881 lines
119 KiB
XML
881 lines
119 KiB
XML
<document id="7C847DD47F26BDCFEFC15FBE2DA5EB96" ID-DOI="10.1126/science.1193304" ID-GBIF-Dataset="7578fc2c-3631-4bb4-96b6-0783a099c26b" ID-Zenodo-Dep="3744287" IM.metadata_requiresApprovalFor="plazi" IM.taxonomicNames_requiresApprovalFor="plazi" IM.treatments_requiresApprovalFor="plazi" checkinTime="1586340223561" checkinUser="jeremy" docAuthor="Stephen L. Brusatte, Mark A. Norell, Thomas D. Carr, Gregory M. Erickson, John R. Hutchinson, Amy M. Balanoff, Gabe S. Bever, Jonah N. Choiniere, Peter J. Makovicky & Xing Xu" docDate="2010" docId="03F35F238F44C006E135FED78BC9D855" docLanguage="en" docName="Brusatteetal2010.pdf.imf" docOrigin="Science 329" docStyle="DocumentStyle{}" docTitle="Tyrannosaur Paleobiology: New Research on Ancient Exemplar Organisms" docType="treatment" docVersion="7" lastPageNumber="1485" masterDocId="FFCA275B8F45C003E500FF9C882ADA6A" masterDocTitle="Tyrannosaur Paleobiology: New Research on Ancient Exemplar Organisms" masterLastPageNumber="1485" masterPageNumber="1481" pageNumber="1481" updateTime="1698736444923" updateUser="plazi">
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<mods:titleInfo id="0C64A083F19FED4515C4337958AA94CF">
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<mods:title id="28AEA5F85DC3009C6D781DEE7041FE01">Tyrannosaur Paleobiology: New Research on Ancient Exemplar Organisms</mods:title>
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<mods:name id="11CA9F94C03B49B2384E0C4F98766E46" type="personal">
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<mods:roleTerm id="A50D5762FD55ECC6086B1540BF44486B">Author</mods:roleTerm>
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<mods:namePart id="E74DF28DC4C335CA98F9A3E60061F9DA">Stephen L. Brusatte</mods:namePart>
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<mods:affiliation id="5AAB48E37DCE33CD3DC4D4D4234D4303">Division of Paleontology, AmericanMuseumof Natural History, Central Park West at 79 th Street, New York, NY 10024, USA. Department of Earth and Environmental Sciences, Columbia University, New York, NY 10964, USA.</mods:affiliation>
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<mods:nameIdentifier id="2D15065AFEB2640571053ED4F0B3B5FC" type="email">sbrusatte@amnh.org</mods:nameIdentifier>
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<mods:roleTerm id="0E0B25E81D9D665ECE724DED0B27B54D">Author</mods:roleTerm>
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<mods:namePart id="4CB225557D818224818F8AEAC4C4AA56">Mark A. Norell</mods:namePart>
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<mods:affiliation id="C2D5ED9FAB01C90CE14CF57A774D0856">Division of Paleontology, AmericanMuseumof Natural History, Central Park West at 79 th Street, New York, NY 10024, USA.</mods:affiliation>
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<mods:namePart id="0D7265DD56C4E65D14961A7B04DF8ABA">Thomas D. Carr</mods:namePart>
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<mods:affiliation id="E72C74D7680F4C028EF0695C978234A2">Department of Biology, Carthage College, Kenosha, WI 53140, USA.</mods:affiliation>
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</mods:name>
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<mods:roleTerm id="340B95970EA664FB4C70E30B9E3A69D0">Author</mods:roleTerm>
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<mods:namePart id="1B113508EDAD3C033451FE02ED2FA90B">Gregory M. Erickson</mods:namePart>
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<mods:affiliation id="134BC4A97242C7501CB87FD1BF191A59">Division of Paleontology, AmericanMuseumof Natural History, Central Park West at 79 th Street, New York, NY 10024, USA. Department of Biological Science, Florida StateUniversity, Tallahassee, FL 32306, USA.</mods:affiliation>
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</mods:name>
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<mods:namePart id="52A8A5C20DC6715A0F8C39F16B06DB60">John R. Hutchinson</mods:namePart>
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<mods:affiliation id="2AC6BC26C487303780E20340BA864304">Department of Veterinary Basic Sciences, The Royal Veterinary College, Hatfield, Herts AL 9 7 TA, UK.</mods:affiliation>
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<mods:namePart id="15580538EDCEAC2274259564977B2467">Amy M. Balanoff</mods:namePart>
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<mods:affiliation id="5BEB186966DE04A11CDA18F758604DCA">Division of Paleontology, AmericanMuseumof Natural History, Central Park West at 79 th Street, New York, NY 10024, USA. Department of Earth and Environmental Sciences, Columbia University, New York, NY 10964, USA.</mods:affiliation>
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<mods:namePart id="82C7F563E1A0B40656EEFA93EDD8BC5E">Gabe S. Bever</mods:namePart>
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<mods:affiliation id="1551631A126F3513B0754E0C0D222530">Department of Geology and Geophysics, Yale University, New Haven, CT 06520, USA.</mods:affiliation>
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<mods:namePart id="BC3561C3474E91BBF8F06E251A909D5B">Jonah N. Choiniere</mods:namePart>
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<mods:affiliation id="85E2AE90243A911B5228B3B2B1A1E01A">Division of Paleontology, AmericanMuseumof Natural History, Central Park West at 79 th Street, New York, NY 10024, USA. Department of Biological Sciences, The George Washington University, Washington, DC 20052, USA.</mods:affiliation>
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<mods:name id="2F13613415BDC7FE62FBDC1D543918DC" type="personal">
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<mods:namePart id="FE7F3A042986561FBCA44AB50E0130CA">Peter J. Makovicky</mods:namePart>
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<mods:affiliation id="2023088EACF508BB8D0549995FB6FF11">Department of Geology, The Field Museum of Natural History, Chicago, IL 60605, USA.</mods:affiliation>
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<mods:namePart id="04C1E07B86BB68D954C95431879AAC44">Xing Xu</mods:namePart>
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<mods:affiliation id="647F96C949B3C99A047F6330E1FA6F59">Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, People’s Republic of China.</mods:affiliation>
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<mods:title id="906A64C1A9D59250D5F4C4D95F378438">Science</mods:title>
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<mods:date id="E34CD0E141A7665D5CEBBE6D848C3AE1">2010</mods:date>
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<mods:number id="A0B2FB0FE3BD083F12B020E02F3D4AB7">329</mods:number>
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<mods:classification id="8D14381ACCB69A780B1C1CBF2BB7D368">journal article</mods:classification>
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<mods:identifier id="CC4F41E93689A450F14F797442753724" type="DOI">10.1126/science.1193304</mods:identifier>
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<treatment id="03F35F238F44C006E135FED78BC9D855" ID-DOI="http://doi.org/10.5281/zenodo.3809613" ID-GBIF-Taxon="163640473" ID-Zenodo-Dep="3809613" LSID="urn:lsid:plazi:treatment:03F35F238F44C006E135FED78BC9D855" httpUri="http://treatment.plazi.org/id/03F35F238F44C006E135FED78BC9D855" lastPageId="5" lastPageNumber="1485" pageId="1" pageNumber="1481">
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<subSubSection id="C340BDBE8F44C002E135FED78D73DB81" pageId="1" pageNumber="1481" type="discussion">
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<paragraph id="8BE5EE358F44C002E135FED78D73DB81" blockId="1.[1045,1488,136,491]" pageId="1" pageNumber="1481">Here we assess the current state of tyrannosaur research, with a focus on the phylogenetic relationships and large-scale evolutionary patterns exhibited by the group, the biology of tyrannosaurs as living organisms, and information revealed from the newest discoveries.</paragraph>
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</subSubSection>
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<subSubSection id="C340BDBE8F44C002E115FD958C9BD850" pageId="1" pageNumber="1481" type="nomenclature">
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<paragraph id="8BE5EE358F44C002E115FD958C9BD850" blockId="1.[1045,1488,521,826]" pageId="1" pageNumber="1481">
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<emphasis id="B92E32278F44C002E115FD958C9BD850" bold="true" pageId="1" pageNumber="1481">Phylogenetic Relationships and Evolution of Tyrannosaurs</emphasis>
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</paragraph>
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</subSubSection>
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<paragraph id="8BE5EE358F44C001E115FDDA89ECDA9A" blockId="1.[1045,1488,521,826]" lastBlockId="2.[96,539,108,1579]" lastPageId="2" lastPageNumber="1482" pageId="1" pageNumber="1481">
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Tyrannosaurs, which formally comprise the clade
|
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<taxonomicName id="4C5A95B68F44C002E115FDFE8C90D81D" box="[1045,1210,610,631]" kingdom="Animalia" order="Dinosauria" pageId="1" pageNumber="1481" phylum="Chordata" rank="superFamily" superFamily="Tyrannosauroidea">Tyrannosauroidea</taxonomicName>
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, are a relatively derived group of theropod dinosaurs, more closely related to birds than to other large theropods such as allosauroids and spinosaurids (
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<emphasis id="B92E32278F44C002E030FD2A8D11D8A1" box="[1328,1339,694,715]" italics="true" pageId="1" pageNumber="1481">1</emphasis>
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,
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<bibRefCitation id="EFCB93C48F44C002E04DFD2A8D4ED8A1" author="T. R. Holtz" box="[1357,1380,694,715]" editor="D. B. Weishampel & P. Dodson & H. Osmolska" journalOrPublisher="Univ. of California Press, Berkeley" pageId="1" pageNumber="1481" pagination="111 - 136" part="2" refId="ref5482" refString="17. T. R. Holtz, in The Dinosauria, D. B. Weishampel, P. Dodson, H. Osmolska, Eds. (Univ. of California Press, Berkeley, ed. 2, 2004), pp. 111 - 136." type="journal article" volumeTitle="The Dinosauria" year="2004">
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<emphasis id="B92E32278F44C002E04DFD2A8D4ED8A1" box="[1357,1380,694,715]" italics="true" pageId="1" pageNumber="1481">17</emphasis>
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</bibRefCitation>
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).
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<subSubSection id="C340BDBE8F44C001E07DFD2A89ECDA9A" lastPageId="2" lastPageNumber="1482" pageId="1" pageNumber="1481" type="description">
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Approximately 20 tyrannosauroid genera are currently known, 5 of which were described during the past year. To assess their interrelationships, we conducted a phylogenetic analysis, which includes all well-known genera scored for 307 morphological characters (
|
||
<emphasis id="B92E32278F47C001E5C7FF1488F4DAF7" box="[199,222,136,157]" italics="true" pageId="2" pageNumber="1482">18</emphasis>
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). The data set is based on personal observation of specimens and includes 123 novel characters (40% of total) based on recently discovered tyrannosaur taxa (
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<bibRefCitation id="EFCB93C48F47C001E469FF47895EDA9A" author="P. C. Sereno" box="[361,372,219,240]" journalOrPublisher="Science" pageId="2" pageNumber="1482" pagination="418" part="326" refId="ref5155" refString="4. P. C. Sereno et al., Science 326, 418 (2009)." type="journal article" year="2009">
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<emphasis id="B92E32278F47C001E469FF47895EDA9A" box="[361,372,219,240]" italics="true" pageId="2" pageNumber="1482">4</emphasis>
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</bibRefCitation>
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,
|
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<emphasis id="B92E32278F47C001E481FF478990DA9A" box="[385,442,218,240]" italics="true" pageId="2" pageNumber="1482">
|
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<bibRefCitation id="EFCB93C48F47C001E481FF4789B2DA9A" author="S. L. Brusatte & T. D. Carr & G. M. Erickson & G. S. Bever & M. A. Norell" box="[385,408,219,240]" journalOrPublisher="Proc. Natl. Acad. Sci. U. S. A." pageId="2" pageNumber="1482" pagination="17261" part="106" refId="ref5542" refString="19. S. L. Brusatte, T. D. Carr, G. M. Erickson, G. S. Bever, M. A. Norell, Proc. Natl. Acad. Sci. U. S. A. 106, 17261 (2009)." type="journal article" year="2009">19</bibRefCitation>
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–
|
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<bibRefCitation id="EFCB93C48F47C001E4A3FF478990DA9A" author="D. Li & M. A. Norell & K. Q. Gao & N. D. Smith & P. J. Makovicky" box="[419,442,219,240]" journalOrPublisher="Proc. Biol. Sci." pageId="2" pageNumber="1482" pagination="183" part="277" refId="ref5622" refString="21. D. Li, M. A. Norell, K. Q. Gao, N. D. Smith, P. J. Makovicky, Proc. Biol. Sci. 277, 183 (2010)." type="journal article" year="2010">21</bibRefCitation>
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</emphasis>
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).
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||
</subSubSection>
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</paragraph>
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<footnote id="E841F23B8F44C002E560FA47888ADD47" pageId="1" pageNumber="1481">
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Division of Paleontologyι American Museum of Natural Historyι central Park West at 79th Streetι New Yorkι NY 10024ι USA.
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Department of Earth and Environmental Sciencesι columbia Universityι New Yorkι NY 10964ι USA.
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Department of Biologyι carthage collegeι Kenoshaι WI 53140ι USA.
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Department of Biological Scienceι Florida State Universityι Tallahasseeι FL 32306ι USA.
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Department of Veterinary Basic Sciencesι The Royal Veterinary collegeι Hatfieldι Herts AL9 7TAι UK.
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Department of Geology and Geophysicsι Yale Universityι New Havenι cT 06520ι USA.
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Department of Biological Sciencesι The George Washington Universityι Washingtonι Dc 20052ι USA.
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<superScript id="7C2F437D8F44C002E473F9218950DCA2" attach="right" box="[371,378,1725,1736]" fontSize="5" pageId="1" pageNumber="1481">8</superScript>
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Department of Geologyι The Field Museum of Natural Historyι chicagoι IL 60605ι USA.
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Institute of Vertebrate Paleontology and Paleoanthropologyι chinese Academy of Sciencesι Beijing 100044ι People’ s Republic of china.
