681 lines
281 KiB
XML
681 lines
281 KiB
XML
<document ID-DOI="10.1093/zoolinnean/zlac033" ID-GBIF-Dataset="d18be66e-8788-47d3-bba3-11ad8bb0f126" ID-ISSN="0024-4082" ID-Zenodo-Dep="7922143" IM.bibliography_approvedBy="juliana" IM.illustrations_approvedBy="juliana" IM.materialsCitations_approvedBy="juliana" IM.metadata_approvedBy="juliana" IM.taxonomicNames_approvedBy="juliana" IM.treatments_approvedBy="juliana" checkinTime="1683701348189" checkinUser="plazi" docAuthor="Macungo, Zanildo, Benoit, Julien, Fernandez, Vincent & Araújo, Ricardo M N" docDate="2023" docId="3F6A87ABFFA5FFEC7262F916FAD2FE6B" docLanguage="en" docName="zlac033.pdf" docOrigin="Zoological Journal of the Linnean Society 198 (1)" docSource="https://academic.oup.com/zoolinnean/article/198/1/1/6596559" docStyle="DocumentStyle:36B3BD6A90C22AB4F7F465C853188CC8.7:ZoolJLinnSoc.2017-.journal_article" docStyleId="36B3BD6A90C22AB4F7F465C853188CC8" docStyleName="ZoolJLinnSoc.2017-.journal_article" docStyleVersion="7" docTitle="Myosaurus gracilis Haughton 1917" docType="treatment" docVersion="2" lastPageNumber="20" masterDocId="C353FFD3FFA9FFFF7115FFA9FFFCFFDA" masterDocTitle="X-ray microcomputed and synchrotron tomographic analysis of the basicranial axis of emydopoid dicynodonts: implications for fossoriality and phylogeny" masterLastPageNumber="46" masterPageNumber="1" pageNumber="13" updateTime="1683750160436" updateUser="ExternalLinkService">
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<mods:title>X-ray microcomputed and synchrotron tomographic analysis of the basicranial axis of emydopoid dicynodonts: implications for fossoriality and phylogeny</mods:title>
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<mods:roleTerm>Author</mods:roleTerm>
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<mods:namePart>Macungo, Zanildo</mods:namePart>
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<mods:roleTerm>Author</mods:roleTerm>
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<mods:namePart>Benoit, Julien</mods:namePart>
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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<mods:namePart>Fernandez, Vincent</mods:namePart>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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<mods:namePart>Araújo, Ricardo M N</mods:namePart>
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<mods:title>Zoological Journal of the Linnean Society</mods:title>
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<mods:part>
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<mods:date>2023</mods:date>
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<mods:detail type="pubDate">
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<mods:number>2023-05-01</mods:number>
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<mods:detail type="volume">
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<mods:number>198</mods:number>
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<mods:number>1</mods:number>
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<mods:url>https://academic.oup.com/zoolinnean/article/198/1/1/6596559</mods:url>
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<mods:classification>journal article</mods:classification>
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<mods:identifier type="DOI">10.1093/zoolinnean/zlac033</mods:identifier>
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<mods:identifier type="GBIF-Dataset">d18be66e-8788-47d3-bba3-11ad8bb0f126</mods:identifier>
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<mods:identifier type="ISSN">0024-4082</mods:identifier>
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<mods:identifier type="Zenodo-Dep">7922143</mods:identifier>
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<treatment ID-DOI="http://doi.org/10.5281/zenodo.7922163" ID-Zenodo-Dep="7922163" LSID="urn:lsid:plazi:treatment:3F6A87ABFFA5FFEC7262F916FAD2FE6B" httpUri="http://treatment.plazi.org/id/3F6A87ABFFA5FFEC7262F916FAD2FE6B" lastPageId="19" lastPageNumber="20" pageId="12" pageNumber="13">
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<subSubSection box="[887,1346,1726,1751]" pageId="12" pageNumber="13" type="nomenclature">
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<paragraph blockId="12.[887,1346,1726,1751]" box="[887,1346,1726,1751]" pageId="12" pageNumber="13">
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<heading box="[887,1346,1726,1751]" centered="true" fontSize="9" level="2" pageId="12" pageNumber="13" reason="2">
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<taxonomicName authority="HAUGHTON, 1917" authorityName="Haughton" authorityYear="1917" box="[887,1346,1726,1751]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="12" pageNumber="3" phylum="Chordata" rank="species" species="gracilis">
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<emphasis box="[887,1139,1727,1750]" italics="true" pageId="12" pageNumber="13">
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<smallCapsWord baselines="1744,1745" box="[887,1029,1727,1750]" lowerCaseFontSize="8" mainFontSize="10" normCase="title" normString="Myosaurus" pageId="12" pageNumber="13">MYOSAURUS</smallCapsWord>
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<smallCapsWord baselines="1745" box="[1036,1139,1730,1750]" lowerCaseFontSize="8" mainFontSize="10" normCase="lower" normString="gracilis" pageId="12" pageNumber="13">GRACILIS</smallCapsWord>
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</emphasis>
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<bibRefCitation author="Haughton SH" box="[1146,1346,1726,1751]" pageId="12" pageNumber="13" pagination="164 - 172" refId="ref37008" refString="Haughton SH. 1917. Investigations in South African reptiles and amphibia. Annals of the South African Museum 12: 164 - 172." type="journal article" year="1917">
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<smallCapsWord baselines="1745,1745" box="[1146,1276,1726,1751]" lowerCaseFontSize="8" mainFontSize="10" normCase="title" normString="Haughton" pageId="12" pageNumber="13">HAUGHTON</smallCapsWord>
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, 1917
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</bibRefCitation>
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</taxonomicName>
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</heading>
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</paragraph>
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</subSubSection>
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<subSubSection lastPageId="19" lastPageNumber="20" pageId="12" pageNumber="13" type="description">
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<paragraph blockId="12.[809,1425,1766,1819]" pageId="12" pageNumber="13">
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<emphasis box="[809,935,1767,1788]" italics="true" pageId="12" pageNumber="13">Specimens:</emphasis>
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<materialsCitation box="[954,1073,1766,1788]" collectionCode="BP" pageId="12" pageNumber="13" specimenCode="BP/1" specimenCount="1">
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<specimenCode box="[954,1005,1766,1788]" collectionCode="BP" pageId="12" pageNumber="13">BP/1</specimenCode>
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/2690
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</materialsCitation>
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,
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<materialsCitation collectionCode="BP" pageId="12" pageNumber="13" specimenCode="BP/1" specimenCount="1">
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<specimenCode box="[1083,1136,1767,1788]" collectionCode="BP" pageId="12" pageNumber="13">BP/1</specimenCode>
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/2701a (the description is a composite of the
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<specimenCount box="[1020,1189,1797,1819]" pageId="12" pageNumber="13" type="generic">two specimens</specimenCount>
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)
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</materialsCitation>
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.
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</paragraph>
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<paragraph blockId="12.[809,1425,1860,1912]" lastBlockId="14.[145,762,197,986]" lastPageId="14" lastPageNumber="15" pageId="12" pageNumber="13">
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<emphasis box="[809,1000,1860,1881]" italics="true" pageId="12" pageNumber="13">Orbitosphenoid:</emphasis>
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The orbitosphenoid of
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<taxonomicName box="[1294,1425,1861,1882]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="12" pageNumber="13" phylum="Chordata" rank="genus">
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<emphasis box="[1294,1425,1861,1882]" italics="true" pageId="12" pageNumber="13">Myosaurus</emphasis>
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</taxonomicName>
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displays the typical Y-shape in anterior view (
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<figureCitation box="[171,241,1764,1786]" captionStart="Figure 2" captionStartId="5.[163,243,1355,1377]" captionTargetBox="[277,1343,174,1316]" captionTargetId="figure-208@5.[1099,1331,1099,1306]" captionTargetPageId="5" captionText="Figure 2. Comparisons of the braincase between Pristerodon and emydopoids. Pristerodon mackayi (BP/1/2642) in (A) anterior, (B) left lateral, (C) posterior and (D) ventral views. Myosaurus gracilis (BP/1/2690) in (E) anterior, (F) left lateral, (G) posterior and (H) ventral views. The Malawian cistecephalid (DMMM-PK-16-1) in (I) anterior, (J) left lateral, (K) posterior and (L) ventral views. Kaaeingasaurus fossilis (GPIT-PV-117032) in (M) anterior, (N) left lateral, (O) posterior and (P) ventral views. Dark green – supraoccipital; Purple – orbitosphenoid; Dark orange – opisthotic; Light orange – pterygoid; Green – basioccipital; Magenta – exoccipital; Cyan blue – parasphenoid rostrum; Navy blue – prootic; Aqua blue – basisphenoid; Light Rose – epipterygoid. Same color code scheme is used in the following figures." figureDoi="http://doi.org/10.5281/zenodo.7922151" httpUri="https://zenodo.org/record/7922151/files/figure.png" pageId="13" pageNumber="14">Figs 2</figureCitation>
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,
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<figureCitation box="[255,269,1764,1786]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="13" pageNumber="14">6</figureCitation>
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). It is generally thicker than in
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<taxonomicName authorityName="Huxley" authorityYear="1868" box="[639,772,1764,1785]" class="Reptilia" genus="Pristerodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="13" pageNumber="14" phylum="Chordata" rank="genus">
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<emphasis box="[639,772,1764,1785]" italics="true" pageId="13" pageNumber="14">Pristerodon</emphasis>
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</taxonomicName>
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, shorter dorsoventrally but mediolaterally wider (height-to-width ratio
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<quantity box="[442,512,1825,1847]" metricMagnitude="-2" metricUnit="m" metricValue="2.032" pageId="13" pageNumber="14" unit="in" value="0.8">0.8 in</quantity>
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<taxonomicName box="[522,655,1826,1847]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="13" pageNumber="14" phylum="Chordata" rank="genus">
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<emphasis box="[522,655,1826,1847]" italics="true" pageId="13" pageNumber="14">Myosaurus</emphasis>
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</taxonomicName>
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vs.
