockId="19.[826,1443,377,1902]" pageId="19" pageNumber="534">
<taxonomicName id="4C4993A4A001FFF928455AD57DC0FC77" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[851,977,899,920]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF928455AD57DC0FC77" box="[851,977,899,920]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
is intermediate with regard to the number of cervical vertebrae, which are here defined as the centra with parapophyses as used by
<bibRefCitation id="EFD895D6A001FFF92FFA5A967B8FFC39" author="Sander PM" box="[1260,1438,960,982]" pageId="19" pageNumber="534" pagination="163 - 173" refId="ref16814" refString="Sander PM. 1989 b. The large ichthyosaur Cymbospondylus buchseri, sp. nov. from the Middle Triassic of Monte San Giorgio (Switzerland), with a survey of the genus in Europe. Journal of Vertebrate Paleontology 9: 163 - 173." type="journal article" year="1989">Sander (1989b)</bibRefCitation>
.
<taxonomicName id="4C4993A4A001FFF9282C5A897DA9FC1B" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[826,952,991,1012]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A001FFF9282C5A897DA9FC1B" box="[826,952,991,1012]" italics="true" pageId="19" pageNumber="534">C. buchseri</emphasis>
</taxonomicName>
has six cervical vertebrae,
<taxonomicName id="4C4993A4A001FFF92FE55A897B63FC1B" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1267,1394,991,1012]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF92FE55A897B63FC1B" box="[1267,1394,991,1012]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
has between eight and ten cervicals, while
<taxonomicName id="4C4993A4A001FFF92FE15AA87B63FBFC" box="[1271,1394,1022,1043]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF92FE15AA87B63FBFC" box="[1271,1394,1022,1043]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
has 12.
</paragraph>
<paragraph id="8BF6E827A001FFF928455D6D7B03FA4D" blockId="19.[826,1443,377,1902]" pageId="19" pageNumber="534">
A synapomorphy of
<taxonomicName id="4C4993A4A001FFF92F5B5D6D7B1CFBBF" authorityName="NICHOLLSI" authorityYear="2006" box="[1101,1293,1083,1104]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A001FFF92F5B5D6D7B1CFBBF" box="[1101,1293,1083,1104]" italics="true" pageId="19" pageNumber="534">Cymbospondylus</emphasis>
</taxonomicName>
is the ventrally elongated, anteriorly slanting diapophyses, which are truncated by the anterior margin of the centrum (
<bibRefCitation id="EFD895D6A001FFF928955DC17AE3FB42" author="Sander PM &amp; Rieppel OC &amp; Bucher H" box="[899,1266,1175,1197]" pageId="19" pageNumber="534" pagination="676 - 680" refId="ref16981" refString="Sander PM, Rieppel OC, Bucher H. 1994. New marine vertebrate fauna from the Middle Triassic of Nevada. Journal of Paleontology 68: 676 - 680." type="journal article" year="1994">Sander, Rieppel &amp; Bucher, 1994</bibRefCitation>
) (
<figureCitation id="1372F4A2A001FFF92E1F5DC17B4CFB42" box="[1289,1373,1175,1197]" captionStart="Figure 8" captionStartId="14.[806,884,755,774]" captionTargetBox="[810,1418,190,723]" captionTargetId="figure-806@14.[810,1419,398,723]" captionTargetPageId="14" captionText="Figure 8. A, drawing of cervical vertebrae 5–8 and presacral vertebrae 26 and 27 as example for the vertebral structures in specimen FMNH PR2251. B, drawing of neural arches 9–12 of specimen FMNH PR2251. Anterior is to the right. Scale bar = 5 cm." figureDoi="http://doi.org/10.5281/zenodo.4634757" httpUri="https://zenodo.org/record/4634757/files/figure.png" pageId="19" pageNumber="534">Fig. 8A</figureCitation>
). This pattern is clearly seen in
<taxonomicName id="4C4993A4A001FFF92F765DE07ACFFB25" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1120,1246,1205,1227]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF92F765DE07ACFFB25" box="[1120,1246,1205,1227]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
, even in the posteriorly preserved vertebrae, despite their heavily weathered surface. At variance with
<bibRefCitation id="EFD895D6A001FFF92FCC5DA57DA0FAC7" author="McGowan C &amp; Motani R" pageId="19" pageNumber="534" refId="ref16449" refString="McGowan C, Motani R. 2003. Ichthyopterygia. Handbook of Paleoherpetology, 8. Munich: Dr. Friedrich Pfeil." type="book" year="2003">McGowan &amp; Motani (2003)</bibRefCitation>
, the morphology of the diapophysis is well suited to assign fragmentary specimens to this genus if the character is present in its entirety, and not only an anteriorly truncated diapophsis, which is plesiomorphic for ichthyosaurs (
<bibRefCitation id="EFD895D6A001FFF92F7C5CDA7B17FA4D" author="Motani R" box="[1130,1286,1420,1442]" pageId="19" pageNumber="534" pagination="473 - 496" refId="ref16529" refString="Motani R. 1999. Phylogeny of the Ichthyopterygia. Journal of Vertebrate Paleontology 19: 473 - 496." type="journal article" year="1999">Motani, 1999</bibRefCitation>
).