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</paragraph>
|
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</footnote>
|
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<caption id="DF25BEBD8F44C002E73BF9138D23DD10" ID-DOI="http://doi.org/10.5281/zenodo.3744289" ID-Zenodo-Dep="3744289" httpUri="https://zenodo.org/record/3744289/files/figure.png" pageId="1" pageNumber="1481" startId="1.[571,606,1679,1701]" targetBox="[576,1485,848,1650]" targetPageId="1">
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<paragraph id="8BE5EE358F44C002E73BF9138D23DD10" blockId="1.[571,1489,1679,1914]" pageId="1" pageNumber="1481">
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Fig. 1. The anatomy of tyrannosaurs, showing the variety of skeletal and cranial morphology in the group. (A) A skeletal reconstruction of
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<emphasis id="B92E32278F44C002E64DF9378B89DCAA" bold="true" box="[845,931,1707,1728]" italics="true" pageId="1" pageNumber="1481">Alioramus</emphasis>
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, a gracile and long-snouted tyrannosaurid, which exhibits many features of the generalized tyrannosaurid body plan (large skull, small arms, long hindlimbs, long tail). (B to D) skulls of the basal tyrannosauroids
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<emphasis id="B92E32278F44C002E687F97C8BF0DC9F" bold="true" box="[903,986,1760,1781]" italics="true" pageId="1" pageNumber="1481">Guanlong</emphasis>
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(B),
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<emphasis id="B92E32278F44C002E105F97C8C17DC9F" bold="true" box="[1029,1085,1760,1781]" italics="true" pageId="1" pageNumber="1481">Dilong</emphasis>
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(C), and
|
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<emphasis id="B92E32278F44C002E18DF97C8D2FDC9F" bold="true" box="[1165,1285,1760,1781]" italics="true" pageId="1" pageNumber="1481">Bistahieversor</emphasis>
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(D). (E and F) skulls of juvenile (E) and adult (F)
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<taxonomicName id="4C5A95B68F44C002E60EF9678BA1DD7A" authority="Osborn, 1905" box="[782,907,1787,1808]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="1" pageNumber="1481" phylum="Chordata" rank="genus">
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<emphasis id="B92E32278F44C002E60EF9678BA1DD7A" bold="true" box="[782,907,1787,1808]" italics="true" pageId="1" pageNumber="1481">Tyrannosaurus</emphasis>
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</taxonomicName>
|
||
scaled to the same length, illustrating the transition from a longer to a deeper skull during ontogeny. All scale bars equal 10 cm. Credits:F. Ippolito, American Museum of Natural History (AMNH) (A); I. Block, National Geographic stock (B); M. Ellison, AMNH (C); D. Baccadutre, New Mexico Museum of Natural History and science (D); s. Williams, Burpee Museum of Natural History (E); AMNH Photo Archives (#2752,
|
||
<taxonomicName id="4C5A95B68F44C002E64AF8F98BEDDD10" authority="Osborn, 1905" box="[842,967,1893,1914]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="1" pageNumber="1481" phylum="Chordata" rank="genus">
|
||
<emphasis id="B92E32278F44C002E64AF8F98BEDDD10" bold="true" box="[842,967,1893,1914]" italics="true" pageId="1" pageNumber="1481">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
skull as mounted in the old hall) (F).
|
||
</paragraph>
|
||
</caption>
|
||
<footnote id="E841F23B8F44C002E560F8A689F9DD12" pageId="1" pageNumber="1481">
|
||
<paragraph id="8BE5EE358F44C002E560F8A688D4DD08" blockId="1.[96,541,1850,1913]" pageId="1" pageNumber="1481">*To whom correspondence should be addressed. E-mail: sbrusatte@amnh.org</paragraph>
|
||
<paragraph id="8BE5EE358F44C002E560F8FB89F9DD12" blockId="1.[96,541,1850,1913]" box="[96,467,1895,1913]" pageId="1" pageNumber="1481">†These authors contributed equally to this work.</paragraph>
|
||
</footnote>
|
||
<paragraph id="8BE5EE358F47C001E580FF6B89E1D950" blockId="2.[96,539,108,1579]" pageId="2" pageNumber="1482">
|
||
<taxonomicName id="4C5A95B68F47C001E580FF6B88D1DB66" authority="Osborn, 1905" box="[128,251,247,268]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="2" pageNumber="1482" phylum="Chordata" rank="genus">Tyrannosaurs</taxonomicName>
|
||
are a long-lived group that originated by the Middle Jurassic, ~165 million years ago (
|
||
<bibRefCitation id="EFCB93C48F47C001E5C4FEB388E5DB2E" author="O. W. M. Rauhut & A. C. Milner & S. Moore-Fay" box="[196,207,303,324]" journalOrPublisher="Zool. J. Linn. Soc" pageId="2" pageNumber="1482" pagination="155" part="158" refId="ref5174" refString="5. O. W. M. Rauhut, A. C. Milner, S. Moore-Fay, Zool. J. Linn. Soc. 158, 155 (2010)." type="journal article" year="2010">
|
||
<emphasis id="B92E32278F47C001E5C4FEB388E5DB2E" box="[196,207,303,324]" italics="true" pageId="2" pageNumber="1482">5</emphasis>
|
||
</bibRefCitation>
|
||
) (
|
||
<figureCitation id="1361F2B08F47C001E5E4FEB38931DB2E" box="[228,283,303,324]" captionStart="Fig. 2" captionStartId="2.[571,606,1387,1409]" captionTargetBox="[559,1535,68,1380]" captionTargetId="graphics@2.[792,1479,141,1369]" captionTargetPageId="2" captionText="Fig. 2. Phylogenetic relationships of tyrannosauroid theropodsι assessed by a cladistic analysis (18). single most parsimonious treeι showing the relationships of 19 tyrannosaursι scaled to the geologic time scale (in millions of years agoι Ma). Taxa in blue are those that have been described during the past year. silhouettes indicate relative body size (based on femur length as a proxy). Thick red bars indicate major ghost lineages. Thick black bars represent the finest age resolution for each taxonι not actual duration." figureDoi="http://doi.org/10.5281/zenodo.3744291" httpUri="https://zenodo.org/record/3744291/files/figure.png" pageId="2" pageNumber="1482">Fig. 2</figureCitation>
|
||
). The oldest and most basal tyrannosaurs comprise a speciose subclade,
|
||
<taxonomicName id="4C5A95B68F47C001E4E1FED788E4DB16" class="Reptilia" family="Proceratosauridae" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="2" pageNumber="1482" phylum="Chordata" rank="family">Proceratosauridae</taxonomicName>
|
||
, which includes mostly small-bodied animals no larger than a human, many of which possessed elaborate cranial crests (
|
||
<bibRefCitation id="EFCB93C48F47C001E4A2FE028993DBD9" author="X. Xu" box="[418,441,414,435]" journalOrPublisher="Nature" pageId="2" pageNumber="1482" pagination="715" part="439" refId="ref5665" refString="22. X. Xu et al., Nature 439, 715 (2006)." type="journal article" year="2006">
|
||
<emphasis id="B92E32278F47C001E4A2FE028993DBD9" box="[418,441,414,435]" italics="true" pageId="2" pageNumber="1482">22</emphasis>
|
||
</bibRefCitation>
|
||
). Progressively more derived tyrannosaurs form a pectinate series on the line toward
|
||
<taxonomicName id="4C5A95B68F47C001E438FE4A89E1DB81" box="[312,459,470,491]" class="Reptilia" family="Tyrannosauridae" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="2" pageNumber="1482" phylum="Chordata" rank="family">Tyrannosauridae</taxonomicName>
|
||
, the subclade of multi-ton, deep-skulled behemoths from the terminal Cretaceous (Campanian-Maastrichtian), including
|
||
<taxonomicName id="4C5A95B68F47C001E5BCFDB6896ED855" authority="Osborn, 1905" box="[188,324,554,575]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="2" pageNumber="1482" phylum="Chordata" rank="genus">
|
||
<emphasis id="B92E32278F47C001E5BCFDB6896ED855" box="[188,324,554,575]" italics="true" pageId="2" pageNumber="1482">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName id="4C5A95B68F47C001E451FDB689E9D855" authorityName="Maleev" authorityYear="1955" box="[337,451,554,575]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="2" pageNumber="1482" phylum="Chordata" rank="genus">
|
||
<emphasis id="B92E32278F47C001E451FDB689E9D855" box="[337,451,554,575]" italics="true" pageId="2" pageNumber="1482">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName id="4C5A95B68F47C001E4D0FDB688B7D831" authorityName="Osborn" authorityYear="1905" class="Reptilia" family="Tyrannosauridae" genus="Albertosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="2" pageNumber="1482" phylum="Chordata" rank="genus">
|
||
<emphasis id="B92E32278F47C001E4D0FDB688B7D831" italics="true" pageId="2" pageNumber="1482">Albertosaurus</emphasis>
|
||
</taxonomicName>
|
||
, and close relatives (
|
||
<emphasis id="B92E32278F47C001E45EFDDA8943D831" box="[350,361,582,603]" italics="true" pageId="2" pageNumber="1482">1</emphasis>
|
||
). Taxa phylogenetically intermediate between proceratosaurids and tyrannosaurids include a range of genera from the Late Jurassic–early Late Cretaceous of Asia, North America, and Europe, most of which have been recently discovered (
|
||
<bibRefCitation id="EFCB93C48F47C001E41CFD4D890DD88C" author="P. C. Sereno" box="[284,295,721,742]" journalOrPublisher="Science" pageId="2" pageNumber="1482" pagination="418" part="326" refId="ref5155" refString="4. P. C. Sereno et al., Science 326, 418 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F47C001E41CFD4D890DD88C" box="[284,295,721,742]" italics="true" pageId="2" pageNumber="1482">4</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F47C001E433FD4D8960D88C" author="X. Xu" box="[307,330,721,742]" journalOrPublisher="Nature" pageId="2" pageNumber="1482" pagination="680" part="431" refId="ref5406" refString="14. X. Xu et al., Nature 431, 680 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F47C001E433FD4D8960D88C" box="[307,330,721,742]" italics="true" pageId="2" pageNumber="1482">14</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F47C001E455FD4D8946D88C" author="T. D. Carr & T. E. Williamson" box="[341,364,721,742]" journalOrPublisher="J. Vertebr. Paleontol." pageId="2" pageNumber="1482" pagination="1" part="30" refId="ref5595" refString="20. T. D. Carr, T. E. Williamson, J. Vertebr. Paleontol. 30, 1 (2010)." type="journal article" year="2010">
|
||
<emphasis id="B92E32278F47C001E455FD4D8946D88C" box="[341,364,721,742]" italics="true" pageId="2" pageNumber="1482">20</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F47C001E477FD4D89A4D88C" author="D. Li & M. A. Norell & K. Q. Gao & N. D. Smith & P. J. Makovicky" box="[375,398,721,742]" journalOrPublisher="Proc. Biol. Sci." pageId="2" pageNumber="1482" pagination="183" part="277" refId="ref5622" refString="21. D. Li, M. A. Norell, K. Q. Gao, N. D. Smith, P. J. Makovicky, Proc. Biol. Sci. 277, 183 (2010)." type="journal article" year="2010">
|
||
<emphasis id="B92E32278F47C001E477FD4D89A4D88C" box="[375,398,721,742]" italics="true" pageId="2" pageNumber="1482">21</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F47C001E499FD4D899AD88C" author="S. Hutt & D. W. Naish & D. M. Martill & M. J. Barker & P. Newberry" box="[409,432,721,742]" journalOrPublisher="Cretac. Res" pageId="2" pageNumber="1482" pagination="227" part="22" refId="ref5682" refString="23. S. Hutt, D. W. Naish, D. M. Martill, M. J. Barker, P. Newberry, Cretac. Res. 22, 227 (2001)." type="journal article" year="2001">
|
||
<emphasis id="B92E32278F47C001E499FD4D899AD88C" box="[409,432,721,742]" italics="true" pageId="2" pageNumber="1482">23</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F47C001E4BBFD4D89F8D88C" author="R. B. J. Benson & J. Vertebr" box="[443,466,721,742]" journalOrPublisher="Paleontol" pageId="2" pageNumber="1482" pagination="732" part="28" refId="ref5721" refString="24. R. B. J. Benson, J. Vertebr. Paleontol. 28, 732 (2008)." type="journal article" year="2008">
|
||
<emphasis id="B92E32278F47C001E4BBFD4D89F8D88C" box="[443,466,721,742]" italics="true" pageId="2" pageNumber="1482">24</emphasis>
|
||
</bibRefCitation>
|
||
). These taxa run the gamut from small to medium size (~1.4 to 9.0 m in length), and few were likely apex predators in their ecosystems (
|
||
<bibRefCitation id="EFCB93C48F47C001E4A7FCB98994D950" author="D. Li & M. A. Norell & K. Q. Gao & N. D. Smith & P. J. Makovicky" box="[423,446,805,826]" journalOrPublisher="Proc. Biol. Sci." pageId="2" pageNumber="1482" pagination="183" part="277" refId="ref5622" refString="21. D. Li, M. A. Norell, K. Q. Gao, N. D. Smith, P. J. Makovicky, Proc. Biol. Sci. 277, 183 (2010)." type="journal article" year="2010">
|
||
<emphasis id="B92E32278F47C001E4A7FCB98994D950" box="[423,446,805,826]" italics="true" pageId="2" pageNumber="1482">21</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F47C001E580FCDD89F3DC41" blockId="2.[96,539,108,1579]" pageId="2" pageNumber="1482">
|
||
Until recently, the prevailing notion was that tyrannosaur body size gradually, and progressively, increased over time, in concert with the piecemeal accumulation of signature tyrannosaur skeletal features (
|
||
<bibRefCitation id="EFCB93C48F47C001E5FFFC2D893CD9AC" author="X. Xu" box="[255,278,945,966]" journalOrPublisher="Nature" pageId="2" pageNumber="1482" pagination="680" part="431" refId="ref5406" refString="14. X. Xu et al., Nature 431, 680 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F47C001E5FFFC2D893CD9AC" box="[255,278,945,966]" italics="true" pageId="2" pageNumber="1482">14</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F47C001E422FC2D8913D9AC" author="D. Li & M. A. Norell & K. Q. Gao & N. D. Smith & P. J. Makovicky" box="[290,313,945,966]" journalOrPublisher="Proc. Biol. Sci." pageId="2" pageNumber="1482" pagination="183" part="277" refId="ref5622" refString="21. D. Li, M. A. Norell, K. Q. Gao, N. D. Smith, P. J. Makovicky, Proc. Biol. Sci. 277, 183 (2010)." type="journal article" year="2010">
|
||
<emphasis id="B92E32278F47C001E422FC2D8913D9AC" box="[290,313,945,966]" italics="true" pageId="2" pageNumber="1482">21</emphasis>
|
||
</bibRefCitation>
|
||
). However, new discoveries have led to a reassessment. The Early Cretaceous proceratosaurid
|
||
<emphasis id="B92E32278F47C001E440FC748992D997" box="[320,440,1000,1021]" italics="true" pageId="2" pageNumber="1482">Sinotyrannus</emphasis>
|
||
may have approached 10 m in body length, demonstrating that tyrannosaurs could attain a large size early in their history (
|
||
<bibRefCitation id="EFCB93C48F47C001E5DCFBA088D9DE3B" author="Q. Ji & S. - A. Ji & L. - J. Zhang" box="[220,243,1084,1105]" journalOrPublisher="Geol. Bull. China" pageId="2" pageNumber="1482" pagination="1369" part="28" refId="ref5744" refString="25. Q. Ji, S. - A. Ji, L. - J. Zhang, Geol. Bull. China 28, 1369 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F47C001E5DCFBA088D9DE3B" box="[220,243,1084,1105]" italics="true" pageId="2" pageNumber="1482">25</emphasis>
|
||
</bibRefCitation>
|
||
). More striking, the close tyrannosaurid outgroup
|
||
<emphasis id="B92E32278F47C001E40DFBC48977DE07" box="[269,349,1112,1133]" italics="true" pageId="2" pageNumber="1482">Raptorex</emphasis>
|
||
is only 2 to 3 m in length, suggesting that there was great size variability among close tyrannosaurid relatives and perhaps that the immediate ancestors of tyrannosaurids were small animals (
|
||
<bibRefCitation id="EFCB93C48F47C001E468FB5B8959DEB6" author="P. C. Sereno" box="[360,371,1223,1244]" journalOrPublisher="Science" pageId="2" pageNumber="1482" pagination="418" part="326" refId="ref5155" refString="4. P. C. Sereno et al., Science 326, 418 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F47C001E468FB5B8959DEB6" box="[360,371,1223,1244]" italics="true" pageId="2" pageNumber="1482">4</emphasis>
|
||
</bibRefCitation>
|
||
). Truly enormous size, however, is restricted to the latest Cretaceous tyrannosaurids, some of which grew to lengths of 13 m and masses of 5 to 8 tons (
|
||
<bibRefCitation id="EFCB93C48F47C001E482FA8789A7DF5A" author="G. M. Erickson" box="[386,397,1307,1328]" journalOrPublisher="Nature" pageId="2" pageNumber="1482" pagination="772" part="430" refId="ref5257" refString="8. G. M. Erickson et al., Nature 430, 772 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F47C001E482FA8789A7DF5A" box="[386,397,1307,1328]" italics="true" pageId="2" pageNumber="1482">8</emphasis>
|
||
</bibRefCitation>
|
||
). Therefore, for the first 80 million years of their history tyrannosaurs were mostly small- to mid-sized animals that lived in the shadow of other giant predators (e.g., allosauroids, megalosauroids), and only during the final 20 million years of the Mesozoic did they develop into some of the largest terrestrial carnivores to ever live (
|
||
<bibRefCitation id="EFCB93C48F47C001E491FA438982DF9E" author="S. L. Brusatte" box="[401,424,1503,1524]" journalOrPublisher="Naturwissenschaften" pageId="2" pageNumber="1482" pagination="1051" part="96" refId="ref5776" refString="26. S. L. Brusatte et al., Naturwissenschaften 96, 1051 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F47C001E491FA438982DF9E" box="[401,424,1503,1524]" italics="true" pageId="2" pageNumber="1482">26</emphasis>
|
||
</bibRefCitation>
|
||
). The dominance of tyrannosaurs as megapredators was purely a latest Cretaceous phenomenon.
