1068 lines
235 KiB
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1068 lines
235 KiB
XML
<document id="BC186623C225FC75A5829094C0546427" ID-CLB-Dataset="21669" ID-DOI="10.5281/zenodo.3898946" ID-GBIF-Dataset="6a6c7cfe-460a-4186-a040-48f5dd80b4b3" ID-Zenodo-Dep="3898946" IM.metadata_requiresApprovalFor="plazi" IM.tables_requiresApprovalFor="existingObjects,plazi" IM.taxonomicNames_requiresApprovalFor="plazi" checkinTime="1592390151756" checkinUser="jeremy" docAuthor="Lawrence M. Witmer & Ryan C. Ridgely" docDate="2010" docId="03E1879F023C0C04E75CA83CFB48F94A" docLanguage="en" docName="WitmerRidgely2010.pdf.imf" docOrigin="Kirtlandia 57" docStyle="DocumentStyle{}" docTitle="Tyrannosaurus rex Osborn 1905" docType="treatment" docVersion="13" lastPageNumber="78" masterDocId="FFD8FFE7023B0C15E416AF14FFDEFFE8" masterDocTitle="The Cleveland tyrannosaur skull (Nanotyrannus or Tyrannosaurus): new findings based on CT scanning, with special reference to the braincase" masterLastPageNumber="81" masterPageNumber="61" pageNumber="68" updateTime="1698842568931" updateUser="ExternalLinkService">
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<mods:title id="2EA74831284477345C87E6663021F8E8">The Cleveland tyrannosaur skull (Nanotyrannus or Tyrannosaurus): new findings based on CT scanning, with special reference to the braincase</mods:title>
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<mods:name id="35B50D1388CE55AB7E1CB9BB19348736" type="personal">
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<mods:roleTerm id="6ECC06999334416B5BB7A693451730B8">Author</mods:roleTerm>
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<mods:namePart id="44A15144094702A88960C564A45494E0">Lawrence M. Witmer</mods:namePart>
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<mods:affiliation id="32F3A6629E3CE8C55F8BC31D5CAC435A">Department of Biomedical Sciences, College of Osteopathic Medicine Ohio University, Athens, Ohio 45701</mods:affiliation>
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<mods:namePart id="D73833974A69D8FC0A21071458C865B6">Ryan C. Ridgely</mods:namePart>
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<mods:affiliation id="9EDEC0B1ED2FEEF4537DAA4A5AF5294C">Department of Biomedical Sciences, College of Osteopathic Medicine Ohio University, Athens, Ohio 45701</mods:affiliation>
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<mods:title id="FAAA2CDC9077BF4D788531443547F914">Kirtlandia</mods:title>
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<mods:date id="D97B9185DD1C0B306F5DB6B098420F96">2010</mods:date>
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<mods:number id="F1E465F8A65F8652CDC843A4BD5E5227">2010-11-30</mods:number>
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<mods:number id="2CD5EC3C19D1E065DA8586A86A5FDCE1">57</mods:number>
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<mods:identifier id="BAAD1287EEE13147DCCE6D82FA6A5113" type="CLB-Dataset">21669</mods:identifier>
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<mods:identifier id="75667EAC965BE263E9583B47FA4AA567" type="DOI">10.5281/zenodo.3898946</mods:identifier>
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<treatment id="03E1879F023C0C04E75CA83CFB48F94A" ID-DOI="http://doi.org/10.5281/zenodo.5204538" ID-GBIF-Taxon="164612906" ID-Zenodo-Dep="5204538" LSID="urn:lsid:plazi:treatment:03E1879F023C0C04E75CA83CFB48F94A" httpUri="http://treatment.plazi.org/id/03E1879F023C0C04E75CA83CFB48F94A" lastPageId="17" lastPageNumber="78" pageId="7" pageNumber="68">
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<paragraph id="8BF73689023C0C1CE75CA83CFF2CFEAD" blockId="7.[818,1489,1797,2001]" lastBlockId="9.[117,788,186,2001]" lastPageId="9" lastPageNumber="70" pageId="7" pageNumber="68">
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The primary specimen used in this study was
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<materialsCitation id="3B203CD4023C0C12E13AA83CFA67F8D6" ID-GBIF-Occurrence="2636386303" box="[1324,1465,1832,1854]" collectionCode="CMNH" pageId="7" pageNumber="68" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
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, a nearly complete skull of a probably juvenile tyrannosaurid, collected from the Hell Creek Formation of Carter County, Montana (see
|
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<bibRefCitation id="EFD94B78023C0C12E7F2A894FB54F87E" author="Gilmore, C. W." box="[996,1162,1920,1942]" firstAuthor="Gilmore" journalOrPublisher="Smithsonian Miscellaneous Collections" pageId="7" pageNumber="68" pagination="1 - 19" part="106" refId="ref11374" refString="Gilmore, C. W. 1946. A new carnivorous dinosaur from the Lance formation of Montana. Smithsonian Miscellaneous Collections, 106: 1 - 19." title="A new carnivorous dinosaur from the Lance formation of Montana" type="journal article" year="1946">Gilmore, 1946</bibRefCitation>
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, for collection details and geological setting). A variety of other tyrannosaurid specimens were studied in connection with this project (for a full listing, see
|
||
<bibRefCitation id="EFD94B7802320C1CE4BEAFAEFE36FF38" author="Witmer, L. M. & R. C. Ridgely" box="[168,488,186,208]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="9" pageNumber="70" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
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). In addition to general observation, the major tool used in this study was CT scanning (computed x-ray tomography), followed by 3D analysis and visualization.
|
||
<materialsCitation id="3B203CD402320C1CE51FAE06FE4CFEC0" ID-GBIF-Occurrence="2636386336" box="[265,402,274,296]" collectionCode="CMNH" pageId="9" pageNumber="70" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
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has been CT scanned no fewer than three times.
|
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</paragraph>
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||
<caption id="DF37660102330C1DE486A9E5FE00F8A9" ID-DOI="http://doi.org/10.5281/zenodo.3898962" ID-Zenodo-Dep="3898962" httpUri="https://zenodo.org/record/3898962/files/figure.png" pageId="8" pageNumber="69" startId="8.[144,208,1777,1799]" targetBox="[310,1348,177,1740]" targetPageId="8">
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<paragraph id="8BF7368902330C1DE486A9E5FE00F8A9" blockId="8.[144,1515,1777,1857]" pageId="8" pageNumber="69">
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<emphasis id="B93CEA9B02330C1DE486A9E5FF35F8EF" bold="true" box="[144,235,1777,1799]" pageId="8" pageNumber="69">Figure 8.</emphasis>
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Cleveland tyrannosaur skull,
|
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<materialsCitation id="3B203CD402330C1DE632A9E5FD6EF8EF" ID-GBIF-Occurrence="2636386371" box="[548,688,1777,1799]" collectionCode="CMNH" pageId="8" pageNumber="69" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
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||
. Surface renderings of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 7A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations.
|
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</paragraph>
|
||
</caption>
|
||
<paragraph id="8BF7368902320C1CE49BAE5AFCD4FDD9" blockId="9.[117,788,186,2001]" pageId="9" pageNumber="70">
|
||
The first scans were done in 1990 on a medical scanner at a Toronto hospital, in the presence of Michael Williams, Andrew Leitch, and Robert T. Bakker (
|
||
<bibRefCitation id="EFD94B7802320C1CE5D3AE9CFD8AFE76" author="Bakker, R. T." box="[453,596,392,414]" firstAuthor="Bakker" journalOrPublisher="Discover" pageId="9" pageNumber="70" pagination="58 - 69" part="13" refId="ref10730" refString="Bakker, R. T. 1992. Inside the head of a tiny T. rex. Discover, 13: 58 - 69." title="Inside the head of a tiny T. rex" type="journal article" year="1992">Bakker, 1992</bibRefCitation>
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||
). Scanning details have not been published, but results were presented in a popular article by
|
||
<bibRefCitation id="EFD94B7802320C1CE4CDAED7FEB1FE31" author="Bakker, R. T." box="[219,367,451,473]" firstAuthor="Bakker" journalOrPublisher="Discover" pageId="9" pageNumber="70" pagination="58 - 69" part="13" refId="ref10730" refString="Bakker, R. T. 1992. Inside the head of a tiny T. rex. Discover, 13: 58 - 69." title="Inside the head of a tiny T. rex" type="journal article" year="1992">Bakker (1992)</bibRefCitation>
|
||
, who reconstructed the brain cavity and, within the nasal cavity, an elongate turbinate. The same CT data were used later by J. A. Ruben to refute the finding of respiratory turbinates in this skull (
|
||
<bibRefCitation id="EFD94B7802320C1CE57AAD0FFE2CFDD9" author="Ruben, J." box="[364,498,539,561]" editor="I. A. Johnston & A. F. Bennett" firstAuthor="Ruben" journalOrPublisher="Cambridge University Press, Cambridge" pageId="9" pageNumber="70" pagination="347 - 376" refId="ref12086" refString="Ruben, J. 1996. Evolution of endothermy in mammals, birds, and their ancestors, p. 347 - 376. In I. A. Johnston and A. F. Bennett (eds.), Animals and Temperature. Cambridge University Press, Cambridge." title="Evolution of endothermy in mammals, birds, and their ancestors" type="book chapter" volumeTitle="Animals and Temperature" year="1996">Ruben, 1996</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802320C1CE5E8AD0FFD60FDD9" author="Ruben, J. A. & W. J. Hillenius & N. R. Geist & A. Leitch & T. D. Jones & P. J. Currie & J. R. Horner & G. Espe III." box="[510,702,539,561]" etAl="et al." firstAuthor="Ruben" journalOrPublisher="Science" pageId="9" pageNumber="70" pagination="1204 - 1207" part="273" refId="ref12137" refString="Ruben, J. A., W. J. Hillenius, N. R. Geist, A. Leitch, T. D. Jones, P. J. Currie, J. R. Horner, and G. Espe III. 1996. The metabolic status of some Late Cretaceous dinosaurs. Science, 273: 1204 - 1207." title="The metabolic status of some Late Cretaceous dinosaurs" type="journal article" year="1996">Ruben et al., 1996</bibRefCitation>
|
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,
|
||
<bibRefCitation id="EFD94B7802320C1CE6DCAD0FFD20FDD9" author="Ruben, J. A. & W. J. Hillenius & A. Leitch & N. R. Geist & T. D. Jones" box="[714,766,539,561]" editor="J. O. Farlow & M. K. Brett- Surman" firstAuthor="Ruben" journalOrPublisher="Purdue University Press, Ashland" pageId="9" pageNumber="70" pagination="505 - 518" refId="ref12203" refString="Ruben, J. A., W. J. Hillenius, A. Leitch, N. R. Geist, and T. D. Jones. 1997. New insights into the metabolic physiology of dinosaurs, p. 505 - 518. In J. O. Farlow and M. K. Brett- Surman (eds.), The Complete Dinosaur. Purdue University Press, Ashland." title="New insights into the metabolic physiology of dinosaurs" type="book chapter" volumeTitle="The Complete Dinosaur" year="1997">1997</bibRefCitation>
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||
).
|
||
</paragraph>
|
||
<paragraph id="8BF7368902320C1CE49BAD2DFEF6FCD1" blockId="9.[117,788,186,2001]" pageId="9" pageNumber="70">The Cleveland skull was scanned for the second time in 1998 at the Boeing Rocketdyne CT Lab in California under the auspices of the Cleveland Museum of Natural History with funding from the Field Museum of Natural History. The skull was scanned at a slice thickness of 1 mm with slices in the horizontal plane, yielding 300 slices; voxel sizes were 0.4042 X 0.4042 X 1.0 mm. As part of the collaboration with M. Williams, the Cleveland Museum of Natural History provided Witmer with the full 16-bit dataset from these scans.</paragraph>
|
||
<paragraph id="8BF7368902320C1CE49BAC57FEA9FA35" blockId="9.[117,788,186,2001]" pageId="9" pageNumber="70">In hopes of revealing aspects of anatomy that are unclear in the Boeing dataset, the skull was scanned for the third time in 2005 at O’Bleness Memorial Hospital, Athens, Ohio, on a General Electric LightSpeed Ultra MultiSlice CT scanner equipped with the Extended Hounsfield option, which enhances the ability to resolve details from dense objects such as fossils. Because the Boeing dataset was derived from scans of the skull in the horizontal plane, the x-rays had to pass through the full length of the skull, which can produce artifacts. Thus, we scanned the skull axially, which minimized the amount of material the x-rays had to penetrate. The full skull was scanned helically with a slice thickness of 1.25 mm at 140 kV and 300 mA, yielding 483 slices and voxel sizes of 0.082 X 0.082 X 1.25 mm. The skull was then scanned again, this time focusing on the braincase, tightening the field of view and extending from the caudal end of the skull through the orbits and ending rostrally just in front of the lacrimals’ jugal processes; slice thickness was 625 microns (0.625 mm) at 140 kV and 170 mA, yielding 385 slices and voxel sizes of 0.049 X 0.049 X 0.625 mm. No CT scan is free from artifact, and both the Boeing and Athens datasets have their advantages and disadvantages. Ultimately, much of the work presented here is based on a composite ‘‘superdataset’’ created by registering and combining the Boeing and multiple Athens datasets.</paragraph>
|
||
<paragraph id="8BF7368902320C1CE49BAAF1FE08F8C8" blockId="9.[117,788,186,2001]" pageId="9" pageNumber="70">Viewing, analysis, and visualization of the scan data were done using Amira 3.1.1 and 4.2 (Mercury-TGS, Chelmsford, MA) on 32- and 64-bit Windows XP PCs equipped with nVidia Quadro FX graphics cards and 2–8 GB of RAM. Structures of interest were highlighted (segmented) using Amira’s segmentation tools and visualized either in isolation or combined with other structures or the whole skull. Both surfaces and volumes were generated, and these served as the basis for most of the illustrations in this article. Additional information, such as interactive movies and 3D PDFs, are available on the authors’ website: www.ohio.edu/witmerlab.</paragraph>
|
||
<paragraph id="8BF7368902320C1CE49BA83DFAC1FEE2" blockId="9.[117,788,186,2001]" lastBlockId="9.[818,1488,186,266]" pageId="9" pageNumber="70">Museum abbreviations used in this paper are: AMNH, American Museum of Natural History, New York City, New York; BMR, Burpee Museum of Natural History, Rockford, Illinois; CMNH, Cleveland Museum of Natural History, Cleveland, Ohio; FMNH, Field Museum of Natural History, Chicago, Illinois; MOR, Museum of the Rockies, Bozeman, Montana; OMNH, Oklahoma Museum of Natural History, Norman, Oklahoma; ROM, Royal Ontario Museum, Toronto, Ontario; and TMP, Royal Tyrrell Museum of Palaeontology, Drumheller, Alberta.</paragraph>
|
||
<paragraph id="8BF7368902320C1CE04FAE24FB74FEA0" blockId="9.[818,1488,304,623]" box="[1113,1194,304,328]" pageId="9" pageNumber="70">
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<heading id="D0BF81E502320C1CE04FAE24FB74FEA0" bold="true" box="[1113,1194,304,328]" centered="true" fontSize="10" level="1" pageId="9" pageNumber="70" reason="0">
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<emphasis id="B93CEA9B02320C1CE04FAE24FB74FEA0" bold="true" box="[1113,1194,304,328]" pageId="9" pageNumber="70">Results</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BF7368902320C1CE75CAE46FBA1FD87" blockId="9.[818,1488,304,623]" pageId="9" pageNumber="70">
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<materialsCitation id="3B203CD402320C1CE75CAE46FC06FE80" ID-GBIF-Occurrence="2636386332" box="[842,984,338,360]" collectionCode="CMNH" pageId="9" pageNumber="70" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
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has been the subject of at least three major anatomical studies (
|
||
<bibRefCitation id="EFD94B7802320C1CE01FAE7BFB7BFE6D" author="Gilmore, C. W." box="[1033,1189,367,389]" firstAuthor="Gilmore" journalOrPublisher="Smithsonian Miscellaneous Collections" pageId="9" pageNumber="70" pagination="1 - 19" part="106" refId="ref11374" refString="Gilmore, C. W. 1946. A new carnivorous dinosaur from the Lance formation of Montana. Smithsonian Miscellaneous Collections, 106: 1 - 19." title="A new carnivorous dinosaur from the Lance formation of Montana" type="journal article" year="1946">Gilmore, 1946</bibRefCitation>
|
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;
|
||
<bibRefCitation id="EFD94B7802320C1CE0A3AE7BFA57FE6D" author="Bakker, R. T. & M. Williams & P. J. Currie" box="[1205,1417,367,389]" etAl="et al." firstAuthor="Bakker" journalOrPublisher="Hunteria" pageId="9" pageNumber="70" pagination="1 - 30" part="1" refId="ref10756" refString="Bakker, R. T., M. Williams, and P. J. Currie. 1988. Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana. Hunteria, 1: 1 - 30." title="Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana" type="journal article" year="1988">Bakker et al., 1988</bibRefCitation>
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||
;
|
||
<bibRefCitation id="EFD94B7802320C1CE18CAE7BFCBBFE4A" author="Carr, T. D." firstAuthor="Carr" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="9" pageNumber="70" pagination="497 - 520" part="19" refId="ref10976" refString="Carr, T. D. 1999. Craniofacial ontogeny in tyrannosaurid dinosaurs (Dinosauria, Coelurosauria). Journal of Vertebrate Paleontology, 19: 497 - 520." title="Craniofacial ontogeny in tyrannosaurid dinosaurs (Dinosauria, Coelurosauria)" type="journal article" year="1999">Carr, 1999</bibRefCitation>
|
||
), and thus there is no need for in-depth anatomical description here. Instead, our intent is to focus on a few areas that have not been adequately discussed in print and that are revealed by the CT scan data. It is also our intent to capitalize on the new-found visualization capabilities provided by the new imaging technologies and software, and so we emphasize illustration over text (in the spirit of the old adage of a picture being worth a thousand words).
|
||
</paragraph>
|
||
<paragraph id="8BF7368902320C1CE724AD83FC23FD47" blockId="9.[818,1488,663,1065]" box="[818,1021,663,687]" pageId="9" pageNumber="70">
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<heading id="D0BF81E502320C1CE724AD83FC23FD47" bold="true" box="[818,1021,663,687]" fontSize="10" level="3" pageId="9" pageNumber="70" reason="0">
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<emphasis id="B93CEA9B02320C1CE724AD83FC23FD47" bold="true" box="[818,1021,663,687]" pageId="9" pageNumber="70">General attributes</emphasis>
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</heading>
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||
</paragraph>
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<paragraph id="8BF7368902320C1CE75CADA0FBD4FBC1" blockId="9.[818,1488,663,1065]" pageId="9" pageNumber="70">
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<figureCitation id="13732A0C02320C1CE75CADA0FC1DFD22" box="[842,963,692,714]" captionStart-0="Figure 1" captionStart-1="Figure 2" captionStart-2="Figure 3" captionStartId-0="1.[117,181,1505,1527]" captionStartId-1="2.[144,208,1762,1784]" captionStartId-2="3.[117,181,1752,1774]" captionTargetBox-0="[246,1342,173,1458]" captionTargetBox-1="[316,1342,167,1714]" captionTargetBox-2="[269,1338,187,1723]" captionTargetId-0="figure@1.[230,1372,163,1486]" captionTargetId-1="figure@2.[316,1342,167,1728]" captionTargetId-2="figure@3.[266,1338,180,1724]" captionTargetPageId-0="1" captionTargetPageId-1="2" captionTargetPageId-2="3" captionText-0="Figure 1. Cleveland tyrannosaur skull, CMNH 7541. Stereophotographs of skull in A, left lateral view; B, right lateral view. Orientations reflect posture with lateral semicircular canal horizontal. Scale bars equal 10 cm." captionText-1="Figure 2. Cleveland tyrannosaur skull, CMNH 7541. Stereophotographs of A, close-up of left antorbital region; B, skull in rostral view; C, skull in ventral view. Orientations reflect posture with lateral semicircular canal horizontal. Scale bars equal 10 cm." captionText-2="Figure 3. Cleveland tyrannosaur skull, CMNH 7541. Stereophotographs of A, skull in dorsal view; B, skull in caudal view; C, close-up of cranial base in ventral view. Orientations reflect posture with lateral semicircular canal horizontal. Scale bars equal 10 cm." figureDoi-0="http://doi.org/10.5281/zenodo.3898948" figureDoi-1="http://doi.org/10.5281/zenodo.3898950" figureDoi-2="http://doi.org/10.5281/zenodo.3898952" httpUri-0="https://zenodo.org/record/3898948/files/figure.png" httpUri-1="https://zenodo.org/record/3898950/files/figure.png" httpUri-2="https://zenodo.org/record/3898952/files/figure.png" pageId="9" pageNumber="70">Figures 1–3</figureCitation>
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||
provide stereophotographs of the skull in several views, showing not just bony structure but also the amount of matrix remaining in the skull and, to a certain extent, the amount of plaster restoration. Plaster is relatively low density and homogenous and is easily identified and removed in volume renderings of the CT data.