</paragraph>
<paragraph id="8BF6E827A001FFF928455CFD7DACF8DF" blockId="19.[826,1443,377,1902]" pageId="19" pageNumber="534">
Although the
<typeStatus id="54F25685A001FFF928E25CFD7A44FA2E" box="[1012,1109,1451,1473]" pageId="19" pageNumber="534" type="holotype">holotype</typeStatus>
of the new
<taxonomicName id="4C4993A4A001FFF92FF75CFD7BB0FA2F" authorityName="NICHOLLSI" authorityYear="2006" box="[1249,1441,1451,1472]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A001FFF92FF75CFD7BB0FA2F" box="[1249,1441,1451,1472]" italics="true" pageId="19" pageNumber="534">Cymbospondylus</emphasis>
</taxonomicName>
species is only preserved to the middle dorsal region, an increase of the height of the centra and a change in their shape from circular to triangular can be ascertained in this specimen, as also reported for
<taxonomicName id="4C4993A4A001FFF9282C5F127A6CF9B5" authority="(Merriam, 1908)" baseAuthorityName="Merriam" baseAuthorityYear="1908" box="[826,1149,1604,1626]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF9282C5F127DA7F9B5" box="[826,950,1604,1626]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
(
<bibRefCitation id="EFD895D6A001FFF928DE5F127A67F9B5" author="Merriam JC" box="[968,1142,1604,1626]" pageId="19" pageNumber="534" pagination="1 - 155" refId="ref16501" refString="Merriam JC. 1908. Triassic Ichthyosauria, with special reference to the American forms. Memoirs of the University of California 1: 1 - 155." type="journal article" year="1908">Merriam, 1908</bibRefCitation>
)
</taxonomicName>
and
<taxonomicName id="4C4993A4A001FFF92FAA5F127D9BF996" authority="(Sander, 1989 b)" baseAuthorityName="Sander" baseAuthorityYear="1989" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A001FFF92FAA5F127B2BF9B6" box="[1212,1338,1604,1625]" italics="true" pageId="19" pageNumber="534">C. buchseri</emphasis>
(
<bibRefCitation id="EFD895D6A001FFF92E5D5F127D90F996" author="Sander PM" pageId="19" pageNumber="534" pagination="163 - 173" refId="ref16814" refString="Sander PM. 1989 b. The large ichthyosaur Cymbospondylus buchseri, sp. nov. from the Middle Triassic of Monte San Giorgio (Switzerland), with a survey of the genus in Europe. Journal of Vertebrate Paleontology 9: 163 - 173." type="journal article" year="1989">Sander, 1989b</bibRefCitation>
)
</taxonomicName>
. However, the ratio between height and length of the centra is higher than in
<taxonomicName id="4C4993A4A001FFF92FB45FD47B0EF979" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[1186,1311,1665,1687]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A001FFF92FB45FD47B0EF979" box="[1186,1311,1665,1687]" italics="true" pageId="19" pageNumber="534">C. buchseri</emphasis>
</taxonomicName>
, which has a ratio of 1.55 for the eighth and 1.74 for the 14th centrum. In
<taxonomicName id="4C4993A4A001FFF928B25FE97A33F93B" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[932,1058,1727,1748]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF928B25FE97A33F93B" box="[932,1058,1727,1748]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
, the ratio for the fourth centrum is 1.65, and for the 28th it is 2.35.