|
||
</paragraph>
|
||
<caption id="DF25BEBD8F47C001E73BFAF78DE1DF81" ID-DOI="http://doi.org/10.5281/zenodo.3744291" ID-Zenodo-Dep="3744291" httpUri="https://zenodo.org/record/3744291/files/figure.png" pageId="2" pageNumber="1482" startId="2.[571,606,1387,1409]" targetBox="[559,1535,68,1380]" targetPageId="2">
|
||
<paragraph id="8BE5EE358F47C001E73BFAF78DE1DF81" blockId="2.[571,1489,1387,1515]" pageId="2" pageNumber="1482">
|
||
<emphasis id="B92E32278F47C001E73BFAF78D86DFEB" bold="true" box="[571,1452,1387,1409]" pageId="2" pageNumber="1482">Fig. 2. Phylogenetic relationships of tyrannosauroid theropodsι assessed by a cladistic analysis (</emphasis>
|
||
<emphasis id="B92E32278F47C001E0ACFAF08DE9DFEB" box="[1452,1475,1388,1409]" italics="true" pageId="2" pageNumber="1482">18</emphasis>
|
||
). single most parsimonious treeι showing the relationships of 19 tyrannosaursι scaled to the geologic time scale (in millions of years agoι Ma). Taxa in blue are those that have been described during the past year. silhouettes indicate relative body size (based on femur length as a proxy). Thick red bars indicate major ghost lineages. Thick black bars represent the finest age resolution for each taxonι not actual duration.
|
||
</paragraph>
|
||
</caption>
|
||
<paragraph id="8BE5EE358F47C001E560F9D4891EDC37" blockId="2.[96,539,1608,1914]" box="[96,308,1608,1629]" pageId="2" pageNumber="1482">
|
||
<heading id="D0AD59598F47C001E560F9D4891EDC37" bold="true" box="[96,308,1608,1629]" fontSize="9" level="3" pageId="2" pageNumber="1482" reason="6">
|
||
<emphasis id="B92E32278F47C001E560F9D4891EDC37" bold="true" box="[96,308,1608,1629]" pageId="2" pageNumber="1482">Tyrannosaur Anatomy</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F47C001E560F9F68969DD10" blockId="2.[96,539,1608,1914]" pageId="2" pageNumber="1482">
|
||
The spate of new discoveries has prompted a renewed focus on tyrannosaur anatomy, including external, internal, and soft-tissue morphology (
|
||
<figureCitation id="1361F2B08F47C001E567F922888BDCB9" box="[103,161,1726,1747]" captionStart="Fig. 3" captionStartId="3.[453,488,1313,1335]" captionTargetBox="[455,1486,608,1295]" captionTargetId="figure@3.[455,1486,608,1295]" captionText="Fig. 3. Tyrannosaur soft tissuesι feedingι and locomotion. (A) CT imagery of internal pneumatic sinuses of the braincase of Alioramus altai (19). (B) Endocast of brainι cranial nervesι and semicircularcanals of A.altai (19). (C) Finite element analysis of a skull of T. rex (11ι 47)ι showing high stresses (red colors) in the nasal and cheek regions (courtesy of E. Rayfield).(D) Lacrimal of A. altai (reversed)ι showing pneumatic spaces that housed air sacs (credit:M. Ellison). (E) Feathery integument along the tail of Dilong paradoxus. (F) Three-dimensional biomechanical model based on muscle reconstruction of the right hindlimb of T. rex (16)ι used to assess running mechanics." figureDoi="http://doi.org/10.5281/zenodo.3744293" httpUri="https://zenodo.org/record/3744293/files/figure.png" pageId="2" pageNumber="1482">Fig. 3</figureCitation>
|
||
). All tyrannosaurs are bipedal predators and possess several unique features, including a small premaxilla with D-shaped “incisor”-like teeth, fused nasals, extreme pneumaticity in the skull roof and lower jaws, a pronounced muscle attachment ridge on the ilium, and an elevated femoral head (
|
||
<bibRefCitation id="EFCB93C48F47C001E5E5F8F988DADD10" author="A. Brochu" box="[229,240,1893,1914]" journalOrPublisher="Soc. Vert. Paleontol. Mem" pageId="2" pageNumber="1482" pagination="1" part="7" refId="ref5209" refString="6. C. A. Brochu, Soc. Vert. Paleontol. Mem. 7, 1 (2003)." type="journal article" year="2003">
|
||
<emphasis id="B92E32278F47C001E5E5F8F988DADD10" box="[229,240,1893,1914]" italics="true" pageId="2" pageNumber="1482">6</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F47C001E5FCF8F98939DD10" author="S. L. Brusatte" box="[252,275,1893,1914]" journalOrPublisher="Acta Palaeontol. Pol." pageId="2" pageNumber="1482" pagination="191" part="48" refId="ref5795" refString="27. P. J. Currie, Acta Palaeontol. Pol. 48, 191 (2003)." title="P. J. currie" type="journal article" year="2003">
|
||
<emphasis id="B92E32278F47C001E5FCF8F98939DD10" box="[252,275,1893,1914]" italics="true" pageId="2" pageNumber="1482">27</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F47C001E41FF8F9891CDD10" author="J. H. Hurum & K. Sabath" box="[287,310,1893,1914]" journalOrPublisher="Acta Palaeontol. Pol." pageId="2" pageNumber="1482" pagination="161" part="48" refId="ref5815" refString="28. J. H. Hurum, K. Sabath, Acta Palaeontol. Pol. 48, 161 (2003)." type="journal article" year="2003">
|
||
<emphasis id="B92E32278F47C001E41FF8F9891CDD10" box="[287,310,1893,1914]" italics="true" pageId="2" pageNumber="1482">28</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F47C000E75BF98A88F9DAF7" blockId="2.[571,1014,1558,1914]" lastPageId="3" lastPageNumber="1483" pageId="2" pageNumber="1482">
|
||
A number of derived specializations characterize the giant tyrannosaurids: a large and deep skull with powerful jaw muscles, robust teeth, reinforced sutures between skull bones, and tiny forelimbs (
|
||
<bibRefCitation id="EFCB93C48F47C001E7A1F91A8A86DCF1" author="A. Brochu" box="[673,684,1670,1691]" journalOrPublisher="Soc. Vert. Paleontol. Mem" pageId="2" pageNumber="1482" pagination="1" part="7" refId="ref5209" refString="6. C. A. Brochu, Soc. Vert. Paleontol. Mem. 7, 1 (2003)." type="journal article" year="2003">
|
||
<emphasis id="B92E32278F47C001E7A1F91A8A86DCF1" box="[673,684,1670,1691]" italics="true" pageId="2" pageNumber="1482">6</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F47C001E7BBF91A8AF8DCF1" author="R. E. Molnar" box="[699,722,1670,1691]" journalOrPublisher="Palaeont. A" pageId="2" pageNumber="1482" pagination="137" part="217" refId="ref5839" refString="29. R. E. Molnar, Palaeont. A 217, 137 (1991)." type="journal article" year="1991">
|
||
<emphasis id="B92E32278F47C001E7BBF91A8AF8DCF1" box="[699,722,1670,1691]" italics="true" pageId="2" pageNumber="1482">29</emphasis>
|
||
</bibRefCitation>
|
||
), features often considered adaptations for a hypercarnivore to function at large size (
|
||
<bibRefCitation id="EFCB93C48F47C001E79EF9228A83DCB9" author="P. C. Sereno" box="[670,681,1726,1747]" journalOrPublisher="Science" pageId="2" pageNumber="1482" pagination="418" part="326" refId="ref5155" refString="4. P. C. Sereno et al., Science 326, 418 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F47C001E79EF9228A83DCB9" box="[670,681,1726,1747]" italics="true" pageId="2" pageNumber="1482">4</emphasis>
|
||
</bibRefCitation>
|
||
). Basal tyrannosauroids, in contrast, have smaller skulls and longer arms and generally resemble sleek, bird-like theropods more than their enormous tyrannosaurid cousins (
|
||
<bibRefCitation id="EFCB93C48F47C001E6B3F88D8BE2DD4C" author="X. Xu" box="[947,968,1809,1830]" journalOrPublisher="Nature" pageId="2" pageNumber="1482" pagination="680" part="431" refId="ref5406" refString="14. X. Xu et al., Nature 431, 680 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F47C001E6B3F88D8BE2DD4C" box="[947,968,1809,1830]" italics="true" pageId="2" pageNumber="1482">14</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F47C001E6D3F88D8BC3DD4C" author="X. Xu" box="[979,1001,1809,1830]" journalOrPublisher="Nature" pageId="2" pageNumber="1482" pagination="715" part="439" refId="ref5665" refString="22. X. Xu et al., Nature 439, 715 (2006)." type="journal article" year="2006">
|
||
<emphasis id="B92E32278F47C001E6D3F88D8BC3DD4C" box="[979,1001,1809,1830]" italics="true" pageId="2" pageNumber="1482">22</emphasis>
|
||
</bibRefCitation>
|
||
). New discoveries have shown, however, that the hallmark tyrannosaurid body plan (large and deep skull, robust teeth, etc.) does not uniquely or uniformly characterize the tyrannosaurid clade. Most of these features are now known to be present in
|
||
<emphasis id="B92E32278F47C001E199F9D28CC0DC09" box="[1177,1258,1614,1635]" italics="true" pageId="2" pageNumber="1482">Raptorex</emphasis>
|
||
, the man-sized tyrannosaurid outgroup that lived 40 million years before tyrannosaurids originated (
|
||
<bibRefCitation id="EFCB93C48F47C001E039F91A8D6EDCF1" author="P. C. Sereno" box="[1337,1348,1670,1691]" journalOrPublisher="Science" pageId="2" pageNumber="1482" pagination="418" part="326" refId="ref5155" refString="4. P. C. Sereno et al., Science 326, 418 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F47C001E039F91A8D6EDCF1" box="[1337,1348,1670,1691]" italics="true" pageId="2" pageNumber="1482">4</emphasis>
|
||
</bibRefCitation>
|
||
). Furthermore, the gracile and long-snouted
|
||
<emphasis id="B92E32278F47C001E032F93E8DA5DCDD" box="[1330,1423,1698,1719]" italics="true" pageId="2" pageNumber="1482">Alioramus</emphasis>
|
||
, a tyrannosaurid that is about half the size of close relatives such as
|
||
<taxonomicName id="4C5A95B68F47C001E1AAF9468D33DC85" authorityName="Maleev" authorityYear="1955" box="[1194,1305,1754,1775]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="2" pageNumber="1482" phylum="Chordata" rank="genus">
|
||
<emphasis id="B92E32278F47C001E1AAF9468D33DC85" box="[1194,1305,1754,1775]" italics="true" pageId="2" pageNumber="1482">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<taxonomicName id="4C5A95B68F47C001E046F9468DE0DC85" authority="Osborn, 1905" box="[1350,1482,1754,1775]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="2" pageNumber="1482" phylum="Chordata" rank="genus">
|
||
<emphasis id="B92E32278F47C001E046F9468DE0DC85" box="[1350,1482,1754,1775]" italics="true" pageId="2" pageNumber="1482">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
, lacks a deep and muscular skull and thick teeth (
|
||
<bibRefCitation id="EFCB93C48F47C001E11DF88D8C1EDD4C" author="S. L. Brusatte & T. D. Carr & G. M. Erickson & G. S. Bever & M. A. Norell" box="[1053,1076,1809,1830]" journalOrPublisher="Proc. Natl. Acad. Sci. U. S. A." pageId="2" pageNumber="1482" pagination="17261" part="106" refId="ref5542" refString="19. S. L. Brusatte, T. D. Carr, G. M. Erickson, G. S. Bever, M. A. Norell, Proc. Natl. Acad. Sci. U. S. A. 106, 17261 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F47C001E11DF88D8C1EDD4C" box="[1053,1076,1809,1830]" italics="true" pageId="2" pageNumber="1482">19</emphasis>
|
||
</bibRefCitation>
|
||
). Thus, characteristic tyrannosaurid features did not evolve as a consequence of large body size, but likely originated in small animals, and not even all derived, Late Cretaceous tyrannosaurids are united by a characteristic morphotype (
|
||
<bibRefCitation id="EFCB93C48F46C000E596FF14888BDAF7" author="P. C. Sereno" box="[150,161,136,157]" journalOrPublisher="Science" pageId="3" pageNumber="1483" pagination="418" part="326" refId="ref5155" refString="4. P. C. Sereno et al., Science 326, 418 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E596FF14888BDAF7" box="[150,161,136,157]" italics="true" pageId="3" pageNumber="1483">4</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E5AFFF1488ECDAF7" author="S. L. Brusatte & T. D. Carr & G. M. Erickson & G. S. Bever & M. A. Norell" box="[175,198,136,157]" journalOrPublisher="Proc. Natl. Acad. Sci. U. S. A." pageId="3" pageNumber="1483" pagination="17261" part="106" refId="ref5542" refString="19. S. L. Brusatte, T. D. Carr, G. M. Erickson, G. S. Bever, M. A. Norell, Proc. Natl. Acad. Sci. U. S. A. 106, 17261 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E5AFFF1488ECDAF7" box="[175,198,136,157]" italics="true" pageId="3" pageNumber="1483">19</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F46C000E580FF388896D81D" pageId="3" pageNumber="1483">
|
||
Much is also known about the internal anatomy of the tyrannosaur skull, thanks to the discovery of exceptionally preserved fossils and the application of digital techniques such as computerized tomography (CT) scanning (
|
||
<bibRefCitation id="EFCB93C48F46C000E49AFE8F898FDB42" author="L. M. Witmer & R. C. Ridgely" box="[410,421,275,296]" journalOrPublisher="Anat. Rec." pageId="3" pageNumber="1483" pagination="1266" part="292" refId="ref5232" refString="7. L. M. Witmer, R. C. Ridgely, Anat. Rec. 292, 1266 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E49AFE8F898FDB42" box="[410,421,275,296]" italics="true" pageId="3" pageNumber="1483">7</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E4B1FE8F89EDDB42" author="A. Brochu & J. Vertebr" box="[433,455,275,296]" journalOrPublisher="Paleontol" pageId="3" pageNumber="1483" pagination="1" part="20" refId="ref5857" refString="30. C. A. Brochu, J. Vertebr. Paleontol. 20, 1 (2000)." type="journal article" year="2000">
|
||
<emphasis id="B92E32278F46C000E4B1FE8F89EDDB42" box="[433,455,275,296]" italics="true" pageId="3" pageNumber="1483">30</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E4D3FE8F89C0DB42" author="D. K. Zelenitsky & F. Therrien & Y. Kobayashi" box="[467,490,275,296]" journalOrPublisher="Proc. Biol. Sci." pageId="3" pageNumber="1483" pagination="667" part="276" refId="ref5878" refString="31. D. K. Zelenitsky, F. Therrien, Y. Kobayashi, Proc. Biol. Sci. 276, 667 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E4D3FE8F89C0DB42" box="[467,490,275,296]" italics="true" pageId="3" pageNumber="1483">31</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
<taxonomicName id="4C5A95B68F46C000E4FCFE8F88EADB2E" authority="Osborn, 1905" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="1483" phylum="Chordata" rank="genus">Tyrannosaurs</taxonomicName>
|
||
possessed the required neuroanatomy to lead the active, predatory life-style expected of derived theropods (