|
||
<figureCitation id="13732A0C02320C1CE04EAC52FB71FCB4" box="[1112,1199,838,860]" captionStart="Figure 4" captionStartId="4.[144,208,1624,1646]" captionTargetBox="[199,1460,175,1584]" captionTargetId="figure@4.[187,1474,170,1605]" captionTargetPageId="4" captionText="Figure 4. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings of the skull derived from the CT data in A, rostral view; B, right lateral view; C, left lateral view; D, dorsal view; E, caudal view; F, ventral view. Densities corresponding to plaster have been excluded, revealing the extent of plaster restoration. Arrows in C indicate the transverse oblique plane of fracture that the specimen experienced prior to restoration. Scale bar equals 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898954" httpUri="https://zenodo.org/record/3898954/files/figure.png" pageId="9" pageNumber="70">Figure 4</figureCitation>
|
||
presents views of the skull with the plaster (and some regions of thin matrix) dropped out. Examination of
|
||
<figureCitation id="13732A0C02320C1CE7C1AC94FBF0FC7E" box="[983,1070,896,918]" captionStart="Figure 4" captionStartId="4.[144,208,1624,1646]" captionTargetBox="[199,1460,175,1584]" captionTargetId="figure@4.[187,1474,170,1605]" captionTargetPageId="4" captionText="Figure 4. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings of the skull derived from the CT data in A, rostral view; B, right lateral view; C, left lateral view; D, dorsal view; E, caudal view; F, ventral view. Densities corresponding to plaster have been excluded, revealing the extent of plaster restoration. Arrows in C indicate the transverse oblique plane of fracture that the specimen experienced prior to restoration. Scale bar equals 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898954" httpUri="https://zenodo.org/record/3898954/files/figure.png" pageId="9" pageNumber="70">Figure 4</figureCitation>
|
||
reveals that the snout had been fractured along an oblique transverse plane running caudodorsally to rostroventrally (arrows in
|
||
<figureCitation id="13732A0C02320C1CE05AACAFFB6BFC39" box="[1100,1205,955,977]" captionStart="Figure 4" captionStartId="4.[144,208,1624,1646]" captionTargetBox="[199,1460,175,1584]" captionTargetId="figure@4.[187,1474,170,1605]" captionTargetPageId="4" captionText="Figure 4. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings of the skull derived from the CT data in A, rostral view; B, right lateral view; C, left lateral view; D, dorsal view; E, caudal view; F, ventral view. Densities corresponding to plaster have been excluded, revealing the extent of plaster restoration. Arrows in C indicate the transverse oblique plane of fracture that the specimen experienced prior to restoration. Scale bar equals 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898954" httpUri="https://zenodo.org/record/3898954/files/figure.png" pageId="9" pageNumber="70">Figure 4C</figureCitation>
|
||
) such that, when repaired and restored in plaster (quite expertly, it may be said), much of the central parts of the nasal and antorbital cavities wound up being largely plaster.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902320C1CE724AB58FC41FB8C" blockId="9.[818,1489,1100,2001]" box="[818,927,1100,1124]" pageId="9" pageNumber="70">
|
||
<heading id="D0BF81E502320C1CE724AB58FC41FB8C" bold="true" box="[818,927,1100,1124]" fontSize="10" level="3" pageId="9" pageNumber="70" reason="0">
|
||
<emphasis id="B93CEA9B02320C1CE724AB58FC41FB8C" bold="true" box="[818,927,1100,1124]" pageId="9" pageNumber="70">Braincase</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BF7368902320C1CE75CAB7FFB84F90F" blockId="9.[818,1489,1100,2001]" pageId="9" pageNumber="70">
|
||
The braincase of
|
||
<materialsCitation id="3B203CD402320C1CE7E9AB7FFB56FB69" ID-GBIF-Occurrence="2636386369" box="[1023,1160,1131,1153]" collectionCode="CMNH" pageId="9" pageNumber="70" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
is visible in dorsal, caudal, and ventral views in the actual (physical) specimen (
|
||
<figureCitation id="13732A0C02320C1CE122AB9CFA47FB76" box="[1332,1433,1160,1182]" captionStart="Figure 2" captionStartId="2.[144,208,1762,1784]" captionTargetBox="[316,1342,167,1714]" captionTargetId="figure@2.[316,1342,167,1728]" captionTargetPageId="2" captionText="Figure 2. Cleveland tyrannosaur skull, CMNH 7541. Stereophotographs of A, close-up of left antorbital region; B, skull in rostral view; C, skull in ventral view. Orientations reflect posture with lateral semicircular canal horizontal. Scale bars equal 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898950" httpUri="https://zenodo.org/record/3898950/files/figure.png" pageId="9" pageNumber="70">Figures 2</figureCitation>
|
||
D–E, 3A–C), but the other surfaces are obscured by matrix and other bones. To more easily compare the braincase to those of other theropods, the braincase of
|
||
<materialsCitation id="3B203CD402320C1CE0B8ABF4FAE2FB1E" ID-GBIF-Occurrence="2636386314" box="[1198,1340,1248,1270]" collectionCode="CMNH" pageId="9" pageNumber="70" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
was digitally ‘‘disarticulated’’ along sutures and then extracted so that it could be viewed in isolation (
|
||
<figureCitation id="13732A0C02320C1CE0B1AA0EFAF6FAD8" box="[1191,1320,1306,1328]" captionStart-0="Figure 5" captionStart-1="Figure 6" captionStart-2="Figure 7" captionStart-3="Figure 8" captionStartId-0="5.[117,181,1722,1744]" captionStartId-1="6.[144,208,1771,1793]" captionStartId-2="7.[117,181,1684,1706]" captionStartId-3="8.[144,208,1777,1799]" captionTargetBox-0="[277,1319,167,1673]" captionTargetBox-1="[309,1349,173,1729]" captionTargetBox-2="[277,1320,176,1644]" captionTargetBox-3="[310,1348,177,1740]" captionTargetId-0="figure@5.[277,1319,161,1682]" captionTargetId-1="figure@6.[309,1349,173,1729]" captionTargetId-2="figure@7.[277,1320,173,1654]" captionTargetId-3="figure@8.[307,1348,177,1740]" captionTargetPageId-0="5" captionTargetPageId-1="6" captionTargetPageId-2="7" captionTargetPageId-3="8" captionText-0="Figure 5. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings (stereopairs) of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 6A–C provides corresponding labeled views. Scale bar equals 10 cm." captionText-1="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." captionText-2="Figure 7. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings (stereopairs) of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 8A–C provides corresponding labeled views. Scale bar equals 10 cm." captionText-3="Figure 8. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 7A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi-0="http://doi.org/10.5281/zenodo.3898956" figureDoi-1="http://doi.org/10.5281/zenodo.3898958" figureDoi-2="http://doi.org/10.5281/zenodo.3898960" figureDoi-3="http://doi.org/10.5281/zenodo.3898962" httpUri-0="https://zenodo.org/record/3898956/files/figure.png" httpUri-1="https://zenodo.org/record/3898958/files/figure.png" httpUri-2="https://zenodo.org/record/3898960/files/figure.png" httpUri-3="https://zenodo.org/record/3898962/files/figure.png" pageId="9" pageNumber="70">Figures 5–8</figureCitation>
|
||
). The general conformation of the braincase is fairly similar to those of other tyrannosaurs in having a well developed otosphenoidal crest (= crista prootica) running from the otoccipital bone caudally and arching rostrally and then ventrally on the prootic, laterosphenoid, and basisphenoid bones (
|
||
<figureCitation id="13732A0C02320C1CE0D6AAB8FAF1FA2A" box="[1216,1327,1452,1474]" captionStart="Figure 6" captionStartId="6.[144,208,1771,1793]" captionTargetBox="[309,1349,173,1729]" captionTargetId="figure@6.[309,1349,173,1729]" captionTargetPageId="6" captionText="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898958" httpUri="https://zenodo.org/record/3898958/files/figure.png" pageId="9" pageNumber="70">Figure 6B</figureCitation>
|
||
). Tucked ventrally or caudoventrally below the margin of the otosphenoidal crest, from caudal to rostral, are the caudal tympanic recess aperture, columellar recess (with the columella [= stapes] in place in the fenestra vestibuli), the maxillomandibular and facial foramina (for CN V
|
||
<subScript id="17CC34CC02320C1CE04EA95CFBAAF9BE" attach="left" box="[1112,1140,1608,1622]" fontSize="6" pageId="9" pageNumber="70">2–3</subScript>
|
||
and CN VII, respectively), the rostral tympanic recess, and cerebral carotid foramen. As in other tyrannosaurids, the facial foramen opens so close to the maxillomandibular foramen that the two essentially share an aperture laterally (
|
||
<bibRefCitation id="EFD94B7802320C1CE7E9A9A7FB04F921" author="Witmer, L. M. & R. C. Ridgely" box="[1023,1242,1715,1737]" editor="P. J. Currie & W. Langston, Jr. & D. H. Tanke" etAl="et al." firstAuthor="Witmer" journalOrPublisher="National Research Council of Canada Monograph Series, Ottawa" pageId="9" pageNumber="70" pagination="117 - 144" refId="ref12819" refString="Witmer, L. M., and R. C. Ridgely. 2008 a. Structure of the brain cavity and inner ear of the centrosaurine ceratopsid Pachyrhinosaurus based on CT scanning and 3 D visualization, p. 117 - 144. In P. J. Currie, W. Langston, Jr., and D. H. Tanke (eds.), A New Horned Dinosaur from an Upper Cretaceous Bone Bed in Alberta. National Research Council of Canada Monograph Series, Ottawa." title="Structure of the brain cavity and inner ear of the centrosaurine ceratopsid Pachyrhinosaurus based on CT scanning and 3 D visualization" type="book chapter" volumeTitle="A New Horned Dinosaur from an Upper Cretaceous Bone Bed in Alberta" year="2008">Witmer et al., 2008</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802320C1CE0FCA9A7FCB8F90F" author="Witmer, L. M. & R. C. Ridgely" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="9" pageNumber="70" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802320C1CE765A9C5FB91F90F" author="Brusatte, S. L. & T. D. Carr & G. M. Erickson & G. S. Bever & M. A. Norell" box="[883,1103,1745,1767]" etAl="et al." firstAuthor="Brusatte" journalOrPublisher="Proceedings of the National Academy of Sciences" pageId="9" pageNumber="70" pagination="17261 - 17266" part="106" refId="ref10867" refString="Brusatte, S. L., T. D. Carr, G. M. Erickson, G. S. Bever, and M. A. Norell. 2009. A long-snouted, multihorned tyrannosaurid from the Late Cretaceous of Mongolia. Proceedings of the National Academy of Sciences, 106: 17261 - 17266." title="A long-snouted, multihorned tyrannosaurid from the Late Cretaceous of Mongolia" type="journal article" year="2009">Brusatte et al., 2009</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BF7368902320C1FE75CA9FAFE84FD08" blockId="9.[818,1489,1100,2001]" lastBlockId="10.[144,814,186,2001]" lastPageId="10" lastPageNumber="71" pageId="9" pageNumber="70">
|
||
As in other tyrannosaurids, perhaps all coelurosaurs, and many tetanurans (
|
||
<bibRefCitation id="EFD94B7802320C1CE7A7A81FFB3EF8C9" author="Sampson, S. D. & L. M. Witmer" box="[945,1248,1803,1825]" firstAuthor="Sampson" journalOrPublisher="Society of Vertebrate Paleontology Memoir" pageId="9" pageNumber="70" pagination="32 - 102" part="8" refId="ref12390" refString="Sampson, S. D., and L. M. Witmer. 2007. Craniofacial anatomy of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar. Society of Vertebrate Paleontology Memoir, 8: 32 - 102." title="Craniofacial anatomy of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar" type="journal article" year="2007">Sampson and Witmer, 2007</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802320C1CE0F9A81FFCB8F8D7" author="Witmer, L. M. & R. C. Ridgely" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="9" pageNumber="70" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
), the ophthalmic nerve (CN V
|
||
<subScript id="17CC34CC02320C1CE0A0A826FB61F8A8" attach="right" box="[1206,1215,1842,1856]" fontSize="6" pageId="9" pageNumber="70">1</subScript>
|
||
) exits the laterosphenoid rostrally via its own foramen. Another attribute shared with other tyrannosaurids is the almost complete ossification of the front of the braincase, with orbitosphenoid and sphenethmoid ossifications contacting their fellows in the midline and enclosing foramina for the olfactory bulbs and tracts, optic nerves (CN II), oculomotor nerves (CN III), and abducens nerves (CN VI) (
|
||
<figureCitation id="13732A0C02310C1FE480AFC3FF24FF05" box="[150,250,215,237]" captionStart="Figure 6" captionStartId="6.[144,208,1771,1793]" captionTargetBox="[309,1349,173,1729]" captionTargetId="figure@6.[309,1349,173,1729]" captionTargetPageId="6" captionText="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898958" httpUri="https://zenodo.org/record/3898958/files/figure.png" pageId="10" pageNumber="71">Figures 6</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02310C1FE507AFC3FEC1FF05" box="[273,287,215,237]" captionStart="Figure 8" captionStartId="8.[144,208,1777,1799]" captionTargetBox="[310,1348,177,1740]" captionTargetId="figure@8.[307,1348,177,1740]" captionTargetPageId="8" captionText="Figure 8. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 7A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898962" httpUri="https://zenodo.org/record/3898962/files/figure.png" pageId="10" pageNumber="71">8</figureCitation>
|
||
). The sphenethmoid is particularly significant because it preserves details relating to the olfactory apparatus. The sphenethmoid itself is divided by a midline osseous septum (mesethmoid), which in life would have separated the rostral terminations of the olfactory tracts (i.e., the olfactory bulbs), as described for other theropods (
|
||
<bibRefCitation id="EFD94B7802310C1FE5DDAE7EFD35FE68" author="Sampson, S. D. & L. M. Witmer" box="[459,747,362,384]" firstAuthor="Sampson" journalOrPublisher="Society of Vertebrate Paleontology Memoir" pageId="10" pageNumber="71" pagination="32 - 102" part="8" refId="ref12390" refString="Sampson, S. D., and L. M. Witmer. 2007. Craniofacial anatomy of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar. Society of Vertebrate Paleontology Memoir, 8: 32 - 102." title="Craniofacial anatomy of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar" type="journal article" year="2007">Sampson and Witmer, 2007</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE6E3AE7EFF37FE75" author="Ali, F. & D. K. Zelenitsky & F. Therrien & D. B. Weishampel" etAl="et al." firstAuthor="Ali" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="10" pageNumber="71" pagination="123 - 133" part="28" refId="ref10672" refString="Ali, F., D. K. Zelenitsky, F. Therrien, and D. B. Weishampel. 2008. Homology of the '' ethmoid complex' ' of tyrannosaurids and its implications for the reconstruction of the olfactory apparatus of non-avian theropods. Journal of Vertebrate Paleontology, 28: 123 - 133." title="Homology of the '' ethmoid complex' ' of tyrannosaurids and its implications for the reconstruction of the olfactory apparatus of non-avian theropods" type="journal article" year="2008">Ali et al., 2008</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE4E5AE93FDDBFE75" author="Witmer, L. M. & R. C. Ridgely" box="[243,517,391,413]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="10" pageNumber="71" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
). Lateral to the region of the olfactory bulbs are a series of thin bony laminae descending from the roof of the sphenethmoid and possibly also the frontal (
|
||
<figureCitation id="13732A0C02310C1FE480AECBFEF7FE1D" box="[150,297,479,501]" captionStart="Figure 6" captionStartId="6.[144,208,1771,1793]" captionTargetBox="[309,1349,173,1729]" captionTargetId="figure@6.[309,1349,173,1729]" captionTargetPageId="6" captionText="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898958" httpUri="https://zenodo.org/record/3898958/files/figure.png" pageId="10" pageNumber="71">Figures 6A, B</figureCitation>
|
||
;
|
||
<figureCitation id="13732A0C02310C1FE525AEF4FEB0FE1D" box="[307,366,479,501]" captionStart="Figure 7" captionStartId="7.[117,181,1684,1706]" captionTargetBox="[277,1320,176,1644]" captionTargetId="figure@7.[277,1320,173,1654]" captionTargetPageId="7" captionText="Figure 7. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings (stereopairs) of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 8A–C provides corresponding labeled views. Scale bar equals 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898960" httpUri="https://zenodo.org/record/3898960/files/figure.png" pageId="10" pageNumber="71">7B, C</figureCitation>
|
||
;
|
||
<figureCitation id="13732A0C02310C1FE56EAECBFE58FE1D" box="[376,390,479,501]" captionStart="Figure 8" captionStartId="8.[144,208,1777,1799]" captionTargetBox="[310,1348,177,1740]" captionTargetId="figure@8.[307,1348,177,1740]" captionTargetPageId="8" captionText="Figure 8. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 7A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898962" httpUri="https://zenodo.org/record/3898962/files/figure.png" pageId="10" pageNumber="71">8</figureCitation>
|
||
). These laminae are external to the neural domain and would be within the nasal cavity, and thus these laminae are best interpreted as olfactory turbinates that would have supported the sensory olfactory epithelium, as observed in extant taxa. The olfactory apparatus indeed seems well developed in
|
||
<materialsCitation id="3B203CD402310C1FE4BCAD66FEEDFD60" ID-GBIF-Occurrence="2636386317" box="[170,307,626,648]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, which is consistent with its large olfactory bulbs, as well as with the large bulbs and expansive nasal olfactory regions seen in other tyrannosaurs (
|
||
<bibRefCitation id="EFD94B7802310C1FE610ADB9FD0AFD2B" author="Witmer, L. M. & R. C. Ridgely" box="[518,724,685,707]" editor="P. J. Currie & W. Langston, Jr. & D. H. Tanke" etAl="et al." firstAuthor="Witmer" journalOrPublisher="National Research Council of Canada Monograph Series, Ottawa" pageId="10" pageNumber="71" pagination="117 - 144" refId="ref12819" refString="Witmer, L. M., and R. C. Ridgely. 2008 a. Structure of the brain cavity and inner ear of the centrosaurine ceratopsid Pachyrhinosaurus based on CT scanning and 3 D visualization, p. 117 - 144. In P. J. Currie, W. Langston, Jr., and D. H. Tanke (eds.), A New Horned Dinosaur from an Upper Cretaceous Bone Bed in Alberta. National Research Council of Canada Monograph Series, Ottawa." title="Structure of the brain cavity and inner ear of the centrosaurine ceratopsid Pachyrhinosaurus based on CT scanning and 3 D visualization" type="book chapter" volumeTitle="A New Horned Dinosaur from an Upper Cretaceous Bone Bed in Alberta" year="2008">Witmer et al., 2008</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE6F6ADB9FE91FD08" author="Witmer, L. M. & R. C. Ridgely" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="10" pageNumber="71" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BF7368902310C1FE4B1ADFCFF05FC01" blockId="10.[144,814,186,2001]" pageId="10" pageNumber="71">
|
||
<materialsCitation id="3B203CD402310C1FE4B1ADFCFEE9FD16" ID-GBIF-Occurrence="2636386322" box="[167,311,744,766]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
shares with other tyrannosauroids modestlysized but widely-spaced basal tubera (
|
||
<bibRefCitation id="EFD94B7802310C1FE608AC12FD37FCF4" author="Bakker, R. T. & M. Williams & P. J. Currie" box="[542,745,774,796]" etAl="et al." firstAuthor="Bakker" journalOrPublisher="Hunteria" pageId="10" pageNumber="71" pagination="1 - 30" part="1" refId="ref10756" refString="Bakker, R. T., M. Williams, and P. J. Currie. 1988. Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana. Hunteria, 1: 1 - 30." title="Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana" type="journal article" year="1988">Bakker et al., 1988</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE6E1AC12FF1CFCD1" author="Carr, T. D." firstAuthor="Carr" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="10" pageNumber="71" pagination="497 - 520" part="19" refId="ref10976" refString="Carr, T. D. 1999. Craniofacial ontogeny in tyrannosaurid dinosaurs (Dinosauria, Coelurosauria). Journal of Vertebrate Paleontology, 19: 497 - 520." title="Craniofacial ontogeny in tyrannosaurid dinosaurs (Dinosauria, Coelurosauria)" type="journal article" year="1999">Carr, 1999</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE4CEAC37FE6AFCD1" author="Currie, P. J. & J. H. Hurum & K. Sabath" box="[216,436,803,825]" etAl="et al." firstAuthor="Currie" journalOrPublisher="Acta Palaeontologica Polonica" pageId="10" pageNumber="71" pagination="227 - 234" part="48" refId="ref11279" refString="Currie, P. J., J. H. Hurum, and K. Sabath. 2003. Skull structure and evolution in tyrannosaurid dinosaurs. Acta Palaeontologica Polonica, 48: 227 - 234." title="Skull structure and evolution in tyrannosaurid dinosaurs" type="journal article" year="2003">Currie et al., 2003</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE5DFAC37FDA2FCD1" author="Li, D. & M. A. Norell & K. - Q. Gao & N. D. Smith & P. J. Makovicky" box="[457,636,803,825]" etAl="et al." firstAuthor="Li" journalOrPublisher="Proceedings of the Royal Society B" pageId="10" pageNumber="71" pagination="183 - 190" part="277" refId="ref11875" refString="Li, D., M. A. Norell, K. - Q. Gao, N. D. Smith, and P. J. Makovicky. 2010. A longirostrine tyrannosauroid from the Early Cretaceous of China. Proceedings of the Royal Society B, 277: 183 - 190." title="A longirostrine tyrannosauroid from the Early Cretaceous of China" type="journal article" year="2010">Li et al., 2010</bibRefCitation>
|
||
), yet it retains strong basipterygoid processes. Likewise, all tyrannosaurids, including
|
||
<materialsCitation id="3B203CD402310C1FE54EAC4AFE34FC9C" ID-GBIF-Occurrence="2636386309" box="[344,490,862,884]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, share extensive pneumaticity associated with the middle ear and pharynx (rostral and caudal tympanic recesses, basisphenoid recesses, subcondylar recess, subsellar recess;
|
||
<bibRefCitation id="EFD94B7802310C1FE528ACA2FE05FC24" author="Witmer, L. M." box="[318,475,950,972]" editor="P. J. Currie & K. Padian" firstAuthor="Witmer" journalOrPublisher="Academic Press, New York" pageId="10" pageNumber="71" pagination="151 - 159" refId="ref12774" refString="Witmer, L. M. 1997 b. Craniofacial air sinus systems, p. 151 - 159. In P. J. Currie and K. Padian (eds.), Encyclopedia of Dinosaurs. Academic Press, New York." title="Craniofacial air sinus systems" type="book chapter" volumeTitle="Encyclopedia of Dinosaurs" year="1997" yearSuffix="b">Witmer, 1997b</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE5FFACA2FCDCFC24" author="Witmer, L. M. & R. C. Ridgely" box="[489,770,950,972]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="10" pageNumber="71" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
; see below).
|
||
</paragraph>
|
||
<paragraph id="8BF7368902310C1FE4B1ACE5FF03F9FF" blockId="10.[144,814,186,2001]" pageId="10" pageNumber="71">
|
||
Despite the similarities with other tyrannosaurids noted above,
|
||
<materialsCitation id="3B203CD402310C1FE486AB1AFEC7FBCC" ID-GBIF-Occurrence="2636386356" box="[144,281,1038,1060]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
displays a number of noteworthy differences. For example, the cultriform process (parasphenoid rostrum) is relatively low and straight (
|
||
<figureCitation id="13732A0C02310C1FE5A0AB5DFDF3FBB7" box="[438,557,1097,1119]" captionStart="Figure 5" captionStartId="5.[117,181,1722,1744]" captionTargetBox="[277,1319,167,1673]" captionTargetId="figure@5.[277,1319,161,1682]" captionTargetPageId="5" captionText="Figure 5. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings (stereopairs) of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 6A–C provides corresponding labeled views. Scale bar equals 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898956" httpUri="https://zenodo.org/record/3898956/files/figure.png" pageId="10" pageNumber="71">Figures 5A</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02310C1FE62DAB5DFD82FBB7" box="[571,604,1097,1119]" captionStart="Figure 6" captionStartId="6.[144,208,1771,1793]" captionTargetBox="[309,1349,173,1729]" captionTargetId="figure@6.[309,1349,173,1729]" captionTargetPageId="6" captionText="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898958" httpUri="https://zenodo.org/record/3898958/files/figure.png" pageId="10" pageNumber="71">6A</figureCitation>
|
||
), rather than, as in most other tyrannosaurids (
|
||
<bibRefCitation id="EFD94B7802310C1FE5ACAB72FD94FB94" author="Russell, D. A." box="[442,586,1126,1148]" firstAuthor="Russell" journalOrPublisher="National Museums of Canada Publications in Paleontology" pageId="10" pageNumber="71" pagination="1 - 34" part="1" refId="ref12278" refString="Russell, D. A. 1970. Tyrannosaurs from the Late Cretaceous of western Canada. National Museums of Canada Publications in Paleontology, 1: 1 - 34." title="Tyrannosaurs from the Late Cretaceous of western Canada" type="journal article" year="1970">Russell, 1970</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE64EAB72FD12FB94" author="Carr, T. D." box="[600,716,1126,1148]" firstAuthor="Carr" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="10" pageNumber="71" pagination="497 - 520" part="19" refId="ref10976" refString="Carr, T. D. 1999. Craniofacial ontogeny in tyrannosaurid dinosaurs (Dinosauria, Coelurosauria). Journal of Vertebrate Paleontology, 19: 497 - 520." title="Craniofacial ontogeny in tyrannosaurid dinosaurs (Dinosauria, Coelurosauria)" type="journal article" year="1999">Carr, 1999</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE6CDAB72FF1DFB72" author="Brochu, C. A." firstAuthor="Brochu" journalOrPublisher="Society of Vertebrate Paleontology Memoir" pageId="10" pageNumber="71" pagination="1 - 140" part="7" refId="ref10827" refString="Brochu, C. A. 2003. Osteology of Tyrannosaurus rex: insights from a nearly complete skeleton and high-resolution computed tomographic analysis of the skull. Society of Vertebrate Paleontology Memoir, 7: 1 - 140." title="Osteology of Tyrannosaurus rex: insights from a nearly complete skeleton and high-resolution computed tomographic analysis of the skull" type="journal article" year="2003">Brochu, 2003</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE4DDAB90FE84FB72" author="Currie, P. J." box="[203,346,1156,1178]" firstAuthor="Currie" journalOrPublisher="Acta Palaeontologica Polonica" pageId="10" pageNumber="71" pagination="191 - 226" part="48" refId="ref11246" refString="Currie, P. J. 2003 b. Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada. Acta Palaeontologica Polonica, 48: 191 - 226." title="Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada" type="journal article" year="2003" yearSuffix="b">Currie, 2003b</bibRefCitation>
|
||
), having a strongly arched ventral margin that sweeps dorsally before leveling off parallel to the frontals. This may relate to
|
||
<materialsCitation id="3B203CD402310C1FE533ABAAFE70FB3C" ID-GBIF-Occurrence="2636386380" box="[293,430,1214,1236]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
having a relatively smaller subsellar recess (a ventral pneumatic chamber in the base of the cultriform process;
|
||
<figureCitation id="13732A0C02310C1FE4FCABEDFE82FAE7" box="[234,348,1273,1295]" captionStart="Figure 6" captionStartId="6.[144,208,1771,1793]" captionTargetBox="[309,1349,173,1729]" captionTargetId="figure@6.[309,1349,173,1729]" captionTargetPageId="6" captionText="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898958" httpUri="https://zenodo.org/record/3898958/files/figure.png" pageId="10" pageNumber="71">Figures 6B</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02310C1FE57CABEDFEA8FAE7" box="[362,374,1273,1295]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="10" pageNumber="71">9</figureCitation>
|
||
) relative to other tyrannosaurids. Among tyrannosaurids, the conformation of the cultriform process and subsellar recess is most similar to that of
|
||
<taxonomicName id="4C484D0A02310C1FE646AA20FD10FAA1" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" box="[592,718,1332,1353]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="10" pageNumber="71" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02310C1FE646AA20FD10FAA1" box="[592,718,1332,1353]" italics="true" pageId="10" pageNumber="71">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
(
|
||
<bibRefCitation id="EFD94B7802310C1FE6C8AA20FE97FA8F" author="Witmer, L. M. & R. C. Ridgely" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="10" pageNumber="71" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
) and
|
||
<emphasis id="B93CEA9B02310C1FE595AA45FE34FA8E" box="[387,490,1361,1382]" italics="true" pageId="10" pageNumber="71">Alioramus</emphasis>
|
||
(
|
||
<bibRefCitation id="EFD94B7802310C1FE5E1AA45FD19FA8F" author="Brusatte, S. L. & T. D. Carr & G. M. Erickson & G. S. Bever & M. A. Norell" box="[503,711,1361,1383]" etAl="et al." firstAuthor="Brusatte" journalOrPublisher="Proceedings of the National Academy of Sciences" pageId="10" pageNumber="71" pagination="17261 - 17266" part="106" refId="ref10867" refString="Brusatte, S. L., T. D. Carr, G. M. Erickson, G. S. Bever, and M. A. Norell. 2009. A long-snouted, multihorned tyrannosaurid from the Late Cretaceous of Mongolia. Proceedings of the National Academy of Sciences, 106: 17261 - 17266." title="A long-snouted, multihorned tyrannosaurid from the Late Cretaceous of Mongolia" type="journal article" year="2009">Brusatte et al., 2009</bibRefCitation>