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<quantity box="[708,778,1825,1847]" metricMagnitude="-2" metricUnit="m" metricValue="4.064" pageId="13" pageNumber="14" unit="in" value="1.6">1.6 in</quantity>
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<taxonomicName authorityName="Huxley" authorityYear="1868" box="[163,302,1856,1877]" class="Reptilia" genus="Pristerodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="13" pageNumber="14" phylum="Chordata" rank="genus">
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<emphasis box="[163,302,1856,1877]" italics="true" pageId="13" pageNumber="14">Pristerodon</emphasis>
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||
</taxonomicName>
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||
). These different proportions may be a by-product of the allometric effect determining the lower limit of the olfactory bulbs, which then may be proportionally larger in
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<taxonomicName box="[1160,1291,1795,1816]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="13" pageNumber="14" phylum="Chordata" rank="genus">
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<emphasis box="[1160,1291,1795,1816]" italics="true" pageId="13" pageNumber="14">Myosaurus</emphasis>
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</taxonomicName>
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||
. As in other dicynodonts, the orbitosphenoid comprises a vertical median process (obvp, the mesethmoid) anteriorly and the dorsally projecting wings (obw) posteriorly (
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<bibRefCitation author="Castanhinha R & Araujo R & Junior LC & Angielczyk KD & Martins GG & Martins RM & Chaouiya C & Beckmann F & Wilde F" box="[154,458,197,219]" pageId="14" pageNumber="15" pagination="80974" refId="ref35640" refString="Castanhinha R, Araujo R, Junior LC, Angielczyk KD, Martins GG, Martins RM, Chaouiya C, Beckmann F, Wilde F. 2013. Bringing dicynodonts back to life: paleobiology and anatomy of a new emydopoid genus from the Upper Permian of Mozambique. PLoS One 8: e 80974." type="journal article" year="2013">
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||
Castanhinha
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<emphasis box="[321,383,197,219]" italics="true" pageId="14" pageNumber="15">et al.</emphasis>
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, 2013
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||
</bibRefCitation>
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||
). The gutter (obgu) that hosts the olfactory bulbs dorsally is wider than in
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<taxonomicName authorityName="Huxley" authorityYear="1868" box="[145,280,258,279]" class="Reptilia" genus="Pristerodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
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<emphasis box="[145,280,258,279]" italics="true" pageId="14" pageNumber="15">Pristerodon</emphasis>
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</taxonomicName>
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. In anterior view, the orbitosphenoid has tall wings that open at a greater angle from the sagittal plane, which results in a broad olfactory cavity. The wings are less curved than in
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<taxonomicName authorityName="Huxley" authorityYear="1868" box="[506,643,350,371]" class="Reptilia" genus="Pristerodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
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<emphasis box="[506,643,350,371]" italics="true" pageId="14" pageNumber="15">Pristerodon</emphasis>
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</taxonomicName>
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||
(
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<figureCitation box="[661,746,350,372]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6A</figureCitation>
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). The median vertical process (obvp) has a prominent vertical crest (obacr) on its anteriormost edge that is flanked by two lateral sulci (obasu) visible in anterior view. The dorsal aspect of the median process of the orbitosphenoid thickens dorsally in
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<taxonomicName box="[577,707,504,525]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
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<emphasis box="[577,707,504,525]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
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||
</taxonomicName>
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and bears a distinct horizontal fossa (obdfo,
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<figureCitation box="[655,745,534,556]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6B</figureCitation>
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||
). Anterior to this fossa, an approximately
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<quantity box="[618,704,565,587]" metricMagnitude="-3" metricUnit="m" metricValue="1.4" pageId="14" pageNumber="15" unit="mm" value="1.4">1.4 mm</quantity>
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long spine (obsp) projects anteriorly in the prolongation of the medial wall.
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</paragraph>
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||
<caption ID-DOI="http://doi.org/10.5281/zenodo.7922161" ID-Zenodo-Dep="7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="13" pageNumber="14" startId="13.[163,244,1327,1349]" targetBox="[295,1306,200,1288]" targetPageId="13" targetType="figure">
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||
<paragraph blockId="13.[163,1443,1327,1731]" pageId="13" pageNumber="14">
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<emphasis bold="true" box="[163,271,1327,1349]" pageId="13" pageNumber="14">Figure 6.</emphasis>
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The anterior, ventral and lateral walls of the braincase of
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<taxonomicName authorityName="Haughton" authorityYear="1917" box="[917,1124,1328,1350]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="13" pageNumber="14" phylum="Chordata" rank="species" species="gracilis">
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<emphasis box="[917,1124,1328,1350]" italics="true" pageId="13" pageNumber="14">Myosaurus gracilis</emphasis>
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||
</taxonomicName>
|
||
(BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process; obw, orbitosphenoid wings; ofc, olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N).
|
||
</paragraph>
|
||
</caption>
|
||
<paragraph blockId="14.[145,762,197,986]" pageId="14" pageNumber="15">
|
||
In lateral view, the orbitosphenoid is subrectangular in
|
||
<taxonomicName box="[176,303,688,709]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[176,303,688,709]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
. It is short anteroposteriorly compared to
|
||
<emphasis box="[181,379,719,740]" italics="true" pageId="14" pageNumber="15">Kaaeingasaurus</emphasis>
|
||
(length-to-width ratio
|
||
<quantity box="[686,759,718,740]" metricMagnitude="-2" metricUnit="m" metricValue="2.286" pageId="14" pageNumber="15" unit="in" value="0.9">0.9 in</quantity>
|
||
<taxonomicName box="[145,278,750,771]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[145,278,750,771]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
vs.
|
||
<quantity box="[331,401,749,771]" metricMagnitude="-2" metricUnit="m" metricValue="4.826" pageId="14" pageNumber="15" unit="in" value="1.9">1.9 in</quantity>
|
||
<emphasis box="[412,603,750,771]" italics="true" pageId="14" pageNumber="15">Kaaeingasaurus</emphasis>
|
||
). The dorsal margin of the wings is not horizontal as in
|
||
<taxonomicName authorityName="Huxley" authorityYear="1868" box="[623,755,780,801]" class="Reptilia" genus="Pristerodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[623,755,780,801]" italics="true" pageId="14" pageNumber="15">Pristerodon</emphasis>
|
||
</taxonomicName>
|
||
, but slightly curved (
|
||
<figureCitation box="[388,473,810,832]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6C</figureCitation>
|
||
). The plate-like vertical wall, which supports the wings of the orbitosphenoid, is dorsoventrally short in
|
||
<taxonomicName box="[416,542,872,893]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[416,542,872,893]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
and it is traversed by two oblique crests (ltcr) in lateral view (
|
||
<figureCitation box="[661,746,902,924]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6C</figureCitation>
|
||
). The ventralmost crest is long, and the dorsal one is much shorter.
|
||
</paragraph>
|
||
<paragraph blockId="14.[145,762,1026,1907]" pageId="14" pageNumber="15">
|
||
<emphasis box="[145,264,1026,1047]" italics="true" pageId="14" pageNumber="15">Pterygoid:</emphasis>
|
||
The pterygoid (pt) is incomplete in both studied specimens of
|
||
<taxonomicName box="[414,547,1058,1079]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[414,547,1058,1079]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
, missing the left quadrate ramus in specimen BP/1/2701a, and the left palatal ramus and both quadrate rami in specimen BP/1/2690 (
|
||
<figureCitation box="[284,379,1149,1171]" captionStart="Figure 2" captionStartId="5.[163,243,1355,1377]" captionTargetBox="[277,1343,174,1316]" captionTargetId="figure-208@5.[1099,1331,1099,1306]" captionTargetPageId="5" captionText="Figure 2. Comparisons of the braincase between Pristerodon and emydopoids. Pristerodon mackayi (BP/1/2642) in (A) anterior, (B) left lateral, (C) posterior and (D) ventral views. Myosaurus gracilis (BP/1/2690) in (E) anterior, (F) left lateral, (G) posterior and (H) ventral views. The Malawian cistecephalid (DMMM-PK-16-1) in (I) anterior, (J) left lateral, (K) posterior and (L) ventral views. Kaaeingasaurus fossilis (GPIT-PV-117032) in (M) anterior, (N) left lateral, (O) posterior and (P) ventral views. Dark green – supraoccipital; Purple – orbitosphenoid; Dark orange – opisthotic; Light orange – pterygoid; Green – basioccipital; Magenta – exoccipital; Cyan blue – parasphenoid rostrum; Navy blue – prootic; Aqua blue – basisphenoid; Light Rose – epipterygoid. Same color code scheme is used in the following figures." figureDoi="http://doi.org/10.5281/zenodo.7922151" httpUri="https://zenodo.org/record/7922151/files/figure.png" pageId="14" pageNumber="15">Figs 2H</figureCitation>
|
||
,
|
||
<figureCitation box="[394,408,1149,1171]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">6</figureCitation>
|
||
). It has the typical X-shaped dicynodont morphology in ventral view. The palatal rami (aptr) are more horizontal than in
|
||
<taxonomicName authorityName="Huxley" authorityYear="1868" box="[619,755,1210,1231]" class="Reptilia" genus="Pristerodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[619,755,1210,1231]" italics="true" pageId="14" pageNumber="15">Pristerodon</emphasis>
|
||
</taxonomicName>
|
||
, forming an angle of 22° with the anteroposterior median axis of the skull. The quadrate ramus (ptqr) angles ~61° from the sagittal axis of the skull and ~102° from the palatal ramus. The palatal ramus of the pterygoid in
|
||
<taxonomicName box="[297,426,1364,1385]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[297,426,1364,1385]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
is longer than the quadrate ramus (
|
||
<figureCitation box="[236,320,1394,1416]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6G</figureCitation>
|
||
). In dorsal view, the palatal ramus of BP/1/2701a is mediolaterally thinner in
|
||
<taxonomicName box="[631,761,1426,1447]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[631,761,1426,1447]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
than in
|
||
<taxonomicName authorityName="Huxley" authorityYear="1868" box="[233,365,1456,1477]" class="Reptilia" genus="Pristerodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[233,365,1456,1477]" italics="true" pageId="14" pageNumber="15">Pristerodon</emphasis>
|
||
</taxonomicName>
|
||
. On the anterior half of the palatal ramus, the pterygoid of
|
||
<taxonomicName box="[425,552,1487,1508]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[425,552,1487,1508]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
is excavated by a narrow anteroposterior groove (pt gr) dorsally (
|
||
<figureCitation captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6D, G</figureCitation>
|
||
). Posterior to this groove, there is an anteromedial process (pt amp) projecting over the palatal ramus and terminating posteriorly at the anterior end of the pterygoid median plate in specimen BP/1/2701a (
|
||
<figureCitation captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6G</figureCitation>
|
||
). This process is damaged in specimen BP/1/2690. The quadrate ramus is co-ossified to a small portion of the epipterygoid dorsally.