|
||
<bibRefCitation id="EFCB93C48F46C000E412FEFB8937DB16" author="L. M. Witmer & R. C. Ridgely" box="[274,285,359,380]" journalOrPublisher="Anat. Rec." pageId="3" pageNumber="1483" pagination="1266" part="292" refId="ref5232" refString="7. L. M. Witmer, R. C. Ridgely, Anat. Rec. 292, 1266 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E412FEFB8937DB16" box="[274,285,359,380]" italics="true" pageId="3" pageNumber="1483">7</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E42CFEFB8969DB16" author="A. Brochu & J. Vertebr" box="[300,323,359,380]" journalOrPublisher="Paleontol" pageId="3" pageNumber="1483" pagination="1" part="20" refId="ref5857" refString="30. C. A. Brochu, J. Vertebr. Paleontol. 20, 1 (2000)." type="journal article" year="2000">
|
||
<emphasis id="B92E32278F46C000E42CFEFB8969DB16" box="[300,323,359,380]" italics="true" pageId="3" pageNumber="1483">30</emphasis>
|
||
</bibRefCitation>
|
||
). Their encephalization quotient
|
||
<emphasis id="B92E32278F46C000E5A7FE1E8894DBF2" box="[167,190,386,408]" italics="true" pageId="3" pageNumber="1483">—</emphasis>
|
||
an estimate of relative brain size
|
||
<emphasis id="B92E32278F46C000E4D0FE1E89CDDBF2" box="[464,487,386,408]" italics="true" pageId="3" pageNumber="1483">—</emphasis>
|
||
varies between 2.0 and 2.4, larger than in basal theropods but lower than that of birds and their closest relatives (
|
||
<bibRefCitation id="EFCB93C48F46C000E597FE4A8887DB81" author="S. L. Brusatte & T. D. Carr & G. M. Erickson & G. S. Bever & M. A. Norell" box="[151,173,470,491]" journalOrPublisher="Proc. Natl. Acad. Sci. U. S. A." pageId="3" pageNumber="1483" pagination="17261" part="106" refId="ref5542" refString="19. S. L. Brusatte, T. D. Carr, G. M. Erickson, G. S. Bever, M. A. Norell, Proc. Natl. Acad. Sci. U. S. A. 106, 17261 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E597FE4A8887DB81" box="[151,173,470,491]" italics="true" pageId="3" pageNumber="1483">19</emphasis>
|
||
</bibRefCitation>
|
||
). Large olfactory lobes indicate a strong sense of smell (
|
||
<bibRefCitation id="EFCB93C48F46C000E5E7FE6E88D8D86D" author="L. M. Witmer & R. C. Ridgely" box="[231,242,498,519]" journalOrPublisher="Anat. Rec." pageId="3" pageNumber="1483" pagination="1266" part="292" refId="ref5232" refString="7. L. M. Witmer, R. C. Ridgely, Anat. Rec. 292, 1266 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E5E7FE6E88D8D86D" box="[231,242,498,519]" italics="true" pageId="3" pageNumber="1483">7</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E5FCFE6E8938D86D" author="D. K. Zelenitsky & F. Therrien & Y. Kobayashi" box="[252,274,498,519]" journalOrPublisher="Proc. Biol. Sci." pageId="3" pageNumber="1483" pagination="667" part="276" refId="ref5878" refString="31. D. K. Zelenitsky, F. Therrien, Y. Kobayashi, Proc. Biol. Sci. 276, 667 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E5FCFE6E8938D86D" box="[252,274,498,519]" italics="true" pageId="3" pageNumber="1483">31</emphasis>
|
||
</bibRefCitation>
|
||
). Elongate cochlear and semicircular canals apparently support elevated sensitivity to low-frequency sound and highly coordinated head and eye movements (
|
||
<bibRefCitation id="EFCB93C48F46C000E5A4FDFE8885D81D" author="L. M. Witmer & R. C. Ridgely" box="[164,175,610,631]" journalOrPublisher="Anat. Rec." pageId="3" pageNumber="1483" pagination="1266" part="292" refId="ref5232" refString="7. L. M. Witmer, R. C. Ridgely, Anat. Rec. 292, 1266 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E5A4FDFE8885D81D" box="[164,175,610,631]" italics="true" pageId="3" pageNumber="1483">7</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F46C000E580FDE28914DFB2" pageId="3" pageNumber="1483">
|
||
Several tyrannosaurid specimens have been reported to preserve integumentary structures and other soft tissues, which rarely fossilize in dinosaurs. Although impressions of scaly skin have been described for large tyrannosaurids (
|
||
<bibRefCitation id="EFCB93C48F46C000E5EEFCB9892ED950" author="P. J. Currie & D. Badamgarav & E. B. Koppelhus" box="[238,260,805,826]" journalOrPublisher="Ichnos" pageId="3" pageNumber="1483" pagination="1" part="10" refId="ref5907" refString="32. P. J. Currie, D. Badamgarav, E. B. Koppelhus, Ichnos 10, 1 (2003)." type="journal article" year="2003">
|
||
<emphasis id="B92E32278F46C000E5EEFCB9892ED950" box="[238,260,805,826]" italics="true" pageId="3" pageNumber="1483">32</emphasis>
|
||
</bibRefCitation>
|
||
), simple filamentous integument, interpreted as homologous to feathers, is clearly preserved in a specimen of the basal tyrannosauroid
|
||
<emphasis id="B92E32278F46C000E5A6FC0988CED9C0" box="[166,228,917,938]" italics="true" pageId="3" pageNumber="1483">Dilong</emphasis>
|
||
(
|
||
<bibRefCitation id="EFCB93C48F46C000E5F0FC09892DD9C0" author="X. Xu" box="[240,263,917,938]" journalOrPublisher="Nature" pageId="3" pageNumber="1483" pagination="680" part="431" refId="ref5406" refString="14. X. Xu et al., Nature 431, 680 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F46C000E5F0FC09892DD9C0" box="[240,263,917,938]" italics="true" pageId="3" pageNumber="1483">14</emphasis>
|
||
</bibRefCitation>
|
||
). These branched filaments appear to have extensively covered the body, as they are observed near the skull and tail. A recent study suggests that much larger tyrannosauroids were covered with elongate, broader integumentary structures (
|
||
<bibRefCitation id="EFCB93C48F46C000E59CFBC48899DE07" author="X. Xu & X. T. Zheng & H. L. You" box="[156,179,1112,1133]" journalOrPublisher="Nature" pageId="3" pageNumber="1483" pagination="1338" part="464" refId="ref5933" refString="33. X. Xu, X. T. Zheng, H. L. You, Nature 464, 1338 (2010)." type="journal article" year="2010">
|
||
<emphasis id="B92E32278F46C000E59CFBC48899DE07" box="[156,179,1112,1133]" italics="true" pageId="3" pageNumber="1483">33</emphasis>
|
||
</bibRefCitation>
|
||
), which were likely used for display (
|
||
<bibRefCitation id="EFCB93C48F46C000E5D3FBE888C0DEE3" author="X. Xu & X. T. Zheng & H. L. You" box="[211,234,1140,1161]" journalOrPublisher="Proc. Natl. Acad. Sci. U. S. A." pageId="3" pageNumber="1483" pagination="832" part="106" refId="ref5959" refString="34. X. Xu, X. T. Zheng, H. L. You, Proc. Natl. Acad. Sci. U. S. A. 106, 832 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E5D3FBE888C0DEE3" box="[211,234,1140,1161]" italics="true" pageId="3" pageNumber="1483">34</emphasis>
|
||
</bibRefCitation>
|
||
). Several easily degraded soft tissues, such as cells, blood vessels, and collagen,have been reported from a specimen of
|
||
<taxonomicName id="4C5A95B68F46C000E469FB5B889EDE92" authority="Osborn, 1905" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="1483" phylum="Chordata" rank="genus">
|
||
<emphasis id="B92E32278F46C000E469FB5B889EDE92" italics="true" pageId="3" pageNumber="1483">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
(
|
||
<bibRefCitation id="EFCB93C48F46C000E5C5FB7F88F6DE92" author="M. H. Schweitzer & J. L. Wittmeyer & J. R. Horner & J. K. Toporski" box="[197,220,1251,1272]" journalOrPublisher="Science" pageId="3" pageNumber="1483" pagination="1952" part="307" refId="ref5423" refString="15. M. H. Schweitzer, J. L. Wittmeyer, J. R. Horner, J. K. Toporski, Science 307, 1952 (2005)." type="journal article" year="2005">
|
||
<emphasis id="B92E32278F46C000E5C5FB7F88F6DE92" box="[197,220,1251,1272]" italics="true" pageId="3" pageNumber="1483">15</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E5ECFB7F8929DE92" author="M. H. Schweitzer" box="[236,259,1251,1272]" journalOrPublisher="Science" pageId="3" pageNumber="1483" pagination="277" part="316" refId="ref5998" refString="35. M. H. Schweitzer et al., Science 316, 277 (2007)." type="journal article" year="2007">
|
||
<emphasis id="B92E32278F46C000E5ECFB7F8929DE92" box="[236,259,1251,1272]" italics="true" pageId="3" pageNumber="1483">35</emphasis>
|
||
</bibRefCitation>
|
||
). Some of these findings have been met with skepticism (
|
||
<bibRefCitation id="EFCB93C48F46C000E59DFA87889EDF5A" author="T. G. Kaye & G. Gaugler & Z. Sawlowicz & A. Stepanova" box="[157,180,1307,1328]" journalOrPublisher="PLoS ONE" pageId="3" pageNumber="1483" pagination="e 2808" part="3" refId="ref6017" refString="36. T. G. Kaye, G. Gaugler, Z. Sawlowicz, A. Stepanova, PLoS ONE 3, e 2808 (2008)." type="journal article" year="2008">
|
||
<emphasis id="B92E32278F46C000E59DFA87889EDF5A" box="[157,180,1307,1328]" italics="true" pageId="3" pageNumber="1483">36</emphasis>
|
||
</bibRefCitation>
|
||
), and they remain to be validated by other research groups. However, if correct, they promise to give radical new insight into the process of fossilization and may allow for molecular phylogenetic analysis of these extinct taxa (
|
||
<bibRefCitation id="EFCB93C48F46C000E41BFA5F891BDFB2" author="C. L. Organ" box="[283,305,1475,1496]" journalOrPublisher="Science" pageId="3" pageNumber="1483" pagination="499" part="320" refId="ref6047" refString="37. C. L. Organ et al., Science 320, 499 (2008)." type="journal article" year="2008">
|
||
<emphasis id="B92E32278F46C000E41BFA5F891BDFB2" box="[283,305,1475,1496]" italics="true" pageId="3" pageNumber="1483">37</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<caption id="DF25BEBD8F46C000E4C5FABD8C9DDFD1" ID-DOI="http://doi.org/10.5281/zenodo.3744293" ID-Zenodo-Dep="3744293" httpUri="https://zenodo.org/record/3744293/files/figure.png" pageId="3" pageNumber="1483" targetBox="[455,1486,608,1295]" targetPageId="3">
|
||
<paragraph id="8BE5EE358F46C000E4C5FABD8C9DDFD1" pageId="3" pageNumber="1483">
|
||
Fig. 3. Tyrannosaur soft tissuesι feedingι and locomotion. (A) CT imagery of internal pneumatic sinuses of the braincase of
|
||
<emphasis id="B92E32278F46C000E733FAA08A9DDF3B" bold="true" box="[563,695,1340,1361]" italics="true" pageId="3" pageNumber="1483">Alioramus altai</emphasis>
|
||
(
|
||
<bibRefCitation id="EFCB93C48F46C000E7C2FAA08AF3DF3B" author="S. L. Brusatte & T. D. Carr & G. M. Erickson & G. S. Bever & M. A. Norell" box="[706,729,1340,1361]" journalOrPublisher="Proc. Natl. Acad. Sci. U. S. A." pageId="3" pageNumber="1483" pagination="17261" part="106" refId="ref5542" refString="19. S. L. Brusatte, T. D. Carr, G. M. Erickson, G. S. Bever, M. A. Norell, Proc. Natl. Acad. Sci. U. S. A. 106, 17261 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E7C2FAA08AF3DF3B" bold="true" box="[706,729,1340,1361]" italics="true" pageId="3" pageNumber="1483">19</emphasis>
|
||
</bibRefCitation>
|
||
). (B) Endocast of brainι cranial nervesι and semicircular canals of
|
||
<emphasis id="B92E32278F46C000E011FAA08D67DF3B" bold="true" box="[1297,1357,1340,1361]" italics="true" pageId="3" pageNumber="1483">A. altai</emphasis>
|
||
(
|
||
<bibRefCitation id="EFCB93C48F46C000E058FAA08D45DF3B" author="S. L. Brusatte & T. D. Carr & G. M. Erickson & G. S. Bever & M. A. Norell" box="[1368,1391,1340,1361]" journalOrPublisher="Proc. Natl. Acad. Sci. U. S. A." pageId="3" pageNumber="1483" pagination="17261" part="106" refId="ref5542" refString="19. S. L. Brusatte, T. D. Carr, G. M. Erickson, G. S. Bever, M. A. Norell, Proc. Natl. Acad. Sci. U. S. A. 106, 17261 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E058FAA08D45DF3B" bold="true" box="[1368,1391,1340,1361]" italics="true" pageId="3" pageNumber="1483">19</emphasis>
|
||
</bibRefCitation>
|
||
). (C) Finite element analysis of a skull of
|
||
<taxonomicName id="4C5A95B68F46C000E7C5FACB8AD9DF06" authority="Osborn, 1905" box="[709,755,1367,1388]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="1483" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F46C000E7C5FACB8AD9DF06" bold="true" box="[709,755,1367,1388]" italics="true" pageId="3" pageNumber="1483">T. rex</emphasis>
|
||
</taxonomicName>
|
||
(
|
||
<emphasis id="B92E32278F46C000E7FFFACB8B3CDF06" bold="true" box="[767,790,1367,1388]" italics="true" pageId="3" pageNumber="1483">11</emphasis>
|
||
ι
|
||
<emphasis id="B92E32278F46C000E621FACB8B12DF06" bold="true" box="[801,824,1367,1388]" italics="true" pageId="3" pageNumber="1483">47</emphasis>
|
||
)ι showing high stresses (red colors) in the nasal and cheek regions (courtesy of E. Rayfield). (D) Lacrimal of
|
||
<emphasis id="B92E32278F46C000E7CFFAED8B26DFEC" bold="true" box="[719,780,1393,1414]" italics="true" pageId="3" pageNumber="1483">A. altai</emphasis>
|
||
(reversed)ι showing pneumatic spaces that housed air sacs (credit: M. Ellison). (E) Feathery integument along the tail of
|
||
<emphasis id="B92E32278F46C000E612FA108B86DFCB" bold="true" box="[786,940,1420,1441]" italics="true" pageId="3" pageNumber="1483">Dilong paradoxus</emphasis>
|
||
. (F) Three-dimensional biomechanical model based on muscle reconstruction of the right hindlimb of
|
||
<taxonomicName id="4C5A95B68F46C000E620FA3A8B65DFD1" authority="Osborn, 1905" box="[800,847,1446,1467]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="1483" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F46C000E620FA3A8B65DFD1" bold="true" box="[800,847,1446,1467]" italics="true" pageId="3" pageNumber="1483">T. rex</emphasis>
|
||
</taxonomicName>
|
||
(
|
||
<bibRefCitation id="EFCB93C48F46C000E65CFA3A8B59DFD1" author="M. T. Carrano & J. R. Hutchinson" box="[860,883,1446,1467]" journalOrPublisher="J. Morphol" pageId="3" pageNumber="1483" pagination="207" part="253" refId="ref5457" refString="16. M. T. Carrano, J. R. Hutchinson, J. Morphol. 253, 207 (2002)." type="journal article" year="2002">
|
||
<emphasis id="B92E32278F46C000E65CFA3A8B59DFD1" bold="true" box="[860,883,1446,1467]" italics="true" pageId="3" pageNumber="1483">16</emphasis>
|
||
</bibRefCitation>
|
||
)ι used to assess running mechanics.