|
||
). Another difference is that
|
||
<materialsCitation id="3B203CD402310C1FE554AA7AFE14FA6C" ID-GBIF-Occurrence="2636386319" box="[322,458,1390,1412]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
has a much less projecting preotic pendant (
|
||
<figureCitation id="13732A0C02310C1FE4E6AA98FE83FA4A" box="[240,349,1420,1442]" captionStart="Figure 6" captionStartId="6.[144,208,1771,1793]" captionTargetBox="[309,1349,173,1729]" captionTargetId="figure@6.[309,1349,173,1729]" captionTargetPageId="6" captionText="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898958" httpUri="https://zenodo.org/record/3898958/files/figure.png" pageId="10" pageNumber="71">Figure 6A</figureCitation>
|
||
), whereas in other tyrannosaurids it is a large and rugose structure associated with the otosphenoidal crest (
|
||
<bibRefCitation id="EFD94B7802310C1FE480AAD2FE6FFA34" author="Holliday, C. M. & L. M. Witmer" box="[150,433,1478,1500]" firstAuthor="Holliday" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="10" pageNumber="71" pagination="1073 - 1088" part="28" refId="ref11476" refString="Holliday, C. M., and L. M. Witmer. 2008. Cranial kinesis in dinosaurs: intracranial joints, protractor muscles, and their significance for cranial evolution and function in diapsids. Journal of Vertebrate Paleontology, 28: 1073 - 1088." title="Cranial kinesis in dinosaurs: intracranial joints, protractor muscles, and their significance for cranial evolution and function in diapsids" type="journal article" year="2008">Holliday and Witmer, 2008</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE5ACAAD2FD14FA34" author="Witmer, L. M. & R. C. Ridgely" box="[442,714,1478,1500]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="10" pageNumber="71" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
); its weak development in
|
||
<materialsCitation id="3B203CD402310C1FE521AAF0FE1EFA12" ID-GBIF-Occurrence="2636386379" box="[311,448,1508,1530]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
may relate to the small size of the animal.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902310C1FE4B1A90BFCD3F8EB" blockId="10.[144,814,186,2001]" pageId="10" pageNumber="71">
|
||
Other differences relate to the location of the vagus foramen (CN X) on the occiput and to the structure of the subcondylar recesses of the basicranium. In most other tyrannosaurids (certainly
|
||
<taxonomicName id="4C484D0A02310C1FE4EEA96CFEE9F965" authorityName="Osborn" authorityYear="1905" box="[248,311,1656,1677]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="10" pageNumber="71" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02310C1FE4EEA96CFEE9F965" box="[248,311,1656,1677]" italics="true" pageId="10" pageNumber="71">T. rex</emphasis>
|
||
</taxonomicName>
|
||
), the vagus foramen (CN X) is located medially in the caudal surface of the otoccipital within a paracondylar pocket or recess adjacent to the occipital condyle. In
|
||
<materialsCitation id="3B203CD402310C1FE6CBA9A6FF1DF90D" ID-GBIF-Occurrence="2636386316" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, however, the vagus foramen is located more laterally (
|
||
<figureCitation id="13732A0C02310C1FE480A9F9FEDCF8EB" box="[150,258,1773,1795]" captionStart="Figure 6" captionStartId="6.[144,208,1771,1793]" captionTargetBox="[309,1349,173,1729]" captionTargetId="figure@6.[309,1349,173,1729]" captionTargetPageId="6" captionText="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898958" httpUri="https://zenodo.org/record/3898958/files/figure.png" pageId="10" pageNumber="71">Figure 6C</figureCitation>
|
||
), in a position more typical of other coelurosaurs.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902310C1FE4B1A81FFB32FD4E" blockId="10.[144,814,186,2001]" lastBlockId="10.[845,1515,186,2001]" pageId="10" pageNumber="71">
|
||
Ornithomimids, all tyrannosaurids (although apparently not the tyrannosauroid
|
||
<emphasis id="B93CEA9B02310C1FE574A83CFE26F8D5" box="[354,504,1832,1853]" italics="true" pageId="10" pageNumber="71">Xiongguanlong</emphasis>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE61FA83CFD7BF8D6" author="Li, D. & M. A. Norell & K. - Q. Gao & N. D. Smith & P. J. Makovicky" box="[521,677,1832,1854]" etAl="et al." firstAuthor="Li" journalOrPublisher="Proceedings of the Royal Society B" pageId="10" pageNumber="71" pagination="183 - 190" part="277" refId="ref11875" refString="Li, D., M. A. Norell, K. - Q. Gao, N. D. Smith, and P. J. Makovicky. 2010. A longirostrine tyrannosauroid from the Early Cretaceous of China. Proceedings of the Royal Society B, 277: 183 - 190." title="A longirostrine tyrannosauroid from the Early Cretaceous of China" type="journal article" year="2010">Li et al., 2010</bibRefCitation>
|
||
), and potentially even some non-coelurosaurs (
|
||
<bibRefCitation id="EFD94B7802310C1FE617A851FCF8F8B3" author="Sampson, S. D. & L. M. Witmer" box="[513,806,1861,1883]" firstAuthor="Sampson" journalOrPublisher="Society of Vertebrate Paleontology Memoir" pageId="10" pageNumber="71" pagination="32 - 102" part="8" refId="ref12390" refString="Sampson, S. D., and L. M. Witmer. 2007. Craniofacial anatomy of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar. Society of Vertebrate Paleontology Memoir, 8: 32 - 102." title="Craniofacial anatomy of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar" type="journal article" year="2007">Sampson and Witmer, 2007</bibRefCitation>
|
||
) have subcondylar recesses (lateral and medial), which are pneumatic recesses located ventral to the occipital condyle and which excavate the basioccipital and otoccipital in the region above the basal tubera. Furthermore, in most tyrannosaurids, there are pneumatic apertures in the floor of the recess leading into chambers within the basioccipital and otoccipital (
|
||
<bibRefCitation id="EFD94B7802310C1FE1B7AFC3FC53FEE3" author="Currie, P. J." firstAuthor="Currie" journalOrPublisher="Acta Palaeontologica Polonica" pageId="10" pageNumber="71" pagination="191 - 226" part="48" refId="ref11246" refString="Currie, P. J. 2003 b. Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada. Acta Palaeontologica Polonica, 48: 191 - 226." title="Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada" type="journal article" year="2003" yearSuffix="b">Currie, 2003b</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE78CAFE1FB6DFEE3" author="Witmer, L. M. & R. C. Ridgely" box="[922,1203,245,267]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="10" pageNumber="71" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
). The subcondylar recesses of
|
||
<materialsCitation id="3B203CD402310C1FE75BAE06FC04FEC0" ID-GBIF-Occurrence="2636386339" box="[845,986,274,296]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
differ from those of
|
||
<taxonomicName id="4C484D0A02310C1FE0DAAE07FACEFEC0" authorityName="Osborn" authorityYear="1905" box="[1228,1296,275,296]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="10" pageNumber="71" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02310C1FE0DAAE07FACEFEC0" box="[1228,1296,275,296]" italics="true" pageId="10" pageNumber="71">T. rex</emphasis>
|
||
</taxonomicName>
|
||
. In the former, the recesses as a whole are deeper and the basioccipital and otoccipital pneumatic apertures (leading into the medial and lateral subcondylar sinuses, respectively) are much closer together (essentially adjacent to each other and within a shared fossa; see
|
||
<figureCitation id="13732A0C02310C1FE75BAEB1FC1FFE53" box="[845,961,421,443]" captionStart="Figure 5" captionStartId="5.[117,181,1722,1744]" captionTargetBox="[277,1319,167,1673]" captionTargetId="figure@5.[277,1319,161,1682]" captionTargetPageId="5" captionText="Figure 5. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings (stereopairs) of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 6A–C provides corresponding labeled views. Scale bar equals 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898956" httpUri="https://zenodo.org/record/3898956/files/figure.png" pageId="10" pageNumber="71">Figures 5C</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02310C1FE7C1AEB1FC28FE53" box="[983,1014,421,443]" captionStart="Figure 6" captionStartId="6.[144,208,1771,1793]" captionTargetBox="[309,1349,173,1729]" captionTargetId="figure@6.[309,1349,173,1729]" captionTargetPageId="6" captionText="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898958" httpUri="https://zenodo.org/record/3898958/files/figure.png" pageId="10" pageNumber="71">6C</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02310C1FE01BAEB1FBC5FE53" box="[1037,1051,421,443]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="10" pageNumber="71">9</figureCitation>
|
||
). Related to this difference is that the ventromedial wall of the subcondylar recess (the condylotuberal crest;
|
||
<figureCitation id="13732A0C02310C1FE79FAEF4FC23FE1E" box="[905,1021,480,502]" captionStart="Figure 5" captionStartId="5.[117,181,1722,1744]" captionTargetBox="[277,1319,167,1673]" captionTargetId="figure@5.[277,1319,161,1682]" captionTargetPageId="5" captionText="Figure 5. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings (stereopairs) of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 6A–C provides corresponding labeled views. Scale bar equals 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898956" httpUri="https://zenodo.org/record/3898956/files/figure.png" pageId="10" pageNumber="71">Figures 5C</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02310C1FE011AEF4FBF9FE1E" box="[1031,1063,480,502]" captionStart="Figure 6" captionStartId="6.[144,208,1771,1793]" captionTargetBox="[309,1349,173,1729]" captionTargetId="figure@6.[309,1349,173,1729]" captionTargetPageId="6" captionText="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898958" httpUri="https://zenodo.org/record/3898958/files/figure.png" pageId="10" pageNumber="71">6C</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02310C1FE027AEF4FBE3FE1E" box="[1073,1085,480,502]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="10" pageNumber="71">9</figureCitation>
|
||
) is much stronger in
|
||
<materialsCitation id="3B203CD402310C1FE103AEF4FA42FE1E" ID-GBIF-Occurrence="2636386351" box="[1301,1436,480,502]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
than in specimens of
|
||
<taxonomicName id="4C484D0A02310C1FE7CAAEEAFBC2FDFB" authorityName="Osborn" authorityYear="1905" box="[988,1052,510,531]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="10" pageNumber="71" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02310C1FE7CAAEEAFBC2FDFB" box="[988,1052,510,531]" italics="true" pageId="10" pageNumber="71">T. rex</emphasis>
|
||
</taxonomicName>
|
||
. Taken together, the subcondylar region of
|
||
<materialsCitation id="3B203CD402310C1FE75BAD0EFC02FDD8" ID-GBIF-Occurrence="2636386349" box="[845,988,538,560]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
is more primitive than that of
|
||
<taxonomicName id="4C484D0A02310C1FE147AD0FFA49FDD8" authorityName="Osborn" authorityYear="1905" box="[1361,1431,539,560]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="10" pageNumber="71" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02310C1FE147AD0FFA49FDD8" box="[1361,1431,539,560]" italics="true" pageId="10" pageNumber="71">T. rex</emphasis>
|
||
</taxonomicName>
|
||
and is intermediate between the latter and more basal tyrannosaurids (e.g.,
|
||
<taxonomicName id="4C484D0A02310C1FE79FAD41FBD9FD82" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" baseAuthorityYear="2009" box="[905,1031,597,618]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="10" pageNumber="71" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02310C1FE79FAD41FBD9FD82" box="[905,1031,597,618]" italics="true" pageId="10" pageNumber="71">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
, ROM 1247;
|
||
<taxonomicName id="4C484D0A02310C1FE088AD41FAE8FD82" authorityName="Russell" authorityYear="1970" box="[1182,1334,597,618]" class="Reptilia" family="Tyrannosauridae" genus="Daspletosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="10" pageNumber="71" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02310C1FE088AD41FAE8FD82" box="[1182,1334,597,618]" italics="true" pageId="10" pageNumber="71">Daspletosaurus</emphasis>
|
||
</taxonomicName>
|
||
, FMNH PR308; see
|
||
<bibRefCitation id="EFD94B7802310C1FE763AD66FB53FD60" author="Witmer, L. M. & R. C. Ridgely" box="[885,1165,626,648]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="10" pageNumber="71" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
) and even more basal theropods (e.g.,
|
||
<taxonomicName id="4C484D0A02310C1FE791AD84FBE7FD4D" authorityName="Stovall & Langston" authorityYear="1950" box="[903,1081,656,677]" class="Reptilia" family="Carcharodontosauridae" genus="Acrocanthosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="10" pageNumber="71" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02310C1FE791AD84FBE7FD4D" box="[903,1081,656,677]" italics="true" pageId="10" pageNumber="71">Acrocanthosaurus</emphasis>
|
||
</taxonomicName>
|
||
, OMNH 10146).
|
||
</paragraph>
|
||
<paragraph id="8BF7368902310C1FE773ADBAFC44FA8F" blockId="10.[845,1515,186,2001]" pageId="10" pageNumber="71">
|
||
Other workers (e.g.,
|
||
<bibRefCitation id="EFD94B7802310C1FE029ADBAFB08FD2C" author="Gilmore, C. W." box="[1087,1238,686,708]" firstAuthor="Gilmore" journalOrPublisher="Smithsonian Miscellaneous Collections" pageId="10" pageNumber="71" pagination="1 - 19" part="106" refId="ref11374" refString="Gilmore, C. W. 1946. A new carnivorous dinosaur from the Lance formation of Montana. Smithsonian Miscellaneous Collections, 106: 1 - 19." title="A new carnivorous dinosaur from the Lance formation of Montana" type="journal article" year="1946">Gilmore, 1946</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE0F5ADBAFA75FD2C" author="Bakker, R. T. & M. Williams & P. J. Currie" box="[1251,1451,686,708]" etAl="et al." firstAuthor="Bakker" journalOrPublisher="Hunteria" pageId="10" pageNumber="71" pagination="1 - 30" part="1" refId="ref10756" refString="Bakker, R. T., M. Williams, and P. J. Currie. 1988. Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana. Hunteria, 1: 1 - 30." title="Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana" type="journal article" year="1988">Bakker et al., 1988</bibRefCitation>
|
||
) have pointed out the divergent nature of the apertures within the basisphenoid pneumatic recess of
|
||
<materialsCitation id="3B203CD402310C1FE0A0ADFDFA9DFD17" ID-GBIF-Occurrence="2636386310" box="[1206,1347,745,767]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, but 3D visualization of the pneumatic sinuses helps clarify the situation in comparison to other tyrannosaurids. In general, the basisphenoid recess of
|
||
<materialsCitation id="3B203CD402310C1FE7A0AC55FB9CFCBF" ID-GBIF-Occurrence="2636386302" box="[950,1090,833,855]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
more closely resembles that of
|
||
<taxonomicName id="4C484D0A02310C1FE1B2AC55FC52FC9C" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" baseAuthorityYear="2009" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="10" pageNumber="71" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02310C1FE1B2AC55FC52FC9C" italics="true" pageId="10" pageNumber="71">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<taxonomicName id="4C484D0A02310C1FE7C0AC4BFBB0FC9C" authorityName="Russell" authorityYear="1970" box="[982,1134,863,884]" class="Reptilia" family="Tyrannosauridae" genus="Daspletosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="10" pageNumber="71" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02310C1FE7C0AC4BFBB0FC9C" box="[982,1134,863,884]" italics="true" pageId="10" pageNumber="71">Daspletosaurus</emphasis>
|
||
</taxonomicName>
|
||
in having a longer rostrocaudal distance between the intertuberal and interbasipterygoid laminae (= basituberal and basipterygoid webs, respectively, of
|
||
<bibRefCitation id="EFD94B7802310C1FE1B6AC8DFC60FC24" author="Bakker, R. T. & M. Williams & P. J. Currie" etAl="et al." firstAuthor="Bakker" journalOrPublisher="Hunteria" pageId="10" pageNumber="71" pagination="1 - 30" part="1" refId="ref10756" refString="Bakker, R. T., M. Williams, and P. J. Currie. 1988. Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana. Hunteria, 1: 1 - 30." title="Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana" type="journal article" year="1988">Bakker et al., 1988</bibRefCitation>
|
||
; see
|
||
<figureCitation id="13732A0C02310C1FE7F8ACA2FBB4FC24" box="[1006,1130,950,972]" captionStart-0="Figure 5" captionStart-1="Figure 6" captionStart-2="Figure 7" captionStart-3="Figure 8" captionStartId-0="5.[117,181,1722,1744]" captionStartId-1="6.[144,208,1771,1793]" captionStartId-2="7.[117,181,1684,1706]" captionStartId-3="8.[144,208,1777,1799]" captionTargetBox-0="[277,1319,167,1673]" captionTargetBox-1="[309,1349,173,1729]" captionTargetBox-2="[277,1320,176,1644]" captionTargetBox-3="[310,1348,177,1740]" captionTargetId-0="figure@5.[277,1319,161,1682]" captionTargetId-1="figure@6.[309,1349,173,1729]" captionTargetId-2="figure@7.[277,1320,173,1654]" captionTargetId-3="figure@8.[307,1348,177,1740]" captionTargetPageId-0="5" captionTargetPageId-1="6" captionTargetPageId-2="7" captionTargetPageId-3="8" captionText-0="Figure 5. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings (stereopairs) of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 6A–C provides corresponding labeled views. Scale bar equals 10 cm." captionText-1="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." captionText-2="Figure 7. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings (stereopairs) of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 8A–C provides corresponding labeled views. Scale bar equals 10 cm." captionText-3="Figure 8. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 7A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi-0="http://doi.org/10.5281/zenodo.3898956" figureDoi-1="http://doi.org/10.5281/zenodo.3898958" figureDoi-2="http://doi.org/10.5281/zenodo.3898960" figureDoi-3="http://doi.org/10.5281/zenodo.3898962" httpUri-0="https://zenodo.org/record/3898956/files/figure.png" httpUri-1="https://zenodo.org/record/3898958/files/figure.png" httpUri-2="https://zenodo.org/record/3898960/files/figure.png" httpUri-3="https://zenodo.org/record/3898962/files/figure.png" pageId="10" pageNumber="71">Figures 5–8</figureCitation>
|
||
), whereas in
|
||
<taxonomicName id="4C484D0A02310C1FE0F8ACA3FAF2FC24" authorityName="Osborn" authorityYear="1905" box="[1262,1324,951,972]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="10" pageNumber="71" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02310C1FE0F8ACA3FAF2FC24" box="[1262,1324,951,972]" italics="true" pageId="10" pageNumber="71">T. rex</emphasis>
|
||
</taxonomicName>
|
||
these two laminae are quite closely appressed (
|
||
<bibRefCitation id="EFD94B7802310C1FE071ACC0FAA6FC02" author="Witmer, L. M. & R. C. Ridgely" box="[1127,1400,980,1002]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="10" pageNumber="71" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
). However, what makes
|
||
<materialsCitation id="3B203CD402310C1FE7D8ACE5FB88FBEF" ID-GBIF-Occurrence="2636386355" box="[974,1110,1009,1031]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
so divergent is the pattern of apertures within the basisphenoid recess. As preserved (
|
||
<figureCitation id="13732A0C02310C1FE12DAB1AFA71FBCC" box="[1339,1455,1038,1060]" captionStart="Figure 3" captionStartId="3.[117,181,1752,1774]" captionTargetBox="[269,1338,187,1723]" captionTargetId="figure@3.[266,1338,180,1724]" captionTargetPageId="3" captionText="Figure 3. Cleveland tyrannosaur skull, CMNH 7541. Stereophotographs of A, skull in dorsal view; B, skull in caudal view; C, close-up of cranial base in ventral view. Orientations reflect posture with lateral semicircular canal horizontal. Scale bars equal 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898952" httpUri="https://zenodo.org/record/3898952/files/figure.png" pageId="10" pageNumber="71">Figures 3C</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02310C1FE1A9AB1AFA00FBCC" box="[1471,1502,1038,1060]" captionStart="Figure 6" captionStartId="6.[144,208,1771,1793]" captionTargetBox="[309,1349,173,1729]" captionTargetId="figure@6.[309,1349,173,1729]" captionTargetPageId="6" captionText="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898958" httpUri="https://zenodo.org/record/3898958/files/figure.png" pageId="10" pageNumber="71">6C</figureCitation>
|
||
), there are three asymmetrical apertures, unlike any other known theropod. When traced dorsally into the pneumatic sinuses using the CT data, the caudal two apertures can be seen to represent a pair (even if they are not fully bilaterally symmetrical) because they expand into paired (i.e., left and right) sinuses (the caudal basisphenoid sinuses;
|
||
<figureCitation id="13732A0C02310C1FE039ABAAFB7CFB3C" box="[1071,1186,1214,1236]" captionStart="Figure 8" captionStartId="8.[144,208,1777,1799]" captionTargetBox="[310,1348,177,1740]" captionTargetId="figure@8.[307,1348,177,1740]" captionTargetPageId="8" captionText="Figure 8. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 7A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898962" httpUri="https://zenodo.org/record/3898962/files/figure.png" pageId="10" pageNumber="71">Figures 8C</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02310C1FE0B8ABAAFB64FB3C" box="[1198,1210,1214,1236]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="10" pageNumber="71">9</figureCitation>
|
||
) that lead into the basioccipital and communicate on either side of the occiput with the medial subcondylar recesses. Expansion of the basisphenoid recess into sinuses within the basioccipital is fairly common in theropods generally, although the pattern of apertures in
|
||
<materialsCitation id="3B203CD402310C1FE150AA20FA0EFAA2" ID-GBIF-Occurrence="2636386345" box="[1350,1488,1332,1354]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
is unique.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902310C1FE773AA64FC3FF839" blockId="10.[845,1515,186,2001]" pageId="10" pageNumber="71">
|
||
The third and most rostral aperture within the basisphenoid recess has been difficult to interpret. Other tyrannosaurids have a rostral pair of foramina (left and right) in the interbasipterygoid lamina that lead into pneumatic chambers within the basisphenoid (
|
||
<bibRefCitation id="EFD94B7802310C1FE7F4AAF1FBB1FA13" author="Russell, D. A." box="[994,1135,1509,1531]" firstAuthor="Russell" journalOrPublisher="National Museums of Canada Publications in Paleontology" pageId="10" pageNumber="71" pagination="1 - 34" part="1" refId="ref12278" refString="Russell, D. A. 1970. Tyrannosaurs from the Late Cretaceous of western Canada. National Museums of Canada Publications in Paleontology, 1: 1 - 34." title="Tyrannosaurs from the Late Cretaceous of western Canada" type="journal article" year="1970">Russell, 1970</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE06CAAF1FAE1FA13" author="Bakker, R. T. & M. Williams & P. J. Currie" box="[1146,1343,1509,1531]" etAl="et al." firstAuthor="Bakker" journalOrPublisher="Hunteria" pageId="10" pageNumber="71" pagination="1 - 30" part="1" refId="ref10756" refString="Bakker, R. T., M. Williams, and P. J. Currie. 1988. Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana. Hunteria, 1: 1 - 30." title="Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana" type="journal article" year="1988">Bakker et al., 1988</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE15CAAF1FA39FA13" author="Witmer, L. M." box="[1354,1511,1509,1531]" editor="P. J. Currie & K. Padian" firstAuthor="Witmer" journalOrPublisher="Academic Press, New York" pageId="10" pageNumber="71" pagination="151 - 159" refId="ref12774" refString="Witmer, L. M. 1997 b. Craniofacial air sinus systems, p. 151 - 159. In P. J. Currie and K. Padian (eds.), Encyclopedia of Dinosaurs. Academic Press, New York." title="Craniofacial air sinus systems" type="book chapter" volumeTitle="Encyclopedia of Dinosaurs" year="1997" yearSuffix="b">Witmer, 1997b</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE75BA916FC33F9F0" author="Currie, P. J." box="[845,1005,1538,1560]" firstAuthor="Currie" journalOrPublisher="Acta Palaeontologica Polonica" pageId="10" pageNumber="71" pagination="191 - 226" part="48" refId="ref11246" refString="Currie, P. J. 2003 b. Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada. Acta Palaeontologica Polonica, 48: 191 - 226." title="Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada" type="journal article" year="2003" yearSuffix="b">Currie, 2003b</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802310C1FE013A916FA9BF9F0" author="Witmer, L. M. & R. C. Ridgely" box="[1029,1349,1538,1560]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="10" pageNumber="71" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
). Tracing the seemingly single aperture in
|
||
<materialsCitation id="3B203CD402310C1FE063A934FB20F9DE" ID-GBIF-Occurrence="2636386368" box="[1141,1278,1568,1590]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
in the CT data reveals that the aperture branches dorsally into essentially left and right sinuses (the rostral basisphenoid sinuses) that expand within the basisphenoid and eventually communicate with the rostral tympanic recesses on their respective sides (
|
||
<figureCitation id="13732A0C02310C1FE108A981FA4BF943" box="[1310,1429,1685,1707]" captionStart="Figure 7" captionStartId="7.[117,181,1684,1706]" captionTargetBox="[277,1320,176,1644]" captionTargetId="figure@7.[277,1320,173,1654]" captionTargetPageId="7" captionText="Figure 7. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings (stereopairs) of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 8A–C provides corresponding labeled views. Scale bar equals 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898960" httpUri="https://zenodo.org/record/3898960/files/figure.png" pageId="10" pageNumber="71">Figures 7C</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02310C1FE1B4A981FA1CF943" box="[1442,1474,1685,1707]" captionStart="Figure 8" captionStartId="8.[144,208,1777,1799]" captionTargetBox="[310,1348,177,1740]" captionTargetId="figure@8.[307,1348,177,1740]" captionTargetPageId="8" captionText="Figure 8. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 7A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898962" httpUri="https://zenodo.org/record/3898962/files/figure.png" pageId="10" pageNumber="71">8C</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02310C1FE1C6A981FA01F943" box="[1488,1503,1685,1707]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="10" pageNumber="71">9</figureCitation>
|
||
). As a result, it would seem that the pair of foramina in the interbasipterygoid lamina of other tyrannosaurids is present in
|
||
<materialsCitation id="3B203CD402310C1FE75BA9F9FC07F8EB" ID-GBIF-Occurrence="2636386372" box="[845,985,1773,1795]" collectionCode="CMNH" pageId="10" pageNumber="71" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, but that the two apertures share a common fossa that is diverted towards the right side somewhat. Thus in sum, we are proposing that the basisphenoid pneumatic sinuses are fundamentally similar to those of other tyrannosaurids, albeit highly modified.
|
||
<bibRefCitation id="EFD94B7802310C1FE010A877FB7CF891" author="Gilmore, C. W." box="[1030,1186,1891,1913]" firstAuthor="Gilmore" journalOrPublisher="Smithsonian Miscellaneous Collections" pageId="10" pageNumber="71" pagination="1 - 19" part="106" refId="ref11374" refString="Gilmore, C. W. 1946. A new carnivorous dinosaur from the Lance formation of Montana. Smithsonian Miscellaneous Collections, 106: 1 - 19." title="A new carnivorous dinosaur from the Lance formation of Montana" type="journal article" year="1946">Gilmore (1946</bibRefCitation>
|
||
, p. 10) explained this unusual and asymmetric morphology as representing ‘‘an unhealthy condition of the bone,’’ but there is no overt sign of pathology in this region.
|
||
</paragraph>
|
||
<caption id="DF37660102300C1EE463A9B8FC4CF915" ID-DOI="http://doi.org/10.5281/zenodo.3898964" ID-Zenodo-Dep="3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="11" pageNumber="72" startId="11.[117,181,1708,1730]" targetBox="[246,1350,165,1658]" targetPageId="11">
|
||
<paragraph id="8BF7368902300C1EE463A9B8FC4CF915" blockId="11.[117,1488,1708,1789]" pageId="11" pageNumber="72">
|
||
<emphasis id="B93CEA9B02300C1EE463A9B8FF0EF92A" bold="true" box="[117,208,1708,1730]" pageId="11" pageNumber="72">Figure 9.</emphasis>
|
||
Cleveland tyrannosaur skull,
|
||
<materialsCitation id="3B203CD402300C1EE611A9B8FD4CF92A" ID-GBIF-Occurrence="2636386370" box="[519,658,1708,1730]" collectionCode="CMNH" pageId="11" pageNumber="72" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations.
