934 lines
142 KiB
XML
934 lines
142 KiB
XML
<document ID-DOI="10.1016/j.cretres.2016.02.007" ID-GBIF-Dataset="ec6be03d-946c-4cf8-ac6e-ab40440290df" ID-Zenodo-Dep="3897669" approvalRequired="1" approvalRequired_for_document="1" checkinTime="1592236950088" checkinUser="jeremy" docAuthor="Stephen L. Brusatte, Thomas D. Carr, Thomas E. Williamson, Thomas R. Holtz Jr., David W. E. Hone & Scott A. Williams" docDate="2016" docId="039687A9335CFF8704F7F9BFFC519B99" docLanguage="en" docName="Brusatteetal2016.pdf.imf" docOrigin="Cretaceous Research 65" docStyle="DocumentStyle{}" docTitle="Tyrannosaurus rex Osborn 1905" docType="treatment" docVersion="11" lastPageNumber="5" masterDocId="FFAFFFD1335DFF820466FFE8FFD19933" masterDocTitle="Dentary groove morphology does not distinguish ‘ Nanotyrannus’ as a valid taxon of tyrannosauroid dinosaur. Comment on: “ Distribution of the dentary groove of theropod dinosaurs: Im ..." masterLastPageNumber="237" masterPageNumber="232" pageNumber="1" updateTime="1673602429021" updateUser="jeremy">
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<mods:mods xmlns:mods="http://www.loc.gov/mods/v3">
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<mods:titleInfo>
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<mods:title>Dentary groove morphology does not distinguish ‘ Nanotyrannus’ as a valid taxon of tyrannosauroid dinosaur. Comment on: “ Distribution of the dentary groove of theropod dinosaurs: Im ...</mods:title>
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</mods:titleInfo>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Stephen L. Brusatte</mods:namePart>
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<mods:affiliation>School of GeoSciences, University of Edinburgh, Grant Institute, James Hutton Road, Edinburgh, EH 9 3 FE, United Kingdom</mods:affiliation>
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<mods:nameIdentifier type="email">Stephen.Brusatte@ed.ac.uk</mods:nameIdentifier>
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</mods:name>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Thomas D. Carr</mods:namePart>
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<mods:affiliation>Department of Biology, Carthage College, 2001 Alford Park Drive, Kenosha, WI 53140, USA</mods:affiliation>
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</mods:name>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Thomas E. Williamson</mods:namePart>
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<mods:affiliation>New Mexico Museum of Natural History and Science, 1801 Mountain Road, NW, Albuquerque, NM 87104, USA</mods:affiliation>
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</mods:name>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Thomas R. Holtz Jr.</mods:namePart>
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<mods:affiliation>Department of Geology, University of Maryland, 8000 Regents Drive, College Park, MD 20742, USA, Department of Paleobiology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA</mods:affiliation>
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</mods:name>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>David W. E. Hone</mods:namePart>
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<mods:affiliation>School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E 1 4 NS, United Kingdom</mods:affiliation>
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</mods:name>
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<mods:name type="personal">
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<mods:role>
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<mods:roleTerm>Author</mods:roleTerm>
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</mods:role>
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<mods:namePart>Scott A. Williams</mods:namePart>
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<mods:affiliation>Burpee Museum of Natural History, 737 North Main Street, Rockford, IL 60115, USA</mods:affiliation>
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</mods:name>
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<mods:typeOfResource>text</mods:typeOfResource>
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<mods:title>Cretaceous Research</mods:title>
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<mods:date>2016</mods:date>
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<mods:detail type="pubDate">
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<mods:number>2016-02-15</mods:number>
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</mods:detail>
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<mods:detail type="volume">
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<mods:number>65</mods:number>
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<mods:start>232</mods:start>
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<mods:classification>journal article</mods:classification>