|
||
</paragraph>
|
||
</caption>
|
||
<paragraph id="8BE5EE358F46C000E560FA69890EDC60" box="[96,292,1525,1546]" pageId="3" pageNumber="1483">Tyrannosaur Growth</paragraph>
|
||
<paragraph id="8BE5EE358F46C000E560F98A88E3DC84" pageId="3" pageNumber="1483">
|
||
Arguably we know more about tyrannosaur biology than that of any other dinosaurs (
|
||
<figureCitation id="1361F2B08F46C000E4DBF9AE8A30DC2D" box="[475,538,1586,1607]" captionStart="Fig. 3" captionStartId="3.[453,488,1313,1335]" captionTargetBox="[455,1486,608,1295]" captionTargetId="figure@3.[455,1486,608,1295]" captionText="Fig. 3. Tyrannosaur soft tissuesι feedingι and locomotion. (A) CT imagery of internal pneumatic sinuses of the braincase of Alioramus altai (19). (B) Endocast of brainι cranial nervesι and semicircularcanals of A.altai (19). (C) Finite element analysis of a skull of T. rex (11ι 47)ι showing high stresses (red colors) in the nasal and cheek regions (courtesy of E. Rayfield).(D) Lacrimal of A. altai (reversed)ι showing pneumatic spaces that housed air sacs (credit:M. Ellison). (E) Feathery integument along the tail of Dilong paradoxus. (F) Three-dimensional biomechanical model based on muscle reconstruction of the right hindlimb of T. rex (16)ι used to assess running mechanics." figureDoi="http://doi.org/10.5281/zenodo.3744293" httpUri="https://zenodo.org/record/3744293/files/figure.png" pageId="3" pageNumber="1483">Figs. 3</figureCitation>
|
||
and 4). Much of this knowledge has been gained over the past 20 years, through the collection of skeletons of both adults and juveniles, bones of their prey with bite marks, coprolites (fossil feces), stomach contents, and pathological specimens (
|
||
<bibRefCitation id="EFCB93C48F46C000E5A5F9458896DC84" author="G. M. Erickson" box="[165,188,1753,1774]" journalOrPublisher="Sci. Am." pageId="3" pageNumber="1483" pagination="32" part="9" refId="ref6066" refString="38. G. M. Erickson, Sci. Am. 9, 32 (1999)." type="journal article" year="1999">
|
||
<emphasis id="B92E32278F46C000E5A5F9458896DC84" box="[165,188,1753,1774]" italics="true" pageId="3" pageNumber="1483">38</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F46C000E580F9698CC0DA81" pageId="3" pageNumber="1483">
|
||
Much attention has focused on how tyranno- saurs grew, especially on how giants such as
|
||
<taxonomicName id="4C5A95B68F46C000E4EAF88D8A33DD4C" authority="Osborn, 1905" box="[490,537,1809,1830]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="1483" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F46C000E4EAF88D8A33DD4C" box="[490,537,1809,1830]" italics="true" pageId="3" pageNumber="1483">T. rex</emphasis>
|
||
</taxonomicName>
|
||
achieved such massive size and how their skel- etons changed during the transition from embryo to multi-ton adult. Comparative growth curves for several species, which plot body mass (calculated from femur size) against age in years (calculated from counting growth lines in histological section) (
|
||
<bibRefCitation id="EFCB93C48F46C000E742FF238A67DABE" author="G. M. Erickson" box="[578,589,191,212]" journalOrPublisher="Nature" pageId="3" pageNumber="1483" pagination="772" part="430" refId="ref5257" refString="8. G. M. Erickson et al., Nature 430, 772 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F46C000E742FF238A67DABE" box="[578,589,191,212]" italics="true" pageId="3" pageNumber="1483">8</emphasis>
|
||
</bibRefCitation>
|
||
) (
|
||
<figureCitation id="1361F2B08F46C000E768FF238A9CDABE" box="[616,694,191,212]" captionStart="Fig. 4" captionStartId="4.[929,964,1626,1648]" captionTargetBox="[931,1485,108,1608]" captionTargetId="figure@4.[1026,1267,838,980]" captionTargetPageId="4" captionText="Fig. 4. Tyrannosaur growth and ecology. (A) Histological section of a T. rex dorsal ribι showing growth lines whose counts are used to reveal age andlongevity.(B) Growth curves for North American tyrannosaurids derived from growth line counts and body size estimations for individuals showing how size changes with age. No sampled tyrannosaurid adults were more than 30 years oldι and accelerated rather than prolonged development was the key to the great size of T. rex (8). (C) survivorship curve for Albertosaurus sarcophagus. This tyrannosaur exhibited high neonate mortalityι then few deaths after age twoι and then increased mortality at mid-life (8)." figureDoi="http://doi.org/10.5281/zenodo.3744295" httpUri="https://zenodo.org/record/3744295/files/figure.png" pageId="3" pageNumber="1483">Fig. 4B</figureCitation>
|
||
), show that large tyrannosaurids reached somatic maturity around 20 years old, though most rarely lived for more than 25 years.
|
||
<taxonomicName id="4C5A95B68F46C000E6E5FF6B8A7FDB42" authority="Osborn, 1905" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="1483" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F46C000E6E5FF6B8BDADB66" box="[997,1008,247,268]" italics="true" pageId="3" pageNumber="1483">T</emphasis>
|
||
.
|
||
<emphasis id="B92E32278F46C000E73BFE8F8A7FDB42" box="[571,597,275,296]" italics="true" pageId="3" pageNumber="1483">rex</emphasis>
|
||
</taxonomicName>
|
||
evidently attained its large size via acceleration of growth rates relative to closely related species, not by extending its life span.Its maximum growth rate may have exceeded 767 kg per year, equiv- alent to adding a remarkable 2 kg per day (
|
||
<bibRefCitation id="EFCB93C48F46C000E6BCFE1F8BEDDBF2" author="G. M. Erickson" box="[956,967,387,408]" journalOrPublisher="Nature" pageId="3" pageNumber="1483" pagination="772" part="430" refId="ref5257" refString="8. G. M. Erickson et al., Nature 430, 772 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F46C000E6BCFE1F8BEDDBF2" box="[956,967,387,408]" italics="true" pageId="3" pageNumber="1483">8</emphasis>
|
||
</bibRefCitation>
|
||
). Tyrannosaur skeletons changed substantially as individuals matured. Although less is known about the growth of small, basal tyrannosaurs, tyrannosaurids and their closest large-bodied relatives are united by a conservative pattern of growth in which the skulls of juveniles were en- tirely reshaped during ontogeny (
|
||
<bibRefCitation id="EFCB93C48F46C000E66EFA668B53DC65" author="T. D. Carr" box="[878,889,1530,1551]" journalOrPublisher="J. Vertebr. Paleontol." pageId="3" pageNumber="1483" pagination="497" part="19" refId="ref5276" refString="9. T. D. Carr, J. Vertebr. Paleontol. 19, 497 (1999)." type="journal article" year="1999">
|
||
<emphasis id="B92E32278F46C000E66EFA668B53DC65" box="[878,889,1530,1551]" italics="true" pageId="3" pageNumber="1483">9</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E684FA668BB1DC65" author="T. D. Carr & T. E. Williamson" box="[900,923,1530,1551]" journalOrPublisher="J. Vertebr. Paleontol." pageId="3" pageNumber="1483" pagination="1" part="30" refId="ref5595" refString="20. T. D. Carr, T. E. Williamson, J. Vertebr. Paleontol. 30, 1 (2010)." type="journal article" year="2010">
|
||
<emphasis id="B92E32278F46C000E684FA668BB1DC65" box="[900,923,1530,1551]" italics="true" pageId="3" pageNumber="1483">20</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E6A4FA668B91DC65" author="T. D. Carr & T. E. Williamson" box="[932,955,1530,1551]" journalOrPublisher="Zool. J. Linn. Soc." pageId="3" pageNumber="1483" pagination="479" part="142" refId="ref6085" refString="39. T. D. Carr, T. E. Williamson, Zool. J. Linn. Soc. 142, 479 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F46C000E6A4FA668B91DC65" box="[932,955,1530,1551]" italics="true" pageId="3" pageNumber="1483">39</emphasis>
|
||
</bibRefCitation>
|
||
). This sequence has been reconstructed by cladistic analysis, based on the principle that ontogeny, like phylogeny, involves a hierarchically nested series of character changes (
|
||
<bibRefCitation id="EFCB93C48F46C000E642F9F68B73DC15" author="S. L. Brusatte & T. D. Carr & G. M. Erickson & G. S. Bever & M. A. Norell" box="[834,857,1642,1663]" journalOrPublisher="Proc. Natl. Acad. Sci. U. S. A." pageId="3" pageNumber="1483" pagination="17261" part="106" refId="ref5542" refString="19. S. L. Brusatte, T. D. Carr, G. M. Erickson, G. S. Bever, M. A. Norell, Proc. Natl. Acad. Sci. U. S. A. 106, 17261 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E642F9F68B73DC15" box="[834,857,1642,1663]" italics="true" pageId="3" pageNumber="1483">19</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E666F9F68B57DC15" author="T. D. Carr & T. E. Williamson" box="[870,893,1642,1663]" journalOrPublisher="Zool. J. Linn. Soc." pageId="3" pageNumber="1483" pagination="479" part="142" refId="ref6085" refString="39. T. D. Carr, T. E. Williamson, Zool. J. Linn. Soc. 142, 479 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F46C000E666F9F68B57DC15" box="[870,893,1642,1663]" italics="true" pageId="3" pageNumber="1483">39</emphasis>
|
||
</bibRefCitation>
|
||
). During the growth of an individual species, the skull and jaws deepened, pneumatic bones inflated, orna- mented structures enlarged and coarsened, sutural surfaces deepened and became more rugose, and the teeth became larger and thicker (
|
||
<bibRefCitation id="EFCB93C48F46C000E677F9698BA8DD60" author="T. D. Carr" box="[887,898,1781,1802]" journalOrPublisher="J. Vertebr. Paleontol." pageId="3" pageNumber="1483" pagination="497" part="19" refId="ref5276" refString="9. T. D. Carr, J. Vertebr. Paleontol. 19, 497 (1999)." type="journal article" year="1999">
|
||
<emphasis id="B92E32278F46C000E677F9698BA8DD60" box="[887,898,1781,1802]" italics="true" pageId="3" pageNumber="1483">9</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E68CF9698B88DD60" author="P. J. Currie" box="[908,930,1781,1802]" journalOrPublisher="Can. J. Earth Sci." pageId="3" pageNumber="1483" pagination="651" part="40" refId="ref6114" refString="40. P. J. Currie, Can. J. Earth Sci. 40, 651 (2003)." type="journal article" year="2003">
|
||
<emphasis id="B92E32278F46C000E68CF9698B88DD60" box="[908,930,1781,1802]" italics="true" pageId="3" pageNumber="1483">40</emphasis>
|
||
</bibRefCitation>
|
||
) (
|
||
<figureCitation id="1361F2B08F46C000E6B5F9698BCDDD60" box="[949,999,1781,1802]" captionStart="Fig. 1" captionStartId="1.[571,606,1679,1701]" captionTargetBox="[576,1485,848,1650]" captionTargetId="figure@1.[573,1485,848,1662]" captionTargetPageId="1" captionText="Fig. 1. The anatomy of tyrannosaurs, showing the variety of skeletal and cranial morphology in the group. (A) A skeletal reconstruction of Alioramus, a gracile and long-snouted tyrannosauridι which exhibits many features of the generalizedtyrannosaurid body plan (large skull, small arms, long hindlimbsι long tail).(B to D) skulls of the basal tyrannosauroids Guanlong (B), Dilong (C), and Bistahieversor (D). (E and F) skulls of juvenile(E) and adult (F) Tyrannosaurus scaled tothe same length,illustrating the transitionfrom a longer to a deeperskull during ontogeny.All scale barsequal 10cm. Credits:F. Ippolito, American Museum of Natural History (AMNH) (A); I. Blockι National Geographic stock (B); M. Ellison, AMNH (C); D. Baccadutre, New Mexico Museum of Natural History and science (D); s. Williams, Burpee Museum of Natural History (E); AMNH Photo Archives (#2752, Tyrannosaurus skull as mounted in the old hall) (F)." figureDoi="http://doi.org/10.5281/zenodo.3744289" httpUri="https://zenodo.org/record/3744289/files/figure.png" pageId="3" pageNumber="1483">Fig. 1</figureCitation>
|
||
). Changes have also been documented in the post- cranial skeleton.Most notably, the forearm shortened and the long shin and foot of juveniles became shorter and stockier in adults (
|
||
<bibRefCitation id="EFCB93C48F46C000E662F8F98B53DD10" author="P. J. Currie" box="[866,889,1893,1914]" journalOrPublisher="Can. J. Earth Sci." pageId="3" pageNumber="1483" pagination="651" part="40" refId="ref6114" refString="40. P. J. Currie, Can. J. Earth Sci. 40, 651 (2003)." type="journal article" year="2003">
|
||
<emphasis id="B92E32278F46C000E662F8F98B53DD10" box="[866,889,1893,1914]" italics="true" pageId="3" pageNumber="1483">40</emphasis>
|
||
</bibRefCitation>
|
||
). The differences between juvenile and adult tyrannosaurids are so great that different growth stages have often been mistaken for different species (
|
||
<bibRefCitation id="EFCB93C48F46C000E09FFF3F8D81DAD2" author="D. A. Russell" box="[1439,1451,163,184]" journalOrPublisher="Nat. Mus. Nat. Sci. Pub. Palaeontol" pageId="3" pageNumber="1483" pagination="1" part="1" refId="ref5129" refString="3. D. A. Russell, Nat. Mus. Nat. Sci. Pub. Palaeontol 1, 1 (1970)." type="journal article" year="1970">
|
||
<emphasis id="B92E32278F46C000E09FFF3F8D81DAD2" box="[1439,1451,163,184]" italics="true" pageId="3" pageNumber="1483">3</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E0B7FF3F8DE9DAD2" author="T. D. Carr" box="[1463,1475,163,184]" journalOrPublisher="J. Vertebr. Paleontol." pageId="3" pageNumber="1483" pagination="497" part="19" refId="ref5276" refString="9. T. D. Carr, J. Vertebr. Paleontol. 19, 497 (1999)." type="journal article" year="1999">
|
||
<emphasis id="B92E32278F46C000E0B7FF3F8DE9DAD2" box="[1463,1475,163,184]" italics="true" pageId="3" pageNumber="1483">9</emphasis>
|
||
</bibRefCitation>
|
||
). Tyrannosaur Behavior
|
||
</paragraph>
|
||
<subSubSection id="C340BDBE8F46C006E115FF6B8BD8DABE" lastPageId="5" lastPageNumber="1485" pageId="3" pageNumber="1483" type="biology_ecology">
|
||
<paragraph id="8BE5EE358F46C000E115FF6B8DFBDBF2" pageId="3" pageNumber="1483">
|
||
A variety of studies have used biomechanical mod- eling, which incorporates mathematics, physics, and computer programming (
|
||
<bibRefCitation id="EFCB93C48F46C000E025FEB38D16DB2E" author="S. M. Gatesy & M. Baker & J. R. Hutchinson" box="[1317,1340,303,324]" journalOrPublisher="J. Vertebr. Paleontol." pageId="3" pageNumber="1483" pagination="535" part="29" refId="ref6136" refString="41. S. M. Gatesy, M. Baker, J. R. Hutchinson, J. Vertebr. Paleontol. 29, 535 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E025FEB38D16DB2E" box="[1317,1340,303,324]" italics="true" pageId="3" pageNumber="1483">41</emphasis>
|
||
</bibRefCitation>
|
||
), to infer tyran- nosaur behavior. Tyrannosaurs, especially the large, derived forms, have often been used as exemplars to demonstrate the utility of such computer models.