|
||
</paragraph>
|
||
<paragraph blockId="14.[145,762,1026,1907]" lastBlockId="14.[809,1426,197,1261]" pageId="14" pageNumber="15">
|
||
In lateral view, the palatal ramus in
|
||
<taxonomicName box="[629,761,1763,1784]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[629,761,1763,1784]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
is taller than the quadrate ramus. The specimens of
|
||
<taxonomicName box="[145,272,1824,1845]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[145,272,1824,1845]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
described here do not have a ventral keel (
|
||
<figureCitation box="[153,274,1854,1876]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6E, H</figureCitation>
|
||
), which is consistent with previous work on
|
||
<taxonomicName box="[179,305,1886,1907]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[179,305,1886,1907]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
in which this structure is not described (
|
||
<bibRefCitation author="Haughton SH" box="[818,1017,197,219]" pageId="14" pageNumber="15" pagination="164 - 172" refId="ref37008" refString="Haughton SH. 1917. Investigations in South African reptiles and amphibia. Annals of the South African Museum 12: 164 - 172." type="journal article" year="1917">Haughton, 1917</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Hammer WR & Cosgriff JW" box="[1035,1357,197,219]" pageId="14" pageNumber="15" pagination="410 - 424" refId="ref36975" refString="Hammer WR, Cosgriff JW. 1981. Myosaurus gracilis, an anomodont reptile from the Lower Triassic of Antarctica and South Africa. Journal of Palaeontology 55: 410 - 424." type="journal article" year="1981">Hammer & Cosgriff, 1981</bibRefCitation>
|
||
), but
|
||
<bibRefCitation author="Cluver MA" box="[809,982,228,250]" pageId="14" pageNumber="15" pagination="35 - 54" refId="ref35877" refString="Cluver MA. 1974 b. The cranial morphology of the Lower Triassic dicynodont Myosaurus gracilis. Annals of the South African Museum 66: 35 - 54." type="journal article" year="1974">Cluver (1974b)</bibRefCitation>
|
||
reports the presence of this structure on the anterior palatal ramus of the pterygoid. The anteromedial process is triangular and gives a Y-shape to the pterygoid in lateral view in specimen BP/1/2701a (
|
||
<figureCitation box="[971,1064,350,372]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6H</figureCitation>
|
||
). This process is longer and more developed dorsally than in
|
||
<taxonomicName authorityName="Huxley" authorityYear="1868" box="[1186,1319,381,402]" class="Reptilia" genus="Pristerodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1186,1319,381,402]" italics="true" pageId="14" pageNumber="15">Pristerodon</emphasis>
|
||
</taxonomicName>
|
||
. It forms an angle of 52° from the rest of the palatal ramus in
|
||
<taxonomicName box="[842,974,443,464]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[842,974,443,464]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
specimen BP/1/2701a. The quadrate ramus of the pterygoid attaches to the median pterygoid plate on the short posterior process of the median pterygoid plate. The quadrate ramus has a dorsoventrally flattened and pointed end in lateral view in BP/1/2701a (
|
||
<figureCitation box="[1046,1130,595,617]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6H</figureCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="14.[809,1426,197,1261]" pageId="14" pageNumber="15">
|
||
In ventral view, the palatal ramus of the pterygoid has a constant width (
|
||
<figureCitation box="[1077,1161,657,679]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6F</figureCitation>
|
||
). The median plate of the pterygoid (ptmp) is narrow in
|
||
<taxonomicName box="[1246,1380,688,709]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1246,1380,688,709]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
. In ventral view, it contacts the basisphenoid along an interdigitating suture posteriorly and sends a short process posteriorly to meet the clinoid process of the basisphenoid (
|
||
<figureCitation box="[986,1072,810,832]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6F</figureCitation>
|
||
).
|
||
<taxonomicName box="[1098,1230,811,832]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1098,1230,811,832]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
has a V-shaped crista oesophagea (co) that converges posteriorly on the midline between the two carotid foramina and bifurcates anteriorly onto the palatal rami. In BP/1/2690, the crista oesophagea is flat, but in the better-preserved specimen SAM-PK-K10974, it forms a thin median ridge. This difference between the
|
||
<specimenCount box="[809,986,1025,1047]" pageId="14" pageNumber="15" type="generic">two specimens</specimenCount>
|
||
may be the result of taphonomy or preparation. The suture between the two pterygoids is visible and marked by a weakly pronounced anteroposterior furrow (apf) at the midline (
|
||
<figureCitation box="[1328,1410,1117,1139]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6F</figureCitation>
|
||
). The interpterygoid vacuity is narrower and more elongated in
|
||
<taxonomicName box="[952,1077,1179,1200]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[952,1077,1179,1200]" italics="true" pageId="14" pageNumber="15">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
than in
|
||
<taxonomicName authorityName="Huxley" authorityYear="1868" box="[1169,1301,1178,1199]" class="Reptilia" genus="Pristerodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="14" pageNumber="15" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1169,1301,1178,1199]" italics="true" pageId="14" pageNumber="15">Pristerodon</emphasis>
|
||
</taxonomicName>
|
||
. In ventral view, the quadrate ramus is expanded anteriorly and has a robust posterior edge.
|
||
</paragraph>
|
||
<paragraph blockId="14.[809,1426,1302,1907]" lastBlockId="15.[163,779,197,740]" lastPageId="15" lastPageNumber="16" pageId="14" pageNumber="15">
|
||
<emphasis box="[809,982,1302,1323]" italics="true" pageId="14" pageNumber="15">Epipterygoid:</emphasis>
|
||
The epipterygoid is a vertically elongated braincase sidewall element that usually rests on the quadrate ramus ventrally and ascends to contact the descending flanges of the parietal dorsally in dicynodonts (
|
||
<bibRefCitation author="Keyser AW" box="[1010,1168,1425,1446]" pageId="14" pageNumber="15" pagination="1 - 71" refId="ref37958" refString="Keyser AW. 1973. A preliminary study of the type area of the Cistecephalus Zone of the Beaufort Series, and a revision of the anomodont family Cistecephalidae. Geological SurVey of South Africa 62: 1 - 71." type="journal article" year="1973">Keyser, 1973</bibRefCitation>
|
||
,
|
||
<bibRefCitation author="Keyser AW" box="[1185,1243,1425,1446]" pageId="14" pageNumber="15" pagination="57 - 68" refId="ref37999" refString="Keyser AW. 1974. Evolutionary trends in Triassic Dicynodontia (Reptilia Therapsida). Palaeontologia Africana 17: 57 - 68." type="journal article" year="1974">1974</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Angielczyk KD & Sullivan C" pageId="14" pageNumber="15" pagination="788 - 802" refId="ref34311" refString="Angielczyk KD, Sullivan C. 2008. Diictodon feliceps (Owen, 1876), a dicynodont (Therapsida, Anomodontia) species with a Pangaean distribution. Journal of Vertebrate Paleontology 28: 788 - 802." type="journal article" year="2008">Angielczyk & Sullivan, 2008</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Castanhinha R & Araujo R & Junior LC & Angielczyk KD & Martins GG & Martins RM & Chaouiya C & Beckmann F & Wilde F" box="[985,1262,1455,1477]" pageId="14" pageNumber="15" pagination="80974" refId="ref35640" refString="Castanhinha R, Araujo R, Junior LC, Angielczyk KD, Martins GG, Martins RM, Chaouiya C, Beckmann F, Wilde F. 2013. Bringing dicynodonts back to life: paleobiology and anatomy of a new emydopoid genus from the Upper Permian of Mozambique. PLoS One 8: e 80974." type="journal article" year="2013">
|
||
Castanhinha
|
||
<emphasis box="[1139,1195,1455,1477]" italics="true" pageId="14" pageNumber="15">et al.</emphasis>
|
||
, 2013
|
||
</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Angielczyk KD & Kammerer CF" pageId="14" pageNumber="15" pagination="513 - 545" refId="ref34004" refString="Angielczyk KD, Kammerer CF. 2017. The cranial morphology, phylogenetic position and biogeography of the Upper Permian dicynodont Compsodon helmoedi Van Hoepen (Therapsida, Anomodontia). Papers in Palaeontology 3: 513 - 545." type="journal article" year="2017">Angielczyk & Kammerer, 2017</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Laass M & Kaestner A" box="[1016,1285,1486,1507]" pageId="14" pageNumber="15" pagination="1033 - 1057" refId="ref38292" refString="Laass M, Kaestner A. 2017. Evidence for convergent evolution of a neocortex-like structure in a Late Permian therapsid. Journal of Morphology 278: 1033 - 1057." type="journal article" year="2017">Laass & Kaestner, 2017</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Angielczyk KD & Benoit J & Rubidge BS" pageId="14" pageNumber="15" pagination="405 - 446" refId="ref33801" refString="Angielczyk KD, Benoit J, Rubidge BS. 2019. A new tusked cistecephalid dicynodont (Therapsida, Anomodontia) from the Upper Permian Upper Madumabisa Mudstone Formation, Luangwa Basin, Zambia. Papers in Palaeontology 7: 405 - 446." type="journal article" year="2019">
|
||
Angielczyk
|
||
<emphasis box="[809,864,1517,1538]" italics="true" pageId="14" pageNumber="15">et al.</emphasis>
|
||
, 2019
|
||
</bibRefCitation>
|
||
). The epipterygoid is preserved in specimen BP/1/2701a (
|
||
<figureCitation box="[956,1019,1547,1569]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6</figureCitation>
|
||
I-K) and comprises a subhorizontal footplate ventrally (epft) and a rod-like ascending ramus dorsally (epar). The footplate consists of a short anterior ramus and a posterior quadrate ramus that is broken off close to its mid-length (
|
||
<figureCitation box="[1245,1357,1670,1692]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6J, K</figureCitation>
|
||
). The preserved portion of the quadrate ramus is taller and longer than the anterior ramus in lateral view (
|
||
<figureCitation captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="14" pageNumber="15">Fig. 6J</figureCitation>
|
||
). The ventromedial surface of the footplate rests entirely on the dorsal side of the quadrate ramus of the pterygoid as in other emydopoids (
|
||
<bibRefCitation author="Keyser AW" box="[1268,1418,1823,1845]" pageId="14" pageNumber="15" pagination="1 - 71" refId="ref37958" refString="Keyser AW. 1973. A preliminary study of the type area of the Cistecephalus Zone of the Beaufort Series, and a revision of the anomodont family Cistecephalidae. Geological SurVey of South Africa 62: 1 - 71." type="journal article" year="1973">Keyser, 1973</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Fourie H" box="[809,961,1854,1876]" pageId="14" pageNumber="15" refId="ref36362" refString="Fourie H. 1991. A detailed description of the skull of Emydops (Therapsida: Dicynodontia). Master's Thesis, University of the Witwatersrand." type="book" year="1991">Fourie, 1991</bibRefCitation>
|
||
,
|
||
<bibRefCitation author="Fourie H" box="[978,1036,1854,1875]" pageId="14" pageNumber="15" pagination="103 - 111" refId="ref36389" refString="Fourie H. 1993. A detailed description of the internal structure of the skull of Emydops (Therapsida: Dicynodontia). Palaeontologia Africana 30: 103 - 111." type="journal article" year="1993">1993</bibRefCitation>
|
||
), such that the suture between the two bones (the footplate of the epipterygoid and the quadrate ramus of the pterygoid) follows the longitudinal plane of the skull. The epipterygoid footplate does not contact the parabasisphenoid in
|
||
<taxonomicName box="[163,293,290,311]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[163,293,290,311]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
. As observed in lateral view, the lateral surface of the epipterygoid is nearly flat but its medial surface is concave (
|
||
<figureCitation box="[476,586,350,372]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6J, K</figureCitation>
|
||
). In dorsal view, the quadrate ramus of the epipterygoid footplate is mediolaterally wider than the anterior ramus.