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<mods:identifier type="DOI">10.1016/j.cretres.2016.02.007</mods:identifier>
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<treatment ID-DOI="http://doi.org/10.5281/zenodo.4707077" ID-GBIF-Taxon="164612587" ID-Zenodo-Dep="4707077" LSID="urn:lsid:plazi:treatment:039687A9335CFF8704F7F9BFFC519B99" httpUri="http://treatment.plazi.org/id/039687A9335CFF8704F7F9BFFC519B99" lastPageId="5" lastPageNumber="5" pageId="1" pageNumber="1">
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<subSubSection lastPageId="4" lastPageNumber="4" pageId="1" pageNumber="1" type="discussion">
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<paragraph blockId="1.[113,784,1621,1810]" lastBlockId="1.[831,1501,1567,1893]" pageId="1" pageNumber="1">
|
||
In a recent
|
||
<emphasis box="[256,451,1621,1641]" italics="true" pageId="1" pageNumber="1">Cretaceous Research</emphasis>
|
||
article,
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." journalOrPublisher="Cretaceous Research" pageId="1" pageNumber="1" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
argued that the controversial tyrannosauroid dinosaur ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[118,352,1677,1697]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="1" pageNumber="1" phylum="Chordata" rank="species" species="lancensis">
|
||
<emphasis box="[118,352,1677,1697]" italics="true" pageId="1" pageNumber="1">Nanotyrannus lancensis</emphasis>
|
||
</taxonomicName>
|
||
’ from the uppermost Cretaceous of North America is a valid taxon, as originally proposed by
|
||
<bibRefCitation author="Bakker, R. T. & William, M. & Currie, P." journalOrPublisher="Hunteria" pageId="1" pageNumber="1" pagination="1 - 28" part="1" refId="ref5336" refString="Bakker, R. T., William, M., Currie, P., 1988. Nanotyrannus, a new genus of pygmy tyrannosaur, from the Latest Cretaceous of Montana. Hunteria 1, 1 - 28." title="Nanotyrannus, a new genus of pygmy tyrannosaur, from the Latest Cretaceous of Montana" type="journal article" year="1988">Bakker et al. (1988)</bibRefCitation>
|
||
. There has been considerable debate recently about the affinities of ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[234,371,1761,1781]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="1" pageNumber="1" phylum="Chordata" rank="genus">
|
||
<emphasis box="[234,371,1761,1781]" italics="true" pageId="1" pageNumber="1">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’, with some authors considering it a distinct taxon (e.g.,
|
||
<bibRefCitation author="Currie, P. J." box="[347,488,1790,1809]" journalOrPublisher="Acta Palaeontologica Polonica" pageId="1" pageNumber="1" pagination="191 - 226" part="48" refId="ref5996" refString="Currie, P. J., 2003. Cranial anatomy of tyrannosaurid dinosaus from the Late Cretaceous of Alberta, Canada. Acta Palaeontologica Polonica 48, 191 - 226." title="Cranial anatomy of tyrannosaurid dinosaus from the Late Cretaceous of Alberta, Canada" type="journal article" year="2003">Currie, 2003</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Larson, P." box="[510,648,1790,1810]" editor="Parrish, J. M. & Molnar, R. E. & Currie, P. J. & Koppelhus, E. B." journalOrPublisher="Indiana University Press, Bloomington, Indiana" pageId="1" pageNumber="1" pagination="14 - 53" refId="ref6431" refString="Larson, P., 2013. The case for Nanotyrannus. In: Parrish, J. M., Molnar, R. E., Currie, P. J., Koppelhus, E. B. (Eds.), Tyrannosaurid Paleobiology. Indiana University Press, Bloomington, Indiana, pp. 14 - 53." title="The case for Nanotyrannus" type="book chapter" volumeTitle="Tyrannosaurid Paleobiology" year="2013">Larson, 2013</bibRefCitation>
|
||
), but most tyrannosauroid specialists regarding its holotype skull (
|
||
<materialsCitation ID-GBIF-Occurrence="2636230309" collectionCode="CMNH" pageId="1" pageNumber="1" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
) and other possibly referred specimens (e.g.,
|
||
<materialsCitation ID-GBIF-Occurrence="2636230308" box="[1341,1494,1595,1614]" collectionCode="BMRP" pageId="1" pageNumber="1" specimenCode="BMRP 2002.4.1">BMRP 2002.4.1</materialsCitation>
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||
) as belonging to juveniles of the contemporaneous
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="1" pageNumber="1" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis italics="true" pageId="1" pageNumber="1">Tyrannosaurus rex</emphasis>
|
||
</taxonomicName>
|
||
(e.g.,
|
||