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F46C007E135FE028924DAD3" lastBlockId="4.[96,540,108,1914]" lastPageId="4" lastPageNumber="1484" pageId="3" pageNumber="1483">
|
||
Most studies have suggested that although large tyrannosaurids might have been able to run at slow to moderate speeds at best (top speeds between 5 and 11 ms −1), they could not run near- ly as fast as large athletic animals today, such as racehorses (~20 ms −1) (
|
||
<bibRefCitation id="EFCB93C48F46C000E1F5FA438D21DF9E" author="J. R. Hutchinson & M. Garcia" box="[1269,1291,1503,1524]" journalOrPublisher="Nature" pageId="3" pageNumber="1483" pagination="1018" part="415" refId="ref5352" refString="12. J. R. Hutchinson, M. Garcia, Nature 415, 1018 (2002)." type="journal article" year="2002">
|
||
<emphasis id="B92E32278F46C000E1F5FA438D21DF9E" box="[1269,1291,1503,1524]" italics="true" pageId="3" pageNumber="1483">12</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E01CFA438D18DF9E" author="S. M. Gatesy & M. Baker & J. R. Hutchinson" box="[1308,1330,1503,1524]" journalOrPublisher="J. Vertebr. Paleontol." pageId="3" pageNumber="1483" pagination="535" part="29" refId="ref6136" refString="41. S. M. Gatesy, M. Baker, J. R. Hutchinson, J. Vertebr. Paleontol. 29, 535 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E01CFA438D18DF9E" box="[1308,1330,1503,1524]" italics="true" pageId="3" pageNumber="1483">41</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E043FA438D73DF9E" author="W. I. Sellers & P. L. Manning" box="[1347,1369,1503,1524]" journalOrPublisher="Proc. Biol. Sci." pageId="3" pageNumber="1483" pagination="2711" part="274" refId="ref6167" refString="42. W. I. Sellers, P. L. Manning, Proc. Biol. Sci. 274, 2711 (2007)." type="journal article" year="2007">
|
||
<emphasis id="B92E32278F46C000E043FA438D73DF9E" box="[1347,1369,1503,1524]" italics="true" pageId="3" pageNumber="1483">42</emphasis>
|
||
</bibRefCitation>
|
||
). Consensus also is building that even though large tyranno- saurids were not restricted to a pillar-like columnar limb posture to maximize mechanical advantage, they were still far from having very crouched, more birdlike postures (
|
||
<bibRefCitation id="EFCB93C48F46C000E1F5F9F68D21DC15" author="J. R. Hutchinson & M. Garcia" box="[1269,1291,1642,1663]" journalOrPublisher="Nature" pageId="3" pageNumber="1483" pagination="1018" part="415" refId="ref5352" refString="12. J. R. Hutchinson, M. Garcia, Nature 415, 1018 (2002)." type="journal article" year="2002">
|
||
<emphasis id="B92E32278F46C000E1F5F9F68D21DC15" box="[1269,1291,1642,1663]" italics="true" pageId="3" pageNumber="1483">12</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E01BF9F68D1BDC15" author="S. M. Gatesy & M. Baker & J. R. Hutchinson" box="[1307,1329,1642,1663]" journalOrPublisher="J. Vertebr. Paleontol." pageId="3" pageNumber="1483" pagination="535" part="29" refId="ref6136" refString="41. S. M. Gatesy, M. Baker, J. R. Hutchinson, J. Vertebr. Paleontol. 29, 535 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F46C000E01BF9F68D1BDC15" box="[1307,1329,1642,1663]" italics="true" pageId="3" pageNumber="1483">41</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F46C000E040F9F68D7DDC15" author="W. I. Sellers & P. L. Manning" box="[1344,1367,1642,1663]" journalOrPublisher="Proc. Biol. Sci." pageId="3" pageNumber="1483" pagination="2711" part="274" refId="ref6167" refString="42. W. I. Sellers, P. L. Manning, Proc. Biol. Sci. 274, 2711 (2007)." type="journal article" year="2007">
|
||
<emphasis id="B92E32278F46C000E040F9F68D7DDC15" box="[1344,1367,1642,1663]" italics="true" pageId="3" pageNumber="1483">42</emphasis>
|
||
</bibRefCitation>
|
||
). Aspects of tyrannosaurid anatomy, such as the long legs and large pelvic limb muscles, which intuitively seem to indicate fast running capacity, were inherited from small, presumably fast-running ancestors. Modeling studies have incorporated these features and shown that they did not make large tyranno- saurids extremely fast. However, it is worth noting that these studies rely on estimates of muscle size and attachment points, a somewhat conjecturaexercise, albeit constrained by the anatomy of extant relatives (
|
||
<bibRefCitation id="EFCB93C48F41C007E5FDFF148939DAF7" author="J. R. Hutchinson & M. Garcia" box="[253,275,136,157]" journalOrPublisher="Nature" pageId="4" pageNumber="1484" pagination="1018" part="415" refId="ref5352" refString="12. J. R. Hutchinson, M. Garcia, Nature 415, 1018 (2002)." type="journal article" year="2002">
|
||
<emphasis id="B92E32278F41C007E5FDFF148939DAF7" box="[253,275,136,157]" italics="true" pageId="4" pageNumber="1484">12</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F41C007E425FF148911DAF7" author="M. T. Carrano & J. R. Hutchinson" box="[293,315,136,157]" journalOrPublisher="J. Morphol" pageId="4" pageNumber="1484" pagination="207" part="253" refId="ref5457" refString="16. M. T. Carrano, J. R. Hutchinson, J. Morphol. 253, 207 (2002)." type="journal article" year="2002">
|
||
<emphasis id="B92E32278F41C007E425FF148911DAF7" box="[293,315,136,157]" italics="true" pageId="4" pageNumber="1484">16</emphasis>
|
||
</bibRefCitation>
|
||
), that plagues all such functional analyses.
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F41C007E580FF238994D88C" blockId="4.[96,540,108,1914]" pageId="4" pageNumber="1484">
|
||
Both trace fossils (bite marks, coprolites) and quantitative techniques have helped to reveal what tyrannosaurs ate and how they fed. Tyrannosaurid bite marks have been found on the bones of a wide diversity of species, including various other tyrannosaurs, demonstrating that they were ecological generalists (
|
||
<bibRefCitation id="EFCB93C48F41C007E410FEFB890DDB16" author="A. R. Jacobsen" box="[272,295,359,380]" journalOrPublisher="Hist. Biol." pageId="4" pageNumber="1484" pagination="17" part="13" refId="ref6194" refString="43. A. R. Jacobsen, Hist. Biol. 13, 17 (1998)." type="journal article" year="1998">
|
||
<emphasis id="B92E32278F41C007E410FEFB890DDB16" box="[272,295,359,380]" italics="true" pageId="4" pageNumber="1484">43</emphasis>
|
||
</bibRefCitation>
|
||
). Bite mark patterns show that tyrannosaurids characteristically bit deeply into carcasses, often through bones, and then pulled back, creating long cuts [puncture-pull feeding sensu (
|
||
<bibRefCitation id="EFCB93C48F41C007E583FE4A88B0DB81" author="G. M. Erickson & K. H. Olson" box="[131,154,470,491]" journalOrPublisher="J. Vertebr. Paleontol." pageId="4" pageNumber="1484" pagination="175" part="16" refId="ref6213" refString="44. G. M. Erickson, K. H. Olson, J. Vertebr. Paleontol. 16, 175 (1996)." type="journal article" year="1996">
|
||
<emphasis id="B92E32278F41C007E583FE4A88B0DB81" box="[131,154,470,491]" italics="true" pageId="4" pageNumber="1484">44</emphasis>
|
||
</bibRefCitation>
|
||
)]. Some
|
||
<taxonomicName id="4C5A95B68F41C007E5F3FE4A890DDB81" authority="Osborn, 1905" box="[243,295,470,491]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="1484" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F41C007E5F3FE4A88D4DB81" box="[243,254,470,491]" italics="true" pageId="4" pageNumber="1484">T</emphasis>
|
||
.
|
||
<emphasis id="B92E32278F41C007E40CFE4A890DDB81" box="[268,295,470,491]" italics="true" pageId="4" pageNumber="1484">rex</emphasis>
|
||
</taxonomicName>
|
||
bite marks (
|
||
<bibRefCitation id="EFCB93C48F41C007E4A2FE4A8993DB81" author="G. M. Erickson & K. H. Olson" box="[418,441,470,491]" journalOrPublisher="J. Vertebr. Paleontol." pageId="4" pageNumber="1484" pagination="175" part="16" refId="ref6213" refString="44. G. M. Erickson, K. H. Olson, J. Vertebr. Paleontol. 16, 175 (1996)." type="journal article" year="1996">
|
||
<emphasis id="B92E32278F41C007E4A2FE4A8993DB81" box="[418,441,470,491]" italics="true" pageId="4" pageNumber="1484">44</emphasis>
|
||
</bibRefCitation>
|
||
) and coprolites with bone chunks (
|
||
<bibRefCitation id="EFCB93C48F41C007E453FE6E8943D86D" author="K. Chin & T. T. Tokaryk & G. M. Erickson & L. C. Calk" box="[339,361,498,519]" journalOrPublisher="Nature" pageId="4" pageNumber="1484" pagination="680" part="393" refId="ref6240" refString="45. K. Chin, T. T. Tokaryk, G. M. Erickson, L. C. Calk, Nature 393, 680 (1998)." type="journal article" year="1998">
|
||
<emphasis id="B92E32278F41C007E453FE6E8943D86D" box="[339,361,498,519]" italics="true" pageId="4" pageNumber="1484">45</emphasis>
|
||
</bibRefCitation>
|
||
) indicate that bone was fractured, ingested, and used for sustenance, a mammal-like attribute not seen in extant reptiles. The bite forces needed to crunch through bone would have been enormous. Biomechanical experiments have replicated the size and depth of fossilized bite marks and suggest that
|
||
<taxonomicName id="4C5A95B68F41C007E4B9FD0689C1D8C5" authority="Osborn, 1905" box="[441,491,666,687]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="1484" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F41C007E4B9FD0689EED8C5" box="[441,452,666,687]" italics="true" pageId="4" pageNumber="1484">T</emphasis>
|
||
.
|
||
<emphasis id="B92E32278F41C007E4D0FD0689C1D8C5" box="[464,491,666,687]" italics="true" pageId="4" pageNumber="1484">rex</emphasis>
|
||
</taxonomicName>
|
||
generated bite forces of at least 13,400 N. Maximal bite forces were probably greater (
|
||
<bibRefCitation id="EFCB93C48F41C007E49AFD4D899BD88C" author="G. M. Erickson" box="[410,433,721,742]" journalOrPublisher="Nature" pageId="4" pageNumber="1484" pagination="706" part="382" refId="ref6272" refString="46. G. M. Erickson et al., Nature 382, 706 (1996)." type="journal article" year="1996">
|
||
<emphasis id="B92E32278F41C007E49AFD4D899BD88C" box="[410,433,721,742]" italics="true" pageId="4" pageNumber="1484">46</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F41C007E580FD718976DECF" blockId="4.[96,540,108,1914]" pageId="4" pageNumber="1484">
|
||
Such large bite forces would have exerted tremendous stress on the skull. Tyrannosaurid skull shape and its relation to bite-induced stress have been extensively studied by finite element analysis. The results indicate that large tyrannosaurids had skulls optimized to endure strong bites, as various sutures absorbed stress and the fused nasals strengthened the snout (
|
||
<bibRefCitation id="EFCB93C48F41C007E4B2FC2D89ECD9AC" author="E. J. Rayfield" box="[434,454,945,966]" journalOrPublisher="Proc. Biol. Sci" pageId="4" pageNumber="1484" pagination="1451" part="271" refId="ref5331" refString="11. E. J. Rayfield, Proc. Biol. Sci. 271, 1451 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F41C007E4B2FC2D89ECD9AC" box="[434,454,945,966]" italics="true" pageId="4" pageNumber="1484">11</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F41C007E4D3FC2D89C0D9AC" author="E. J. Rayfield" box="[467,490,945,966]" journalOrPublisher="Zool. J. Linn. Soc." pageId="4" pageNumber="1484" pagination="309" part="144" refId="ref6291" refString="47. E. J. Rayfield, Zool. J. Linn. Soc. 144, 309 (2005)." type="journal article" year="2005">
|
||
<emphasis id="B92E32278F41C007E4D3FC2D89C0D9AC" box="[467,490,945,966]" italics="true" pageId="4" pageNumber="1484">47</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F41C007E4F7FC2D8A24D9AC" author="E. Snively & D. M. Henderson & D. S. Phillips" box="[503,526,945,966]" journalOrPublisher="Acta Palaeontol. Pol." pageId="4" pageNumber="1484" pagination="435" part="51" refId="ref6314" refString="48. E. Snively, D. M. Henderson, D. S. Phillips, Acta Palaeontol. Pol. 51, 435 (2006)." type="journal article" year="2006">
|
||
<emphasis id="B92E32278F41C007E4F7FC2D8A24D9AC" box="[503,526,945,966]" italics="true" pageId="4" pageNumber="1484">48</emphasis>
|
||
</bibRefCitation>
|
||
). Similar biomechanical techniques have also been used to examine the role of the tyrannosaur neck in feeding, showing that it was important for generating pulling forces on food items and in inertial feeding (
|
||
<bibRefCitation id="EFCB93C48F41C007E403FBA08930DE3B" author="E. Snively & A. P. Russell" box="[259,282,1084,1105]" journalOrPublisher="Paleobiology" pageId="4" pageNumber="1484" pagination="610" part="33" refId="ref6344" refString="49. E. Snively, A. P. Russell, Paleobiology 33, 610 (2007)." type="journal article" year="2007">
|
||
<emphasis id="B92E32278F41C007E403FBA08930DE3B" box="[259,282,1084,1105]" italics="true" pageId="4" pageNumber="1484">49</emphasis>
|
||
</bibRefCitation>
|
||
), and the function of the unusual “pinched metatarsus” of the foot in turning, indicating that it was structured to resist shearing and twisting forces (
|
||
<bibRefCitation id="EFCB93C48F41C007E439FB0C897ADECF" author="E. Snively & A. P. Russell" box="[313,336,1168,1189]" journalOrPublisher="J. Morphol." pageId="4" pageNumber="1484" pagination="215" part="255" refId="ref6364" refString="50. E. Snively, A. P. Russell, J. Morphol. 255, 215 (2003)." type="journal article" year="2003">
|
||
<emphasis id="B92E32278F41C007E439FB0C897ADECF" box="[313,336,1168,1189]" italics="true" pageId="4" pageNumber="1484">50</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F41C007E580FB308927DD28" blockId="4.[96,540,108,1914]" pageId="4" pageNumber="1484">
|
||
Little is known about the ecological community structure for most extinct animals, but large sample sizes permit some understanding of tyrannosaur ecology. Late Cretaceous tyrannosaurids were the first dinosaurs for which population dynamics—the balance between deaths and births that create a population’ s age structure— could be assessed (
|
||
<bibRefCitation id="EFCB93C48F41C007E40CFAF38908DFEE" author="G. M. Erickson & P. J. Currie & B. D. Inouye & A. A. Winn" box="[268,290,1391,1412]" journalOrPublisher="Science" pageId="4" pageNumber="1484" pagination="213" part="313" refId="ref5297" refString="10. G. M. Erickson, P. J. Currie, B. D. Inouye, A. A. Winn, Science 313, 213 (2006)." type="journal article" year="2006">
|
||
<emphasis id="B92E32278F41C007E40CFAF38908DFEE" box="[268,290,1391,1412]" italics="true" pageId="4" pageNumber="1484">10</emphasis>
|
||
</bibRefCitation>
|
||
) (
|
||
<figureCitation id="1361F2B08F41C007E436FAF38954DFEE" box="[310,382,1391,1412]" captionStart="Fig. 4" captionStartId="4.[929,964,1626,1648]" captionTargetBox="[931,1485,108,1608]" captionTargetId="figure@4.[1026,1267,838,980]" captionTargetPageId="4" captionText="Fig. 4. Tyrannosaur growth and ecology. (A) Histological section of a T. rex dorsal ribι showing growth lines whose counts are used to reveal age andlongevity.(B) Growth curves for North American tyrannosaurids derived from growth line counts and body size estimations for individuals showing how size changes with age. No sampled tyrannosaurid adults were more than 30 years oldι and accelerated rather than prolonged development was the key to the great size of T. rex (8). (C) survivorship curve for Albertosaurus sarcophagus. This tyrannosaur exhibited high neonate mortalityι then few deaths after age twoι and then increased mortality at mid-life (8)." figureDoi="http://doi.org/10.5281/zenodo.3744295" httpUri="https://zenodo.org/record/3744295/files/figure.png" pageId="4" pageNumber="1484">Fig. 4C</figureCitation>
|
||
). Like large birds and mammals, but unlike living reptiles, tyrannosaurids probably experienced extremely high neonate mortality, followed by few deaths after 2 years of age (presumably a release from predation), and then increased mortality at mid-life (probably from the rigors of reproduction), so that few individuals had a long reproductive life span. Furthermore, a number of fossil sites have preserved multiple individuals, suggesting that tyrannosaurs were at least occasionally gregarious (
|
||
<bibRefCitation id="EFCB93C48F41C007E4F8F91A8A24DCF1" author="P. J. Currie" box="[504,526,1670,1691]" journalOrPublisher="Gaia" pageId="4" pageNumber="1484" pagination="271" part="15" refId="ref6387" refString="51. P. J. Currie, Gaia 15, 271 (2000)." type="journal article" year="2000">
|
||
<emphasis id="B92E32278F41C007E4F8F91A8A24DCF1" box="[504,526,1670,1691]" italics="true" pageId="4" pageNumber="1484">51</emphasis>
|
||
</bibRefCitation>
|
||
). Bite marks indicate that individuals of the same species bit each other in the face during encounters (
|
||
<bibRefCitation id="EFCB93C48F41C007E5BEF94588FCDC84" author="D. H. Tanke & P. J. currie" box="[190,214,1753,1774]" journalOrPublisher="Gaia" pageId="4" pageNumber="1484" pagination="168" part="15" refId="ref6403" refString="52. D. H. Tanke, P. J. Currie, Gaia 15, 168 (2000)." type="journal article" year="2000">
|
||
<emphasis id="B92E32278F41C007E5BEF94588FCDC84" box="[190,214,1753,1774]" italics="true" pageId="4" pageNumber="1484">52</emphasis>
|
||
</bibRefCitation>
|
||
), and many older individuals with gout, bacterial legions, and bone fractures have been reported, showing that disease and injury were common (
|
||
<bibRefCitation id="EFCB93C48F41C007E5EBF8B1892BDD28" author="D. H. Tanke & B. M. Rothschild" box="[235,257,1837,1858]" journalOrPublisher="New Mex. Mus. Nat. Hist. Sci. Bull" pageId="4" pageNumber="1484" pagination="1" part="20" refId="ref6425" refString="53. D. H. Tanke, B. M. Rothschild, New Mex. Mus. Nat. Hist. Sci. Bull 20, 1 (2001)." type="journal article" year="2001">
|
||
<emphasis id="B92E32278F41C007E5EBF8B1892BDD28" box="[235,257,1837,1858]" italics="true" pageId="4" pageNumber="1484">53</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<caption id="DF25BEBD8F41C007E6A1F9C68CE5DD10" ID-DOI="http://doi.org/10.5281/zenodo.3744295" ID-Zenodo-Dep="3744295" httpUri="https://zenodo.org/record/3744295/files/figure.png" pageId="4" pageNumber="1484" startId="4.[929,964,1626,1648]" targetBox="[931,1485,108,1608]" targetPageId="4">
|
||
<paragraph id="8BE5EE358F41C007E6A1F9C68CE5DD10" blockId="4.[929,1488,1626,1914]" pageId="4" pageNumber="1484">
|
||
Fig. 4. Tyrannosaur growth and ecology. (A) Histological section of a
|
||
<taxonomicName id="4C5A95B68F41C007E10BF9EA8C13DCE1" authority="Osborn, 1905" box="[1035,1081,1654,1675]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="1484" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F41C007E10BF9EA8C13DCE1" bold="true" box="[1035,1081,1654,1675]" italics="true" pageId="4" pageNumber="1484">T. rex</emphasis>
|
||
</taxonomicName>
|
||
dorsal rib, showing growth lines whose counts are used to reveal age and longevity. (B) Growth curves for North American tyrannosaurids derived from growth line counts and body size estimations for individuals showing how size changes with age. No sampled tyrannosaurid adults were more than 30 years old, and accelerated rather than prolonged development was the key to the great size of
|
||
<taxonomicName id="4C5A95B68F41C007E1B7F8898CCCDD40" authority="Osborn, 1905" box="[1207,1254,1813,1834]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="1484" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F41C007E1B7F8898CEADD40" bold="true" box="[1207,1216,1813,1834]" italics="true" pageId="4" pageNumber="1484">T</emphasis>
|
||
.