|
||
</paragraph>
|
||
</caption>
|
||
<paragraph id="8BF7368902300C1EE463A851FE24F8B5" blockId="11.[117,787,1861,2001]" box="[117,506,1861,1885]" pageId="11" pageNumber="72">
|
||
<heading id="D0BF81E502300C1EE463A851FE24F8B5" bold="true" box="[117,506,1861,1885]" fontSize="10" level="3" pageId="11" pageNumber="72" reason="0">
|
||
<emphasis id="B93CEA9B02300C1EE463A851FE24F8B5" bold="true" box="[117,506,1861,1885]" pageId="11" pageNumber="72">Pneumatic sinuses of the braincase</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BF7368902300C19E49BA876FECDFD15" blockId="11.[117,787,1861,2001]" lastBlockId="12.[144,814,186,2001]" lastPageId="12" lastPageNumber="73" pageId="11" pageNumber="72">
|
||
The pneumatic recesses of
|
||
<materialsCitation id="3B203CD402300C1EE5B7A876FDF7F890" ID-GBIF-Occurrence="2636386358" box="[417,553,1890,1912]" collectionCode="CMNH" pageId="11" pageNumber="72" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
have been touched on above, but they will receive fuller treatment here in that they have been reconstructed in three dimensions using the CT-scan data (
|
||
<figureCitation id="13732A0C02300C1EE46AA8AFFF08F839" box="[124,214,1979,2001]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="11" pageNumber="72">Figure 9</figureCitation>
|
||
). As noted, there is a clear aperture leading into the caudal tympanic recess, and, as in most other coelurosaurs (
|
||
<bibRefCitation id="EFD94B7802300C1EE72FA876FC03F890" author="Witmer, L. M." box="[825,989,1890,1912]" editor="P. J. Currie & K. Padian" firstAuthor="Witmer" journalOrPublisher="Academic Press, New York" pageId="11" pageNumber="72" pagination="151 - 159" refId="ref12774" refString="Witmer, L. M. 1997 b. Craniofacial air sinus systems, p. 151 - 159. In P. J. Currie and K. Padian (eds.), Encyclopedia of Dinosaurs. Academic Press, New York." title="Craniofacial air sinus systems" type="book chapter" volumeTitle="Encyclopedia of Dinosaurs" year="1997" yearSuffix="b">Witmer, 1997b</bibRefCitation>
|
||
), the aperture is located in the base of the paroccipital process adjacent to the columellar recess and bounded by the prootic and opisthotic. In
|
||
<materialsCitation id="3B203CD402300C1EE106A889FA7EF85B" ID-GBIF-Occurrence="2636386350" box="[1296,1440,1949,1971]" collectionCode="CMNH" pageId="11" pageNumber="72" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, the caudal tympanic recess expands within the paroccipital process, giving off two diverticula, one ventrally and the other dorsally. The ventral diverticulum enters the crista tuberalis (= basioccipital wing of the otoccipital, descending ventral root of the paroccipital process of
|
||
<bibRefCitation id="EFD94B7802370C19E59EAE06FD8DFEC0" author="Bakker, R. T. & M. Williams & P. J. Currie" box="[392,595,274,296]" etAl="et al." firstAuthor="Bakker" journalOrPublisher="Hunteria" pageId="12" pageNumber="73" pagination="1 - 30" part="1" refId="ref10756" refString="Bakker, R. T., M. Williams, and P. J. Currie. 1988. Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana. Hunteria, 1: 1 - 30." title="Nanotyrannus, a new genus of pygmy tyrannosaur, from the latest Cretaceous of Montana" type="journal article" year="1988">Bakker et al., 1988</bibRefCitation>
|
||
) where it is broadly confluent with the lateral subcondylar recess. Despite this confluence, the cavity within the crista tuberalis of
|
||
<materialsCitation id="3B203CD402370C19E6B3AE59FCF3FE8B" ID-GBIF-Occurrence="2636386365" box="[677,813,333,355]" collectionCode="CMNH" pageId="12" pageNumber="73" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
clearly derives as a primary diverticulum of the lateral subcondylar recess, because, in other tyrannosaurids (e.g.,
|
||
<taxonomicName id="4C484D0A02370C19E6F2AE9DFCF9FE76" authorityName="Osborn" authorityYear="1905" box="[740,807,393,414]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02370C19E6F2AE9DFCF9FE76" box="[740,807,393,414]" italics="true" pageId="12" pageNumber="73">T. rex</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName id="4C484D0A02370C19E486AEB1FED0FE52" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" baseAuthorityYear="2009" box="[144,270,421,442]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02370C19E486AEB1FED0FE52" box="[144,270,421,442]" italics="true" pageId="12" pageNumber="73">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
), the communication between the two pneumatic spaces is slight to nonexistent, and it is the lateral subcondylar sinus that occupies the crista tuberalis (
|
||
<bibRefCitation id="EFD94B7802370C19E65EAEF4FF1AFDFB" author="Witmer, L. M. & R. C. Ridgely" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="12" pageNumber="73" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
). The dorsal diverticulum certainly derives as an outgrowth of the caudal tympanic recess and forms a series of interconnecting chambers medially within the otoccipital and supraoccipital and laterally within the paroccipital process (
|
||
<figureCitation id="13732A0C02370C19E640AD41FD6EFD83" box="[598,688,597,619]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="12" pageNumber="73">Figure 9</figureCitation>
|
||
), as in other tyrannosaurids and indeed most other coelurosaurs (
|
||
<bibRefCitation id="EFD94B7802370C19E6CEAD66FF11FD4E" author="Witmer, L. M." editor="P. J. Currie & K. Padian" firstAuthor="Witmer" journalOrPublisher="Academic Press, New York" pageId="12" pageNumber="73" pagination="151 - 159" refId="ref12774" refString="Witmer, L. M. 1997 b. Craniofacial air sinus systems, p. 151 - 159. In P. J. Currie and K. Padian (eds.), Encyclopedia of Dinosaurs. Academic Press, New York." title="Craniofacial air sinus systems" type="book chapter" volumeTitle="Encyclopedia of Dinosaurs" year="1997" yearSuffix="b">Witmer, 1997b</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802370C19E4F6AD84FDDBFD4E" author="Witmer, L. M. & R. C. Ridgely" box="[224,517,656,678]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="12" pageNumber="73" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
). There may be a tenuous communication between contralateral recesses within the supraoccipital but not the broad communication observed in
|
||
<taxonomicName id="4C484D0A02370C19E6D2ADDFFCDFFD08" authorityName="Osborn" authorityYear="1905" box="[708,769,715,736]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02370C19E6D2ADDFFCDFFD08" box="[708,769,715,736]" italics="true" pageId="12" pageNumber="73">T. rex</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<taxonomicName id="4C484D0A02370C19E486ADFCFED0FD15" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" baseAuthorityYear="2009" box="[144,270,744,765]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02370C19E486ADFCFED0FD15" box="[144,270,744,765]" italics="true" pageId="12" pageNumber="73">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902370C19E4B1AC12FD65FA57" blockId="12.[144,814,186,2001]" pageId="12" pageNumber="73">
|
||
The rostral tympanic recess is located, again fairly typically, in the region where the cerebral carotid artery enters the braincase under shelter of the otosphenoidal crest, that is, in the area where the basisphenoid, prootic, and laterosphenoid contact each other (
|
||
<figureCitation id="13732A0C02370C19E480AC6FFF2FFC79" box="[150,241,891,913]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="12" pageNumber="73">Figure 9</figureCitation>
|
||
). The rostral tympanic recess expands within the basisphenoid where it communicates with both the rostral and caudal basisphenoid sinuses, but more broadly with the rostral basisphenoid sinus. The rostral tympanic recess has a major dorsal diverticulum (the ascending diverticulum;
|
||
<figureCitation id="13732A0C02370C19E68CACE5FCF8FBEE" box="[666,806,1009,1031]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="12" pageNumber="73">Figure 9A, B</figureCitation>
|
||
) that leads into the substance of the laterosphenoid bone, occupying the region between the canals for the ophthalmic nerve (CN V
|
||
<subScript id="17CC34CC02370C19E503AB46FEC0FB88" attach="left" box="[277,286,1106,1120]" fontSize="6" pageId="12" pageNumber="73">1</subScript>
|
||
) rostrally and maxillomandibular nerve (CN V
|
||
<subScript id="17CC34CC02370C19E71CAB46FCFBFB88" attach="left" box="[778,805,1106,1120]" fontSize="6" pageId="12" pageNumber="73">2–3</subScript>
|
||
) caudally. The connection between the ascending diverticulum and the rostral tympanic recess is very narrow. The ascending diverticulum is present in
|
||
<taxonomicName id="4C484D0A02370C19E5B2ABB5FDFCFB5E" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" baseAuthorityYear="2009" box="[420,546,1185,1206]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02370C19E5B2ABB5FDFCFB5E" box="[420,546,1185,1206]" italics="true" pageId="12" pageNumber="73">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
but is usually absent (or very rudimentary) in adult
|
||
<taxonomicName id="4C484D0A02370C19E5B2ABABFE3CFB3C" authorityName="Osborn" authorityYear="1905" box="[420,482,1215,1236]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02370C19E5B2ABABFE3CFB3C" box="[420,482,1215,1236]" italics="true" pageId="12" pageNumber="73">T. rex</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<emphasis id="B93CEA9B02370C19E603ABAAFD7AFB3B" box="[533,676,1214,1235]" italics="true" pageId="12" pageNumber="73">Dapletosaurus</emphasis>
|
||
(
|
||
<bibRefCitation id="EFD94B7802370C19E6A7ABAAFEF4FB19" author="Witmer, L. M. & R. C. Ridgely" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="12" pageNumber="73" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
), which could be a legitimate, systematically informative difference. However, a newly discovered, very young skull of
|
||
<taxonomicName id="4C484D0A02370C19E4F2AA02FEBEFAC3" box="[228,352,1302,1323]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02370C19E4F2AA02FEBEFAC3" box="[228,352,1302,1323]" italics="true" pageId="12" pageNumber="73">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
(just 29 cm total skull length;
|
||
<bibRefCitation id="EFD94B7802370C19E689AA02FF1DFAA1" author="Tsuihiji, T. & M. Watabe & L. M. Witmer & T. Tsubamoto & K. Tsogtbaatar" etAl="et al." firstAuthor="Tsuihiji" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="12" pageNumber="73" pagination="160 A" part="27 (Supplement to 3)" refId="ref12554" refString="Tsuihiji, T., M. Watabe, L. M. Witmer, T. Tsubamoto, and K. Tsogtbaatar. 2007. A juvenile skeleton of Tarbosaurus with a nearly complete skull and its implications for ontogenetic change in tyrannosaurids. Journal of Vertebrate Paleontology, 27 (Supplement to 3), 160 A." title="A juvenile skeleton of Tarbosaurus with a nearly complete skull and its implications for ontogenetic change in tyrannosaurids" type="journal article" year="2007">Tsuihiji et al., 2007</bibRefCitation>
|
||
, in review) displays a well developed ascending diverticulum of the rostral tympanic recess; although we lack comparable CT data for adult
|
||
<taxonomicName id="4C484D0A02370C19E556AA7AFE62FA6B" box="[320,444,1390,1411]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02370C19E556AA7AFE62FA6B" box="[320,444,1390,1411]" italics="true" pageId="12" pageNumber="73">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
, if we assume that
|
||
<taxonomicName id="4C484D0A02370C19E6A7AA7AFCF3FA6B" box="[689,813,1390,1411]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02370C19E6A7AA7AFCF3FA6B" box="[689,813,1390,1411]" italics="true" pageId="12" pageNumber="73">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
resembled adult
|
||
<taxonomicName id="4C484D0A02370C19E558AA98FE46FA49" authorityName="Osborn" authorityYear="1905" box="[334,408,1420,1441]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02370C19E558AA98FE46FA49" box="[334,408,1420,1441]" italics="true" pageId="12" pageNumber="73">T. rex</emphasis>
|
||
</taxonomicName>
|
||
, ontogenetic loss of the ascending diverticulum in tyrannosaurines remains a possibility.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902370C19E4B1AAD3FDB9F920" blockId="12.[144,814,186,2001]" pageId="12" pageNumber="73">
|
||
The rostral tympanic recess has another, more medial, diverticulum (the retrohypophyseal sinus,
|
||
<figureCitation id="13732A0C02370C19E649AAF0FD30FA12" box="[607,750,1508,1530]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="12" pageNumber="73">Figure 9A, B</figureCitation>
|
||
) that extends dorsomedially within the clivus of the basisphenoid just caudal to the hypophyseal (pituitary) fossa. This sinus represents a contralateral communication of the left and right rostral tympanic recesses, and has been found in all the tyrannosaurids studied here (
|
||
<bibRefCitation id="EFD94B7802370C19E536A963FDE3F965" author="Witmer, L. M. & R. C. Ridgely" box="[288,573,1655,1677]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="12" pageNumber="73" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
). In
|
||
<materialsCitation id="3B203CD402370C19E664A963FCDEF965" ID-GBIF-Occurrence="2636386357" box="[626,768,1655,1677]" collectionCode="CMNH" pageId="12" pageNumber="73" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, the retrohypophyseal sinus itself sends a small median diverticulum between the paired abducens (CN VI) canals.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902370C19E4B1A9C4FA69FE52" blockId="12.[144,814,186,2001]" lastBlockId="12.[845,1515,186,1848]" pageId="12" pageNumber="73">
|
||
The sinuses associated with the basisphenoid recess have been mentioned above in connection with their external apertures. Given the asymmetry of their bony apertures, it is not surprising that the sinuses themselves are quite asymmetrical, much more so than the caudal and rostral tympanic recesses and their associated diverticula. The caudal basisphenoid sinuses expand dorsally and somewhat caudally, passing through the basioccipital, as noted above, to become broadly confluent with the medial subcondylar recess on the occiput (
|
||
<figureCitation id="13732A0C02370C19E57CA8AFFE1AF839" box="[362,452,1979,2001]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="12" pageNumber="73">Figure 9</figureCitation>
|
||
). The caudal basisphenoid sinus has some communication with the rostral tympanic recess (more so on the left side). The rostral basisphenoid sinuses expand dorsally and rostrally within the basisphenoid. Interestingly, although the shared aperture of the two rostral basisphenoid sinuses within the recess is shifted to the right side, the left sinus is larger and more broadly communicates with the rostral tympanic recess (
|
||
<figureCitation id="13732A0C02370C19E193AE58FA00FE8A" box="[1413,1502,332,354]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="12" pageNumber="73">Figure 9</figureCitation>
|
||
). This asymmetry could be natural but some small amount of postmortem crushing cannot be ruled out, as the right side of the braincase is generally not as well preserved as is the left side.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902370C19E773AED6FA35FD82" blockId="12.[845,1515,186,1848]" pageId="12" pageNumber="73">
|
||
The subsellar recess is located rostral to the interbasipterygoid lamina at the ventral base of the cultriform process (
|
||
<figureCitation id="13732A0C02370C19E192AECBFA00FE1D" box="[1412,1502,479,501]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="12" pageNumber="73">Figure 9</figureCitation>
|
||
). The subsellar recess is relatively small in comparison to that of
|
||
<taxonomicName id="4C484D0A02370C19E1C2AEE9FCB0FDC7" authorityName="Osborn" authorityYear="1905" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02370C19E1C2AEE9FCB0FDC7" italics="true" pageId="12" pageNumber="73">T. rex</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<taxonomicName id="4C484D0A02370C19E7BBAD0EFB9BFDC7" authorityName="Russell" authorityYear="1970" box="[941,1093,538,559]" class="Reptilia" family="Tyrannosauridae" genus="Daspletosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02370C19E7BBAD0EFB9BFDC7" box="[941,1093,538,559]" italics="true" pageId="12" pageNumber="73">Daspletosaurus</emphasis>
|
||
</taxonomicName>
|
||
but is similar in size to that of some juvenile
|
||
<taxonomicName id="4C484D0A02370C19E7B3AD23FBFDFDA4" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" baseAuthorityYear="2009" box="[933,1059,567,588]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02370C19E7B3AD23FBFDFDA4" box="[933,1059,567,588]" italics="true" pageId="12" pageNumber="73">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
specimens (e.g., ROM 1247). There are no pneumatic foramina within the subsellar recess on
|
||
<materialsCitation id="3B203CD402370C19E14AAD40FA39FD82" ID-GBIF-Occurrence="2636386342" box="[1372,1511,596,618]" collectionCode="CMNH" pageId="12" pageNumber="73" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902370C19E773AD66FA35FC44" blockId="12.[845,1515,186,1848]" pageId="12" pageNumber="73">
|
||
On the right side of
|
||
<materialsCitation id="3B203CD402370C19E02CAD66FB18FD60" ID-GBIF-Occurrence="2636386330" box="[1082,1222,626,648]" collectionCode="CMNH" pageId="12" pageNumber="73" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, but not the left, there is an aperture in the basisphenoid bone just dorsal to the base of the basipterygoid process. The aperture is surrounded by a shallow fossa, and these features can be regarded as a basipterygoid recess (
|
||
<bibRefCitation id="EFD94B7802370C19E742ADF3FBBDFD15" author="Chure, D. J. & J. H. Madsen" box="[852,1123,743,765]" firstAuthor="Chure" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="12" pageNumber="73" pagination="63 - 66" part="16" refId="ref11156" refString="Chure, D. J., and J. H. Madsen. 1996. Variation in aspects of the tympanic pneumatic system in a population of Allosaurus fragilis from the Morrison Formation (Upper Jurassic). Journal of Vertebrate Paleontology, 16: 63 - 66." title="Variation in aspects of the tympanic pneumatic system in a population of Allosaurus fragilis from the Morrison Formation (Upper Jurassic)" type="journal article" year="1996">Chure and Madsen, 1996</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802370C19E064ADF3FACFFD15" author="Witmer, L. M." box="[1138,1297,743,765]" editor="P. J. Currie & K. Padian" firstAuthor="Witmer" journalOrPublisher="Academic Press, New York" pageId="12" pageNumber="73" pagination="151 - 159" refId="ref12774" refString="Witmer, L. M. 1997 b. Craniofacial air sinus systems, p. 151 - 159. In P. J. Currie and K. Padian (eds.), Encyclopedia of Dinosaurs. Academic Press, New York." title="Craniofacial air sinus systems" type="book chapter" volumeTitle="Encyclopedia of Dinosaurs" year="1997" yearSuffix="b">Witmer, 1997b</bibRefCitation>
|
||
). The aperture leads into a sinus (the basipterygoid sinus) that ascends dorsally within the basisphenoid. Its communications with other sinuses in the basisphenoid are slight to nonexistent, although it does appear to breach the interbasipterygoid lamina within the basisphenoid recess, where, if so, it would then communicate with the air sinus located there. The basipterygoid process itself is not pneumatized.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902370C19E773ACA0FABAFA53" blockId="12.[845,1515,186,1848]" pageId="12" pageNumber="73">
|
||
Finally, the subcondylar recesses open into a pneumatic fossa on the occiput below the occipital condyle (
|
||
<bibRefCitation id="EFD94B7802370C19E10EACC5FA6BFC0F" author="Witmer, L. M." box="[1304,1461,977,999]" editor="P. J. Currie & K. Padian" firstAuthor="Witmer" journalOrPublisher="Academic Press, New York" pageId="12" pageNumber="73" pagination="151 - 159" refId="ref12774" refString="Witmer, L. M. 1997 b. Craniofacial air sinus systems, p. 151 - 159. In P. J. Currie and K. Padian (eds.), Encyclopedia of Dinosaurs. Academic Press, New York." title="Craniofacial air sinus systems" type="book chapter" volumeTitle="Encyclopedia of Dinosaurs" year="1997" yearSuffix="b">Witmer, 1997b</bibRefCitation>
|
||
) and have been mentioned above in connection with pneumatic apertures located in the otoccipital and basioccipital within the fossa (
|
||
<figureCitation id="13732A0C02370C19E799AB3DFC22FBD7" box="[911,1020,1065,1087]" captionStart="Figure 9" captionStartId="11.[117,181,1708,1730]" captionTargetBox="[246,1350,165,1658]" captionTargetId="figure@11.[243,1350,158,1658]" captionTargetPageId="11" captionText="Figure 9. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data, made partially transparent to reveal brain endocast (light blue) and internal pneumatic sinuses, in A, left lateral; B, left rostroventrolateral; C, caudoventral views. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898964" httpUri="https://zenodo.org/record/3898964/files/figure.png" pageId="12" pageNumber="73">Figure 9C</figureCitation>
|
||
).
|
||
<bibRefCitation id="EFD94B7802370C19E019AB3DFB58FBD7" author="Carr, T. D." box="[1039,1158,1065,1087]" firstAuthor="Carr" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="12" pageNumber="73" pagination="497 - 520" part="19" refId="ref10976" refString="Carr, T. D. 1999. Craniofacial ontogeny in tyrannosaurid dinosaurs (Dinosauria, Coelurosauria). Journal of Vertebrate Paleontology, 19: 497 - 520." title="Craniofacial ontogeny in tyrannosaurid dinosaurs (Dinosauria, Coelurosauria)" type="journal article" year="1999">Carr (1999)</bibRefCitation>
|
||
and
|
||
<bibRefCitation id="EFD94B7802370C19E0ADAB3DFA8CFBD7" author="Currie, P. J." box="[1211,1362,1065,1087]" firstAuthor="Currie" journalOrPublisher="Acta Palaeontologica Polonica" pageId="12" pageNumber="73" pagination="191 - 226" part="48" refId="ref11246" refString="Currie, P. J. 2003 b. Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada. Acta Palaeontologica Polonica, 48: 191 - 226." title="Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada" type="journal article" year="2003" yearSuffix="b">Currie (2003b)</bibRefCitation>
|
||
both regarded the fossa for the subcondylar recesses of
|
||
<materialsCitation id="3B203CD402370C19E0FBAB52FAAAFBB4" ID-GBIF-Occurrence="2636386323" box="[1261,1396,1094,1116]" collectionCode="CMNH" pageId="12" pageNumber="73" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
as shallow, but to our eyes it seems intermediate between the deep recess of young
|
||
<taxonomicName id="4C484D0A02370C19E782AB95FBCCFB7E" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" baseAuthorityYear="2009" box="[916,1042,1153,1174]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02370C19E782AB95FBCCFB7E" box="[916,1042,1153,1174]" italics="true" pageId="12" pageNumber="73">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
specimens (ROM 1247) and the very shallow recess of mature specimens of
|
||
<taxonomicName id="4C484D0A02370C19E093AB8BFB1DFB5C" authorityName="Osborn" authorityYear="1905" box="[1157,1219,1183,1204]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02370C19E093AB8BFB1DFB5C" box="[1157,1219,1183,1204]" italics="true" pageId="12" pageNumber="73">T. rex</emphasis>
|
||
</taxonomicName>
|
||
(e.g., AMNH 5027, AMNH 5117, FMNH PR2081; see
|
||
<bibRefCitation id="EFD94B7802370C19E071ABAFFAA5FB39" author="Witmer, L. M. & R. C. Ridgely" box="[1127,1403,1211,1233]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="12" pageNumber="73" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
). As noted above, the otoccipital aperture of the lateral subcondylar recess expands into a sinus within the crista tuberalis (where it communicates with the caudal tympanic recess), whereas the basioccipital aperture leads to the medial subcondylar sinus that communicates with the caudal basisphenoid sinus. The medial subcondylar sinus does not pneumatize the occipital condyle but just the very base of the neck, as
|
||
<bibRefCitation id="EFD94B7802370C19E08AAA9CFAF1FA76" author="Osborn, H. F." box="[1180,1327,1416,1438]" firstAuthor="Osborn" journalOrPublisher="Memoirs of the American Museum of Natural History" pageId="12" pageNumber="73" pagination="1 - 30" part="1" refId="ref11931" refString="Osborn, H. F. 1912. Crania of Tyrannosaurus and Allosaurus. Memoirs of the American Museum of Natural History, 1: 1 - 30." title="Crania of Tyrannosaurus and Allosaurus" type="journal article" year="1912">Osborn (1912)</bibRefCitation>
|
||
showed for
|
||
<taxonomicName id="4C484D0A02370C19E1BBAA9DFA34FA76" authorityName="Osborn" authorityYear="1905" box="[1453,1514,1417,1438]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="12" pageNumber="73" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02370C19E1BBAA9DFA34FA76" box="[1453,1514,1417,1438]" italics="true" pageId="12" pageNumber="73">T. rex</emphasis>
|
||
</taxonomicName>
|
||
(AMNH 5029; see also
|
||
<bibRefCitation id="EFD94B7802370C19E055AAB1FA87FA53" author="Witmer, L. M. & R. C. Ridgely" box="[1091,1369,1445,1467]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="12" pageNumber="73" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BF7368902370C19E773AAD7FA45F8D0" blockId="12.[845,1515,186,1848]" pageId="12" pageNumber="73">
|
||
Thus in summary,
|
||
<materialsCitation id="3B203CD402370C19E035AAD7FB76FA31" ID-GBIF-Occurrence="2636386353" box="[1059,1192,1475,1497]" collectionCode="CMNH" pageId="12" pageNumber="73" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
has an extensively pneumatized braincase, with clearly identifiable rostral and caudal tympanic recesses, a series of basisphenoid sinuses arising rostrally and caudally from the basisphenoid recess, medial and lateral subcondylar recesses, a small subsellar recess, and, on one side only, a basipterygoid recess. Virtually all of these sinuses communicate broadly with adjacent sinuses. The two tympanic recesses are clearly derived from the middle ear sac (as their names imply), but the basisphenoid and subsellar recesses may derive from a separate median pharyngeal system (
|
||
<bibRefCitation id="EFD94B7802370C19E0CAA9DEFAA7F908" author="Witmer, L. M." box="[1244,1401,1738,1760]" editor="P. J. Currie & K. Padian" firstAuthor="Witmer" journalOrPublisher="Academic Press, New York" pageId="12" pageNumber="73" pagination="151 - 159" refId="ref12774" refString="Witmer, L. M. 1997 b. Craniofacial air sinus systems, p. 151 - 159. In P. J. Currie and K. Padian (eds.), Encyclopedia of Dinosaurs. Academic Press, New York." title="Craniofacial air sinus systems" type="book chapter" volumeTitle="Encyclopedia of Dinosaurs" year="1997" yearSuffix="b">Witmer, 1997b</bibRefCitation>
|
||
). Likewise, although the subcondylar recesses could be tympanic in origin, it is not possible to rule out pneumatization via a cervical pulmonary diverticulum (
|
||
<bibRefCitation id="EFD94B7802370C19E7CCA836FBABF8D0" author="Witmer, L. M." box="[986,1141,1826,1848]" editor="P. J. Currie & K. Padian" firstAuthor="Witmer" journalOrPublisher="Academic Press, New York" pageId="12" pageNumber="73" pagination="151 - 159" refId="ref12774" refString="Witmer, L. M. 1997 b. Craniofacial air sinus systems, p. 151 - 159. In P. J. Currie and K. Padian (eds.), Encyclopedia of Dinosaurs. Academic Press, New York." title="Craniofacial air sinus systems" type="book chapter" volumeTitle="Encyclopedia of Dinosaurs" year="1997" yearSuffix="b">Witmer, 1997b</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802370C19E069A836FA4EF8D0" author="Witmer, L. M. & R. C. Ridgely" box="[1151,1424,1826,1848]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="12" pageNumber="73" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BF7368902370C19E75BA875FBE9F891" blockId="12.[845,1515,1888,2001]" box="[845,1079,1888,1913]" pageId="12" pageNumber="73">
|
||
<heading id="D0BF81E502370C19E75BA875FBE9F891" bold="true" box="[845,1079,1888,1913]" fontSize="10" level="3" pageId="12" pageNumber="73" reason="0">
|
||
<emphasis id="B93CEA9B02370C19E75BA875FBE9F891" bold="true" box="[845,1079,1888,1913]" pageId="12" pageNumber="73">Columella (= stapes)</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BF7368902370C18E773A894FF25FB41" blockId="12.[845,1515,1888,2001]" lastBlockId="13.[117,787,935,1193]" lastPageId="13" lastPageNumber="74" pageId="12" pageNumber="73">
|
||
The columella is clearly preserved in natural position on the left side (
|
||
<figureCitation id="13732A0C02370C19E7A3A88AFB9AF85B" box="[949,1092,1950,1972]" captionStart="Figure 6" captionStartId="6.[144,208,1771,1793]" captionTargetBox="[309,1349,173,1729]" captionTargetId="figure@6.[309,1349,173,1729]" captionTargetPageId="6" captionText="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898958" httpUri="https://zenodo.org/record/3898958/files/figure.png" pageId="12" pageNumber="73">Figure 6A, B</figureCitation>
|
||
;
|
||
<figureCitation id="13732A0C02370C19E043A88AFB44F85B" box="[1109,1178,1950,1972]" captionStart="Figure 8" captionStartId="8.[144,208,1777,1799]" captionTargetBox="[310,1348,177,1740]" captionTargetId="figure@8.[307,1348,177,1740]" captionTargetPageId="8" captionText="Figure 8. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 7A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898962" httpUri="https://zenodo.org/record/3898962/files/figure.png" pageId="12" pageNumber="73">8A, B</figureCitation>
|
||
). It is a very delicate element, extending from the fenestra vestibuli within the columellar recess, passing along the paroccipital process below the otosphenoidal crest, to end laterally just caudomedial to the dorsal head of the quadrate. The columella is only about 1.4 mm in diameter, yet is 71.7 mm in length. The length is probably an underestimate in that the lateral tip is exposed in the actual fossil, and it is unknown how much was lost in collection, preparation, etc. The fact that the columella is preserved in situ and is straight suggests that the braincase region as a whole has not undergone significant deformation.