<bibRefCitation author="Carr, T. D." box="[929,1037,1651,1670]" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="1" pageNumber="1" pagination="497 - 520" part="19" refId="ref5650" refString="Carr, T. D., 1999. Craniofacial ontogeny in Tyrannosauridae (Dinosauria, Coelurosauria). Journal of Vertebrate Paleontology 19, 497 - 520." title="Craniofacial ontogeny in Tyrannosauridae (Dinosauria, Coelurosauria)" type="journal article" year="1999">Carr, 1999</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Brochu, C. A." box="[1052,1194,1651,1670]" journalOrPublisher="Journal of Vertebrate Paleontology Memoir" pageId="1" pageNumber="1" pagination="1 - 138" part="7" refId="ref5378" refString="Brochu, C. A., 2003. Osteology of Tyrannosaurus rex: insights from a nearly complete skeleton and high-resolution computed tomographic analysis of the skull. Journal of Vertebrate Paleontology Memoir 7, 1 - 138." title="Osteology of Tyrannosaurus rex: insights from a nearly complete skeleton and high-resolution computed tomographic analysis of the skull" type="journal article" year="2003">Brochu, 2003</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Carr, T. D. & Williamson, T. E." box="[1208,1496,1651,1670]" journalOrPublisher="Zoological Journal of the Linnean Society" pageId="1" pageNumber="1" pagination="479 - 523" part="142" refId="ref5679" refString="Carr, T. D., Williamson, T. E., 2004. Diversity of late Maastrichtian Tyrannosauridae (Dinosauria: Theropoda) from western North America. Zoological Journal of the Linnean Society 142, 479 - 523." title="Diversity of late Maastrichtian Tyrannosauridae (Dinosauria: Theropoda) from western North America" type="journal article" year="2004">Carr and Williamson, 2004</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Holtz, T. R." box="[831,953,1679,1698]" editor="Weishampel, D. B. & Dodson, P. & Osmolska, H." journalOrPublisher="University of California Press, Los Angeles, California" pageId="1" pageNumber="1" pagination="111 - 136" refId="ref6268" refString="Holtz, T. R., 2004. Tyrannosauroidea. In: Weishampel, D. B., Dodson, P., Osmolska, H. (Eds.), The Dinosauria. University of California Press, Los Angeles, California, pp. 111 - 136." title="Tyrannosauroidea" type="book chapter" volumeTitle="The Dinosauria" year="2004">Holtz, 2004</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Brusatte, S. L. & Norell, M. A. & Carr, T. D. & Erickson, G. M. & Hutchinson, J. R. & Balanoff, A. M. & Bever, G. S. & Choiniere, J. N. & Makovicky, P. J. & Xu, X." box="[964,1170,1679,1698]" journalOrPublisher="Science" pageId="1" pageNumber="1" pagination="1481 - 1485" part="329" refId="ref5508" refString="Brusatte, S. L., Norell, M. A., Carr, T. D., Erickson, G. M., Hutchinson, J. R., Balanoff, A. M., Bever, G. S., Choiniere, J. N., Makovicky, P. J., Xu, X., 2010. Tyrannosaur paleobiology: new research on ancient exemplar organisms. Science 329, 1481 - 1485." title="Tyrannosaur paleobiology: new research on ancient exemplar organisms" type="journal article" year="2010">Brusatte et al., 2010</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Brusatte, S. L. & Carr, T. D." box="[1182,1421,1679,1698]" journalOrPublisher="Scientific Reports" pageId="1" pageNumber="1" pagination="20252" part="6" refId="ref5418" refString="Brusatte, S. L., Carr, T. D., 2016. The phylogeny and evolutionary history of tyrannosauroid dinosaurs. Scientific Reports 6, 20252." title="The phylogeny and evolutionary history of tyrannosauroid dinosaurs" type="journal article" year="2016">Brusatte and Carr, 2016</bibRefCitation>
|
||
). These latter authors have recognized differences between purported ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[836,973,1733,1753]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="1" pageNumber="1" phylum="Chordata" rank="genus">
|
||
<emphasis box="[836,973,1733,1753]" italics="true" pageId="1" pageNumber="1">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ specimens (which are clearly juveniles based on bone histology and possession of characters seen in the early growth stages of other tyrannosauroids:
|
||
<bibRefCitation author="Carr, T. D." box="[1234,1337,1790,1809]" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="1" pageNumber="1" pagination="497 - 520" part="19" refId="ref5650" refString="Carr, T. D., 1999. Craniofacial ontogeny in Tyrannosauridae (Dinosauria, Coelurosauria). Journal of Vertebrate Paleontology 19, 497 - 520." title="Craniofacial ontogeny in Tyrannosauridae (Dinosauria, Coelurosauria)" type="journal article" year="1999">Carr, 1999</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Erickson, G. M." box="[1345,1492,1790,1809]" journalOrPublisher="Trends in Ecology and Evolution" pageId="1" pageNumber="1" pagination="677 - 684" part="20" refId="ref6028" refString="Erickson, G. M., 2005. Assessing dinosaur growth patterns: a microscopic revolution. Trends in Ecology and Evolution 20, 677 - 684." title="Assessing dinosaur growth patterns: a microscopic revolution" type="journal article" year="2005">Erickson, 2005</bibRefCitation>
|
||
) and large specimens of
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[1072,1124,1817,1837]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="1" pageNumber="1" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[1072,1082,1817,1837]" italics="true" pageId="1" pageNumber="1">T</emphasis>
|
||
.