|
||
</paragraph>
|
||
<paragraph blockId="15.[163,779,197,740]" pageId="15" pageNumber="16">
|
||
In
|
||
<taxonomicName box="[230,374,443,464]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[230,374,443,464]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
, the ascending ramus of the epipterygoid is longer and straighter than in
|
||
<emphasis box="[163,354,504,525]" italics="true" pageId="15" pageNumber="16">Kaaeingasaurus</emphasis>
|
||
, and forms a right angle with the footplate (
|
||
<figureCitation box="[295,382,534,556]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6J</figureCitation>
|
||
). The ascending ramus has an anteroposteriorly wide base. Dorsally, it tapers considerably to become a rod-like bone at its mid-height and broadens dorsally to form an inverted triangular dorsal process (epdp,
|
||
<figureCitation box="[531,637,657,679]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6J, K</figureCitation>
|
||
). The dorsal process of the ascending ramus is slightly concave medially and articulates with the parietal laterally.
|
||
</paragraph>
|
||
<paragraph blockId="15.[163,780,781,1907]" pageId="15" pageNumber="16">
|
||
<emphasis box="[163,375,781,802]" italics="true" pageId="15" pageNumber="16">Parabasisphenoid:</emphasis>
|
||
The parabasisphenoid complex of
|
||
<taxonomicName box="[163,288,812,833]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[163,288,812,833]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
(pbs) is well-preserved and is subtriangular in both dorsal and ventral views (
|
||
<figureCitation box="[539,608,842,864]" captionStart="Figure 2" captionStartId="5.[163,243,1355,1377]" captionTargetBox="[277,1343,174,1316]" captionTargetId="figure-208@5.[1099,1331,1099,1306]" captionTargetPageId="5" captionText="Figure 2. Comparisons of the braincase between Pristerodon and emydopoids. Pristerodon mackayi (BP/1/2642) in (A) anterior, (B) left lateral, (C) posterior and (D) ventral views. Myosaurus gracilis (BP/1/2690) in (E) anterior, (F) left lateral, (G) posterior and (H) ventral views. The Malawian cistecephalid (DMMM-PK-16-1) in (I) anterior, (J) left lateral, (K) posterior and (L) ventral views. Kaaeingasaurus fossilis (GPIT-PV-117032) in (M) anterior, (N) left lateral, (O) posterior and (P) ventral views. Dark green – supraoccipital; Purple – orbitosphenoid; Dark orange – opisthotic; Light orange – pterygoid; Green – basioccipital; Magenta – exoccipital; Cyan blue – parasphenoid rostrum; Navy blue – prootic; Aqua blue – basisphenoid; Light Rose – epipterygoid. Same color code scheme is used in the following figures." figureDoi="http://doi.org/10.5281/zenodo.7922151" httpUri="https://zenodo.org/record/7922151/files/figure.png" pageId="15" pageNumber="16">Figs 2</figureCitation>
|
||
,
|
||
<figureCitation box="[619,633,842,864]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">6</figureCitation>
|
||
). As usual in dicynodonts, the basipostsphenoid forms the posterior end of the bone, and the parasphenoid rostrum and basipresphenoid (PRB) forms its anterior part (
|
||
<bibRefCitation author="Cox CB" pageId="15" pageNumber="16" pagination="321 - 367" refId="ref36046" refString="Cox CB. 1959. On the anatomy of a new dicynodont genus with evidence of the position of the tympanum. Procedings of the Zoological Society of London 132: 321 - 367." type="journal article" year="1959">Cox, 1959</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="15.[163,780,781,1907]" lastBlockId="15.[827,1444,197,1139]" pageId="15" pageNumber="16">
|
||
The PRB is mediolaterally broad in
|
||
<taxonomicName box="[645,779,996,1017]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[645,779,996,1017]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
(length-to-width ratio
|
||
<quantity box="[442,512,1026,1048]" metricMagnitude="-2" metricUnit="m" metricValue="2.794" pageId="15" pageNumber="16" unit="in" value="1.1">1.1 in</quantity>
|
||
<taxonomicName box="[522,655,1027,1048]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[522,655,1027,1048]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
vs.
|
||
<quantity box="[708,778,1026,1048]" metricMagnitude="-2" metricUnit="m" metricValue="3.81" pageId="15" pageNumber="16" unit="in" value="1.5">1.5 in</quantity>
|
||
<taxonomicName authorityName="Huxley" authorityYear="1868" box="[163,304,1057,1078]" class="Reptilia" genus="Pristerodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[163,304,1057,1078]" italics="true" pageId="15" pageNumber="16">Pristerodon</emphasis>
|
||
</taxonomicName>
|
||
). In dorsal view, it is excavated by an anteroposteriorly elongated and thin sulcus (pss). This sulcus is bordered by two low lateral crests (psc,
|
||
<figureCitation box="[222,302,1149,1171]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6L</figureCitation>
|
||
). Posteriorly, this sulcus ends in a small, anteroposteriorly oval foramen in the parasphenoid (psf). This pit opens on the ventral side of the bone within a circular cavity (
|
||
<figureCitation box="[443,526,1241,1263]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6N</figureCitation>
|
||
). As this pit is located anterior to the carotid foramina in BP/1/2690 (
|
||
<figureCitation captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6L</figureCitation>
|
||
), it forms a notch on the anterior margin of the carotid foramen in BP/1/2701a and may represent a relictual pituitary fossa. In contrast to what is found in several dicynodont taxa (e.g.
|
||
<taxonomicName box="[535,657,1394,1415]" family="Kingoriidae" genus="Niassodon" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[535,657,1394,1415]" italics="true" pageId="15" pageNumber="16">Niassodon</emphasis>
|
||
</taxonomicName>
|
||
), the PRB and the basipostsphenoid are fused in
|
||
<taxonomicName box="[640,772,1426,1447]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[640,772,1426,1447]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
. The position of the dorsal exit of the carotid foramina gives a rough indication of the suture between the PRB and the basipostsphenoid, and these foramina open dorsally into a single large circular orifice. Posterior to the carotid foramina, in dorsal view, lies the sella turcica (stu), which is a shallow excavation bordered posteriorly by a shallow inconspicuous ridge corresponding to the dorsum sellae (
|
||
<figureCitation box="[620,707,1670,1692]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6L</figureCitation>
|
||
). The sella turcica extends a short distance anteriorly onto the carotid foramina, but it is not confined anteriorly. There is no tuberculum sellae in
|
||
<taxonomicName box="[538,663,1763,1784]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[538,663,1763,1784]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
. The sella turcica in
|
||
<taxonomicName box="[274,399,1794,1815]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[274,399,1794,1815]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
is limited laterally by the dorsally projecting clinoid process (clp) of the basipostsphenoid. The clinoid process sharpens dorsally, its dorsal edge is turned medially and has a concave recess along with its dorsal extension. There is a gap of
|
||
<quantity box="[1293,1384,197,218]" metricMagnitude="-4" metricUnit="m" metricValue="3.0" pageId="15" pageNumber="16" unit="mm" value="0.3">0.3 mm</quantity>
|
||
that separates the clinoid process from the pila antotica, and the two processes are separated posteriorly by the dorsum sellae (ds,
|
||
<figureCitation box="[1039,1118,289,311]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6L</figureCitation>
|
||
). In dorsal view, the dorsum sellae is interrupted posteriorly by the transverse suture with the basioccipital. The basisphenoidal tubera (bpt) project posteroventrally and have a slightly concave dorsal surface that articulates with the basioccipital. As such, the basisphenoidal tubera do not border the fenestra ovalis, because the anteromedial wall of the fenestra is entirely formed by the basioccipital. In lateral view, the parasphenoid rostrum is straight but has a dorsoventrally expanded anterior tip (
|
||
<figureCitation box="[971,1057,595,617]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6M</figureCitation>
|
||
). The clinoid process is offset from the parasphenoid rostrum, forming a notch where they meet. It forms an acute angle with the parasphenoid rostrum in
|
||
<taxonomicName box="[955,1080,688,709]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[955,1080,688,709]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
.