<bibRefCitation id="EFD895D6A001FFF92FAF5F8B7B7DF91B" author="Merriam JC" box="[1209,1388,1757,1780]" pageId="19" pageNumber="534" pagination="1 - 155" refId="ref16501" refString="Merriam JC. 1908. Triassic Ichthyosauria, with special reference to the American forms. Memoirs of the University of California 1: 1 - 155." type="journal article" year="1908">Merriam (1908)</bibRefCitation>
only gives measurements of the caudal vertebrae of
<taxonomicName id="4C4993A4A001FFF9282C5E4D7DA7F8DF" baseAuthorityName="Merriam" baseAuthorityYear="1908" box="[826,950,1819,1840]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A001FFF9282C5E4D7DA7F8DF" box="[826,950,1819,1840]" italics="true" pageId="19" pageNumber="534">C. petrinus</emphasis>
</taxonomicName>
.
</paragraph>
<paragraph id="8BF6E827A001FFFE28455E6F7CA8FD4A" blockId="19.[826,1443,377,1902]" lastBlockId="20.[142,758,195,861]" lastPageId="20" lastPageNumber="535" pageId="19" pageNumber="534">
The neural arches of
<taxonomicName id="4C4993A4A001FFF92F435E6C7AC5F8A1" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[1109,1236,1849,1871]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="19" pageNumber="534" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A001FFF92F435E6C7AC5F8A1" box="[1109,1236,1849,1871]" italics="true" pageId="19" pageNumber="534">C. nichollsi</emphasis>
</taxonomicName>
have an average height of
<quantity id="4CB145C2A001FFF928B25E0E7DE3F881" box="[932,1010,1880,1902]" metricMagnitude="-2" metricUnit="m" metricValue="8.7" pageId="19" pageNumber="534" unit="mm" value="87.0">87 mm</quantity>
and do not vary much in height in the preserved row. The average height of the neural spines in the distinctively smaller
<taxonomicName id="4C4993A4A006FFFE2AF959B47C7CFF18" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[495,621,226,247]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A006FFFE2AF959B47C7CFF18" box="[495,621,226,247]" italics="true" pageId="20" pageNumber="535">C. buchseri</emphasis>
</taxonomicName>
is
<quantity id="4CB145C2A006FFFE29B759B47CE3FF18" box="[673,754,226,248]" metricMagnitude="-2" metricUnit="m" metricValue="6.4" pageId="20" pageNumber="535" unit="mm" value="64.0">64 mm</quantity>
, varying only little. The measurements of the neural spines of
<taxonomicName id="4C4993A4A006FFFE2BEE58767F65FEDA" baseAuthorityName="Merriam" baseAuthorityYear="1908" box="[248,372,288,309]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A006FFFE2BEE58767F65FEDA" box="[248,372,288,309]" italics="true" pageId="20" pageNumber="535">C. petrinus</emphasis>
</taxonomicName>
given by
<bibRefCitation id="EFD895D6A006FFFE2AF758497CDBFEDA" author="Merriam JC" box="[481,714,287,309]" pageId="20" pageNumber="535" pagination="1 - 155" refId="ref16501" refString="Merriam JC. 1908. Triassic Ichthyosauria, with special reference to the American forms. Memoirs of the University of California 1: 1 - 155." type="journal article" year="1908">Merriam (1908: 117)</bibRefCitation>
are mainly for the posterior dorsal and caudal region and therefore cannot be compared directly. In all three species the zygapophyses are well developed and the neural spines are inclined posteriorly. In specimen FMNH PR2251 the zygapophyses of adjacent neural spines are tightly fused and show rough and bulging bone in the area of fusion, which would have greatly stiffened the vertebral column in this region (
<figureCitation id="1372F4A2A006FFFE29285B437C6EFDC4" box="[574,639,533,555]" captionStart="Figure 8" captionStartId="14.[806,884,755,774]" captionTargetBox="[810,1418,190,723]" captionTargetId="figure-806@14.[810,1419,398,723]" captionTargetPageId="14" captionText="Figure 8. A, drawing of cervical vertebrae 5–8 and presacral vertebrae 26 and 27 as example for the vertebral structures in specimen FMNH PR2251. B, drawing of neural arches 9–12 of specimen FMNH PR2251. Anterior is to the right. Scale bar = 5 cm." figureDoi="http://doi.org/10.5281/zenodo.4634757" httpUri="https://zenodo.org/record/4634757/files/figure.png" pageId="20" pageNumber="535">Fig. 8</figureCitation>