|
||
</paragraph>
|
||
<caption id="DF37660102360C18E463ADECFABCFCA0" ID-DOI="http://doi.org/10.5281/zenodo.3898966" ID-Zenodo-Dep="3898966" httpUri="https://zenodo.org/record/3898966/files/figure.png" pageId="13" pageNumber="74" startId="13.[117,181,760,782]" targetBox="[163,1438,178,722]" targetPageId="13">
|
||
<paragraph id="8BF7368902360C18E463ADECFABCFCA0" blockId="13.[117,1488,760,840]" pageId="13" pageNumber="74">
|
||
<emphasis id="B93CEA9B02360C18E463ADECFF00FCE6" bold="true" box="[117,222,760,782]" pageId="13" pageNumber="74">Figure 10.</emphasis>
|
||
Cleveland tyrannosaur skull,
|
||
<materialsCitation id="3B203CD402360C18E636ADECFD70FCE6" ID-GBIF-Occurrence="2636386376" box="[544,686,760,782]" collectionCode="CMNH" pageId="13" pageNumber="74" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
. Volume (A) and surface (B) renderings of digitally extracted left quadrate derived from CT data in medial view. Volume renderings (A) are stereopairs; arrow points to the pneumatic foramen. Surface rendering (B) is partially transparent to reveal the internal pneumatic sinus. Scale bar equals 5 cm. See Appendix for abbreviations.
|
||
</paragraph>
|
||
</caption>
|
||
<paragraph id="8BF7368902360C18E463ABC6FE14FB02" blockId="13.[117,787,1234,1847]" box="[117,458,1234,1258]" pageId="13" pageNumber="74">
|
||
<heading id="D0BF81E502360C18E463ABC6FE14FB02" bold="true" box="[117,458,1234,1258]" fontSize="10" level="3" pageId="13" pageNumber="74" reason="0">
|
||
<emphasis id="B93CEA9B02360C18E463ABC6FE14FB02" bold="true" box="[117,458,1234,1258]" pageId="13" pageNumber="74">Quadrate and its pneumaticity</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BF7368902360C18E49BABE6FF0BF8DF" blockId="13.[117,787,1234,1847]" pageId="13" pageNumber="74">
|
||
The left quadrate was digitally extracted from the full CT dataset to examine and illustrate the position of its pneumatic aperture (
|
||
<figureCitation id="13732A0C02360C18E4CEAA39FEE1FAAB" box="[216,319,1325,1347]" captionStart="Figure 10" captionStartId="13.[117,181,760,782]" captionTargetBox="[163,1438,178,722]" captionTargetId="figure@13.[163,1438,162,734]" captionTargetPageId="13" captionText="Figure 10. Cleveland tyrannosaur skull, CMNH 7541. Volume (A) and surface (B) renderings of digitally extracted left quadrate derived from CT data in medial view. Volume renderings (A) are stereopairs; arrow points to the pneumatic foramen. Surface rendering (B) is partially transparent to reveal the internal pneumatic sinus. Scale bar equals 5 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898966" httpUri="https://zenodo.org/record/3898966/files/figure.png" pageId="13" pageNumber="74">Figure 10</figureCitation>
|
||
). Although a taxonomic difference in position of this foramen has not been noted previously, the quadrate pneumatic foramen of albertosaurines (
|
||
<taxonomicName id="4C484D0A02360C18E63BAA7CFD75FA95" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" baseAuthorityYear="2009" box="[557,683,1384,1405]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="13" pageNumber="74" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02360C18E63BAA7CFD75FA95" box="[557,683,1384,1405]" italics="true" pageId="13" pageNumber="74">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
: AMNH 5363;
|
||
<taxonomicName id="4C484D0A02360C18E4A4AA91FEE3FA72" authorityName="Osborn" authorityYear="1905" box="[178,317,1413,1434]" class="Reptilia" family="Tyrannosauridae" genus="Albertosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="13" pageNumber="74" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02360C18E4A4AA91FEE3FA72" box="[178,317,1413,1434]" italics="true" pageId="13" pageNumber="74">Albertosaurus</emphasis>
|
||
</taxonomicName>
|
||
: TMP 81.10.1; see also
|
||
<bibRefCitation id="EFD94B7802360C18E624AA91FD1CFA73" author="Currie, P. J." box="[562,706,1413,1435]" firstAuthor="Currie" journalOrPublisher="Acta Palaeontologica Polonica" pageId="13" pageNumber="74" pagination="191 - 226" part="48" refId="ref11246" refString="Currie, P. J. 2003 b. Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada. Acta Palaeontologica Polonica, 48: 191 - 226." title="Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada" type="journal article" year="2003" yearSuffix="b">Currie, 2003b</bibRefCitation>
|
||
, p. 200) is in a slightly different position than in
|
||
<taxonomicName id="4C484D0A02360C18E60DAAB7FD6DFA50" authorityName="Russell" authorityYear="1970" box="[539,691,1443,1464]" class="Reptilia" family="Tyrannosauridae" genus="Daspletosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="13" pageNumber="74" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02360C18E60DAAB7FD6DFA50" box="[539,691,1443,1464]" italics="true" pageId="13" pageNumber="74">Daspletosaurus</emphasis>
|
||
</taxonomicName>
|
||
(FMNH PR 308) and
|
||
<taxonomicName id="4C484D0A02360C18E4EBAAD5FE4FFA3E" authorityName="Osborn" authorityYear="1905" box="[253,401,1473,1494]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="13" pageNumber="74" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02360C18E4EBAAD5FE4FFA3E" box="[253,401,1473,1494]" italics="true" pageId="13" pageNumber="74">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
(FMNH PR2081). In the former, the pneumatic foramen is directed more medially, whereas in the latter group the crest of bone above the foramen on the quadrate’s pterygoid ramus is much stronger and diverts the pneumatic foramen to a more rostral position such that it no longer directly faces the tympanic cavity. In
|
||
<materialsCitation id="3B203CD402360C18E5CDA947FDAEF981" ID-GBIF-Occurrence="2636386374" box="[475,624,1619,1641]" collectionCode="CMNH" pageId="13" pageNumber="74" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, the quadrate pneumatic foramen again has more of an intermediate position (
|
||
<figureCitation id="13732A0C02360C18E46AA99AFF3DF94C" box="[124,227,1678,1700]" captionStart="Figure 10" captionStartId="13.[117,181,760,782]" captionTargetBox="[163,1438,178,722]" captionTargetId="figure@13.[163,1438,162,734]" captionTargetPageId="13" captionText="Figure 10. Cleveland tyrannosaur skull, CMNH 7541. Volume (A) and surface (B) renderings of digitally extracted left quadrate derived from CT data in medial view. Volume renderings (A) are stereopairs; arrow points to the pneumatic foramen. Surface rendering (B) is partially transparent to reveal the internal pneumatic sinus. Scale bar equals 5 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898966" httpUri="https://zenodo.org/record/3898966/files/figure.png" pageId="13" pageNumber="74">Figure 10</figureCitation>
|
||
). The foramen itself is relatively small in
|
||
<materialsCitation id="3B203CD402360C18E690A99AFCD1F94C" ID-GBIF-Occurrence="2636386304" box="[646,783,1678,1700]" collectionCode="CMNH" pageId="13" pageNumber="74" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
.
|
||
<materialsCitation id="3B203CD402360C18E463A9B8FEC0F929" ID-GBIF-Occurrence="2636386327" box="[117,286,1707,1729]" collectionCode="BMR" pageId="13" pageNumber="74" specimenCode="BMR P2002.4.1">BMR P2002.4.1</materialsCitation>
|
||
is very similar in these regards. The quadrate pneumatic sinus in
|
||
<materialsCitation id="3B203CD402360C18E52DA9DDFE1CF937" ID-GBIF-Occurrence="2636386378" box="[315,450,1737,1759]" collectionCode="CMNH" pageId="13" pageNumber="74" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
is somewhat better preserved on the right side (not illustrated in
|
||
<figureCitation id="13732A0C02360C18E5A9A9F2FDFAF914" box="[447,548,1766,1788]" captionStart="Figure 10" captionStartId="13.[117,181,760,782]" captionTargetBox="[163,1438,178,722]" captionTargetId="figure@13.[163,1438,162,734]" captionTargetPageId="13" captionText="Figure 10. Cleveland tyrannosaur skull, CMNH 7541. Volume (A) and surface (B) renderings of digitally extracted left quadrate derived from CT data in medial view. Volume renderings (A) are stereopairs; arrow points to the pneumatic foramen. Surface rendering (B) is partially transparent to reveal the internal pneumatic sinus. Scale bar equals 5 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898966" httpUri="https://zenodo.org/record/3898966/files/figure.png" pageId="13" pageNumber="74">Figure 10</figureCitation>
|
||
), but on both sides the sinus extends essentially the full height of the element (
|
||
<figureCitation id="13732A0C02360C18E6F1A817FF17F8DF" captionStart="Figure 10" captionStartId="13.[117,181,760,782]" captionTargetBox="[163,1438,178,722]" captionTargetId="figure@13.[163,1438,162,734]" captionTargetPageId="13" captionText="Figure 10. Cleveland tyrannosaur skull, CMNH 7541. Volume (A) and surface (B) renderings of digitally extracted left quadrate derived from CT data in medial view. Volume renderings (A) are stereopairs; arrow points to the pneumatic foramen. Surface rendering (B) is partially transparent to reveal the internal pneumatic sinus. Scale bar equals 5 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898966" httpUri="https://zenodo.org/record/3898966/files/figure.png" pageId="13" pageNumber="74">Figure 10B</figureCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BF7368902360C18E463A874FDDDF890" blockId="13.[117,787,1888,2001]" box="[117,515,1888,1912]" pageId="13" pageNumber="74">
|
||
<heading id="D0BF81E502360C18E463A874FDDDF890" bold="true" box="[117,515,1888,1912]" fontSize="10" level="3" pageId="13" pageNumber="74" reason="0">
|
||
<emphasis id="B93CEA9B02360C18E463A874FDDDF890" bold="true" box="[117,515,1888,1912]" pageId="13" pageNumber="74">Quadratojugal and its pneumaticity</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BF7368902360C18E49BA894FC03F98F" blockId="13.[117,787,1888,2001]" lastBlockId="13.[818,1488,935,1639]" pageId="13" pageNumber="74">
|
||
The quadratojugal is preserved on only the left side of
|
||
<materialsCitation id="3B203CD402360C18E6D4A894FF76F85B" ID-GBIF-Occurrence="2636386367" collectionCode="CMNH" pageId="13" pageNumber="74" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, and even here the bone is fractured and displaced such that its jugal process remains in articulation with the jugal, whereas its squamosal process has been shifted dorsally and rostrally. The most significant attribute of the quadratojugal is the peculiar foramen in its lateral surface within the ventral apex of the lateral fossa.
|
||
<materialsCitation id="3B203CD402360C18E761AB15FBC0FBFE" ID-GBIF-Occurrence="2636386329" box="[887,1054,1024,1046]" collectionCode="BMR" pageId="13" pageNumber="74" specimenCode="BMR P2002.4.1">BMR P2002.4.1</materialsCitation>
|
||
shows a virtually identical foramen, but such a foramen is absent in adult
|
||
<taxonomicName id="4C484D0A02360C18E093AB0BFB1CFBDC" authorityName="Osborn" authorityYear="1905" box="[1157,1218,1055,1076]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="13" pageNumber="74" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02360C18E093AB0BFB1CFBDC" box="[1157,1218,1055,1076]" italics="true" pageId="13" pageNumber="74">T. rex</emphasis>
|
||
</taxonomicName>
|
||
and has not been reported in other tyrannosaurids, other than a small foramen in a specimen of
|
||
<taxonomicName id="4C484D0A02360C18E746AB4DFC10FB86" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" baseAuthorityYear="2009" box="[848,974,1113,1134]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="13" pageNumber="74" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02360C18E746AB4DFC10FB86" box="[848,974,1113,1134]" italics="true" pageId="13" pageNumber="74">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
sp. reported by P.
|
||
<bibRefCitation id="EFD94B7802360C18E08FAB4EFAF3FB87" author="Larson, N. L." box="[1177,1325,1113,1135]" editor="P. L. Larson & K. Carpenter" firstAuthor="Larson" journalOrPublisher="Indiana University Press, Bloomington" pageId="13" pageNumber="74" pagination="1 - 61" refId="ref11773" refString="Larson, N. L. 2008. One hundred years of Tyrannosaurus rex: the skeletons, p. 1 - 61. In P. L. Larson and K. Carpenter (eds.), Tyrannosaurus rex, the Tyrant King. Indiana University Press, Bloomington." title="One hundred years of Tyrannosaurus rex: the skeletons" type="book chapter" volumeTitle="Tyrannosaurus rex, the Tyrant King" year="2008">Larson (2008)</bibRefCitation>
|
||
. Although only rarely noted in print (e.g., P.
|
||
<bibRefCitation id="EFD94B7802360C18E064AB63FADEFB65" author="Larson, N. L." box="[1138,1280,1143,1165]" editor="P. L. Larson & K. Carpenter" firstAuthor="Larson" journalOrPublisher="Indiana University Press, Bloomington" pageId="13" pageNumber="74" pagination="1 - 61" refId="ref11773" refString="Larson, N. L. 2008. One hundred years of Tyrannosaurus rex: the skeletons, p. 1 - 61. In P. L. Larson and K. Carpenter (eds.), Tyrannosaurus rex, the Tyrant King. Indiana University Press, Bloomington." title="One hundred years of Tyrannosaurus rex: the skeletons" type="book chapter" volumeTitle="Tyrannosaurus rex, the Tyrant King" year="2008">Larson, 2008</bibRefCitation>
|
||
), some tyrannosaur workers have wondered if this difference supports the validity of the taxon
|
||
<taxonomicName id="4C484D0A02360C18E7B2ABA7FB4AFB2F" authority="Bakker, Currie & Williams, 1988" authorityName="Bakker, Currie & Williams" authorityYear="1988" box="[932,1172,1202,1224]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="13" pageNumber="74" phylum="Chordata" rank="species" species="lancensis">
|
||
<emphasis id="B93CEA9B02360C18E7B2ABA7FB4AFB2F" box="[932,1172,1202,1224]" italics="true" pageId="13" pageNumber="74">Nanotyrannus lancensis</emphasis>
|
||
</taxonomicName>
|
||
. To clarify the anatomy, we examined this foramen in the CT dataset and digitally extracted the bone for visualization (
|
||
<figureCitation id="13732A0C02360C18E04DABF9FB1FFAEB" box="[1115,1217,1261,1283]" captionStart="Figure 11" captionStartId="14.[144,208,486,508]" captionTargetBox="[284,1370,178,448]" captionTargetId="figure@14.[284,1370,167,454]" captionTargetPageId="14" captionText="Figure 11. Cleveland tyrannosaur skull, CMNH 7541. Volume (A) and surface (B) renderings of digitally extracted left quadratojugal derived from CT data in lateral view. Both sets are stereopairs. Surface rendering (B) is partially transparent to reveal the internal pneumatic sinus. In the actual specimen, the jugal process was displaced relative to the rest of the bone, but has been digitally reattached here. Scale bar equals 5 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898968" httpUri="https://zenodo.org/record/3898968/files/figure.png" pageId="13" pageNumber="74">Figure 11</figureCitation>
|
||
). The foramen is almost certainly a pneumatic foramen, expanding into a blind cavity within the substance of the bone. The cavity has no medial outlets, only the lateral aperture. This also would tend to indicate that the lateral quadratojugal fossa is a pneumatic fossa, most likely associated with the middle ear. Although it remains possible that presence of this quadratojugal pneumatic foramen is a juvenile feature of
|
||
<taxonomicName id="4C484D0A02360C18E7E4AAAAFBEFFA3B" authorityName="Osborn" authorityYear="1905" box="[1010,1073,1470,1491]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="13" pageNumber="74" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02360C18E7E4AAAAFBEFFA3B" box="[1010,1073,1470,1491]" italics="true" pageId="13" pageNumber="74">T. rex</emphasis>
|
||
</taxonomicName>
|
||
that was lost later in ontogeny, the very young skull of
|
||
<taxonomicName id="4C484D0A02360C18E7C4AACFFB90FA18" box="[978,1102,1499,1520]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="13" pageNumber="74" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02360C18E7C4AACFFB90FA18" box="[978,1102,1499,1520]" italics="true" pageId="13" pageNumber="74">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
described by
|
||
<bibRefCitation id="EFD94B7802360C18E0F4AACEFA6EFA18" author="Tsuihiji, T. & M. Watabe & L. M. Witmer & T. Tsubamoto & K. Tsogtbaatar" box="[1250,1456,1498,1520]" etAl="et al." firstAuthor="Tsuihiji" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="13" pageNumber="74" pagination="160 A" part="27 (Supplement to 3)" refId="ref12554" refString="Tsuihiji, T., M. Watabe, L. M. Witmer, T. Tsubamoto, and K. Tsogtbaatar. 2007. A juvenile skeleton of Tarbosaurus with a nearly complete skull and its implications for ontogenetic change in tyrannosaurids. Journal of Vertebrate Paleontology, 27 (Supplement to 3), 160 A." title="A juvenile skeleton of Tarbosaurus with a nearly complete skull and its implications for ontogenetic change in tyrannosaurids" type="journal article" year="2007">Tsuihiji et al. (2007</bibRefCitation>
|
||
; in review) lacks such a foramen, as do adult
|
||
<taxonomicName id="4C484D0A02360C18E11AAAECFA56F9E5" box="[1292,1416,1528,1549]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="13" pageNumber="74" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02360C18E11AAAECFA56F9E5" box="[1292,1416,1528,1549]" italics="true" pageId="13" pageNumber="74">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
quadratojugals, suggesting that presence and then loss of the pneumatic foramen was not a general ontogenetic sequence of tyrannosaurines.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902360C18E724A984FB68F940" blockId="13.[818,1488,1680,2001]" box="[818,1206,1680,1704]" pageId="13" pageNumber="74">
|
||
<heading id="D0BF81E502360C18E724A984FB68F940" bold="true" box="[818,1206,1680,1704]" fontSize="10" level="3" pageId="13" pageNumber="74" reason="0">
|
||
<emphasis id="B93CEA9B02360C18E724A984FB68F940" bold="true" box="[818,1206,1680,1704]" pageId="13" pageNumber="74">Palatine bone and its pneumaticity</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BF7368902360C1BE75CA9A4FCF0FCE2" blockId="13.[818,1488,1680,2001]" lastBlockId="14.[144,814,667,778]" lastPageId="14" lastPageNumber="75" pageId="13" pageNumber="74">
|
||
The left palatine bone of
|
||
<materialsCitation id="3B203CD402360C18E062A9A4FADCF92E" ID-GBIF-Occurrence="2636386312" box="[1140,1282,1712,1734]" collectionCode="CMNH" pageId="13" pageNumber="74" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
also was digitally extracted (
|
||
<figureCitation id="13732A0C02360C18E789A9DAFBD8F90C" box="[927,1030,1742,1764]" captionStart="Figure 12" captionStartId="14.[144,208,1920,1942]" captionTargetBox="[311,1348,1275,1880]" captionTargetId="figure@14.[311,1348,1258,1898]" captionTargetPageId="14" captionText="Figure 12. Cleveland tyrannosaur skull, CMNH 7541. Volume (A) and surface (B) renderings of digitally extracted left palatine derived from CT data in lateral view. Both sets are stereopairs. Surface rendering (B) is partially transparent to reveal the internal pneumatic sinuses; note that the two sinuses do not communicate. Scale bar equals 2 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898970" httpUri="https://zenodo.org/record/3898970/files/figure.png" pageId="13" pageNumber="74">Figure 12</figureCitation>
|
||
). The bone is a fairly typical tyrannosaurid palatine. The bone is pneumatic as in other tyrannosaurids and some other theropods (
|
||
<bibRefCitation id="EFD94B7802360C18E03FA81DFB18F8F7" author="Witmer, L. M." box="[1065,1222,1801,1823]" firstAuthor="Witmer" journalOrPublisher="Society of Vertebrate Paleontology Memoir" pageId="13" pageNumber="74" pagination="1 - 73" part="3" refId="ref12726" refString="Witmer, L. M. 1997 a. The evolution of the antorbital cavity of archosaurs: a study in soft-tissue reconstruction in the fossil record with an analysis of the function of pneumaticity. Society of Vertebrate Paleontology Memoir, 3: 1 - 73." title="The evolution of the antorbital cavity of archosaurs: a study in soft-tissue reconstruction in the fossil record with an analysis of the function of pneumaticity" type="journal article" year="1997" yearSuffix="a">Witmer, 1997a</bibRefCitation>
|
||
, b;
|
||
<bibRefCitation id="EFD94B7802360C18E0E5A81DFCAEF8D5" author="Witmer, L. M. & R. C. Ridgely" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="13" pageNumber="74" pagination="1362 - 1388" part="291" refId="ref12912" refString="Witmer, L. M., and R. C. Ridgely. 2008 b. The paranasal air sinuses of predatory and armored dinosaurs (Archosauria: Theropoda and Ankylosauria) and their contribution to cephalic architecture. Anatomical Record, 291: 1362 - 1388." title="The paranasal air sinuses of predatory and armored dinosaurs (Archosauria: Theropoda and Ankylosauria) and their contribution to cephalic architecture" type="journal article" year="2008" yearSuffix="b">Witmer and Ridgely, 2008b</bibRefCitation>
|
||
) with two pneumatic foramina plainly visible on the actual skull (
|
||
<figureCitation id="13732A0C02360C18E765A850FC3EF8B2" box="[883,992,1860,1882]" captionStart="Figure 2" captionStartId="2.[144,208,1762,1784]" captionTargetBox="[316,1342,167,1714]" captionTargetId="figure@2.[316,1342,167,1728]" captionTargetPageId="2" captionText="Figure 2. Cleveland tyrannosaur skull, CMNH 7541. Stereophotographs of A, close-up of left antorbital region; B, skull in rostral view; C, skull in ventral view. Orientations reflect posture with lateral semicircular canal horizontal. Scale bars equal 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898950" httpUri="https://zenodo.org/record/3898950/files/figure.png" pageId="13" pageNumber="74">Figure 2A</figureCitation>
|
||
). When examined with CT, however, it can be seen that the two pneumatic sinuses within the bone do not communicate but instead form separate chambers. Although the vomeropterygoid process is fully pneumatized (
|
||
<figureCitation id="13732A0C02360C18E132A889FA44F85B" box="[1316,1434,1949,1971]" captionStart="Figure 12" captionStartId="14.[144,208,1920,1942]" captionTargetBox="[311,1348,1275,1880]" captionTargetId="figure@14.[311,1348,1258,1898]" captionTargetPageId="14" captionText="Figure 12. Cleveland tyrannosaur skull, CMNH 7541. Volume (A) and surface (B) renderings of digitally extracted left palatine derived from CT data in lateral view. Both sets are stereopairs. Surface rendering (B) is partially transparent to reveal the internal pneumatic sinuses; note that the two sinuses do not communicate. Scale bar equals 2 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898970" httpUri="https://zenodo.org/record/3898970/files/figure.png" pageId="13" pageNumber="74">Figure 12B</figureCitation>
|
||
), the bone is not strongly inflated, as seen in many
|
||
<taxonomicName id="4C484D0A02360C18E0E2A8A8FAEEF839" authorityName="Osborn" authorityYear="1905" box="[1268,1328,1980,2001]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="13" pageNumber="74" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02360C18E0E2A8A8FAEEF839" box="[1268,1328,1980,2001]" italics="true" pageId="13" pageNumber="74">T. rex</emphasis>
|
||
</taxonomicName>
|
||
specimens (e.g., FMNH PR2081, MOR 008). In general, the palatine of
|
||
<materialsCitation id="3B203CD402350C1BE6E5AD88FF2CFD27" ID-GBIF-Occurrence="2636386352" collectionCode="BMR" pageId="14" pageNumber="75" specimenCode="BMR P2002.4.1">BMR P2002.4.1</materialsCitation>
|
||
has a similar conformation with a large pneumatic aperture caudally, but, unlike
|
||
<materialsCitation id="3B203CD402350C1BE5D7ADC2FD94FD04" ID-GBIF-Occurrence="2636386306" box="[449,586,726,748]" collectionCode="CMNH" pageId="14" pageNumber="75" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, the rostral pneumatic feature does not breach the bone and so is a fossa, not a foramen.