|
||
</paragraph>
|
||
<paragraph blockId="15.[827,1444,197,1139]" pageId="15" pageNumber="16">
|
||
In ventral view, the PRB tapers more anteriorly than posteriorly. It is excavated by a median trough that envelops the parasphenoid foramen (
|
||
<figureCitation box="[1338,1427,779,801]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6N</figureCitation>
|
||
). The ventral aspect of the base of the PRB is not flat but is irregular due to the interdigitating suture with the pterygoid median plate (
|
||
<figureCitation box="[1183,1273,871,893]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6N</figureCitation>
|
||
). This suture obscures most of the ventral anatomy of the PRB. The basipostsphenoid in
|
||
<taxonomicName box="[1134,1266,933,954]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1134,1266,933,954]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
does not form the ventral depression of the basicranium, which is instead composed of basioccipital. The basisphenoidal tubera border the ventral depression only laterally. The carotid foramina are bordered by thin ridges and they diverge ventrally and follow, to some degree, the basisphenoidal tubera (
|
||
<figureCitation box="[1094,1178,1117,1139]" captionStart="Figure 6" captionStartId="13.[163,244,1327,1349]" captionTargetBox="[295,1306,200,1288]" captionTargetId="figure-105@13.[291,1315,224,1281]" captionTargetPageId="13" captionText="Figure 6. The anterior, ventral and lateral walls of the braincase of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): orbitosphenoid (purple) of BP/1/2690 in (A) anterior, (B) dorsal and (C) right lateral views; the pterygoid (yellow) of BP/1/2690 in (D) dorsal, (E) right lateral and (F) ventral views; ventral braincase floor of BP/1/2701a in (G) dorsal and (H) right lateral views; epipterygoid (pink) of BP/1/2701a in (I) anterior, (J) right lateral and (K) medial views; and the parabasisphenoid (turquoise) of BP/1/2690 in (L) dorsal, (M) left lateral and (N) ventral views. apf, pterygoid anteroposterior furrow; aptr, anterior (palatal) ramus of the pterygoid; bpt, basisphenoidal tubera; clp, clinoid process; co, crista oesophagea; ds, dorsum sellae; epar, epipterygoid ascending ramus; epdp, epipterygoid dorsal plate; epft, epipterygoid footplate; ic, internal carotid foramina; ltcr, oblique crests of the lateral wall; obacr, orbitosphenoid vertical crest; obasu, lateral sulci of the median vertical process; obdfo, orbitosphenoid dorsal fossa; obgu, orbitosphenoid gutter; obvp, orbitosphenoid vertical process; obsp, orbitosphenoid spine process;obw, orbitosphenoid wings; ofc,olfactory cavity; PRB, parasphenoid rostrum + basipresphenoid; ps, parasphenoid (light blue) rostrum; psc, parasphenoidal crests; psf, parasphenoidal foramen; pss, parasphenoidal sulcus; pt amp, anteromedial process of the pterygoid; pt gr, pterygoid dorsal groove; ptmp, pterygoid median plate; ptqr, quadrate ramus of the pterygoid; stu, sella turcica. Scale bars equal 5 mm. The first scale serves for (A-C), the second for (D-F), the third for (G-H), the fourth for (I-K) and the fifth for (L-N)." figureDoi="http://doi.org/10.5281/zenodo.7922161" httpUri="https://zenodo.org/record/7922161/files/figure.png" pageId="15" pageNumber="16">Fig. 6N</figureCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="15.[827,1444,1179,1907]" pageId="15" pageNumber="16">
|
||
<emphasis box="[827,990,1179,1200]" italics="true" pageId="15" pageNumber="16">Basioccipital:</emphasis>
|
||
The basioccipital (bo) in
|
||
<taxonomicName box="[1312,1443,1180,1201]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1312,1443,1180,1201]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
forms more than half the length of the braincase floor at the back of the skull (
|
||
<figureCitation box="[1104,1174,1241,1263]" captionStart="Figure 2" captionStartId="5.[163,243,1355,1377]" captionTargetBox="[277,1343,174,1316]" captionTargetId="figure-208@5.[1099,1331,1099,1306]" captionTargetPageId="5" captionText="Figure 2. Comparisons of the braincase between Pristerodon and emydopoids. Pristerodon mackayi (BP/1/2642) in (A) anterior, (B) left lateral, (C) posterior and (D) ventral views. Myosaurus gracilis (BP/1/2690) in (E) anterior, (F) left lateral, (G) posterior and (H) ventral views. The Malawian cistecephalid (DMMM-PK-16-1) in (I) anterior, (J) left lateral, (K) posterior and (L) ventral views. Kaaeingasaurus fossilis (GPIT-PV-117032) in (M) anterior, (N) left lateral, (O) posterior and (P) ventral views. Dark green – supraoccipital; Purple – orbitosphenoid; Dark orange – opisthotic; Light orange – pterygoid; Green – basioccipital; Magenta – exoccipital; Cyan blue – parasphenoid rostrum; Navy blue – prootic; Aqua blue – basisphenoid; Light Rose – epipterygoid. Same color code scheme is used in the following figures." figureDoi="http://doi.org/10.5281/zenodo.7922151" httpUri="https://zenodo.org/record/7922151/files/figure.png" pageId="15" pageNumber="16">Figs 2</figureCitation>
|
||
,
|
||
<figureCitation box="[1186,1200,1241,1262]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="15" pageNumber="16">7</figureCitation>
|
||
). It is subtrapezoidal in dorsal and ventral views, with the posterior wall being the shortest. Both anteriorly and posteriorly, the basioccipital forms an inverted U-shape. The basioccipital contacts the parabasisphenoid anteriorly, the opisthotic laterally, the prootic anterodorsally and the exoccipital posterodorsally.
|
||
</paragraph>
|
||
<paragraph blockId="15.[827,1444,1179,1907]" pageId="15" pageNumber="16">
|
||
The basioccipital condyle (boc) is the most prominent structure in posterior view and is excavated by two concavities (bocc) that host the exoccipital in posterior view (
|
||
<figureCitation box="[891,969,1547,1569]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="15" pageNumber="16">Fig. 7A</figureCitation>
|
||
). Dorsal to these concavities, the condyle is traversed by an M-shaped ridge (bocdr) that articulates with the anterior tuberosity of the exoccipital (
|
||
<figureCitation box="[1349,1428,1609,1631]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="15" pageNumber="16">Fig. 7B</figureCitation>
|
||
). In dorsal view, the dorsal surface of the basioccipital is slightly concave (
|
||
<figureCitation box="[1024,1105,1670,1692]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="15" pageNumber="16">Fig. 7B</figureCitation>
|
||
). This concavity is divided by a blunt median ridge (bomr). The lateral margin of the basioccipital has sigmoidal ridges in dorsal view. The vestibule of the bony labyrinth (vea) deeply notches the lateral aspects of the basioccipital and opens ventrally as the fenestra ovalis (fo).
|
||
</paragraph>
|
||
<paragraph blockId="15.[827,1444,1179,1907]" lastBlockId="17.[163,780,197,648]" lastPageId="17" lastPageNumber="18" pageId="15" pageNumber="16">
|
||
In ventral view, the basioccipital of
|
||
<taxonomicName box="[1284,1414,1855,1876]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="15" pageNumber="16" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1284,1414,1855,1876]" italics="true" pageId="15" pageNumber="16">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
is excavated by a Y-shaped depression (bod,
|
||
<figureCitation box="[1298,1379,1885,1907]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="15" pageNumber="16">Fig. 7C</figureCitation>
|
||
). The two branches of the Y-shaped depression delineate the semispherical condyle posteriorly. Four nutritive foramina (bonf) aligned on the sagittal axis perforate the basioccipital along the median depression. The basioccipital contacts the parabasisphenoid anteroventrally along an undulating suture with the basisphenoidal tubera extending backward to overlap the basioccipital tubera. The fenestra ovalis is ellipsoidal (3.3 ×
|
||
<quantity box="[400,491,442,464]" metricMagnitude="-3" metricUnit="m" metricValue="1.5" pageId="17" pageNumber="18" unit="mm" value="1.5">1.5 mm</quantity>
|
||
) with its long diameter extending along the coronal axis of the skull.
|
||
</paragraph>
|
||
<caption ID-DOI="http://doi.org/10.5281/zenodo.7922165" ID-Zenodo-Dep="7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" lastPageId="17" lastPageNumber="18" pageId="16" pageNumber="17" startId="16.[145,223,1532,1554]" targetBox="[241,1328,199,1491]" targetPageId="16" targetType="figure">
|
||
<paragraph blockId="16.[145,1425,1532,1876]" pageId="16" pageNumber="17">
|
||
<emphasis bold="true" box="[145,247,1532,1554]" pageId="16" pageNumber="17">Figure 7.</emphasis>
|
||
The posteroventral braincase wall of
|
||
<taxonomicName authorityName="Haughton" authorityYear="1917" box="[638,835,1532,1554]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="16" pageNumber="17" phylum="Chordata" rank="species" species="gracilis">
|
||
<emphasis box="[638,835,1532,1554]" italics="true" pageId="16" pageNumber="17">Myosaurus gracilis</emphasis>
|
||
</taxonomicName>
|
||
(BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic
|
||
</paragraph>
|
||
<paragraph blockId="17.[163,780,197,648]" pageId="17" pageNumber="18">
|
||
In lateral view, the basioccipital is excavated by the jugular foramen (jf) dorsally, between the condyle and the basioccipital tuber (
|
||
<figureCitation box="[483,566,565,587]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="17" pageNumber="18">Fig. 7D</figureCitation>
|
||
). The basioccipital forms only the floor of the jugular foramen (jf) and the major portion comprises the exoccipital and opisthotic.