). No such fusion is present in
<taxonomicName id="4C4993A4A006FFFE2A635B627FE1FDA6" baseAuthorityName="Merriam" baseAuthorityYear="1908" box="[373,496,564,585]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A006FFFE2A635B627FE1FDA6" box="[373,496,564,585]" italics="true" pageId="20" pageNumber="535">C. petrinus</emphasis>
</taxonomicName>
and
<taxonomicName id="4C4993A4A006FFFE293A5B627CB8FDA7" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[556,681,563,585]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A006FFFE293A5B627CB8FDA7" box="[556,681,563,585]" italics="true" pageId="20" pageNumber="535">C. buchseri</emphasis>
</taxonomicName>
and it remains unknown whether this feature represents an autapomorphy for
<taxonomicName id="4C4993A4A006FFFE2A7C5B277FF8FD69" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[362,489,625,646]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A006FFFE2A7C5B277FF8FD69" box="[362,489,625,646]" italics="true" pageId="20" pageNumber="535">C. nichollsi</emphasis>
</taxonomicName>
or is merely a sign of age or a pathology in that particular individual.
</paragraph>
<paragraph id="8BF6E827A006FFFE2BB15BF87F37FCB2" blockId="20.[142,758,195,861]" pageId="20" pageNumber="535">The general characteristics of the ribs and rib articulation are identical in the three species, with all of them showing the double rib articulation of the cervical ribs and the single, elongated rib head in the trunk ribs, which possess a distinctive figure-of-eight cross-section.</paragraph>
<paragraph id="8BF6E827A006FFFE2B985A237F4DFB70" blockId="20.[142,758,885,1521]" pageId="20" pageNumber="535">
<emphasis id="B93D3435A006FFFE2B985A237F83FC65" box="[142,402,885,906]" italics="true" pageId="20" pageNumber="535">Appendicular skeleton:</emphasis>
Only the coracoids and the clavicles are preserved of the shoulder girdle in the new specimen. The shape of the clavicle of
<taxonomicName id="4C4993A4A006FFFE29615AE57CE7FC27" authorityName="Fröbisch &amp; Sander &amp; Rieppel" authorityYear="2006" box="[631,758,947,968]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="nichollsi">
<emphasis id="B93D3435A006FFFE29615AE57CE7FC27" box="[631,758,947,968]" italics="true" pageId="20" pageNumber="535">C. nichollsi</emphasis>
</taxonomicName>
is very like that of
<taxonomicName id="4C4993A4A006FFFE2AB45A847C0FFC08" baseAuthorityName="Merriam" baseAuthorityYear="1908" box="[418,542,978,999]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A006FFFE2AB45A847C0FFC08" box="[418,542,978,999]" italics="true" pageId="20" pageNumber="535">C. petrinus</emphasis>
</taxonomicName>
(
<bibRefCitation id="EFD895D6A006FFFE292F5A877CE3FC08" author="Merriam JC" box="[569,754,977,999]" pageId="20" pageNumber="535" pagination="1 - 155" refId="ref16501" refString="Merriam JC. 1908. Triassic Ichthyosauria, with special reference to the American forms. Memoirs of the University of California 1: 1 - 155." type="journal article" year="1908">Merriam, 1908</bibRefCitation>
: plate 11), although it is somewhat more robust, and the clavicle head is larger and more massive. Preservation of the clavicle of
<taxonomicName id="4C4993A4A006FFFE2ABE5D787C37FBAD" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[424,550,1069,1091]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A006FFFE2ABE5D787C37FBAD" box="[424,550,1069,1091]" italics="true" pageId="20" pageNumber="535">C. buchseri</emphasis>
</taxonomicName>
is insufficient for an interpretation of its original appearance, but it seems to have had a sail-like dorsal part as seen in the other two species.