|
||
</paragraph>
|
||
<caption id="DF37660102350C1BE486AEF2FCA4FDBB" ID-DOI="http://doi.org/10.5281/zenodo.3898968" ID-Zenodo-Dep="3898968" httpUri="https://zenodo.org/record/3898968/files/figure.png" pageId="14" pageNumber="75" startId="14.[144,208,486,508]" targetBox="[284,1370,178,448]" targetPageId="14">
|
||
<paragraph id="8BF7368902350C1BE486AEF2FCA4FDBB" blockId="14.[144,1515,486,595]" pageId="14" pageNumber="75">
|
||
<emphasis id="B93CEA9B02350C1BE486AEF2FF28FE14" bold="true" box="[144,246,486,508]" pageId="14" pageNumber="75">Figure 11.</emphasis>
|
||
Cleveland tyrannosaur skull,
|
||
<materialsCitation id="3B203CD402350C1BE63DAEF2FD6BFE14" ID-GBIF-Occurrence="2636386346" box="[555,693,486,508]" collectionCode="CMNH" pageId="14" pageNumber="75" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
. Volume (A) and surface (B) renderings of digitally extracted left quadratojugal derived from CT data in lateral view. Both sets are stereopairs. Surface rendering (B) is partially transparent to reveal the internal pneumatic sinus. In the actual specimen, the jugal process was displaced relative to the rest of the bone, but has been digitally reattached here. Scale bar equals 5 cm. See Appendix for abbreviations.
|
||
</paragraph>
|
||
</caption>
|
||
<paragraph id="8BF7368902350C1BE486AC5CFF05FC88" blockId="14.[144,813,840,1220]" box="[144,219,840,864]" pageId="14" pageNumber="75">
|
||
<heading id="D0BF81E502350C1BE486AC5CFF05FC88" bold="true" box="[144,219,840,864]" fontSize="10" level="3" pageId="14" pageNumber="75" reason="0">
|
||
<emphasis id="B93CEA9B02350C1BE486AC5CFF05FC88" bold="true" box="[144,219,840,864]" pageId="14" pageNumber="75">Vomer</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BF7368902350C1BE4B1AC7CFB06FB2B" blockId="14.[144,813,840,1220]" lastBlockId="14.[845,1515,667,1220]" pageId="14" pageNumber="75">
|
||
The shape of the rostral end of the vomer is an important character in tyrannosaurid systematics, with basal tyrannosauroids and albertosaurines (
|
||
<taxonomicName id="4C484D0A02350C1BE58DACB0FDC7FC51" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" baseAuthorityYear="2009" box="[411,537,932,953]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="14" pageNumber="75" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02350C1BE58DACB0FDC7FC51" box="[411,537,932,953]" italics="true" pageId="14" pageNumber="75">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<taxonomicName id="4C484D0A02350C1BE659ACB0FD04FC51" authorityName="Osborn" authorityYear="1905" box="[591,730,932,953]" class="Reptilia" family="Tyrannosauridae" genus="Albertosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="14" pageNumber="75" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02350C1BE659ACB0FD04FC51" box="[591,730,932,953]" italics="true" pageId="14" pageNumber="75">Albertosaurus</emphasis>
|
||
</taxonomicName>
|
||
) retaining the primitive condition of a narrow, ‘‘lanceolate’’ vomer and tyrannosaurines (
|
||
<taxonomicName id="4C484D0A02350C1BE55BACCBFE3BFC1C" authorityName="Russell" authorityYear="1970" box="[333,485,991,1012]" class="Reptilia" family="Tyrannosauridae" genus="Daspletosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="14" pageNumber="75" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02350C1BE55BACCBFE3BFC1C" box="[333,485,991,1012]" italics="true" pageId="14" pageNumber="75">Daspletosaurus</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName id="4C484D0A02350C1BE5EAACCBFDA6FC1C" box="[508,632,991,1012]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="14" pageNumber="75" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02350C1BE5EAACCBFDA6FC1C" box="[508,632,991,1012]" italics="true" pageId="14" pageNumber="75">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName id="4C484D0A02350C1BE687ACCBFCFBFC1C" authorityName="Osborn" authorityYear="1905" box="[657,805,991,1012]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="14" pageNumber="75" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02350C1BE687ACCBFCFBFC1C" box="[657,805,991,1012]" italics="true" pageId="14" pageNumber="75">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
) having a derived, laterally expanded, diamond-shaped vomer (
|
||
<bibRefCitation id="EFD94B7802350C1BE481AB0EFECFFBD8" author="Holtz, T. R." box="[151,273,1050,1072]" editor="D. H. Tanke & K. Carpenter" firstAuthor="Holtz" journalOrPublisher="Indiana University Press, Bloomington" pageId="14" pageNumber="75" pagination="64 - 83" refId="ref11525" refString="Holtz, T. R. 2001. The phylogeny and taxonomy of the Tyrannosauridae, p. 64 - 83. In D. H. Tanke and K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Bloomington." title="The phylogeny and taxonomy of the Tyrannosauridae" type="book chapter" volumeTitle="Mesozoic Vertebrate Life" year="2001">Holtz, 2001</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFD94B7802350C1BE50DAB0EFE90FBD8" author="Holtz, T. R." box="[283,334,1050,1072]" editor="D. B. Weishampel & P. Dodson & H. Osmolska" firstAuthor="Holtz" journalOrPublisher="University of California Press, Berkeley" pageId="14" pageNumber="75" pagination="111 - 136" refId="ref11572" refString="Holtz, T. R. 2004. Tyrannosauroidea, p. 111 - 136. In D. B. Weishampel, P. Dodson, and H. Osmolska (eds.), The Dinosauria. University of California Press, Berkeley." title="Tyrannosauroidea" type="book chapter" volumeTitle="The Dinosauria" year="2004">2004</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802350C1BE54EAB0EFDCDFBD8" author="Currie, P. J. & J. H. Hurum & K. Sabath" box="[344,531,1050,1072]" etAl="et al." firstAuthor="Currie" journalOrPublisher="Acta Palaeontologica Polonica" pageId="14" pageNumber="75" pagination="227 - 234" part="48" refId="ref11279" refString="Currie, P. J., J. H. Hurum, and K. Sabath. 2003. Skull structure and evolution in tyrannosaurid dinosaurs. Acta Palaeontologica Polonica, 48: 227 - 234." title="Skull structure and evolution in tyrannosaurid dinosaurs" type="journal article" year="2003">Currie et al., 2003</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802350C1BE60BAB0EFD73FBD8" author="Li, D. & M. A. Norell & K. - Q. Gao & N. D. Smith & P. J. Makovicky" box="[541,685,1050,1072]" etAl="et al." firstAuthor="Li" journalOrPublisher="Proceedings of the Royal Society B" pageId="14" pageNumber="75" pagination="183 - 190" part="277" refId="ref11875" refString="Li, D., M. A. Norell, K. - Q. Gao, N. D. Smith, and P. J. Makovicky. 2010. A longirostrine tyrannosauroid from the Early Cretaceous of China. Proceedings of the Royal Society B, 277: 183 - 190." title="A longirostrine tyrannosauroid from the Early Cretaceous of China" type="journal article" year="2010">Li et al., 2010</bibRefCitation>
|
||
). The vomer of
|
||
<materialsCitation id="3B203CD402350C1BE4BDAB23FEECFBA5" ID-GBIF-Occurrence="2636386320" box="[171,306,1079,1101]" collectionCode="CMNH" pageId="14" pageNumber="75" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
is almost completely enclosed in matrix, with just the caudalmost portion exposed within the antorbital cavity (
|
||
<figureCitation id="13732A0C02350C1BE480AB66FED2FB60" box="[150,268,1138,1160]" captionStart="Figure 1" captionStartId="1.[117,181,1505,1527]" captionTargetBox="[246,1342,173,1458]" captionTargetId="figure@1.[230,1372,163,1486]" captionTargetPageId="1" captionText="Figure 1. Cleveland tyrannosaur skull, CMNH 7541. Stereophotographs of skull in A, left lateral view; B, right lateral view. Orientations reflect posture with lateral semicircular canal horizontal. Scale bars equal 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898948" httpUri="https://zenodo.org/record/3898948/files/figure.png" pageId="14" pageNumber="75">Figures 1A</figureCitation>
|
||
,
|
||
<figureCitation id="13732A0C02350C1BE535AB66FE98FB60" box="[291,326,1138,1160]" captionStart="Figure 2" captionStartId="2.[144,208,1762,1784]" captionTargetBox="[316,1342,167,1714]" captionTargetId="figure@2.[316,1342,167,1728]" captionTargetPageId="2" captionText="Figure 2. Cleveland tyrannosaur skull, CMNH 7541. Stereophotographs of A, close-up of left antorbital region; B, skull in rostral view; C, skull in ventral view. Orientations reflect posture with lateral semicircular canal horizontal. Scale bars equal 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898950" httpUri="https://zenodo.org/record/3898950/files/figure.png" pageId="14" pageNumber="75">2A</figureCitation>
|
||
). So, to shed light on the systematically important end of the bone, we digitally extracted the vomer for visualization (
|
||
<figureCitation id="13732A0C02350C1BE532ABBAFE54FB2C" box="[292,394,1198,1220]" captionStart="Figure 13" captionStartId="15.[117,181,605,627]" captionTargetBox="[221,1387,187,571]" captionTargetId="figure@15.[221,1387,180,571]" captionTargetPageId="15" captionText="Figure 13. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings of digitally extracted vomer derived from CT data in A, dorsal; B, left lateral views. Note that rostral portion of the bone is primitive in being lanceolate and forked. Dotted lines represent restored portions in the area corresponding to the transverse oblique plane of fracture (see Figure 4C). Scale bar equals 5 cm. See Appendix for abbreviations." figureDoi="http://doi.org/10.5281/zenodo.3898974" httpUri="https://zenodo.org/record/3898974/files/figure.png" pageId="14" pageNumber="75">Figure 13</figureCitation>
|
||
). The vomer of
|
||
<materialsCitation id="3B203CD402350C1BE650ABBAFD0CFB2C" ID-GBIF-Occurrence="2636386335" box="[582,722,1198,1220]" collectionCode="CMNH" pageId="14" pageNumber="75" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
has the primitive condition, with a narrow rostral end. In fact, the rostralmost tip has the further primitive attribute of forking to contact the palatal processes of the maxilla and premaxilla. Overall, the vomer is a fairly typical non-tyrannosaurine theropod vomer with a dorsal sulcus and a ventral keel. The vomer of
|
||
<materialsCitation id="3B203CD402350C1BE1A6AC06FC6EFCAC" ID-GBIF-Occurrence="2636386348" collectionCode="BMR" pageId="14" pageNumber="75" specimenCode="BMR P2002.4.1">BMR P2002.4.1</materialsCitation>
|
||
is again almost identical to that of
|
||
<materialsCitation id="3B203CD402350C1BE12AAC3AFA14FCAC" ID-GBIF-Occurrence="2636386311" box="[1340,1482,814,836]" collectionCode="CMNH" pageId="14" pageNumber="75" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
. A valid question is whether this morphology is truly primitive or just reflective of an early ontogenetic stage that would transform later in life to the definitive adult tyrannosaurine condition (i.e.,
|
||
<taxonomicName id="4C484D0A02350C1BE1C2AC9CFCB0FC52" authorityName="Osborn" authorityYear="1905" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="14" pageNumber="75" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02350C1BE1C2AC9CFCB0FC52" italics="true" pageId="14" pageNumber="75">T. rex</emphasis>
|
||
</taxonomicName>
|
||
). In this context, the very young
|
||
<taxonomicName id="4C484D0A02350C1BE117ACB1FAA3FC52" box="[1281,1405,933,954]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="14" pageNumber="75" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02350C1BE117ACB1FAA3FC52" box="[1281,1405,933,954]" italics="true" pageId="14" pageNumber="75">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
specimen described by
|
||
<bibRefCitation id="EFD94B7802350C1BE7C7ACD6FB48FC30" author="Tsuihiji, T. & M. Watabe & L. M. Witmer & T. Tsubamoto & K. Tsogtbaatar" box="[977,1174,962,984]" etAl="et al." firstAuthor="Tsuihiji" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="14" pageNumber="75" pagination="160 A" part="27 (Supplement to 3)" refId="ref12554" refString="Tsuihiji, T., M. Watabe, L. M. Witmer, T. Tsubamoto, and K. Tsogtbaatar. 2007. A juvenile skeleton of Tarbosaurus with a nearly complete skull and its implications for ontogenetic change in tyrannosaurids. Journal of Vertebrate Paleontology, 27 (Supplement to 3), 160 A." title="A juvenile skeleton of Tarbosaurus with a nearly complete skull and its implications for ontogenetic change in tyrannosaurids" type="journal article" year="2007">Tsuihiji et al. (2007</bibRefCitation>
|
||
; in review) is significant in having a rostrally narrow vomer similar to those of
|
||
<materialsCitation id="3B203CD402350C1BE126ACCBFA64FC1D" ID-GBIF-Occurrence="2636386360" box="[1328,1466,991,1013]" collectionCode="CMNH" pageId="14" pageNumber="75" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
and
|
||
<materialsCitation id="3B203CD402350C1BE75BACE9FC28FBFB" ID-GBIF-Occurrence="2636386324" box="[845,1014,1021,1043]" collectionCode="BMR" pageId="14" pageNumber="75" specimenCode="BMR P2002.4.1">BMR P2002.4.1</materialsCitation>
|
||
, suggesting that indeed a lanceolate vomer can ontogenetically transform into a diamond-shaped vomer. That said, if
|
||
<materialsCitation id="3B203CD402350C1BE78EAB2CFBC1FBA6" ID-GBIF-Occurrence="2636386325" box="[920,1055,1080,1102]" collectionCode="CMNH" pageId="14" pageNumber="75" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
pertains to a juvenile
|
||
<taxonomicName id="4C484D0A02350C1BE114AB2DFA9EFBA6" authorityName="Osborn" authorityYear="1905" box="[1282,1344,1081,1102]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="14" pageNumber="75" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02350C1BE114AB2DFA9EFBA6" box="[1282,1344,1081,1102]" italics="true" pageId="14" pageNumber="75">T. rex</emphasis>
|
||
</taxonomicName>
|
||
, then the rate of transformation would have had to have been markedly different in
|
||
<taxonomicName id="4C484D0A02350C1BE766AB60FC69FB61" authorityName="Osborn" authorityYear="1905" box="[880,951,1140,1161]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="14" pageNumber="75" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02350C1BE766AB60FC69FB61" box="[880,951,1140,1161]" italics="true" pageId="14" pageNumber="75">T. rex</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<taxonomicName id="4C484D0A02350C1BE7EAAB67FBA6FB60" box="[1020,1144,1139,1160]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="14" pageNumber="75" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02350C1BE7EAAB67FBA6FB60" box="[1020,1144,1139,1160]" italics="true" pageId="14" pageNumber="75">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
in that an unnumbered juvenile
|
||
<taxonomicName id="4C484D0A02350C1BE75BAB85FC17FB4E" box="[845,969,1169,1190]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="14" pageNumber="75" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02350C1BE75BAB85FC17FB4E" box="[845,969,1169,1190]" italics="true" pageId="14" pageNumber="75">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
skull (only about 27% larger than
|
||
<materialsCitation id="3B203CD402350C1BE140AB84FA3AFB4E" ID-GBIF-Occurrence="2636386334" box="[1366,1508,1168,1190]" collectionCode="CMNH" pageId="14" pageNumber="75" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
) already has a diamond-shaped vomer.
|
||
</paragraph>
|
||
<caption id="DF37660102350C1BE486A894FACCF838" ID-DOI="http://doi.org/10.5281/zenodo.3898970" ID-Zenodo-Dep="3898970" httpUri="https://zenodo.org/record/3898970/files/figure.png" pageId="14" pageNumber="75" startId="14.[144,208,1920,1942]" targetBox="[311,1348,1275,1880]" targetPageId="14">
|
||
<paragraph id="8BF7368902350C1BE486A894FACCF838" blockId="14.[144,1515,1920,2000]" pageId="14" pageNumber="75">
|
||
<emphasis id="B93CEA9B02350C1BE486A894FF2BF87E" bold="true" box="[144,245,1920,1942]" pageId="14" pageNumber="75">Figure 12.</emphasis>
|
||
Cleveland tyrannosaur skull,
|
||
<materialsCitation id="3B203CD402350C1BE630A894FD71F87E" ID-GBIF-Occurrence="2636386366" box="[550,687,1920,1942]" collectionCode="CMNH" pageId="14" pageNumber="75" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
. Volume (A) and surface (B) renderings of digitally extracted left palatine derived from CT data in lateral view. Both sets are stereopairs. Surface rendering (B) is partially transparent to reveal the internal pneumatic sinuses; note that the two sinuses do not communicate. Scale bar equals 2 cm. See Appendix for abbreviations.
|
||
</paragraph>
|
||
</caption>
|
||
<caption id="DF37660102340C1AE463AD49FE47FD23" ID-DOI="http://doi.org/10.5281/zenodo.3898974" ID-Zenodo-Dep="3898974" httpUri="https://zenodo.org/record/3898974/files/figure.png" pageId="15" pageNumber="76" startId="15.[117,181,605,627]" targetBox="[221,1387,187,571]" targetPageId="15">
|
||
<paragraph id="8BF7368902340C1AE463AD49FE47FD23" blockId="15.[117,1488,605,715]" pageId="15" pageNumber="76">
|
||
<emphasis id="B93CEA9B02340C1AE463AD49FF03FD9B" bold="true" box="[117,221,605,627]" pageId="15" pageNumber="76">Figure 13.</emphasis>
|
||
Cleveland tyrannosaur skull,
|
||
<materialsCitation id="3B203CD402340C1AE60CAD49FD78FD9B" ID-GBIF-Occurrence="2636386341" box="[538,678,605,627]" collectionCode="CMNH" pageId="15" pageNumber="76" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
. Volume renderings of digitally extracted vomer derived from CT data in A, dorsal; B, left lateral views. Note that rostral portion of the bone is primitive in being lanceolate and forked. Dotted lines represent restored portions in the area corresponding to the transverse oblique plane of fracture (see Figure 4C). Scale bar equals 5 cm. See Appendix for abbreviations.
|
||
</paragraph>
|
||
</caption>
|
||
<paragraph id="8BF7368902340C1AE463AC07FE14FCC3" blockId="15.[117,787,787,2001]" box="[117,458,787,811]" pageId="15" pageNumber="76">
|
||
<heading id="D0BF81E502340C1AE463AC07FE14FCC3" bold="true" box="[117,458,787,811]" fontSize="10" level="3" pageId="15" pageNumber="76" reason="0">
|
||
<emphasis id="B93CEA9B02340C1AE463AC07FE14FCC3" bold="true" box="[117,458,787,811]" pageId="15" pageNumber="76">Possible respiratory turbinates</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BF7368902340C1AE49BAC27FE72FB01" blockId="15.[117,787,787,2001]" pageId="15" pageNumber="76">
|
||
Respiratory turbinates in amniotes have received a great deal of attention because of their potential role in debates on dinosaur metabolic status (
|
||
<bibRefCitation id="EFD94B7802340C1AE53CAC7BFE68FC6D" author="Bakker, R. T." box="[298,438,879,901]" firstAuthor="Bakker" journalOrPublisher="Discover" pageId="15" pageNumber="76" pagination="58 - 69" part="13" refId="ref10730" refString="Bakker, R. T. 1992. Inside the head of a tiny T. rex. Discover, 13: 58 - 69." title="Inside the head of a tiny T. rex" type="journal article" year="1992">Bakker, 1992</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802340C1AE5D6AC7BFD9AFC6D" author="Ruben, J." box="[448,580,879,901]" editor="I. A. Johnston & A. F. Bennett" firstAuthor="Ruben" journalOrPublisher="Cambridge University Press, Cambridge" pageId="15" pageNumber="76" pagination="347 - 376" refId="ref12086" refString="Ruben, J. 1996. Evolution of endothermy in mammals, birds, and their ancestors, p. 347 - 376. In I. A. Johnston and A. F. Bennett (eds.), Animals and Temperature. Cambridge University Press, Cambridge." title="Evolution of endothermy in mammals, birds, and their ancestors" type="book chapter" volumeTitle="Animals and Temperature" year="1996">Ruben, 1996</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B7802340C1AE646AC7BFCD0FC6D" author="Ruben, J. A. & W. J. Hillenius & N. R. Geist & A. Leitch & T. D. Jones & P. J. Currie & J. R. Horner & G. Espe III." box="[592,782,879,901]" etAl="et al." firstAuthor="Ruben" journalOrPublisher="Science" pageId="15" pageNumber="76" pagination="1204 - 1207" part="273" refId="ref12137" refString="Ruben, J. A., W. J. Hillenius, N. R. Geist, A. Leitch, T. D. Jones, P. J. Currie, J. R. Horner, and G. Espe III. 1996. The metabolic status of some Late Cretaceous dinosaurs. Science, 273: 1204 - 1207." title="The metabolic status of some Late Cretaceous dinosaurs" type="journal article" year="1996">Ruben et al., 1996</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFD94B7802340C1AE463AC99FF77FC4B" author="Ruben, J. A. & W. J. Hillenius & A. Leitch & N. R. Geist & T. D. Jones" box="[117,169,909,931]" editor="J. O. Farlow & M. K. Brett- Surman" firstAuthor="Ruben" journalOrPublisher="Purdue University Press, Ashland" pageId="15" pageNumber="76" pagination="505 - 518" refId="ref12203" refString="Ruben, J. A., W. J. Hillenius, A. Leitch, N. R. Geist, and T. D. Jones. 1997. New insights into the metabolic physiology of dinosaurs, p. 505 - 518. In J. O. Farlow and M. K. Brett- Surman (eds.), The Complete Dinosaur. Purdue University Press, Ashland." title="New insights into the metabolic physiology of dinosaurs" type="book chapter" volumeTitle="The Complete Dinosaur" year="1997">1997</bibRefCitation>
|
||
). The idea promoted by J. A.
|
||
<bibRefCitation id="EFD94B7802340C1AE635AC99FD66FC4B" author="Ruben, J." box="[547,696,909,931]" firstAuthor="Ruben" journalOrPublisher="Annual Review of Physiology" pageId="15" pageNumber="76" pagination="69 - 95" part="57" refId="ref12055" refString="Ruben, J. 1995. The evolution of endothermy in mammals and birds: from physiology to fossils. Annual Review of Physiology, 57: 69 - 95." title="The evolution of endothermy in mammals and birds: from physiology to fossils" type="journal article" year="1995">Ruben (1995)</bibRefCitation>
|
||
is that respiratory turbinates may be mandatory in endothermic animals to help mitigate the effects of respiratory evaporative water loss that would result from the high lung-ventilation rates characteristic of endotherms. As mentioned above, CT scanning of
|
||
<materialsCitation id="3B203CD402340C1AE6D4AB17FF7BFBDF" ID-GBIF-Occurrence="2636386343" collectionCode="CMNH" pageId="15" pageNumber="76" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
has been a major player in this debate.