|
||
</paragraph>
|
||
<paragraph blockId="17.[163,780,689,1478]" pageId="17" pageNumber="18">
|
||
<emphasis box="[163,299,689,710]" italics="true" pageId="17" pageNumber="18">Exoccipital:</emphasis>
|
||
As in other dicynodonts, the exoccipital in
|
||
<taxonomicName box="[193,319,720,741]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="17" pageNumber="18" phylum="Chordata" rank="genus">
|
||
<emphasis box="[193,319,720,741]" italics="true" pageId="17" pageNumber="18">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
contributes to the occipital condyle and borders the ventral half of the foramen magnum (
|
||
<figureCitation box="[706,773,750,772]" captionStart="Figure 2" captionStartId="5.[163,243,1355,1377]" captionTargetBox="[277,1343,174,1316]" captionTargetId="figure-208@5.[1099,1331,1099,1306]" captionTargetPageId="5" captionText="Figure 2. Comparisons of the braincase between Pristerodon and emydopoids. Pristerodon mackayi (BP/1/2642) in (A) anterior, (B) left lateral, (C) posterior and (D) ventral views. Myosaurus gracilis (BP/1/2690) in (E) anterior, (F) left lateral, (G) posterior and (H) ventral views. The Malawian cistecephalid (DMMM-PK-16-1) in (I) anterior, (J) left lateral, (K) posterior and (L) ventral views. Kaaeingasaurus fossilis (GPIT-PV-117032) in (M) anterior, (N) left lateral, (O) posterior and (P) ventral views. Dark green – supraoccipital; Purple – orbitosphenoid; Dark orange – opisthotic; Light orange – pterygoid; Green – basioccipital; Magenta – exoccipital; Cyan blue – parasphenoid rostrum; Navy blue – prootic; Aqua blue – basisphenoid; Light Rose – epipterygoid. Same color code scheme is used in the following figures." figureDoi="http://doi.org/10.5281/zenodo.7922151" httpUri="https://zenodo.org/record/7922151/files/figure.png" pageId="17" pageNumber="18">Figs 2</figureCitation>
|
||
,
|
||
<figureCitation box="[163,177,782,803]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="17" pageNumber="18">7</figureCitation>
|
||
). The exoccipital contacts the supraoccipital dorsally along an oblique suture and meets the opisthotic laterally along a subvertical suture visible in posterior view. Ventrally, it has a semicircular sutural contact with the basioccipital.
|
||
</paragraph>
|
||
<paragraph blockId="17.[163,780,689,1478]" pageId="17" pageNumber="18">
|
||
In anterior view, the two exoccipital condyles (eoc) meet at the ventral midline. The exoccipital contributes to the posterior half of the jugular foramen (jf), which excavates a large subvertical semicylindrical cavity in the ventral aspect of the exoccipital in anterior view. The jugular foramen is bounded by the exoccipitals posteriorly, the opisthotic anteriorly and the basioccipital laterally. The dorsal component has a subtriangular anterior face which is perforated by a deep vertical cylindrical furrow (eovf,
|
||
<figureCitation box="[231,314,1241,1263]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="17" pageNumber="18">Fig. 7G</figureCitation>
|
||
) that hosts the osseous enclosure of the posterior semicircular canal (pscc,
|
||
<figureCitation box="[560,642,1272,1294]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="17" pageNumber="18">Fig. 7E</figureCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="17.[163,780,689,1478]" lastBlockId="17.[827,1444,197,771]" pageId="17" pageNumber="18">
|
||
In posterior view, the exoccipital condyles are semilunate and more prominent than the basioccipital condyle and they form most of the occipital condyle. The dorsal surface of the exoccipital condyle is concave, as it contributes to the ventral margin of the foramen magnum. The dorsal component of the exoccipital (eodc) is subrectangular in posterior view. It descends from the contact with the supraoccipital dorsally to form the dorsomedial border of the jugular foramen in posterior view (
|
||
<figureCitation captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="17" pageNumber="18">Fig. 7F</figureCitation>
|
||
). The dorsal component of the exoccipital and the exoccipital condyle are separated by a shallow sulcus (eopsu) in posterior view.
|
||
</paragraph>
|
||
<paragraph blockId="17.[827,1444,197,771]" pageId="17" pageNumber="18">
|
||
In dorsal view, the exoccipital condyle forms a knob-like anterior tuberosity (eoat) located medial to the jugular foramen that contacts the dorsal aspect of the basioccipital ventrally (
|
||
<figureCitation box="[1202,1292,504,526]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="17" pageNumber="18">Fig. 7G</figureCitation>
|
||
). In ventral view, there is a deep occipital pit (occp) in BP/1/2690 at the intersection of the two exoccipitals and the basioccipital (
|
||
<figureCitation box="[983,1064,596,618]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="17" pageNumber="18">Fig. 7C</figureCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="17.[827,1444,197,771]" pageId="17" pageNumber="18">
|
||
Medially, the exoccipital condyle is pierced by the hypoglossal foramen (hf). The ensuing canal is oriented obliquely connecting the jugular foramen to the foramen magnum (
|
||
<figureCitation box="[1048,1132,718,740]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="17" pageNumber="18">Fig. 7H</figureCitation>
|
||
). The hypoglossal foramen is circular and its diameter is
|
||
<quantity box="[1169,1254,749,771]" metricMagnitude="-4" metricUnit="m" metricValue="5.0" pageId="17" pageNumber="18" unit="mm" value="0.5">0.5 mm</quantity>
|
||
in medial view.
|
||
</paragraph>
|
||
<paragraph blockId="17.[827,1444,811,1477]" pageId="17" pageNumber="18">
|
||
<emphasis box="[827,1007,811,832]" italics="true" pageId="17" pageNumber="18">Supraoccipital:</emphasis>
|
||
The supraoccipital has an inverted U-shape in anterior and posterior views as it forms the dorsal margin of the foramen magnum (
|
||
<figureCitation box="[1283,1352,873,895]" captionStart="Figure 2" captionStartId="5.[163,243,1355,1377]" captionTargetBox="[277,1343,174,1316]" captionTargetId="figure-208@5.[1099,1331,1099,1306]" captionTargetPageId="5" captionText="Figure 2. Comparisons of the braincase between Pristerodon and emydopoids. Pristerodon mackayi (BP/1/2642) in (A) anterior, (B) left lateral, (C) posterior and (D) ventral views. Myosaurus gracilis (BP/1/2690) in (E) anterior, (F) left lateral, (G) posterior and (H) ventral views. The Malawian cistecephalid (DMMM-PK-16-1) in (I) anterior, (J) left lateral, (K) posterior and (L) ventral views. Kaaeingasaurus fossilis (GPIT-PV-117032) in (M) anterior, (N) left lateral, (O) posterior and (P) ventral views. Dark green – supraoccipital; Purple – orbitosphenoid; Dark orange – opisthotic; Light orange – pterygoid; Green – basioccipital; Magenta – exoccipital; Cyan blue – parasphenoid rostrum; Navy blue – prootic; Aqua blue – basisphenoid; Light Rose – epipterygoid. Same color code scheme is used in the following figures." figureDoi="http://doi.org/10.5281/zenodo.7922151" httpUri="https://zenodo.org/record/7922151/files/figure.png" pageId="17" pageNumber="18">Figs 2</figureCitation>
|
||
,
|
||
<figureCitation box="[1365,1379,873,894]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="17" pageNumber="18">7</figureCitation>
|
||
). The morphology of the posterior aspect of the supraoccipital of
|
||
<taxonomicName box="[856,984,935,956]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="17" pageNumber="18" phylum="Chordata" rank="genus">
|
||
<emphasis box="[856,984,935,956]" italics="true" pageId="17" pageNumber="18">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
specimens BP/1/2690 and BP/1/2701a, as well as in other specimens (
|
||
<bibRefCitation author="Haughton SH" box="[1169,1350,965,987]" pageId="17" pageNumber="18" pagination="164 - 172" refId="ref37008" refString="Haughton SH. 1917. Investigations in South African reptiles and amphibia. Annals of the South African Museum 12: 164 - 172." type="journal article" year="1917">Haughton, 1917</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Cluver MA" pageId="17" pageNumber="18" pagination="35 - 54" refId="ref35877" refString="Cluver MA. 1974 b. The cranial morphology of the Lower Triassic dicynodont Myosaurus gracilis. Annals of the South African Museum 66: 35 - 54." type="journal article" year="1974">Cluver, 1974b</bibRefCitation>
|
||
), does not show a distinct medial lobe and lateral alae per se, because it has a rounded dorsal edge (
|
||
<figureCitation captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="17" pageNumber="18">Fig. 7J</figureCitation>
|
||
). Immediately dorsal to the supraoccipital, lies an ‘unossified zone’ (Laass, 2015; Laass
|
||
<emphasis box="[1230,1286,1087,1109]" italics="true" pageId="17" pageNumber="18">et al.</emphasis>
|
||
, 2017), which is bordered by the interparietal dorsally, but this structure does not extend to the anterior surface of the supraoccipital. The main feature of the supraoccipital in anterior view is a buttress that hosts the communis crus of the vestibular organ, limited dorsally by crests but whose posterior surface is smooth and flat. The supraoccipital contacts the exoccipitals in an oblique suture in posterior view.
|
||
</paragraph>
|
||
<paragraph blockId="17.[827,1444,811,1477]" lastBlockId="18.[145,762,197,1568]" lastPageId="18" lastPageNumber="19" pageId="17" pageNumber="18">
|
||
In anterior view, the supraoccipital bears a short descending process (sap) projecting from the anterolateral edge to the level of the contact with the prootic. Ventrally, the edge terminates by the subcylindrical buttress oriented vertically and anteriorly (smb,
|
||
<figureCitation box="[343,420,228,250]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7I</figureCitation>
|
||
). This buttress encircles the crus communis of the bony labyrinth and the anterior semicircular canal (ascc). Lateral to the buttress lies the floccular fossa (flo), which separates the crus communis and the anterior semicircular canal. The floccular fossa is deep (
|
||
<quantity box="[473,564,381,402]" metricMagnitude="-3" metricUnit="m" metricValue="2.2" pageId="18" pageNumber="19" unit="mm" value="2.2">2.2 mm</quantity>
|
||
), cylindrical and is oriented subobliquely to the horizontal plane. Its posterior half is flanked laterally by a sharp semicircular crest (sac) of the supraoccipital (
|
||
<figureCitation box="[661,735,473,495]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7I</figureCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="17.[163,1443,1555,1900]" pageId="17" pageNumber="18">
|
||
lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal
|
||
<quantity box="[1051,1112,1849,1871]" metricMagnitude="-3" metricUnit="m" metricValue="5.0" pageId="17" pageNumber="18" unit="mm" value="5.0">5 mm</quantity>
|
||
. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U).