|
||
<emphasis box="[1094,1124,1817,1837]" italics="true" pageId="1" pageNumber="1">rex</emphasis>
|
||
</taxonomicName>
|
||
, but explain them as ontogenetically variable features that changed as juveniles grew into massive, deep-skulled, strong-biting adults.
|
||
</paragraph>
|
||
<footnote pageId="1" pageNumber="1">
|
||
<paragraph blockId="1.[127,610,1872,1910]" pageId="1" pageNumber="1">
|
||
<emphasis bold="true" box="[127,136,1872,1887]" italics="true" pageId="1" pageNumber="1">*</emphasis>
|
||
Corresponding author.
|
||
<emphasis box="[145,266,1895,1910]" italics="true" pageId="1" pageNumber="1">E-mail address:</emphasis>
|
||
Stephen.Brusatte@ed.ac.uk (S.L. Brusatte).
|
||
</paragraph>
|
||
</footnote>
|
||
<footnote pageId="1" pageNumber="1">
|
||
<paragraph blockId="1.[113,529,1945,1982]" box="[113,485,1945,1959]" pageId="1" pageNumber="1">http://dx.doi.org/10.1016/j.cretres.2016.02.007</paragraph>
|
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<paragraph blockId="1.[113,529,1945,1982]" box="[113,529,1967,1982]" pageId="1" pageNumber="1">
|
||
0195-6671/
|
||
<emphasis bold="true" box="[205,218,1967,1982]" italics="true" pageId="1" pageNumber="1">©</emphasis>
|
||
2016 Elsevier Ltd. All rights reserved.
|
||
</paragraph>
|
||
</footnote>
|
||
<footnote pageId="1" pageNumber="1">
|
||
<paragraph blockId="1.[124,1490,2036,2110]" pageId="1" pageNumber="1">
|
||
Please cite this article in press as: Brusatte, S.L., et al., Dentary groove morphology does not distinguish ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[1163,1295,2036,2056]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="1" pageNumber="1" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1163,1295,2036,2056]" italics="true" pageId="1" pageNumber="1">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ as a valid taxon of tyrannosauroid dinosaur. Comment on: “Distribution of the dentary groove of theropod dinosaurs: Implications for theropod phylogeny and the validity of the genus
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[367,681,2089,2110]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="1" pageNumber="1" phylum="Chordata" rank="genus">
|
||
<emphasis box="[367,499,2089,2109]" italics="true" pageId="1" pageNumber="1">Nanotyrannus</emphasis>
|
||
<bibRefCitation author="Bakker, R. T. & William, M. & Currie, P." box="[505,681,2090,2110]" journalOrPublisher="Hunteria" pageId="1" pageNumber="1" pagination="1 - 28" part="1" refId="ref5336" refString="Bakker, R. T., William, M., Currie, P., 1988. Nanotyrannus, a new genus of pygmy tyrannosaur, from the Latest Cretaceous of Montana. Hunteria 1, 1 - 28." title="Nanotyrannus, a new genus of pygmy tyrannosaur, from the Latest Cretaceous of Montana" type="journal article" year="1988">Bakker et al., 1988</bibRefCitation>
|
||
</taxonomicName>
|
||
”, Cretaceous Research (2016), http://dx.doi.org/10.1016/j.cretres.2016.02.007
|
||
</paragraph>
|
||
</footnote>
|
||
<footnote pageId="2" pageNumber="2">
|
||
<paragraph blockId="2.[98,1464,2036,2110]" pageId="2" pageNumber="2">
|
||
Please cite this article in press as: Brusatte, S.L., et al., Dentary groove morphology does not distinguish ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[1137,1269,2036,2056]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="2" pageNumber="2" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1137,1269,2036,2056]" italics="true" pageId="2" pageNumber="2">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ as a valid taxon of tyrannosauroid dinosaur. Comment on: “Distribution of the dentary groove of theropod dinosaurs: Implications for theropod phylogeny and the validity of the genus
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[341,656,2089,2110]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="2" pageNumber="2" phylum="Chordata" rank="genus">
|
||
<emphasis box="[341,473,2089,2109]" italics="true" pageId="2" pageNumber="2">Nanotyrannus</emphasis>
|
||