</paragraph>
<paragraph id="8BF6E827A006FFFE2BB15DFE7A17FEBB" blockId="20.[142,758,885,1521]" lastBlockId="20.[806,1422,195,340]" pageId="20" pageNumber="535">
The coracoids are almost identical in all three
<taxonomicName id="4C4993A4A006FFFE29AF5DFE7F0BFB33" authorityName="NICHOLLSI" authorityYear="2006" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="genus">
<emphasis id="B93D3435A006FFFE29AF5DFE7F0BFB33" italics="true" pageId="20" pageNumber="535">Cymbospondylus</emphasis>
</taxonomicName>
species.
<bibRefCitation id="EFD895D6A006FFFE2A8F5D917CE7FB32" author="McGowan C &amp; Motani R" box="[409,758,1223,1245]" pageId="20" pageNumber="535" refId="ref16449" refString="McGowan C, Motani R. 2003. Ichthyopterygia. Handbook of Paleoherpetology, 8. Munich: Dr. Friedrich Pfeil." type="book" year="2003">McGowan &amp; Motani (2003)</bibRefCitation>
claimed that the
<typeStatus id="54F25685A006FFFE2A4E5DB37FA8FB14" box="[344,441,1253,1275]" pageId="20" pageNumber="535" type="holotype">holotype</typeStatus>
of
<taxonomicName id="4C4993A4A006FFFE2AF75DB07C4FFB15" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[481,606,1253,1275]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A006FFFE2AF75DB07C4FFB15" box="[481,606,1253,1275]" italics="true" pageId="20" pageNumber="535">C. buchseri</emphasis>
</taxonomicName>
is immature based on its small size compared with
<taxonomicName id="4C4993A4A006FFFE295E5C527CD2FAF5" baseAuthorityName="Merriam" baseAuthorityYear="1908" box="[584,707,1284,1306]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A006FFFE295E5C527CD2FAF5" box="[584,707,1284,1306]" italics="true" pageId="20" pageNumber="535">C. petrinus</emphasis>
</taxonomicName>
and the supposedly incomplete ossification of the humerus. We cannot agree with this latter observation and note that size cannot be used as a proxy for ontogenetic stage in the genus because the new specimen described here is also considerably smaller than typical
<taxonomicName id="4C4993A4A006FFFE2BA85CEA7F2BFA3D" baseAuthorityName="Merriam" baseAuthorityYear="1908" box="[190,314,1468,1490]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A006FFFE2BA85CEA7F2BFA3D" box="[190,314,1468,1490]" italics="true" pageId="20" pageNumber="535">C. petrinus</emphasis>
</taxonomicName>
(see above) but shows no signs of immaturity. However, the difference in humeral shape between
<taxonomicName id="4C4993A4A006FFFE288859927A08FF36" baseAuthorityName="Merriam" baseAuthorityYear="1908" box="[926,1049,196,217]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="petrinus">
<emphasis id="B93D3435A006FFFE288859927A08FF36" box="[926,1049,196,217]" italics="true" pageId="20" pageNumber="535">C. petrinus</emphasis>
</taxonomicName>
and
<taxonomicName id="4C4993A4A006FFFE2F6159927AE4FF37" baseAuthorityName="Sander" baseAuthorityYear="1989" box="[1143,1269,195,217]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="buchseri">
<emphasis id="B93D3435A006FFFE2F6159927AE4FF37" box="[1143,1269,195,217]" italics="true" pageId="20" pageNumber="535">C. buchseri</emphasis>
</taxonomicName>
may have resulted from paedomorphosis in the evolution of the latter from a more plesiomorphic elongate humerus. This would indeed be in accordance with the smaller size of
<taxonomicName id="4C4993A4A006FFFE286158687DEEFEBC" box="[887,1023,318,339]" class="Reptilia" family="Shastasauridae" genus="Cymbospondylus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Ichthyosauria" pageId="20" pageNumber="535" phylum="Chordata" rank="species" species="buschseri">
<emphasis id="B93D3435A006FFFE286158687DEEFEBC" box="[887,1023,318,339]" italics="true" pageId="20" pageNumber="535">C. buschseri</emphasis>
</taxonomicName>
.
</paragraph>
</subSection>
</subSubSection>
</treatment>
</document>
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