|
||
<emphasis id="B92E32278F41C007E1CCF8898CCCDD40" bold="true" box="[1228,1254,1813,1834]" italics="true" pageId="4" pageNumber="1484">rex</emphasis>
|
||
</taxonomicName>
|
||
(
|
||
<bibRefCitation id="EFCB93C48F41C007E1F2F8898CD4DD40" author="G. M. Erickson" box="[1266,1278,1813,1834]" journalOrPublisher="Nature" pageId="4" pageNumber="1484" pagination="772" part="430" refId="ref5257" refString="8. G. M. Erickson et al., Nature 430, 772 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F41C007E1F2F8898CD4DD40" bold="true" box="[1266,1278,1813,1834]" italics="true" pageId="4" pageNumber="1484">8</emphasis>
|
||
</bibRefCitation>
|
||
). (C) survivorship curve for
|
||
<emphasis id="B92E32278F41C007E6C0F8AC8C87DD2F" bold="true" box="[960,1197,1840,1861]" italics="true" pageId="4" pageNumber="1484">
|
||
<taxonomicName id="4C5A95B68F41C007E6C0F8AC8C12DD2F" authorityName="Osborn" authorityYear="1905" box="[960,1080,1840,1861]" class="Reptilia" family="Tyrannosauridae" genus="Albertosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="1484" phylum="Chordata" rank="genus">Albertosaurus</taxonomicName>
|
||
sarcophagus
|
||
</emphasis>
|
||
. This tyrannosaur exhibited high neonate mortality, then few deaths after age two, and then increased mortality at mid-life (
|
||
<bibRefCitation id="EFCB93C48F41C007E1B7F8F98CE9DD10" author="G. M. Erickson" box="[1207,1219,1893,1914]" journalOrPublisher="Nature" pageId="4" pageNumber="1484" pagination="772" part="430" refId="ref5257" refString="8. G. M. Erickson et al., Nature 430, 772 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F41C007E1B7F8F98CE9DD10" bold="true" box="[1207,1219,1893,1914]" italics="true" pageId="4" pageNumber="1484">8</emphasis>
|
||
</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
</caption>
|
||
<paragraph id="8BE5EE358F41C007E580F8D58B7ED997" blockId="4.[96,540,108,1914]" lastBlockId="4.[571,898,108,1914]" pageId="4" pageNumber="1484">
|
||
Multiple lines of evidence indicate that tyrannosaur ecological habits changed during ontogeny. In Late Cretaceous tyrannosaurids, the difference in form between the lightly built, fleet juveniles and the larger, bulkier adults suggests that foraging behavior and targeted prey size changed as tyrannosaurs grew. The deep and muscular adult skull, with reinforced sutures and robust teeth, is well suited for sustaining high bite forces, whereas juveniles had none of these features (
|
||
<bibRefCitation id="EFCB93C48F41C007E621FE1F8B06DBF2" author="T. D. Carr" box="[801,812,387,408]" journalOrPublisher="J. Vertebr. Paleontol." pageId="4" pageNumber="1484" pagination="497" part="19" refId="ref5276" refString="9. T. D. Carr, J. Vertebr. Paleontol. 19, 497 (1999)." type="journal article" year="1999">
|
||
<emphasis id="B92E32278F41C007E621FE1F8B06DBF2" box="[801,812,387,408]" italics="true" pageId="4" pageNumber="1484">9</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F41C007E636FE1F8B61DBF2" author="T. D. Carr & T. E. Williamson" box="[822,843,387,408]" journalOrPublisher="Zool. J. Linn. Soc." pageId="4" pageNumber="1484" pagination="479" part="142" refId="ref6085" refString="39. T. D. Carr, T. E. Williamson, Zool. J. Linn. Soc. 142, 479 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F41C007E636FE1F8B61DBF2" box="[822,843,387,408]" italics="true" pageId="4" pageNumber="1484">39</emphasis>
|
||
</bibRefCitation>
|
||
). Furthermore, the longer and more gracile hind limbs of juveniles indicate that they were relatively faster than adults (
|
||
<bibRefCitation id="EFCB93C48F41C007E77DFE6E8ABED86D" author="P. J. Currie" box="[637,660,498,519]" journalOrPublisher="Can. J. Earth Sci." pageId="4" pageNumber="1484" pagination="651" part="40" refId="ref6114" refString="40. P. J. Currie, Can. J. Earth Sci. 40, 651 (2003)." type="journal article" year="2003">
|
||
<emphasis id="B92E32278F41C007E77DFE6E8ABED86D" box="[637,660,498,519]" italics="true" pageId="4" pageNumber="1484">40</emphasis>
|
||
</bibRefCitation>
|
||
), which has been corroborated by biomechanical analysis (
|
||
<bibRefCitation id="EFCB93C48F41C007E742FDB68A72D855" author="J. R. Hutchinson & M. Garcia" box="[578,600,554,575]" journalOrPublisher="Nature" pageId="4" pageNumber="1484" pagination="1018" part="415" refId="ref5352" refString="12. J. R. Hutchinson, M. Garcia, Nature 415, 1018 (2002)." type="journal article" year="2002">
|
||
<emphasis id="B92E32278F41C007E742FDB68A72D855" box="[578,600,554,575]" italics="true" pageId="4" pageNumber="1484">12</emphasis>
|
||
</bibRefCitation>
|
||
). These differences could have promoted major size-related shifts in ecology and behavior. It is plausible that adults preferentially attack- ed larger, but less mobile, prey than their younger counterparts. Such an ontogenetic shift is not seen in many familiar predators today (e.g., lions), but is present in extant crocodylians (
|
||
<bibRefCitation id="EFCB93C48F41C007E742FCB98A73D950" author="P. Dodson" box="[578,601,805,826]" journalOrPublisher="J. Zool." pageId="4" pageNumber="1484" pagination="315" part="175" refId="ref6458" refString="54. P. Dodson, J. Zool. 175, 315 (1975)." type="journal article" year="1975">
|
||
<emphasis id="B92E32278F41C007E742FCB98A73D950" box="[578,601,805,826]" italics="true" pageId="4" pageNumber="1484">54</emphasis>
|
||
</bibRefCitation>
|
||
). As most basal tyrannosauroids are similar in skull and body proportions to juvenile Late Cretaceous tyrannosaurids, it is likely that they behaved and fed in a similar manner. However, detailed biomechanical analyses have yet to be carried out for most nontyrannosaurid tyrannosauroids.
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F41C007E75BFB988ACEDFD6" blockId="4.[571,898,108,1914]" pageId="4" pageNumber="1484">
|
||
Whether
|
||
<taxonomicName id="4C5A95B68F41C007E7B3FB988AC3DE73" authority="Osborn, 1905" box="[691,745,1028,1049]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="1484" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F41C007E7B3FB988A94DE73" box="[691,702,1028,1049]" italics="true" pageId="4" pageNumber="1484">T</emphasis>
|
||
.
|
||
<emphasis id="B92E32278F41C007E7CCFB988AC3DE73" box="[716,745,1028,1049]" italics="true" pageId="4" pageNumber="1484">rex</emphasis>
|
||
</taxonomicName>
|
||
and other large tyrannosaurs were scavengers or predators has generated much speculation and dispute. Bite marks from mass death assemblages of herbivorous dinosaurs show that tyrannosaurs scavenged on occasion (
|
||
<bibRefCitation id="EFCB93C48F41C007E620FB308B1DDEAB" author="G. M. Erickson" box="[800,823,1196,1217]" journalOrPublisher="Sci. Am." pageId="4" pageNumber="1484" pagination="32" part="9" refId="ref6066" refString="38. G. M. Erickson, Sci. Am. 9, 32 (1999)." type="journal article" year="1999">
|
||
<emphasis id="B92E32278F41C007E620FB308B1DDEAB" box="[800,823,1196,1217]" italics="true" pageId="4" pageNumber="1484">38</emphasis>
|
||
</bibRefCitation>
|
||
). However, multiple reports of healed tyrannosaur bite marks on prey bones (
|
||
<bibRefCitation id="EFCB93C48F41C007E742FB638A72DF7E" author="K. carpenter" box="[578,600,1279,1300]" journalOrPublisher="Gaia" pageId="4" pageNumber="1484" pagination="135" part="15" refId="ref6475" refString="55. K. Carpenter, Gaia 15, 135 (2000)." type="journal article" year="2000">
|
||
<emphasis id="B92E32278F41C007E742FB638A72DF7E" box="[578,600,1279,1300]" italics="true" pageId="4" pageNumber="1484">55</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F41C007E76BFB638AABDF7E" author="J. Happ" box="[619,641,1279,1300]" editor="P. Larson & K. carpenter" journalOrPublisher="Indiana Univ. Press, Bloomington" pageId="4" pageNumber="1484" pagination="354 - 368" refId="ref6489" refString="56. J. Happ, in Tyrannosaurus rex: The Tyrant King, P. Larson, K. Carpenter, Eds. (Indiana Univ. Press, Bloomington, 2008), pp. 354 - 368." type="book chapter" volumeTitle="Tyrannosaurus rex: The Tyrant King" year="2008">
|
||
<emphasis id="B92E32278F41C007E76BFB638AABDF7E" box="[619,641,1279,1300]" italics="true" pageId="4" pageNumber="1484">56</emphasis>
|
||
</bibRefCitation>
|
||
) and tyrannosaur stomach contents containing remains of young dinosaurs (
|
||
<bibRefCitation id="EFCB93C48F41C007E7A2FAAB8A92DF26" author="D. J. Varricchio" box="[674,696,1335,1356]" journalOrPublisher="J. Paleontol." pageId="4" pageNumber="1484" pagination="401" part="75" refId="ref6530" refString="57. D. J. Varricchio, J. Paleontol. 75, 401 (2001)." type="journal article" year="2001">
|
||
<emphasis id="B92E32278F41C007E7A2FAAB8A92DF26" box="[674,696,1335,1356]" italics="true" pageId="4" pageNumber="1484">57</emphasis>
|
||
</bibRefCitation>
|
||
) indicate that tyrannosaurs were capable of active predation. Like most carnivores, tyrannosaurs probably both scavenged and hunted.
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F41C006E75BFA5E894DDAF7" blockId="4.[571,898,108,1914]" lastBlockId="5.[96,538,108,157]" lastPageId="5" lastPageNumber="1485" pageId="4" pageNumber="1484">
|
||
One of the largest voids in our understanding of dinosaur biology is the sex of individual specimens. It has been suggested that female tyrannosaurs required a larger pelvic outlet for the passage of eggs, reflected by a greater span between the ischial bones and a smaller or more posteriorly located first tail chevron,but these indices find little neontological support in living archosaurs (
|
||
<bibRefCitation id="EFCB93C48F41C007E636F9458B67DC84" author="G. M. Erickson & A. K. Lappin & P. Larson" box="[822,845,1753,1774]" journalOrPublisher="Zool" pageId="4" pageNumber="1484" pagination="277" part="108" refId="ref6549" refString="58. G. M. Erickson, A. K. Lappin, P. Larson, Zool 108, 277 (2005)." type="journal article" year="2005">
|
||
<emphasis id="B92E32278F41C007E636F9458B67DC84" box="[822,845,1753,1774]" italics="true" pageId="4" pageNumber="1484">58</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F41C007E65DF9458B5EDC84" author="A. Prieto-Marquez & P. M. Gignac & S. Joshi" box="[861,884,1753,1774]" journalOrPublisher="J. Vertebr. Paleontol." pageId="4" pageNumber="1484" pagination="603" part="27" refId="ref6575" refString="59. A. Prieto-Marquez, P. M. Gignac, S. Joshi, J. Vertebr. Paleontol. 27, 603 (2007)." type="journal article" year="2007">
|
||
<emphasis id="B92E32278F41C007E65DF9458B5EDC84" box="[861,884,1753,1774]" italics="true" pageId="4" pageNumber="1484">59</emphasis>
|
||
</bibRefCitation>
|
||
). More recently, medullary bone, a calcium phosphate deposit for the use of shelling in eggs, was reported in one
|
||
<taxonomicName id="4C5A95B68F41C007E73BF8D58A47DD34" authority="Osborn, 1905" box="[571,621,1865,1886]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="1484" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F41C007E73BF8D58A6CDD34" box="[571,582,1865,1886]" italics="true" pageId="4" pageNumber="1484">T</emphasis>
|
||
.
|
||
<emphasis id="B92E32278F41C007E752F8D58A47DD34" box="[594,621,1865,1886]" italics="true" pageId="4" pageNumber="1484">rex</emphasis>
|
||
</taxonomicName>
|
||
specimen (
|
||
<bibRefCitation id="EFCB93C48F41C007E7D9F8D58ADADD34" author="M. H. Schweitzer & J. L. Wittmeyer & J. R. Horner" box="[729,752,1865,1886]" journalOrPublisher="Science" pageId="4" pageNumber="1484" pagination="1456" part="308" refId="ref6604" refString="60. M. H. Schweitzer, J. L. Wittmeyer, J. R. Horner, Science 308, 1456 (2005)." type="journal article" year="2005">
|
||
<emphasis id="B92E32278F41C007E7D9F8D58ADADD34" box="[729,752,1865,1886]" italics="true" pageId="4" pageNumber="1484">60</emphasis>
|
||
</bibRefCitation>
|
||
). This provides a surefire identification of sex in dino- saurs, and holds much promise for future studies of dinosaur sex and ecology.