|
||
<bibRefCitation id="EFD94B7802340C1AE66DAB35FCCDFBDF" author="Bakker, R. T." box="[635,787,1057,1079]" firstAuthor="Bakker" journalOrPublisher="Discover" pageId="15" pageNumber="76" pagination="58 - 69" part="13" refId="ref10730" refString="Bakker, R. T. 1992. Inside the head of a tiny T. rex. Discover, 13: 58 - 69." title="Inside the head of a tiny T. rex" type="journal article" year="1992">Bakker (1992)</bibRefCitation>
|
||
reconstructed a large scrolled turbinate within the snout of this animal, but, given that the reconstruction was published in a popular magazine (
|
||
<emphasis id="B93CEA9B02340C1AE52AAB6EFE4DFB67" box="[316,403,1146,1167]" italics="true" pageId="15" pageNumber="76">Discover</emphasis>
|
||
), no details were given. Later Ruben and his team (1996, 1997) argued (using the same scan data) that no turbinates were present, and that, moreover, the airway was too small to house turbinates.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902340C1AE49BABE6FF3DF962" blockId="15.[117,787,787,2001]" pageId="15" pageNumber="76">
|
||
Unfortunately,
|
||
<materialsCitation id="3B203CD402340C1AE53BABE6FE6AFAE0" ID-GBIF-Occurrence="2636386315" box="[301,436,1266,1288]" collectionCode="CMNH" pageId="15" pageNumber="76" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
is not the best specimen on which to base a debate, because so much of the snout is damaged and reconstructed with plaster. As noted above, clear
|
||
<emphasis id="B93CEA9B02340C1AE6AFAA39FCCDFAAA" box="[697,787,1325,1346]" italics="true" pageId="15" pageNumber="76">olfactory</emphasis>
|
||
turbinates are present far caudally (
|
||
<figureCitation id="13732A0C02340C1AE60DAA5FFD49FA89" box="[539,663,1355,1377]" captionStart-0="Figure 5" captionStart-1="Figure 6" captionStart-2="Figure 7" captionStart-3="Figure 8" captionStartId-0="5.[117,181,1722,1744]" captionStartId-1="6.[144,208,1771,1793]" captionStartId-2="7.[117,181,1684,1706]" captionStartId-3="8.[144,208,1777,1799]" captionTargetBox-0="[277,1319,167,1673]" captionTargetBox-1="[309,1349,173,1729]" captionTargetBox-2="[277,1320,176,1644]" captionTargetBox-3="[310,1348,177,1740]" captionTargetId-0="figure@5.[277,1319,161,1682]" captionTargetId-1="figure@6.[309,1349,173,1729]" captionTargetId-2="figure@7.[277,1320,173,1654]" captionTargetId-3="figure@8.[307,1348,177,1740]" captionTargetPageId-0="5" captionTargetPageId-1="6" captionTargetPageId-2="7" captionTargetPageId-3="8" captionText-0="Figure 5. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings (stereopairs) of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 6A–C provides corresponding labeled views. Scale bar equals 10 cm." captionText-1="Figure 6. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, left lateral; B, left rostroventrolateral; C, caudal views. Figure 5A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." captionText-2="Figure 7. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings (stereopairs) of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 8A–C provides corresponding labeled views. Scale bar equals 10 cm." captionText-3="Figure 8. Cleveland tyrannosaur skull, CMNH 7541. Surface renderings of digitally extracted braincase derived from CT data in A, rostral; B, rostroventral; C, ventral views. Figure 7A–C shows corresponding stereopairs of volume renderings. Scale bar equals 10 cm. See Appendix for abbreviations." figureDoi-0="http://doi.org/10.5281/zenodo.3898956" figureDoi-1="http://doi.org/10.5281/zenodo.3898958" figureDoi-2="http://doi.org/10.5281/zenodo.3898960" figureDoi-3="http://doi.org/10.5281/zenodo.3898962" httpUri-0="https://zenodo.org/record/3898956/files/figure.png" httpUri-1="https://zenodo.org/record/3898958/files/figure.png" httpUri-2="https://zenodo.org/record/3898960/files/figure.png" httpUri-3="https://zenodo.org/record/3898962/files/figure.png" pageId="15" pageNumber="76">Figures 5–8</figureCitation>
|
||
); they are immediately adjacent to the olfactory bulb fossa and could not have functioned as respiratory turbinates because they are well out of the main nasal airstream (see
|
||
<bibRefCitation id="EFD94B7802340C1AE5F9AAB0FCD0FA52" author="Witmer, L. M. & R. C. Ridgely" box="[495,782,1444,1466]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="15" pageNumber="76" pagination="1362 - 1388" part="291" refId="ref12912" refString="Witmer, L. M., and R. C. Ridgely. 2008 b. The paranasal air sinuses of predatory and armored dinosaurs (Archosauria: Theropoda and Ankylosauria) and their contribution to cephalic architecture. Anatomical Record, 291: 1362 - 1388." title="The paranasal air sinuses of predatory and armored dinosaurs (Archosauria: Theropoda and Ankylosauria) and their contribution to cephalic architecture" type="journal article" year="2008" yearSuffix="b">Witmer and Ridgely, 2008b</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFD94B7802340C1AE463AAD5FF77FA3F" author="Witmer, L. M. & R. C. Ridgely" box="[117,169,1473,1495]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="15" pageNumber="76" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">2009</bibRefCitation>
|
||
). Rostral to the olfactory turbinates is a large segment of matrix in which no ossified or calcified (i.e., fossilized) turbinatelike structures can be seen, and rostral to this is a large plasterreconstructed area (in association with the oblique transverse fracture mentioned earlier; see
|
||
<figureCitation id="13732A0C02340C1AE5B8A92CFDEBF9A6" box="[430,565,1592,1614]" captionStart="Figure 4" captionStartId="4.[144,208,1624,1646]" captionTargetBox="[199,1460,175,1584]" captionTargetId="figure@4.[187,1474,170,1605]" captionTargetPageId="4" captionText="Figure 4. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings of the skull derived from the CT data in A, rostral view; B, right lateral view; C, left lateral view; D, dorsal view; E, caudal view; F, ventral view. Densities corresponding to plaster have been excluded, revealing the extent of plaster restoration. Arrows in C indicate the transverse oblique plane of fracture that the specimen experienced prior to restoration. Scale bar equals 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898954" httpUri="https://zenodo.org/record/3898954/files/figure.png" pageId="15" pageNumber="76">Figure 4B, C</figureCitation>
|
||
). Ironically, this large region is the area in which
|
||
<bibRefCitation id="EFD94B7802340C1AE59AA942FDC9F984" author="Bakker, R. T." box="[396,535,1622,1644]" firstAuthor="Bakker" journalOrPublisher="Discover" pageId="15" pageNumber="76" pagination="58 - 69" part="13" refId="ref10730" refString="Bakker, R. T. 1992. Inside the head of a tiny T. rex. Discover, 13: 58 - 69." title="Inside the head of a tiny T. rex" type="journal article" year="1992">Bakker (1992</bibRefCitation>
|
||
, p. 61) reconstructed his turbinates.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902340C1AE49BA986FB65FBFC" blockId="15.[117,787,787,2001]" lastBlockId="15.[818,1488,787,1044]" pageId="15" pageNumber="76">
|
||
Our new scanning of
|
||
<materialsCitation id="3B203CD402340C1AE568A986FDD3F940" ID-GBIF-Occurrence="2636386347" box="[382,525,1682,1704]" collectionCode="CMNH" pageId="15" pageNumber="76" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, however, has identified structures within the rostral portion of the snout—in front of the region where
|
||
<bibRefCitation id="EFD94B7802340C1AE516A9D9FE4EF90B" author="Bakker, R. T." box="[256,400,1741,1763]" firstAuthor="Bakker" journalOrPublisher="Discover" pageId="15" pageNumber="76" pagination="58 - 69" part="13" refId="ref10730" refString="Bakker, R. T. 1992. Inside the head of a tiny T. rex. Discover, 13: 58 - 69." title="Inside the head of a tiny T. rex" type="journal article" year="1992">Bakker (1992)</bibRefCitation>
|
||
reconstructed a turbinate and behind the region where
|
||
<bibRefCitation id="EFD94B7802340C1AE522A9FFFDDBF8E9" author="Ruben, J. A. & W. J. Hillenius & N. R. Geist & A. Leitch & T. D. Jones & P. J. Currie & J. R. Horner & G. Espe III." box="[308,517,1771,1793]" etAl="et al." firstAuthor="Ruben" journalOrPublisher="Science" pageId="15" pageNumber="76" pagination="1204 - 1207" part="273" refId="ref12137" refString="Ruben, J. A., W. J. Hillenius, N. R. Geist, A. Leitch, T. D. Jones, P. J. Currie, J. R. Horner, and G. Espe III. 1996. The metabolic status of some Late Cretaceous dinosaurs. Science, 273: 1204 - 1207." title="The metabolic status of some Late Cretaceous dinosaurs" type="journal article" year="1996">Ruben et al. (1996)</bibRefCitation>
|
||
showed turbinates to be lacking—that may be interpreted as being respiratory turbinates (
|
||
<figureCitation id="13732A0C02340C1AE46AA832FF3DF8D4" box="[124,227,1830,1852]" captionStart="Figure 14" captionStartId="16.[144,208,1684,1706]" captionTargetBox="[167,791,185,1654]" captionTargetId="figure@16.[167,791,185,1654]" captionTargetPageId="16" captionText="Figure 14. Cleveland tyrannosaur skull, CMNH 7541. A–D, progressively more caudal CT slices through the snout at the position shown in E, showing structures interpretable as respiratory turbinates (arrows). Note that some symmetry is preserved in A and B. In C, a structure (arrow) can be seen to cross a crack. D shows a series of structures associated with the maxilla. Scale bar equals 1 cm." figureDoi="http://doi.org/10.5281/zenodo.3898976" httpUri="https://zenodo.org/record/3898976/files/figure.png" pageId="15" pageNumber="76">Figure 14</figureCitation>
|
||
). The structures in question are located in the main nasal airway above the maxillary antra (which themselves are largely reconstructed in plaster). These structures form a series of thin, but moderately dense laminae visible within undistorted matrix that are associated with both the nasal and the maxilla and project into the nasal airway. There are some regions of symmetry, and some elements that can even be tentatively regarded as ‘‘scrolls’’ (
|
||
<figureCitation id="13732A0C02340C1AE036AC24FB59FCAE" box="[1056,1159,816,838]" captionStart="Figure 14" captionStartId="16.[144,208,1684,1706]" captionTargetBox="[167,791,185,1654]" captionTargetId="figure@16.[167,791,185,1654]" captionTargetPageId="16" captionText="Figure 14. Cleveland tyrannosaur skull, CMNH 7541. A–D, progressively more caudal CT slices through the snout at the position shown in E, showing structures interpretable as respiratory turbinates (arrows). Note that some symmetry is preserved in A and B. In C, a structure (arrow) can be seen to cross a crack. D shows a series of structures associated with the maxilla. Scale bar equals 1 cm." figureDoi="http://doi.org/10.5281/zenodo.3898976" httpUri="https://zenodo.org/record/3898976/files/figure.png" pageId="15" pageNumber="76">Figure 14</figureCitation>
|
||
). The density of these putative turbinates is less than the adjacent nasal and maxilla but more than the surrounding matrix. Whether or not these moderate density values reflect calcification of cartilaginous structures or just very thin bone is difficult to determine. Certainly, they are positioned appropriately to be turbinates with a respiratory function in that they are within the portion of the main nasal airway between the naris and choana.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902340C1AE724AB29FC42FBBD" blockId="15.[818,1488,1085,1727]" box="[818,924,1085,1109]" pageId="15" pageNumber="76">
|
||
<heading id="D0BF81E502340C1AE724AB29FC42FBBD" bold="true" box="[818,924,1085,1109]" fontSize="10" level="3" pageId="15" pageNumber="76" reason="0">
|
||
<emphasis id="B93CEA9B02340C1AE724AB29FC42FBBD" bold="true" box="[818,924,1085,1109]" pageId="15" pageNumber="76">Mandible</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BF7368902340C1AE75CAB49FA7CF957" blockId="15.[818,1488,1085,1727]" pageId="15" pageNumber="76">
|
||
The two mandibles are preserved in full occlusion with the skull, and so, although many details of the mandible can be seen (
|
||
<figureCitation id="13732A0C02340C1AE72FAB8CFC6AFB46" box="[825,948,1176,1198]" captionStart-0="Figure 1" captionStart-1="Figure 2" captionStart-2="Figure 3" captionStartId-0="1.[117,181,1505,1527]" captionStartId-1="2.[144,208,1762,1784]" captionStartId-2="3.[117,181,1752,1774]" captionTargetBox-0="[246,1342,173,1458]" captionTargetBox-1="[316,1342,167,1714]" captionTargetBox-2="[269,1338,187,1723]" captionTargetId-0="figure@1.[230,1372,163,1486]" captionTargetId-1="figure@2.[316,1342,167,1728]" captionTargetId-2="figure@3.[266,1338,180,1724]" captionTargetPageId-0="1" captionTargetPageId-1="2" captionTargetPageId-2="3" captionText-0="Figure 1. Cleveland tyrannosaur skull, CMNH 7541. Stereophotographs of skull in A, left lateral view; B, right lateral view. Orientations reflect posture with lateral semicircular canal horizontal. Scale bars equal 10 cm." captionText-1="Figure 2. Cleveland tyrannosaur skull, CMNH 7541. Stereophotographs of A, close-up of left antorbital region; B, skull in rostral view; C, skull in ventral view. Orientations reflect posture with lateral semicircular canal horizontal. Scale bars equal 10 cm." captionText-2="Figure 3. Cleveland tyrannosaur skull, CMNH 7541. Stereophotographs of A, skull in dorsal view; B, skull in caudal view; C, close-up of cranial base in ventral view. Orientations reflect posture with lateral semicircular canal horizontal. Scale bars equal 10 cm." figureDoi-0="http://doi.org/10.5281/zenodo.3898948" figureDoi-1="http://doi.org/10.5281/zenodo.3898950" figureDoi-2="http://doi.org/10.5281/zenodo.3898952" httpUri-0="https://zenodo.org/record/3898948/files/figure.png" httpUri-1="https://zenodo.org/record/3898950/files/figure.png" httpUri-2="https://zenodo.org/record/3898952/files/figure.png" pageId="15" pageNumber="76">Figures 1–3</figureCitation>
|
||
), details of the tooth-bearing portions are not easily observed. Thus, obtaining information on the common comparative metric of number of tooth positions had been impossible for
|
||
<materialsCitation id="3B203CD402340C1AE724ABE4FC62FAEE" ID-GBIF-Occurrence="2636386344" box="[818,956,1264,1286]" collectionCode="CMNH" pageId="15" pageNumber="76" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
. To remedy this situation, we digitally extracted the right mandible because the dental region is better preserved (
|
||
<figureCitation id="13732A0C02340C1AE72FAA3FFC7FFAA9" box="[825,929,1323,1345]" captionStart="Figure 15" captionStartId="17.[117,181,1119,1141]" captionTargetBox="[282,1330,180,1083]" captionTargetId="figure@17.[280,1330,180,1096]" captionTargetPageId="17" captionText="Figure 15. Cleveland tyrannosaur skull, CMNH 7541. Volume renderings of digitally extracted right mandible derived from CT data in A, dorsal; B, medial; C, lateral views. A–C are stereopairs. D, close-up of mandible in lateral view; numbers correspond to tooth positions, of which there are 16. Scale bars equal 10 cm." figureDoi="http://doi.org/10.5281/zenodo.3898978" httpUri="https://zenodo.org/record/3898978/files/figure.png" pageId="15" pageNumber="76">Figure 15</figureCitation>
|
||
).
|
||
<materialsCitation id="3B203CD402340C1AE7A1AA3FFB9CFAA9" ID-GBIF-Occurrence="2636386333" box="[951,1090,1323,1345]" collectionCode="CMNH" pageId="15" pageNumber="76" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
has at least 16 relatively clear tooth positions, which is similar to
|
||
<materialsCitation id="3B203CD402340C1AE048AA5DFADBFAB6" ID-GBIF-Occurrence="2636386364" box="[1118,1285,1352,1374]" collectionCode="BMR" pageId="15" pageNumber="76" specimenCode="BMR P2002.4.1">BMR P2002.4.1</materialsCitation>
|
||
, which has 16 or 17 (P.
|
||
<bibRefCitation id="EFD94B7802340C1AE740AA72FC3EFA93" author="Larson, N. L." box="[854,992,1381,1403]" editor="P. L. Larson & K. Carpenter" firstAuthor="Larson" journalOrPublisher="Indiana University Press, Bloomington" pageId="15" pageNumber="76" pagination="1 - 61" refId="ref11773" refString="Larson, N. L. 2008. One hundred years of Tyrannosaurus rex: the skeletons, p. 1 - 61. In P. L. Larson and K. Carpenter (eds.), Tyrannosaurus rex, the Tyrant King. Indiana University Press, Bloomington." title="One hundred years of Tyrannosaurus rex: the skeletons" type="book chapter" volumeTitle="Tyrannosaurus rex, the Tyrant King" year="2008">Larson, 2008</bibRefCitation>
|
||
). For comparison,
|
||
<bibRefCitation id="EFD94B7802340C1AE0B5AA71FAC0FA93" author="Holtz, T. R." box="[1187,1310,1381,1403]" editor="D. B. Weishampel & P. Dodson & H. Osmolska" firstAuthor="Holtz" journalOrPublisher="University of California Press, Berkeley" pageId="15" pageNumber="76" pagination="111 - 136" refId="ref11572" refString="Holtz, T. R. 2004. Tyrannosauroidea, p. 111 - 136. In D. B. Weishampel, P. Dodson, and H. Osmolska (eds.), The Dinosauria. University of California Press, Berkeley." title="Tyrannosauroidea" type="book chapter" volumeTitle="The Dinosauria" year="2004">Holtz (2004</bibRefCitation>
|
||
, p. 119) provided a range among tyrannosaurids of 18 in
|
||
<emphasis id="B93CEA9B02340C1AE0D2AA97FA93FA70" box="[1220,1357,1411,1432]" italics="true" pageId="15" pageNumber="76">Alectrosaurus</emphasis>
|
||
and 11 in
|
||
<taxonomicName id="4C484D0A02340C1AE1AFAA90FC8DFA5E" authorityName="Osborn" authorityYear="1905" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="15" pageNumber="76" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02340C1AE1AFAA90FC8DFA5E" italics="true" pageId="15" pageNumber="76">T. rex</emphasis>
|
||
</taxonomicName>
|
||
.
|
||
<bibRefCitation id="EFD94B7802340C1AE772AAB5FBA6FA5E" author="Hurum, J. H. & K. Sabath" box="[868,1144,1440,1462]" firstAuthor="Hurum" journalOrPublisher="Acta Palaeontologica Polonica" pageId="15" pageNumber="76" pagination="161 - 190" part="48" refId="ref11731" refString="Hurum, J. H., and K. Sabath. 2003. Giant theropod dinosaurs from Asia and North America: skulls of Tarbosaurus bataar and Tyrannosaurus rex compared. Acta Palaeontologica Polonica, 48: 161 - 190." title="Giant theropod dinosaurs from Asia and North America: skulls of Tarbosaurus bataar and Tyrannosaurus rex compared" type="journal article" year="2003">Hurum and Sabath (2003</bibRefCitation>
|
||
, p. 187) reported 12–14 dentary tooth positions in
|
||
<taxonomicName id="4C484D0A02340C1AE7FAAAABFBF4FA3C" authorityName="Osborn" authorityYear="1905" box="[1004,1066,1471,1492]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="15" pageNumber="76" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02340C1AE7FAAAABFBF4FA3C" box="[1004,1066,1471,1492]" italics="true" pageId="15" pageNumber="76">T. rex</emphasis>
|
||
</taxonomicName>
|
||
and 14–15 in
|
||
<taxonomicName id="4C484D0A02340C1AE0A1AAAAFAEDFA3B" box="[1207,1331,1470,1491]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="15" pageNumber="76" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02340C1AE0A1AAAAFAEDFA3B" box="[1207,1331,1470,1491]" italics="true" pageId="15" pageNumber="76">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
.
|
||
<bibRefCitation id="EFD94B7802340C1AE157AAAAFA0EFA3C" author="Russell, D. A." box="[1345,1488,1470,1492]" firstAuthor="Russell" journalOrPublisher="National Museums of Canada Publications in Paleontology" pageId="15" pageNumber="76" pagination="1 - 34" part="1" refId="ref12278" refString="Russell, D. A. 1970. Tyrannosaurs from the Late Cretaceous of western Canada. National Museums of Canada Publications in Paleontology, 1: 1 - 34." title="Tyrannosaurs from the Late Cretaceous of western Canada" type="journal article" year="1970">Russell (1970)</bibRefCitation>
|
||
reported 15–16 for
|
||
<taxonomicName id="4C484D0A02340C1AE012AACFFB42FA18" authorityName="Russell" authorityYear="1970" box="[1028,1180,1499,1520]" class="Reptilia" family="Tyrannosauridae" genus="Daspletosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="15" pageNumber="76" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02340C1AE012AACFFB42FA18" box="[1028,1180,1499,1520]" italics="true" pageId="15" pageNumber="76">Daspletosaurus</emphasis>
|
||
</taxonomicName>
|
||
. Thus,
|
||
<materialsCitation id="3B203CD402340C1AE0E4AACFFAA3FA19" ID-GBIF-Occurrence="2636386362" box="[1266,1405,1499,1521]" collectionCode="CMNH" pageId="15" pageNumber="76" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
is fully within the range of
|
||
<taxonomicName id="4C484D0A02340C1AE7EFAAECFB74F9E6" box="[1017,1194,1528,1550]" class="Reptilia" family="Tyrannosauridae" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="15" pageNumber="76" phylum="Chordata" rank="family">Tyrannosauridae</taxonomicName>
|
||
, but does not overlap
|
||
<taxonomicName id="4C484D0A02340C1AE19AAAEDFA14F9E6" authorityName="Osborn" authorityYear="1905" box="[1420,1482,1529,1550]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="15" pageNumber="76" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02340C1AE19AAAEDFA14F9E6" box="[1420,1482,1529,1550]" italics="true" pageId="15" pageNumber="76">T. rex</emphasis>
|
||
</taxonomicName>
|
||
. Significantly,
|
||
<bibRefCitation id="EFD94B7802340C1AE7D4A902FB4DF9C4" author="Tsuihiji, T. & M. Watabe & L. M. Witmer & T. Tsubamoto & K. Tsogtbaatar" box="[962,1171,1558,1580]" etAl="et al." firstAuthor="Tsuihiji" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="15" pageNumber="76" pagination="160 A" part="27 (Supplement to 3)" refId="ref12554" refString="Tsuihiji, T., M. Watabe, L. M. Witmer, T. Tsubamoto, and K. Tsogtbaatar. 2007. A juvenile skeleton of Tarbosaurus with a nearly complete skull and its implications for ontogenetic change in tyrannosaurids. Journal of Vertebrate Paleontology, 27 (Supplement to 3), 160 A." title="A juvenile skeleton of Tarbosaurus with a nearly complete skull and its implications for ontogenetic change in tyrannosaurids" type="journal article" year="2007">Tsuihiji et al. (2007</bibRefCitation>
|
||
; in review) reported the exact same range of dentary tooth positions (14–15) in a very young specimen of
|
||
<taxonomicName id="4C484D0A02340C1AE7A1A945FBEDF98E" box="[951,1075,1617,1638]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="15" pageNumber="76" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02340C1AE7A1A945FBEDF98E" box="[951,1075,1617,1638]" italics="true" pageId="15" pageNumber="76">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
<bibRefCitation id="EFD94B7802340C1AE02BA945FAAEF98F" author="Hurum, J. H. & K. Sabath" box="[1085,1392,1617,1639]" firstAuthor="as Hurum" journalOrPublisher="Acta Palaeontologica Polonica" pageId="15" pageNumber="76" pagination="161 - 190" part="48" refId="ref11731" refString="Hurum, J. H., and K. Sabath. 2003. Giant theropod dinosaurs from Asia and North America: skulls of Tarbosaurus bataar and Tyrannosaurus rex compared. Acta Palaeontologica Polonica, 48: 161 - 190." title="Giant theropod dinosaurs from Asia and North America: skulls of Tarbosaurus bataar and Tyrannosaurus rex compared" type="journal article" year="2003">as Hurum and Sabath (2003)</bibRefCitation>
|
||
reported for adult
|
||
<taxonomicName id="4C484D0A02340C1AE782A97AFBCEF96B" box="[916,1040,1646,1667]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="15" pageNumber="76" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B02340C1AE782A97AFBCEF96B" box="[916,1040,1646,1667]" italics="true" pageId="15" pageNumber="76">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
, suggesting no ontogenetic change in tooth counts in this species that is so closely related to
|
||
<taxonomicName id="4C484D0A02340C1AE13CA998FAB7F949" authorityName="Osborn" authorityYear="1905" box="[1322,1385,1676,1697]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="15" pageNumber="76" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02340C1AE13CA998FAB7F949" box="[1322,1385,1676,1697]" italics="true" pageId="15" pageNumber="76">T. rex</emphasis>
|
||
</taxonomicName>
|
||
, and thus diminishing the case for
|
||
<materialsCitation id="3B203CD402340C1AE024A9BDFB64F957" ID-GBIF-Occurrence="2636386305" box="[1074,1210,1705,1727]" collectionCode="CMNH" pageId="15" pageNumber="76" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
being a young
|
||
<taxonomicName id="4C484D0A02340C1AE14AA9BEFA42F957" authorityName="Osborn" authorityYear="1905" box="[1372,1436,1706,1727]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="15" pageNumber="76" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B02340C1AE14AA9BEFA42F957" box="[1372,1436,1706,1727]" italics="true" pageId="15" pageNumber="76">T. rex</emphasis>
|
||
</taxonomicName>
|
||
.
|
||
</paragraph>
|
||
<paragraph id="8BF7368902340C1AE050A9FCFB65F8E8" blockId="15.[818,1488,1768,2001]" box="[1094,1211,1768,1792]" pageId="15" pageNumber="76">
|
||
<heading id="D0BF81E502340C1AE050A9FCFB65F8E8" bold="true" box="[1094,1211,1768,1792]" centered="true" fontSize="10" level="1" pageId="15" pageNumber="76" reason="0">
|
||
<emphasis id="B93CEA9B02340C1AE050A9FCFB65F8E8" bold="true" box="[1094,1211,1768,1792]" pageId="15" pageNumber="76">Discussion</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BF7368902340C05E75CA81FFC6AFCD1" blockId="15.[818,1488,1768,2001]" lastBlockId="16.[845,1515,186,2001]" lastPageId="16" lastPageNumber="77" pageId="15" pageNumber="76">
|
||
The preceding sections have sought to provide anatomical details of the Cleveland tyrannosaur skull (
|
||
<materialsCitation id="3B203CD402340C1AE111A83CFA4AF8D6" ID-GBIF-Occurrence="2636386337" box="[1287,1428,1832,1854]" collectionCode="CMNH" pageId="15" pageNumber="76" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
) that have not been previously widely available (or available at all). CT scanning—and, more significantly, 3D visualization of the CT scan data—has yielded a new look at this famous fossil. For many workers, the systematic question is paramount, but it is obvious that the ontogenetic question is inextricably linked to any systematic outcome. That is, are the differences observed in
|
||
<materialsCitation id="3B203CD4022B0C05E75BAFC3FC0AFF05" ID-GBIF-Occurrence="2636386354" box="[845,980,215,237]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
attributable to its apparent young age or to it being a different taxon or both? Some of the different ideas were presented in the Introduction, and no firm resolution is offered here, in part because other data pertinent to this debate have yet to be published. Most significant is the discovery of a skull and associated partial postcranium (
|
||
<materialsCitation id="3B203CD4022B0C05E0B4AE7EFA93FE68" ID-GBIF-Occurrence="2636386313" box="[1186,1357,362,384]" collectionCode="BMR" pageId="16" pageNumber="77" specimenCode="BMR P2002.4.1">BMR P2002.4.1</materialsCitation>
|
||
) of an animal that is very similar to
|
||
<materialsCitation id="3B203CD4022B0C05E020AE9CFB61FE76" ID-GBIF-Occurrence="2636386308" box="[1078,1215,392,414]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
and which will be critical in providing information from the postcranial skeleton that could be relevant to the systematic question. Moreover, there are other, still unpublished skulls of young and juvenile tyrannosaurids (
|
||
<bibRefCitation id="EFD94B78022B0C05E745AEE9FBECFDFB" author="Tsuihiji, T. & M. Watabe & L. M. Witmer & T. Tsubamoto & K. Tsogtbaatar" box="[851,1074,509,531]" etAl="et al." firstAuthor="Tsuihiji" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="16" pageNumber="77" pagination="160 A" part="27 (Supplement to 3)" refId="ref12554" refString="Tsuihiji, T., M. Watabe, L. M. Witmer, T. Tsubamoto, and K. Tsogtbaatar. 2007. A juvenile skeleton of Tarbosaurus with a nearly complete skull and its implications for ontogenetic change in tyrannosaurids. Journal of Vertebrate Paleontology, 27 (Supplement to 3), 160 A." title="A juvenile skeleton of Tarbosaurus with a nearly complete skull and its implications for ontogenetic change in tyrannosaurids" type="journal article" year="2007">Tsuihiji et al., 2007</bibRefCitation>
|
||
; in review; N.