|
||
</paragraph>
|
||
</caption>
|
||
<paragraph blockId="18.[145,762,197,1568]" pageId="18" pageNumber="19">
|
||
In posterior view, there is a symmetrical pit (spi) on each side of the supraoccipital, dorsal to the foramen magnum. These have been interpreted as foramina for blood vessels bringing nutrients to the brain (
|
||
<bibRefCitation author="Hammer WR & Cosgriff JW" pageId="18" pageNumber="19" pagination="410 - 424" refId="ref36975" refString="Hammer WR, Cosgriff JW. 1981. Myosaurus gracilis, an anomodont reptile from the Lower Triassic of Antarctica and South Africa. Journal of Palaeontology 55: 410 - 424." type="journal article" year="1981">Hammer & Cosgriff, 1981</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Angielczyk KD & Kammerer CF" box="[354,720,626,648]" pageId="18" pageNumber="19" pagination="513 - 545" refId="ref34004" refString="Angielczyk KD, Kammerer CF. 2017. The cranial morphology, phylogenetic position and biogeography of the Upper Permian dicynodont Compsodon helmoedi Van Hoepen (Therapsida, Anomodontia). Papers in Palaeontology 3: 513 - 545." type="journal article" year="2017">Angielczyk & Kammerer, 2017</bibRefCitation>
|
||
) in other dicynodonts, but in
|
||
<taxonomicName box="[450,579,658,679]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="18" pageNumber="19" phylum="Chordata" rank="genus">
|
||
<emphasis box="[450,579,658,679]" italics="true" pageId="18" pageNumber="19">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
the pits do not form a hole in the bone anteriorly.
|
||
<bibRefCitation author="Cluver MA" box="[581,754,688,710]" pageId="18" pageNumber="19" pagination="35 - 54" refId="ref35877" refString="Cluver MA. 1974 b. The cranial morphology of the Lower Triassic dicynodont Myosaurus gracilis. Annals of the South African Museum 66: 35 - 54." type="journal article" year="1974">Cluver (1974b</bibRefCitation>
|
||
: fig. 3C) previously described the nutrient channel on the suture between the supraoccipital and the squamosal in
|
||
<taxonomicName box="[305,431,780,801]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="18" pageNumber="19" phylum="Chordata" rank="genus">
|
||
<emphasis box="[305,431,780,801]" italics="true" pageId="18" pageNumber="19">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
, also present in BP/1/2701a. However, in specimen BP/1/2690 there are other pits located more medially within the supraoccipital (
|
||
<figureCitation captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig 7J</figureCitation>
|
||
). Interestingly, there is a channel in
|
||
<taxonomicName authorityName="Van Hoepen" authorityYear="1934" box="[576,708,872,893]" genus="Compsodon" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="18" pageNumber="19" phylum="Chordata" rank="genus">
|
||
<emphasis box="[576,708,872,893]" italics="true" pageId="18" pageNumber="19">Compsodon</emphasis>
|
||
</taxonomicName>
|
||
that starts in a homologous position as in BP/1/2690 but continues laterally to reach the position described by Cluver (
|
||
<bibRefCitation author="Angielczyk KD & Kammerer CF" box="[235,578,964,986]" pageId="18" pageNumber="19" pagination="513 - 545" refId="ref34004" refString="Angielczyk KD, Kammerer CF. 2017. The cranial morphology, phylogenetic position and biogeography of the Upper Permian dicynodont Compsodon helmoedi Van Hoepen (Therapsida, Anomodontia). Papers in Palaeontology 3: 513 - 545." type="journal article" year="2017">Angielczyk & Kammerer, 2017</bibRefCitation>
|
||
: fig. 2). Whether these structures are part of the same system has yet to be confirmed. The supraoccipital is bounded laterally by shallow vertical depressions (svd) in posterior view that descend from the dorsal edge of the supraoccipital onto the exoccipital (
|
||
<figureCitation box="[382,460,1117,1139]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7J</figureCitation>
|
||
). The lateroventral corner of the supraoccipital forms the posttemporal fenestra together with the exoccipitals, but the lateral wall of this fenestra is bounded by the opisthotic. As in other dicynodonts, the foramen magnum is dorsoventrally oval in posterior view. In
|
||
<taxonomicName box="[463,595,1271,1292]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="18" pageNumber="19" phylum="Chordata" rank="genus">
|
||
<emphasis box="[463,595,1271,1292]" italics="true" pageId="18" pageNumber="19">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
, the foramen magnum is
|
||
<quantity box="[282,369,1301,1322]" metricMagnitude="-3" metricUnit="m" metricValue="3.9" pageId="18" pageNumber="19" unit="mm" value="3.9">3.9 mm</quantity>
|
||
at its widest point. Ventrally, the supraoccipital is excavated by a conspicuous sulcus for the posterior semicircular canal (pscc,
|
||
<figureCitation box="[582,664,1362,1384]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7K</figureCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="18.[145,762,197,1568]" pageId="18" pageNumber="19">
|
||
The supraoccipital has a lateral vertical recess (slr) formed by the lateral and anterior edges of the supraoccipital, best seen in dorsal view (
|
||
<figureCitation box="[615,696,1454,1476]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7L</figureCitation>
|
||
). The recess descends from the dorsalmost aspect of the supraoccipital to nearly half the height of the foramen magnum.
|
||
</paragraph>
|
||
<paragraph blockId="18.[145,761,1609,1907]" lastBlockId="18.[809,1426,197,1905]" pageId="18" pageNumber="19">
|
||
<emphasis box="[145,237,1610,1631]" italics="true" pageId="18" pageNumber="19">Prootic:</emphasis>
|
||
The prootic of
|
||
<taxonomicName box="[439,571,1610,1631]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="18" pageNumber="19" phylum="Chordata" rank="genus">
|
||
<emphasis box="[439,571,1610,1631]" italics="true" pageId="18" pageNumber="19">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
(pr,
|
||
<figureCitation box="[630,699,1609,1631]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7</figureCitation>
|
||
) is a plate-like, vertically oriented bone in lateral and medial views, that forms the lateral wall of the braincase. As is typical in dicynodonts, the prootic borders the anterior wall of the foramen magnum. It is formed by the pila antotica anteriorly and the alar process posteriorly. The prootic of
|
||
<taxonomicName box="[628,761,1794,1815]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="18" pageNumber="19" phylum="Chordata" rank="genus">
|
||
<emphasis box="[628,761,1794,1815]" italics="true" pageId="18" pageNumber="19">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
specimen BP/1/2690 is not completely fused to the surrounding bones (except the opisthotic) as it displays a gap of a few millimeters from the supraoccipital dorsally and the basioccipital and parabasisphenoid anteroventrally on CT images. We cannot exclude the possibility that the specimens here described are subadult (see discussion below).
|
||
</paragraph>
|
||
<paragraph blockId="18.[809,1426,197,1905]" pageId="18" pageNumber="19">
|
||
In anterior view, the pila antotica (pa) of
|
||
<taxonomicName box="[1300,1425,320,341]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="18" pageNumber="19" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1300,1425,320,341]" italics="true" pageId="18" pageNumber="19">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
is tall, slightly curved medially, mediolaterally compressed and tapers dorsally. Its anteroventral half is bordered by medial and lateral crests (prac) that join dorsally half way up the pila antotica, flanking a shallow vertical trough (
|
||
<figureCitation box="[1087,1174,473,495]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7M</figureCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="18.[809,1426,197,1905]" pageId="18" pageNumber="19">
|
||
In lateral view, the main body of the prootic sends an alar process (ap) posteriorly, which sutures with the opisthotic on its posteroventral part. The suture with the opisthotic is serrated and is oblique in lateral view (see the orientation of the right margin of the prootic where the suture is in
|
||
<figureCitation box="[935,1044,657,679]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Figure 7N</figureCitation>
|
||
). The alar process of the prootic has a sigmoid posterodorsal margin, and its dorsal and ventral margins are horizontal. Its anterior margin is straight and obliquely oriented in lateral view (
|
||
<figureCitation box="[1197,1280,749,771]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7N</figureCitation>
|
||
). A notch for the passage of the trigeminal nerve (CNV) is present at theanteroventralpartofthealarprocessandposteriortothe pila antotica. In lateral view, the pila antotica of
|
||
<taxonomicName box="[1306,1425,841,862]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="18" pageNumber="19" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1306,1425,841,862]" italics="true" pageId="18" pageNumber="19">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
appears as an isosceles triangle; the anterior border is relatively straight and the posterior border slightly convex (
|
||
<figureCitation box="[817,897,933,955]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7N</figureCitation>
|
||
). The pila antotica typically overlaps the clinoid process of the basisphenoid, but in BP/1/2690 they are separated by a
|
||
<quantity box="[968,1049,994,1016]" metricMagnitude="-4" metricUnit="m" metricValue="3.0" pageId="18" pageNumber="19" unit="mm" value="0.3">0.3 mm</quantity>
|
||
gap (gp,
|
||
<figureCitation box="[1141,1215,994,1016]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7R</figureCitation>
|
||
). The medial face of the prootic is slightly depressed in lateral view (best seen in dorsal view,
|
||
<figureCitation box="[978,1057,1055,1077]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7P</figureCitation>
|
||
), and ventral to this depression, the prootic is perforated by the circular facial foramen (fa). Also, the prootic forms the lateral wall of the conical fenestra ovalis which opens on the ventral side of the bone.