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F40C006E560FF26894FDAA5" blockId="5.[96,540,186,1774]" box="[96,357,186,207]" pageId="5" pageNumber="1485">
|
||
<heading id="D0AD59598F40C006E560FF26894FDAA5" bold="true" box="[96,357,186,207]" fontSize="9" level="3" pageId="5" pageNumber="1485" reason="6">
|
||
<emphasis id="B92E32278F40C006E560FF26894FDAA5" bold="true" box="[96,357,186,207]" pageId="5" pageNumber="1485">Tyrannosaur Biogeography</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F40C006E560FF478919D974" blockId="5.[96,540,186,1774]" pageId="5" pageNumber="1485">
|
||
Until recently, all tyrannosaur fossils were limited to Asia and North America, but the discovery and recognition of basal tyrannosauroids over the last decade reveals a more cosmopolitan distribution during their early evolution (
|
||
<bibRefCitation id="EFCB93C48F40C006E460FED78941DB0A" author="O. W. M. Rauhut & A. C. Milner & S. Moore-Fay" box="[352,363,331,352]" journalOrPublisher="Zool. J. Linn. Soc" pageId="5" pageNumber="1485" pagination="155" part="158" refId="ref5174" refString="5. O. W. M. Rauhut, A. C. Milner, S. Moore-Fay, Zool. J. Linn. Soc. 158, 155 (2010)." type="journal article" year="2010">
|
||
<emphasis id="B92E32278F40C006E460FED78941DB0A" box="[352,363,331,352]" italics="true" pageId="5" pageNumber="1485">5</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<emphasis id="B92E32278F40C006E476FED7899ADB0A" box="[374,432,330,352]" italics="true" pageId="5" pageNumber="1485">
|
||
<bibRefCitation id="EFCB93C48F40C006E476FED789A7DB0A" author="X. Xu" box="[374,397,331,352]" journalOrPublisher="Nature" pageId="5" pageNumber="1485" pagination="715" part="439" refId="ref5665" refString="22. X. Xu et al., Nature 439, 715 (2006)." type="journal article" year="2006">22</bibRefCitation>
|
||
–
|
||
<bibRefCitation id="EFCB93C48F40C006E499FED7899ADB0A" author="R. B. J. Benson & J. Vertebr" box="[409,432,331,352]" journalOrPublisher="Paleontol" pageId="5" pageNumber="1485" pagination="732" part="28" refId="ref5721" refString="24. R. B. J. Benson, J. Vertebr. Paleontol. 28, 732 (2008)." type="journal article" year="2008">24</bibRefCitation>
|
||
</emphasis>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F40C006E4BAFED789FBDB0A" author="A. O. Averianov & S. A. Krasnolutskii & S. V. Ivantsov" box="[442,465,331,352]" journalOrPublisher="Proc. Zool. Inst. RAS" pageId="5" pageNumber="1485" pagination="42" part="314" refId="ref6632" refString="61. A. O. Averianov, S. A. Krasnolutskii, S. V. Ivantsov, Proc. Zool. Inst. RAS 314, 42 (2010)." type="journal article" year="2010">
|
||
<emphasis id="B92E32278F40C006E4BAFED789FBDB0A" box="[442,465,331,352]" italics="true" pageId="5" pageNumber="1485">61</emphasis>
|
||
</bibRefCitation>
|
||
). Members of the Middle
|
||
<emphasis id="B92E32278F40C006E408FEFA8939DB16" box="[264,275,358,380]" italics="true" pageId="5" pageNumber="1485">–</emphasis>
|
||
Late Jurassic proceratosaurid radiation are known from Europe and Asia (
|
||
<bibRefCitation id="EFCB93C48F40C006E702FE1F8A27DBF2" author="O. W. M. Rauhut & A. C. Milner & S. Moore-Fay" box="[514,525,387,408]" journalOrPublisher="Zool. J. Linn. Soc" pageId="5" pageNumber="1485" pagination="155" part="158" refId="ref5174" refString="5. O. W. M. Rauhut, A. C. Milner, S. Moore-Fay, Zool. J. Linn. Soc. 158, 155 (2010)." type="journal article" year="2010">
|
||
<emphasis id="B92E32278F40C006E702FE1F8A27DBF2" box="[514,525,387,408]" italics="true" pageId="5" pageNumber="1485">5</emphasis>
|
||
</bibRefCitation>
|
||
), whereas the Late Jurassic genus
|
||
<emphasis id="B92E32278F40C006E485FE028A2DDBD9" box="[389,519,414,435]" italics="true" pageId="5" pageNumber="1485">Stokesosaurus</emphasis>
|
||
is known from both Europe and North America (
|
||
<bibRefCitation id="EFCB93C48F40C006E4F7FE268A27DBA5" author="R. B. J. Benson & J. Vertebr" box="[503,525,442,463]" journalOrPublisher="Paleontol" pageId="5" pageNumber="1485" pagination="732" part="28" refId="ref5721" refString="24. R. B. J. Benson, J. Vertebr. Paleontol. 28, 732 (2008)." type="journal article" year="2008">
|
||
<emphasis id="B92E32278F40C006E4F7FE268A27DBA5" box="[503,525,442,463]" italics="true" pageId="5" pageNumber="1485">24</emphasis>
|
||
</bibRefCitation>
|
||
). However, all well-known tyrannosaurs more derived than
|
||
<emphasis id="B92E32278F40C006E5C1FE6E8903D86D" box="[193,297,498,519]" italics="true" pageId="5" pageNumber="1485">Eotyrannus</emphasis>
|
||
and
|
||
<emphasis id="B92E32278F40C006E456FE6E89FCD86D" box="[342,470,498,519]" italics="true" pageId="5" pageNumber="1485">Stokesosaurus</emphasis>
|
||
exhibit a purely Asian or North American distribution. Faunal interchange between these continents is characteristic of most Campanian-Maastrichtian dinosaur clades and reflects an increasing Laurasian- Gondwanan provincialism during the final stages of the Age of Dinosaurs (
|
||
<bibRefCitation id="EFCB93C48F40C006E44FFD06894FD8C5" author="P. Upchurch & c. A. Hunn & D. B. Norman" box="[335,357,666,687]" journalOrPublisher="Proc. Biol. Sci." pageId="5" pageNumber="1485" pagination="613" part="269" refId="ref6666" refString="62. P. Upchurch, C. A. Hunn, D. B. Norman, Proc. Biol. Sci. 269, 613 (2002)." type="journal article" year="2002">
|
||
<emphasis id="B92E32278F40C006E44FFD06894FD8C5" box="[335,357,666,687]" italics="true" pageId="5" pageNumber="1485">62</emphasis>
|
||
</bibRefCitation>
|
||
). Tyrannosaurs, because of their rich fossil record and well-studied phylogenetic relationships, are one of the primary sources of evidence for this long-established biogeographic hypothesis.
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F40C006E580FCB98A20DF7E" blockId="5.[96,540,186,1774]" pageId="5" pageNumber="1485">
|
||
Emerging evidence, however, indicates that tyrannosaurs were likely present on the southern continents during their early evolutionary history. An isolated pubis from the Early Cretaceous of Australia was recently identified as belonging to a derived tyrannosaur (
|
||
<bibRefCitation id="EFCB93C48F40C006E424FC2D8910D9AC" author="R. B. J. Benson & P. M. Barrett & T. H. Rich & P. Vickers-Rich" box="[292,314,945,966]" journalOrPublisher="Science" pageId="5" pageNumber="1485" pagination="1613" part="327" refId="ref5372" refString="13. R. B. J. Benson, P. M. Barrett, T. H. Rich, P. Vickers-Rich, Science 327, 1613 (2010)." type="journal article" year="2010">
|
||
<emphasis id="B92E32278F40C006E424FC2D8910D9AC" box="[292,314,945,966]" italics="true" pageId="5" pageNumber="1485">13</emphasis>
|
||
</bibRefCitation>
|
||
). As contemporary Earlymid Cretaceous dinosaurs mostly belong to globally distributed clades (
|
||
<bibRefCitation id="EFCB93C48F40C006E465FC748956D997" author="S. L. Brusatte" box="[357,380,1000,1021]" journalOrPublisher="Naturwissenschaften" pageId="5" pageNumber="1485" pagination="1051" part="96" refId="ref5776" refString="26. S. L. Brusatte et al., Naturwissenschaften 96, 1051 (2009)." type="journal article" year="2009">
|
||
<emphasis id="B92E32278F40C006E465FC748956D997" box="[357,380,1000,1021]" italics="true" pageId="5" pageNumber="1485">26</emphasis>
|
||
</bibRefCitation>
|
||
), the absence of Gondwanan tyrannosaurs during this time had been a puzzling anomaly. Even with this discovery, if it is from a tyrannosaur, tyrannosaurs are absent in the well-sampled mid-Late Cretaceous units of South America, Africa, and Madagascar (
|
||
<bibRefCitation id="EFCB93C48F40C006E567FB0C8857DECF" author="D. B. Weishampel" box="[103,125,1168,1189]" editor="D. B. Weishampel & P. Dodson & H. Osmolska" journalOrPublisher="Univ. of california Press, Berkeley" pageId="5" pageNumber="1485" pagination="517 - 606" part="2" refId="ref6697" refString="63. D. B. Weishampel et al., in The Dinosauria, D. B. Weishampel, P. Dodson, H. Osmolska, Eds. (Univ. of California Press, Berkeley, ed. 2, 2004), pp. 517 - 606." type="book chapter" volumeTitle="The Dinosauria" year="2004">
|
||
<emphasis id="B92E32278F40C006E567FB0C8857DECF" box="[103,125,1168,1189]" italics="true" pageId="5" pageNumber="1485">63</emphasis>
|
||
</bibRefCitation>
|
||
). It is possible that tyrannosaurs were rare on the southern continents during the Early-mid Cretaceous, and it is likely that Gondwanan forms did not persist into the latest Cretaceous, at least as common and ecologically dominant carnivores.
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F40C006E580FA878BD8DABE" blockId="5.[96,540,186,1774]" lastBlockId="5.[571,1013,108,212]" pageId="5" pageNumber="1485">
|
||
Most tyrannosaurs are known from mesic (moderate moisture) or seasonally mesic paleoenvironments, and their fossils are notably absent from xeric (dry) facies, even those that interfinger with tyrannosaur-bearing mesic sediments within the same sedimentary rock basins in Asia (
|
||
<bibRefCitation id="EFCB93C48F40C006E4F7FA3B8A24DFD6" author="P. J. Makovicky" box="[503,526,1447,1468]" journalOrPublisher="Proc. Biol. Sci." pageId="5" pageNumber="1485" pagination="191" part="277" refId="ref6750" refString="64. P. J. Makovicky et al., Proc. Biol. Sci. 277, 191 (2010)." type="journal article" year="2010">
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<emphasis id="B92E32278F40C006E4F7FA3B8A24DFD6" box="[503,526,1447,1468]" italics="true" pageId="5" pageNumber="1485">64</emphasis>
|
||
</bibRefCitation>
|
||
). This likely indicates that tyrannosaurs preferred wetter habitats, although it may still reflect a sampling bias. Wherever they were present during the Late Cretaceous in North America and Asia, tyrannosaurs were the sole apex predators in their environments. Multiple large tyrannosaurids co-occurred during some intervals in North America and Asia (
|
||
<bibRefCitation id="EFCB93C48F40C006E411F91A8902DCF1" author="S. L. Brusatte & T. D. Carr & G. M. Erickson & G. S. Bever & M. A. Norell" box="[273,296,1670,1691]" journalOrPublisher="Proc. Natl. Acad. Sci. U. S. A." pageId="5" pageNumber="1485" pagination="17261" part="106" refId="ref5542" refString="19. S. L. Brusatte, T. D. Carr, G. M. Erickson, G. S. Bever, M. A. Norell, Proc. Natl. Acad. Sci. U. S. A. 106, 17261 (2009)." type="journal article" year="2009">
|
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<emphasis id="B92E32278F40C006E411F91A8902DCF1" box="[273,296,1670,1691]" italics="true" pageId="5" pageNumber="1485">19</emphasis>
|
||
</bibRefCitation>
|
||
,
|
||
<bibRefCitation id="EFCB93C48F40C006E433F91A8960DCF1" author="S. L. Brusatte" box="[307,330,1670,1691]" journalOrPublisher="Acta Palaeontol. Pol." pageId="5" pageNumber="1485" pagination="191" part="48" refId="ref5795" refString="27. P. J. Currie, Acta Palaeontol. Pol. 48, 191 (2003)." title="P. J. currie" type="journal article" year="2003">
|
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<emphasis id="B92E32278F40C006E433F91A8960DCF1" box="[307,330,1670,1691]" italics="true" pageId="5" pageNumber="1485">27</emphasis>
|
||
</bibRefCitation>
|
||
), but the Maastrichtian of western North America was solely dominated by
|
||
<taxonomicName id="4C5A95B68F40C006E57DF9228884DCB9" authority="Osborn, 1905" box="[125,174,1726,1747]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="1485" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F40C006E57DF92288A2DCB9" box="[125,136,1726,1747]" italics="true" pageId="5" pageNumber="1485">T</emphasis>
|
||
.
|
||
<emphasis id="B92E32278F40C006E593F9228884DCB9" box="[147,174,1726,1747]" italics="true" pageId="5" pageNumber="1485">rex</emphasis>
|
||
</taxonomicName>
|
||
(
|
||
<bibRefCitation id="EFCB93C48F40C006E5BCF92288F8DCB9" author="T. D. Carr & T. E. Williamson" box="[188,210,1726,1747]" journalOrPublisher="Zool. J. Linn. Soc." pageId="5" pageNumber="1485" pagination="479" part="142" refId="ref6085" refString="39. T. D. Carr, T. E. Williamson, Zool. J. Linn. Soc. 142, 479 (2004)." type="journal article" year="2004">
|
||
<emphasis id="B92E32278F40C006E5BCF92288F8DCB9" box="[188,210,1726,1747]" italics="true" pageId="5" pageNumber="1485">39</emphasis>
|
||
</bibRefCitation>
|
||
). In contrast, most nontyrannosaurid tyrannosauroids are found alongside larger non- tyrannosaur predators, demonstrating that tyrannosaurs did not exclusively dominate the apex predator niche, regardless of where they lived, until the final 20 million years of the Cretaceous.
|
||
</paragraph>
|
||
</subSubSection>
|
||
<subSubSection id="C340BDBE8F40C006E73BFF6E8BC9D855" pageId="5" pageNumber="1485" type="discussion">
|
||
<paragraph id="8BE5EE358F40C006E73BFF6E8A8EDB6D" blockId="5.[571,1014,242,575]" box="[571,676,242,263]" pageId="5" pageNumber="1485">
|
||
<heading id="D0AD59598F40C006E73BFF6E8A8EDB6D" bold="true" box="[571,676,242,263]" fontSize="9" level="3" pageId="5" pageNumber="1485" reason="6">
|
||
<emphasis id="B92E32278F40C006E73BFF6E8A8EDB6D" bold="true" box="[571,676,242,263]" pageId="5" pageNumber="1485">Conclusion</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph id="8BE5EE358F40C006E73BFE8F8BC9D855" blockId="5.[571,1014,242,575]" pageId="5" pageNumber="1485">
|
||
<taxonomicName id="4C5A95B68F40C006E73BFE8F8ADADB42" authority="Osborn, 1905" box="[571,752,275,296]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="1485" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis id="B92E32278F40C006E73BFE8F8ADADB42" box="[571,752,275,296]" italics="true" pageId="5" pageNumber="1485">Tyrannosaurus rex</emphasis>
|
||
</taxonomicName>
|
||
and its close relatives are the most intensely studied dinosaurs. Derived tyrannosaurs such as
|
||
<taxonomicName id="4C5A95B68F40C006E7F8FED78B5FDB0A" authorityName="Osborn" authorityYear="1905" box="[760,885,331,352]" class="Reptilia" family="Tyrannosauridae" genus="Albertosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="1485" phylum="Chordata" rank="genus">
|
||
<emphasis id="B92E32278F40C006E7F8FED78B5FDB0A" box="[760,885,331,352]" italics="true" pageId="5" pageNumber="1485">Albertosaurus</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName id="4C5A95B68F40C006E680FED78BDADB0A" authorityName="Maleev" authorityYear="1955" box="[896,1008,331,352]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="1485" phylum="Chordata" rank="genus">
|
||
<emphasis id="B92E32278F40C006E680FED78BDADB0A" box="[896,1008,331,352]" italics="true" pageId="5" pageNumber="1485">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
, and
|
||
<taxonomicName id="4C5A95B68F40C006E762FEFB8ACDDB16" authority="Osborn, 1905" box="[610,743,359,380]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="1485" phylum="Chordata" rank="genus">
|
||
<emphasis id="B92E32278F40C006E762FEFB8ACDDB16" box="[610,743,359,380]" italics="true" pageId="5" pageNumber="1485">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
are known from more fossils than are most other dinosaurs, and these specimens span the spectrum from juvenile to adult. Many modern analytical approaches have been pioneered with the use of
|
||
<taxonomicName id="4C5A95B68F40C006E643FE4A8BE2DB81" authority="Osborn, 1905" box="[835,968,470,491]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="1485" phylum="Chordata" rank="genus">
|
||
<emphasis id="B92E32278F40C006E643FE4A8BE2DB81" box="[835,968,470,491]" italics="true" pageId="5" pageNumber="1485">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
and close kin, and the results of these studies are allowing for quantitative comparisons between the biology of extinct dinosaurs and living species.
|
||
</paragraph>
|
||
</subSubSection>
|
||
</treatment>
|
||
</document> |