|
||
<bibRefCitation id="EFD94B78022B0C05E0F2AEEAFAABFDFB" author="Larson, N. L." box="[1252,1397,509,531]" editor="P. L. Larson & K. Carpenter" firstAuthor="Larson" journalOrPublisher="Indiana University Press, Bloomington" pageId="16" pageNumber="77" pagination="1 - 61" refId="ref11773" refString="Larson, N. L. 2008. One hundred years of Tyrannosaurus rex: the skeletons, p. 1 - 61. In P. L. Larson and K. Carpenter (eds.), Tyrannosaurus rex, the Tyrant King. Indiana University Press, Bloomington." title="One hundred years of Tyrannosaurus rex: the skeletons" type="book chapter" volumeTitle="Tyrannosaurus rex, the Tyrant King" year="2008">Larson, 2008</bibRefCitation>
|
||
;
|
||
<bibRefCitation id="EFD94B78022B0C05E190AEE9FBDFFDD8" author="Carr, T. D. & T. E. Williamson" firstAuthor="Carr" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="16" pageNumber="77" pagination="1 - 16" part="30" refId="ref11050" refString="Carr, T. D., and T. E. Williamson. 2010. Bistahieversor sealeyi, gen. et sp. nov., a new tyrannosauroid from New Mexico and the origin of deep snouts in Tyrannosauroidea. Journal of Vertebrate Paleontology, 30: 1 - 16." title="Bistahieversor sealeyi, gen. et sp. nov., a new tyrannosauroid from New Mexico and the origin of deep snouts in Tyrannosauroidea" type="journal article" year="2010">Carr and Williamson, 2010</bibRefCitation>
|
||
) that can shed light on patterns of ontogenetic transformation and help with discrimination of primitive versus juvenile characters. Other unpublished, clearly adult specimens have raised the prospect of there being species of tyrannosaurids in the Hell Creek other than
|
||
<taxonomicName id="4C484D0A022B0C05E06CAD85FB67FD4E" authorityName="Osborn" authorityYear="1905" box="[1146,1209,657,678]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="16" pageNumber="77" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B022B0C05E06CAD85FB67FD4E" box="[1146,1209,657,678]" italics="true" pageId="16" pageNumber="77">T. rex</emphasis>
|
||
</taxonomicName>
|
||
(N.
|
||
<bibRefCitation id="EFD94B78022B0C05E0FCAD85FAAAFD4E" author="Larson, N. L." box="[1258,1396,656,678]" editor="P. L. Larson & K. Carpenter" firstAuthor="Larson" journalOrPublisher="Indiana University Press, Bloomington" pageId="16" pageNumber="77" pagination="1 - 61" refId="ref11773" refString="Larson, N. L. 2008. One hundred years of Tyrannosaurus rex: the skeletons, p. 1 - 61. In P. L. Larson and K. Carpenter (eds.), Tyrannosaurus rex, the Tyrant King. Indiana University Press, Bloomington." title="One hundred years of Tyrannosaurus rex: the skeletons" type="book chapter" volumeTitle="Tyrannosaurus rex, the Tyrant King" year="2008">Larson, 2008</bibRefCitation>
|
||
; P.
|
||
<bibRefCitation id="EFD94B78022B0C05E18DAD85FC5FFD2B" author="Larson, N. L." editor="P. L. Larson & K. Carpenter" firstAuthor="Larson" journalOrPublisher="Indiana University Press, Bloomington" pageId="16" pageNumber="77" pagination="1 - 61" refId="ref11773" refString="Larson, N. L. 2008. One hundred years of Tyrannosaurus rex: the skeletons, p. 1 - 61. In P. L. Larson and K. Carpenter (eds.), Tyrannosaurus rex, the Tyrant King. Indiana University Press, Bloomington." title="One hundred years of Tyrannosaurus rex: the skeletons" type="book chapter" volumeTitle="Tyrannosaurus rex, the Tyrant King" year="2008">Larson, 2008</bibRefCitation>
|
||
). The question in this case would be, do these specimens display attributes of
|
||
<materialsCitation id="3B203CD4022B0C05E03FADDFFB6CFD09" ID-GBIF-Occurrence="2636386359" box="[1065,1202,715,737]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
that might indicate that they are adult
|
||
<taxonomicName id="4C484D0A022B0C05E7A4ADFDFB41FD15" authority="Bakker, Currie & Williams, 1988" authorityName="Bakker, Currie & Williams" authorityYear="1988" box="[946,1183,744,766]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="16" pageNumber="77" phylum="Chordata" rank="species" species="lancensis">
|
||
<emphasis id="B93CEA9B022B0C05E7A4ADFDFB41FD15" box="[946,1183,744,766]" italics="true" pageId="16" pageNumber="77">Nanotyrannus lancensis</emphasis>
|
||
</taxonomicName>
|
||
? Until these new specimens are analyzed and published, the status of
|
||
<materialsCitation id="3B203CD4022B0C05E0CEAC11FABFFCF3" ID-GBIF-Occurrence="2636386326" box="[1240,1377,773,795]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
must remain uncertain.
|
||
</paragraph>
|
||
<paragraph id="8BF73689022B0C05E773AC55FBEDFA12" blockId="16.[845,1515,186,2001]" pageId="16" pageNumber="77">
|
||
Having said that, the foregoing discussions have revealed an interesting suite of apparently derived attributes observed in
|
||
<materialsCitation id="3B203CD4022B0C05E75BAC68FC03FC7A" ID-GBIF-Occurrence="2636386377" box="[845,989,892,914]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
that might suggest that it represents a taxon separate from
|
||
<taxonomicName id="4C484D0A022B0C05E7FCAC8EFBF3FC47" authorityName="Osborn" authorityYear="1905" box="[1002,1069,922,943]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="16" pageNumber="77" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B022B0C05E7FCAC8EFBF3FC47" box="[1002,1069,922,943]" italics="true" pageId="16" pageNumber="77">T. rex</emphasis>
|
||
</taxonomicName>
|
||
. For example, the patterns of pneumatic sinuses and their bony apertures in the braincase are quite distinct from other tyrannosaurids. Although pneumatic sinuses certainly can change ontogenetically (
|
||
<bibRefCitation id="EFD94B78022B0C05E066ACE5FADEFBEF" author="Witmer, L. M." box="[1136,1280,1009,1031]" firstAuthor="Witmer" journalOrPublisher="Zoological Journal of the Linnean Society" pageId="16" pageNumber="77" pagination="327 - 378" part="100" refId="ref12693" refString="Witmer, L. M. 1990. The craniofacial air sac system of Mesozoic birds (Aves). Zoological Journal of the Linnean Society, 100: 327 - 378." title="The craniofacial air sac system of Mesozoic birds (Aves)" type="journal article" year="1990">Witmer, 1990</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFD94B78022B0C05E11CACE5FA96FBEF" author="Witmer, L. M." box="[1290,1352,1009,1031]" firstAuthor="Witmer" journalOrPublisher="Society of Vertebrate Paleontology Memoir" pageId="16" pageNumber="77" pagination="1 - 73" part="3" refId="ref12726" refString="Witmer, L. M. 1997 a. The evolution of the antorbital cavity of archosaurs: a study in soft-tissue reconstruction in the fossil record with an analysis of the function of pneumaticity. Society of Vertebrate Paleontology Memoir, 3: 1 - 73." title="The evolution of the antorbital cavity of archosaurs: a study in soft-tissue reconstruction in the fossil record with an analysis of the function of pneumaticity" type="journal article" year="1997" yearSuffix="a">1997a</bibRefCitation>
|
||
, b;
|
||
<bibRefCitation id="EFD94B78022B0C05E179ACE5FC35FBCD" author="Witmer, L. M. & R. C. Ridgely" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="16" pageNumber="77" pagination="1362 - 1388" part="291" refId="ref12912" refString="Witmer, L. M., and R. C. Ridgely. 2008 b. The paranasal air sinuses of predatory and armored dinosaurs (Archosauria: Theropoda and Ankylosauria) and their contribution to cephalic architecture. Anatomical Record, 291: 1362 - 1388." title="The paranasal air sinuses of predatory and armored dinosaurs (Archosauria: Theropoda and Ankylosauria) and their contribution to cephalic architecture" type="journal article" year="2008" yearSuffix="b">Witmer and Ridgely, 2008b</bibRefCitation>
|
||
; and references therein), most of the changes in later ontogeny of most taxa pertain to expansion, contraction, and/or communication of sinuses and not to the basic pattern of bony apertures. For example,
|
||
<taxonomicName id="4C484D0A022B0C05E096AB73FB20FB94" authorityName="Lambe" authorityYear="1914" baseAuthorityName="Lambe" baseAuthorityYear="2009" box="[1152,1278,1127,1148]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="16" pageNumber="77" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B022B0C05E096AB73FB20FB94" box="[1152,1278,1127,1148]" italics="true" pageId="16" pageNumber="77">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<taxonomicName id="4C484D0A022B0C05E126AB7CFA1AFB95" authorityName="Osborn" authorityYear="1905" box="[1328,1476,1128,1149]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="16" pageNumber="77" phylum="Chordata" rank="genus">
|
||
<emphasis id="B93CEA9B022B0C05E126AB7CFA1AFB95" box="[1328,1476,1128,1149]" italics="true" pageId="16" pageNumber="77">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
are more similar to each other in their patterns of basicranial pneumatic foramina than either is to the highly asymmetrical apertures of
|
||
<materialsCitation id="3B203CD4022B0C05E7DBABABFB88FB3D" ID-GBIF-Occurrence="2636386363" box="[973,1110,1215,1237]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, and there is no evidence to suggest that either of the two named taxa went through an ontogenetic stage resembling
|
||
<materialsCitation id="3B203CD4022B0C05E7D5ABEDFB90FAE7" ID-GBIF-Occurrence="2636386301" box="[963,1102,1273,1295]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
. Likewise, the broad communication of the caudal tympanic recess and lateral subcondylar recess in
|
||
<materialsCitation id="3B203CD4022B0C05E75BAA20FC0AFAA2" ID-GBIF-Occurrence="2636386361" box="[845,980,1332,1354]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
is unique among tyrannosaurs sampled thus far. To these apparent apomorphies can be added the findings from the brain endocast of
|
||
<materialsCitation id="3B203CD4022B0C05E01EAA7BFB4EFA6D" ID-GBIF-Occurrence="2636386338" box="[1032,1168,1391,1413]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
(
|
||
<bibRefCitation id="EFD94B78022B0C05E080AA7BFA75FA6D" author="Witmer, L. M. & R. C. Ridgely" box="[1174,1451,1391,1413]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="16" pageNumber="77" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
), such as the rostrally offset pituitary fossa and orbital cranial nerve canals, as well as the strongly downturned endocast and skull as a whole, as indicated by the orientation of the lateral semicircular canal of the inner ear.
|
||
</paragraph>
|
||
</subSubSection>
|
||
<subSubSection id="C3526502022B0C05E773A917FA1AF9F1" box="[869,1476,1539,1561]" lastPageId="16" lastPageNumber="78" pageId="16" pageNumber="77" type="nomenclature">
|
||
<paragraph id="8BF73689022B0C05E773A917FA1AF9F1" blockId="16.[845,1515,186,2001]" box="[869,1476,1539,1561]" pageId="16" pageNumber="77">
|
||
Although many workers have been struck by the
|
||
<taxonomicName id="4C484D0A022B0C05E16AA910FA60F9F1" authorityName="Osborn" authorityYear="1905" box="[1404,1470,1540,1561]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="16" pageNumber="77" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B022B0C05E16AA910FA60F9F1" box="[1404,1470,1540,1561]" italics="true" pageId="16" pageNumber="77">T. rex</emphasis>
|
||
</taxonomicName>
|
||
-
|
||
</paragraph>
|
||
</subSubSection>
|
||
<subSubSection id="C3526502022B0C04E1D2A917FCD6F8F6" lastPageId="17" lastPageNumber="78" pageId="16" pageNumber="77" type="discussion">
|
||
<paragraph id="8BF73689022B0C04E1D2A917FCD6F8F6" blockId="16.[845,1515,186,2001]" lastBlockId="17.[117,787,1294,2001]" lastPageId="17" lastPageNumber="78" pageId="16" pageNumber="77">
|
||
like temporal expansion of
|
||
<materialsCitation id="3B203CD4022B0C05E05FA934FB06F9DE" ID-GBIF-Occurrence="2636386318" box="[1097,1240,1568,1590]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
, this derived character is coupled with a series of primitive attributes, such as the narrow and lanceolate vomer, the uncompressed basisphenoid recess, the pattern of pneumatic apertures in the subcondylar recess, the strength of the condylotuberal crest, the low cultriform process and small subsellar recess, the laterally positioned vagus foramen, and the high number of dentary tooth positions. Although the possibility cannot be ruled out, it seems hard to believe that the animal pertaining to
|
||
<materialsCitation id="3B203CD4022B0C05E024A81FFB60F8C9" ID-GBIF-Occurrence="2636386373" box="[1074,1214,1803,1825]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
would have ontogenetically transformed all of these attributes (both primitive and derived) and grown up to be a typical member of
|
||
<taxonomicName id="4C484D0A022B0C05E134A853FA3AF8B4" authorityName="Osborn" authorityYear="1905" box="[1314,1508,1863,1884]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="16" pageNumber="77" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B022B0C05E134A853FA3AF8B4" box="[1314,1508,1863,1884]" italics="true" pageId="16" pageNumber="77">Tyrannosaurus rex</emphasis>
|
||
</taxonomicName>
|
||
.
|
||
<materialsCitation id="3B203CD4022B0C05E75BA877FC0BF891" ID-GBIF-Occurrence="2636386328" box="[845,981,1891,1913]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
does not pertain to a hatchling, but rather a fairly mature (‘‘teenage’’) animal, though perhaps not yet in the exponential stage of growth (in the sense of
|
||
<bibRefCitation id="EFD94B78022B0C05E155A88AFC5FF839" author="Erickson, G. M. & P. J. Makovicky & P. J. Currie & M. A. Norell & S. A. Yerby & C. A. Brochu" etAl="et al." firstAuthor="Erickson" journalOrPublisher="Nature" pageId="16" pageNumber="77" pagination="772 - 775" part="430" refId="ref11317" refString="Erickson, G. M., P. J. Makovicky, P. J. Currie, M. A. Norell, S. A. Yerby, and C. A. Brochu. 2004. Gigantism and comparative life-history parameters of tyrannosaurid dinosaurs. Nature, 430: 772 - 775." title="Gigantism and comparative life-history parameters of tyrannosaurid dinosaurs" type="journal article" year="2004">Erickson et al., 2004</bibRefCitation>
|
||
), and thus it is hard to envision such major morphological changes. Certainly, significant morphological changes can take place in animals at nearly adult age, as
|
||
<bibRefCitation id="EFD94B78022A0C04E61AAA38FD75FAAA" author="Sampson, S. D." box="[524,683,1324,1346]" firstAuthor="Sampson" journalOrPublisher="Historical Biology" pageId="17" pageNumber="78" pagination="173 - 197" part="13" refId="ref12309" refString="Sampson, S. D. 1999. Sex and destiny: the role of mating signals in speciation and macroevolution. Historical Biology, 13: 173 - 197." title="Sex and destiny: the role of mating signals in speciation and macroevolution" type="journal article" year="1999">Sampson (1999</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFD94B78022A0C04E6A1AA38FD34FAAA" author="Sampson, S. D." box="[695,746,1324,1346]" editor="D. Tanke & K. Carpenter" firstAuthor="Sampson" journalOrPublisher="Indiana University Press, Bloomington" pageId="17" pageNumber="78" pagination="263 - 276" refId="ref12340" refString="Sampson, S. D. 2001. Speculations on the socioecology of ceratopsid dinosaurs (Ornithischia: Neoceratopsia), p. 263 - 276. In D. Tanke and K. Carpenter (eds.), Mesozoic Vertebrate Life. Indiana University Press, Bloomington." title="Speculations on the socioecology of ceratopsid dinosaurs (Ornithischia: Neoceratopsia)" type="book chapter" volumeTitle="Mesozoic Vertebrate Life" year="2001">2001</bibRefCitation>
|
||
; see also
|
||
<bibRefCitation id="EFD94B78022A0C04E4B3AA5EFEA5FA88" author="Sampson, S. D. & M. J. Ryan & D. H. Tanke" box="[165,379,1354,1376]" etAl="et al." firstAuthor="Sampson" journalOrPublisher="Zoological Journal of the Linnean Society" pageId="17" pageNumber="78" pagination="293 - 337" part="221" refId="ref12435" refString="Sampson, S. D., M. J. Ryan, and D. H. Tanke. 1997. Craniofacial ontogeny in centrosaurine dinosaurs (Ornithischia: Ceratopsidae): taxonomic and behavioral implications. Zoological Journal of the Linnean Society, 221: 293 - 337." title="Craniofacial ontogeny in centrosaurine dinosaurs (Ornithischia: Ceratopsidae): taxonomic and behavioral implications" type="journal article" year="1997">Sampson et al., 1997</bibRefCitation>
|
||
) showed for ceratopsids in which many of the attributes relating to sexual display develop at essentially adult body sizes (see also
|
||
<bibRefCitation id="EFD94B78022A0C04E580AA92FD1BFA73" author="Horner, J. R. & M. B. Goodwin" box="[406,709,1413,1435]" firstAuthor="Horner" journalOrPublisher="Proceedings of the Royal Society B" pageId="17" pageNumber="78" pagination="2757 - 2761" part="273" refId="ref11648" refString="Horner, J. R., and M. B. Goodwin. 2006. Major cranial changes during Triceratops ontogeny. Proceedings of the Royal Society B, 273: 2757 - 2761." title="Major cranial changes during Triceratops ontogeny" type="journal article" year="2006">Horner and Goodwin, 2006</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFD94B78022A0C04E6C2AA91FCD6FA73" author="Horner, J. R. & M. B. Goodwin" box="[724,776,1413,1435]" firstAuthor="Horner" journalOrPublisher="PLoS ONE" pageId="17" pageNumber="78" pagination="e 7626" part="4" refId="ref11684" refString="Horner, J. R., and M. B. Goodwin. 2009. Extreme cranial ontogeny in the Upper Cretaceous dinosaur Pachycephalosaurus. PLoS ONE, 4 (10), e 7626. doi: 10.1371 / journal. pone. 0007626." title="Extreme cranial ontogeny in the Upper Cretaceous dinosaur Pachycephalosaurus" type="journal article" year="2009">2009</bibRefCitation>
|
||
). Obviously, few if any of the features listed above for
|
||
<materialsCitation id="3B203CD4022A0C04E69BAAB7FCCDFA51" ID-GBIF-Occurrence="2636386307" box="[653,787,1443,1465]" collectionCode="CMNH" pageId="17" pageNumber="78" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
are of the type that would either be recruited for sexual display or are even remotely related to secondary sexual characteristics. We (
|
||
<bibRefCitation id="EFD94B78022A0C04E46AAAE8FE4CF9FA" author="Witmer, L. M. & R. C. Ridgely" box="[124,402,1532,1554]" firstAuthor="Witmer" journalOrPublisher="Anatomical Record" pageId="17" pageNumber="78" pagination="1266 - 1296" part="292" refId="ref12961" refString="Witmer, L. M., and R. C. Ridgely. 2009. New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior. Anatomical Record, 292: 1266 - 1296." title="New insights into the brain, braincase, and ear region of tyrannosaurs, with implications for sensory organization and behavior" type="journal article" year="2009">Witmer and Ridgely, 2009</bibRefCitation>
|
||
) previously evaluated in some detail other means of explaining our findings, such as diagenetic distortion or pathology, but neither explanation is compelling. That said, we recognize that some aspects of
|
||
<materialsCitation id="3B203CD4022A0C04E648A941FD37F983" ID-GBIF-Occurrence="2636386331" box="[606,745,1621,1643]" collectionCode="CMNH" pageId="17" pageNumber="78" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
are unusual enough that its being simply aberrant may always remain possible, which is why we have never stated definitively that it is not a juvenile
|
||
<taxonomicName id="4C484D0A022A0C04E512A9A4FE9FF92D" authorityName="Osborn" authorityYear="1905" box="[260,321,1712,1733]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="17" pageNumber="78" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B022A0C04E512A9A4FE9FF92D" box="[260,321,1712,1733]" italics="true" pageId="17" pageNumber="78">T. rex</emphasis>
|
||
</taxonomicName>
|
||
. Ultimately, until the known but unpublished specimens are fully analyzed, we regard the taxonomic status of
|
||
<materialsCitation id="3B203CD4022A0C04E463A9FEFEDFF8E8" ID-GBIF-Occurrence="2636386321" box="[117,257,1770,1792]" collectionCode="CMNH" pageId="17" pageNumber="78" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
to be an open question, being either a separate taxon (
|
||
<taxonomicName id="4C484D0A022A0C04E4A9A81DFE72F8F5" authority="Bakker, Currie & Williams, 1988" authorityName="Bakker, Currie & Williams" authorityYear="1988" box="[191,428,1800,1822]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="17" pageNumber="78" phylum="Chordata" rank="species" species="lancensis">
|
||
<emphasis id="B93CEA9B022A0C04E4A9A81DFE72F8F5" box="[191,428,1800,1822]" italics="true" pageId="17" pageNumber="78">Nanotyrannus lancensis</emphasis>
|
||
</taxonomicName>
|
||
) or a juvenile
|
||
<taxonomicName id="4C484D0A022A0C04E653A81DFCDCF8F6" authorityName="Osborn" authorityYear="1905" box="[581,770,1801,1822]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="17" pageNumber="78" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B93CEA9B022A0C04E653A81DFCDCF8F6" box="[581,770,1801,1822]" italics="true" pageId="17" pageNumber="78">Tyrannosaurus rex</emphasis>
|
||
</taxonomicName>
|
||
.
|
||
</paragraph>
|
||
</subSubSection>
|
||
<caption id="DF376601022B0C05E486A980FE0CF8B2" ID-DOI="http://doi.org/10.5281/zenodo.3898976" ID-Zenodo-Dep="3898976" httpUri="https://zenodo.org/record/3898976/files/figure.png" pageId="16" pageNumber="77" startId="16.[144,208,1684,1706]" targetBox="[167,791,185,1654]" targetPageId="16">
|
||
<paragraph id="8BF73689022B0C05E486A980FE0CF8B2" blockId="16.[144,813,1684,1882]" pageId="16" pageNumber="77">
|
||
<emphasis id="B93CEA9B022B0C05E486A980FF23F942" bold="true" box="[144,253,1684,1706]" pageId="16" pageNumber="77">Figure 14.</emphasis>
|
||
Cleveland tyrannosaur skull,
|
||
<materialsCitation id="3B203CD4022B0C05E647A980FD3CF942" ID-GBIF-Occurrence="2636386375" box="[593,738,1684,1706]" collectionCode="CMNH" pageId="16" pageNumber="77" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
. A–D, progressively more caudal CT slices through the snout at the position shown in E, showing structures interpretable as respiratory turbinates (arrows). Note that some symmetry is preserved in A and B. In C, a structure (arrow) can be seen to cross a crack. D shows a series of structures associated with the maxilla. Scale bar equals 1 cm.
|
||
</paragraph>
|
||
</caption>
|
||
<caption id="DF376601022A0C04E463AB4BFD61FB58" ID-DOI="http://doi.org/10.5281/zenodo.3898978" ID-Zenodo-Dep="3898978" httpUri="https://zenodo.org/record/3898978/files/figure.png" pageId="17" pageNumber="78" startId="17.[117,181,1119,1141]" targetBox="[282,1330,180,1083]" targetPageId="17">
|
||
<paragraph id="8BF73689022A0C04E463AB4BFD61FB58" blockId="17.[117,1488,1119,1200]" pageId="17" pageNumber="78">
|
||
<emphasis id="B93CEA9B022A0C04E463AB4BFF04FB9D" bold="true" box="[117,218,1119,1141]" pageId="17" pageNumber="78">Figure 15.</emphasis>
|
||
Cleveland tyrannosaur skull,
|
||
<materialsCitation id="3B203CD4022A0C04E61DAB4BFD4AFB9D" ID-GBIF-Occurrence="2636386340" box="[523,660,1119,1141]" collectionCode="CMNH" pageId="17" pageNumber="78" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
. Volume renderings of digitally extracted right mandible derived from CT data in A, dorsal; B, medial; C, lateral views. A–C are stereopairs. D, close-up of mandible in lateral view; numbers correspond to tooth positions, of which there are 16. Scale bars equal 10 cm.
|
||
</paragraph>
|
||
</caption>
|
||
<subSubSection id="C3526502022A0C04E49BA832FB48F94A" lastPageId="17" lastPageNumber="78" pageId="17" pageNumber="77" type="discussion">
|
||
<paragraph id="8BF73689022A0C04E49BA832FB48F94A" blockId="17.[117,787,1294,2001]" lastBlockId="17.[818,1488,1294,1698]" pageId="17" pageNumber="78">
|
||
Finally, given the finding here of structures interpretable as respiratory turbinates, it is tempting to make broader claims about metabolic physiology and endothermy. We hesitate to do so, because the skull has only a small area well enough preserved to make such assessments, and we would prefer to be able to sample more widely within the nasal cavity. Nevertheless, taking our data at face value, it is difficult to explain the laminar structures within the nasal airway as anything else. They are not artifacts of the CT scanning process, nor are they sedimentary structures. In fact, such structures are found nowhere else in the entire dataset. Assuming that they are indeed real structures projecting into the nasal airway and covered with moist mucosal respiratory epithelium, it is hard to imagine how they would
|
||
<emphasis id="B93CEA9B022A0C04E1A6AAABFA0EFA3C" box="[1456,1488,1471,1492]" italics="true" pageId="17" pageNumber="78">not</emphasis>
|
||
function as counter-current heat exchangers, precisely as postulated by Ruben and colleagues (1996, 1997). Whether or not these structures are indeed causally associated osteological correlates of endothermy or whether these supposed turbinates are extensive enough to have the effect posited by
|
||
<bibRefCitation id="EFD94B78022A0C04E0BDA945FAB1F98F" author="Ruben, J. A. & W. J. Hillenius & N. R. Geist & A. Leitch & T. D. Jones & P. J. Currie & J. R. Horner & G. Espe III." box="[1195,1391,1617,1639]" etAl="et al." firstAuthor="Ruben" journalOrPublisher="Science" pageId="17" pageNumber="78" pagination="1204 - 1207" part="273" refId="ref12137" refString="Ruben, J. A., W. J. Hillenius, N. R. Geist, A. Leitch, T. D. Jones, P. J. Currie, J. R. Horner, and G. Espe III. 1996. The metabolic status of some Late Cretaceous dinosaurs. Science, 273: 1204 - 1207." title="The metabolic status of some Late Cretaceous dinosaurs" type="journal article" year="1996">Ruben et al. (1996)</bibRefCitation>
|
||
is harder to say, but certainly it now seems unreasonable to argue that such structures are absent in dinosaurs.
|
||
</paragraph>
|
||
</subSubSection>
|
||
</treatment>
|
||
</document> |