|
||
</paragraph>
|
||
<paragraph blockId="18.[809,1426,197,1905]" pageId="18" pageNumber="19">
|
||
In medial view, the posterior and anterior margins of the prootic are oblique, whereas the ventral margin is horizontal. The dorsal margin of the prootic is V-shaped as it is traversed by the trigeminal nerve (
|
||
<figureCitation box="[1323,1409,1270,1292]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7O</figureCitation>
|
||
). The prootic forms the anterior wall of the horizontal, large and deep floccular fossa (flo) in medial view. The dorsal and ventral limits of the floccular fossa bear conjoined sigmoidal crests (prmc), with the ventral one being the most prominent. The dorsal crest serves to articulate with the supraoccipital. The suture with the supraoccipital appears sigmoidal in medial view (see the shading in
|
||
<figureCitation box="[984,1101,1515,1537]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Figure 7O</figureCitation>
|
||
). A small circular cavity for the anterior semicircular canal (ascc) perforates the prootic dorsal to the floccular fossa in medial view. This canal connects to another larger cavity located ventral to the floccular fossa, which hosts the vestibule of the inner ear (ve,
|
||
<figureCitation box="[977,1063,1669,1691]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Fig. 7O</figureCitation>
|
||
). As the sutural area between the prootic and opisthotic is visible in medial view, it appears trapezoidal (see the grey shading in
|
||
<figureCitation captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Figure 7O</figureCitation>
|
||
). The base of the pila antotica is robust in medial view, and it overlaps the basioccipital along a nearly rectangular contact (see the green shading in
|
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<figureCitation captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="18" pageNumber="19">Figure 7O</figureCitation>
|
||
). Dorsal to this suture and anterior to the vestibule is the facial foramen.
|
||
</paragraph>
|
||
<paragraph blockId="19.[163,779,197,710]" pageId="19" pageNumber="20">
|
||
In posterior view, the prootic is excavated by a semicircular excavation (ppex), which exits through the posttemporal fenestra (
|
||
<figureCitation box="[522,616,258,280]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="19" pageNumber="20">Fig. 7Q</figureCitation>
|
||
). There is a bulge (prpb) at the concave part of the excavation which contributes to the anterior components of the posttemporal fenestra wall (
|
||
<figureCitation box="[503,589,350,372]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="19" pageNumber="20">Fig. 7Q</figureCitation>
|
||
). The prootic of BP/1/2690 is separated from the supraoccipital by a
|
||
<quantity box="[163,246,412,433]" metricMagnitude="-4" metricUnit="m" metricValue="4.0" pageId="19" pageNumber="20" unit="mm" value="0.4">0.4 mm</quantity>
|
||
gap posteriorly. Along its posteroventral corner, the prootic contacts the opisthotic in posterior view. This contact appears triangular. At the medial part of the suture, the prootic and opisthotic are perforated by the lateral semicircular canal (lscc,
|
||
<figureCitation box="[567,650,534,556]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="19" pageNumber="20">Fig. 7Q</figureCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="19.[163,779,197,710]" pageId="19" pageNumber="20">
|
||
In dorsal view, the prootic forms a vertical buttress (pabt) and sends the alar process laterally. This buttress hosted the anterior semicircular canal. The area between the buttress and the alar process is depressed in dorsal view (
|
||
<figureCitation box="[457,537,688,710]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="19" pageNumber="20">Fig. 7P</figureCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="19.[163,780,750,1907]" pageId="19" pageNumber="20">
|
||
<emphasis box="[163,290,750,771]" italics="true" pageId="19" pageNumber="20">Opisthotic:</emphasis>
|
||
The opisthotic in
|
||
<taxonomicName box="[518,646,751,772]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="19" pageNumber="20" phylum="Chordata" rank="genus">
|
||
<emphasis box="[518,646,751,772]" italics="true" pageId="19" pageNumber="20">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
(op,
|
||
<figureCitation box="[704,770,750,772]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="19" pageNumber="20">Fig. 7</figureCitation>
|
||
) displays a subtrapezoidal shape in posterior view. It bears a well-developed ventromedial process. In anterior view, the lateral margin of the opisthotic forms the posteroventral wall of the posttemporal fenestra. The suture with the prootic is located in the middle of the anterior face of the opisthotic. This surface appears jagged in
|
||
<figureCitation box="[280,396,965,987]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="19" pageNumber="20">Figure 7S</figureCitation>
|
||
as the two bones were partially fused as in most dicynodonts, and was thus difficult to segment. The anteromedial aspect of the opisthotic is characterized by conjoined medial (omc) and lateral crests (olc). The lateral crest is sigmoidal, whereas the medial one is linear and subvertically oriented (
|
||
<figureCitation captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="19" pageNumber="20">Fig. 7S</figureCitation>
|
||
). The lateral crest forms the lateral margin of the opisthotic that sutures with the supraoccipital. The medial one borders the articulation with the prootic. The two crests meet dorsally and ventrally to form a large cavity that hosts the vestibular organ (ve). The ventromedial process of the opisthotic (ovmp) is a thick and robust tuber-like knob in
|
||
<taxonomicName box="[591,720,1334,1355]" class="Reptilia" family="Emydopidae" genus="Myosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Therapsida" pageId="19" pageNumber="20" phylum="Chordata" rank="genus">
|
||
<emphasis box="[591,720,1334,1355]" italics="true" pageId="19" pageNumber="20">Myosaurus</emphasis>
|
||
</taxonomicName>
|
||
. The medial tip of the process expands anteroposteriorly to receive the basioccipital along its medial flat edge and the exoccipital condyle along its dorsal edge.
|
||
</paragraph>
|
||
<paragraph blockId="19.[163,780,750,1907]" lastBlockId="19.[827,1443,197,433]" pageId="19" pageNumber="20">
|
||
In posterior view, the opisthotic is shaped like a horizontal hourglass as its dorsal and ventral aspects are concave (
|
||
<figureCitation box="[322,440,1517,1539]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="19" pageNumber="20">Fig. 7T, U</figureCitation>
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). The ventral margin is the longest in posterior view. The stout oblique body (ob) is flanked by posteromedial (opmb) and lateral vertical buttresses (lvb). The posteromedial buttress of the opisthotic descends onto the dorsal component of the exoccipital ventrally, but remains separated from it by a
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<quantity box="[220,307,1701,1722]" metricMagnitude="-4" metricUnit="m" metricValue="4.0" pageId="19" pageNumber="20" unit="mm" value="0.4">0.4 mm</quantity>
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gap in specimen BP/1/2690. The lateral vertical buttress sutures with the squamosal and descends ventrally to articulate with the quadrate. The two opisthotic buttresses terminate dorsally forming rounded bulges visible in dorsal view (obu). These bulges comprise the posterior part of the posttemporal fenestra posterior to the prootic bulge. The posteromedial aspect of the opisthotic is excavated by an oblique sulcus (osu) that separates the main body of the opisthotic and the ventromedial process. This sulcus extends dorsally to join the exoccipital posterior sulcus. The ventromedial process is more vertical in specimen BP/1/2701a. In ventral view, the process borders the fenestra ovalis (fo) posteriorly and the jugular foramen (jf) anteriorly (
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<figureCitation box="[1230,1310,411,433]" captionStart="Figure 7" captionStartId="16.[145,223,1532,1554]" captionTargetBox="[241,1328,199,1491]" captionTargetId="figure-26@16.[241,1329,216,1487]" captionTargetPageId="16" captionText="Figure 7. The posteroventral braincase wall of Myosaurus gracilis (BP/1/2690 and BP/1/2701a): basioccipital (lime green) in (A) posterior, (B) dorsal, (C) ventral and (D) right lateral views; the exoccipital (pink) in (E) anterior, (F) posterior, (G) dorsal and (H) ventromedial views; supraoccipital (dark green) in (I) anterior, (J) posterior, (K) ventral and (L) dorsal views; prootic (blue) in (M) anterior, (N) left lateral, (O) medial, (P) dorsal and (Q) posterior views; (R) the complete braincase of BP/1/2690 in left lateral view; opisthotic (golden) of BP/1/2690 in (S) anterior and (T) posterior views; right opisthotic of BP/1/2701a in (U) posterior view; the braincase of BP/1/2690 in (V) ventral view. ap, alar process of the prootic; ascc, attachment of the anterior semicircular canal; bo, basioccipital; boc, basioccipital condyly; bocc, basioccipital condyle concavities; bod, basioccipital ventral depression; bocdr, basioccipital condyle dorsal ridge; bomr, basioccipital median ridge; bonf, basioccipital nutritive foramina; bosr, basioccipital lateral ridges; bt, basioccipital tubera; CNV, passage of the cranial nerve five (V); eo, exoccipital; eoat, exoccipital anterior tuberosity; eoc, exoccipital condyle; eodc, exoccipital dorsal component; eopsu, exoccipital posterior sulcus; fa, facial foramen; flo, floccular fossa; fm, foramen magnum; fo, fenestra ovalis; gp, gap between the prootic and the clinoid process; hf, hypoglossal foramen; jf, jugular foramen; lscc, attachment of the lateral semicircular area; lvb, opisthotic lateral vertical buttress; ob, opisthotic body; obu, opisthotic bulges; occp, occipital pit; olc, opisthotic lateral crest; omc, opisthotic medial crest; op, opisthotic; opmb, opisthotic posteromedial buttress; osu, opisthotic posterior vertical sulcus; ovmp, opisthotic ventromedial process; pa, pila antotica; pabt, prootic anterior buttress; pbs, parabasisphenoid; ppex, prootic posterior excavation; pr, prootic; prac, pila antotica anterior crests; prmc, prootic medial crest; prpb, prootic posterior bulge; pscc, attachment of the posterior semicircular canal; pt, pterygoid; ptf, posttemporal fenestra; sac, supraoccipital semicircular crests; sap, supraoccipital anteriorly projected crest; slr, supraoccipital lateral recess; smb, supraoccipital subvertical buttress; spi, supraoccipital posterior pit; su, supraoccipital; svd, supraoccipital posterior vertical depressions; ve, vestibular area. The horizontal square pattern in (O) represents the sutural area between the prootic and supraoccipital; the horizontal line pattern in (O, Q) represents the articular surface between the prootic and the opisthotic and the oblique pattern in (O) represents the articular surface between the prootic and the parabasisphenoid. Finally, the vertical pattern in (S), represents the articular surface for the prootic on the opisthotic. Scale bars equal 5 mm. The first scale serves for (A-H), the second for (I-L), the third for (M-Q, S, T, V), the fourth for (R) and the fifth for (U)." figureDoi="http://doi.org/10.5281/zenodo.7922165" httpUri="https://zenodo.org/record/7922165/files/figure.png" pageId="19" pageNumber="20">Fig. 7V</figureCitation>
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).
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</paragraph>
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</subSubSection>
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</treatment>
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</document> |