<bibRefCitation author="Bakker, R. T. & William, M. & Currie, P." box="[479,656,2090,2110]" journalOrPublisher="Hunteria" pageId="2" pageNumber="2" pagination="1 - 28" part="1" refId="ref5336" refString="Bakker, R. T., William, M., Currie, P., 1988. Nanotyrannus, a new genus of pygmy tyrannosaur, from the Latest Cretaceous of Montana. Hunteria 1, 1 - 28." title="Nanotyrannus, a new genus of pygmy tyrannosaur, from the Latest Cretaceous of Montana" type="journal article" year="1988">Bakker et al., 1988</bibRefCitation>
|
||
</taxonomicName>
|
||
”, Cretaceous Research (2016), http://dx.doi.org/10.1016/j.cretres.2016.02.007
|
||
</paragraph>
|
||
</footnote>
|
||
<paragraph blockId="3.[113,783,179,757]" pageId="3" pageNumber="3">
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[145,473,179,198]" journalOrPublisher="Cretaceous Research" pageId="3" pageNumber="3" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
bring a new piece of evidence to the debate: the morphology of the dentary groove, a depression that extends anteroposteriorly across part of the lateral surface of the dentary and houses neurovascular foramina below the tooth alveoli. Based on the distribution of this feature, they argue that the alleged ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[195,332,317,337]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[195,332,317,337]" italics="true" pageId="3" pageNumber="3">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ specimen
|
||
<materialsCitation ID-GBIF-Occurrence="2636230317" box="[444,594,319,338]" collectionCode="BMRP" pageId="3" pageNumber="3" specimenCode="BMRP 2002.4.1">BMRP 2002.4.1</materialsCitation>
|
||
, which possesses a groove, cannot be referable to
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[427,608,345,365]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[427,608,345,365]" italics="true" pageId="3" pageNumber="3">Tyrannosaurus rex</emphasis>
|
||
</taxonomicName>
|
||
, which is said to lack this feature. They furthermore hypothesize that ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[641,778,373,393]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[641,778,373,393]" italics="true" pageId="3" pageNumber="3">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ is not particularly closely related to
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[480,661,401,421]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[480,661,401,421]" italics="true" pageId="3" pageNumber="3">Tyrannosaurus rex</emphasis>
|
||
</taxonomicName>
|
||
, but groups with the albertosaurine tyrannosaurids (
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[529,662,429,449]" class="Reptilia" family="Tyrannosauridae" genus="Albertosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[529,662,429,449]" italics="true" pageId="3" pageNumber="3">Albertosaurus</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<taxonomicName authorityName="Cope" authorityYear="1866" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis italics="true" pageId="3" pageNumber="3">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
), which also are said to possess the groove. These interpretations hinge on
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[354,704,486,505]" journalOrPublisher="Cretaceous Research" pageId="3" pageNumber="3" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild's (2016)</bibRefCitation>
|
||
correct identification of the groove in tyrannosauroid specimens, their assertion that the groove is not an ontogenetically variable feature, and their contention that a single anatomical feature can be a ‘key’ characteristic for elucidating phylogenetic relationships.
|
||
</paragraph>
|
||
<paragraph blockId="3.[113,783,179,757]" pageId="3" pageNumber="3">
|
||
In this response, we challenge these points. We show that the groove is a widespread feature of tyrannosauroids, and that it is ontogenetically variable. As a result, the presence or absence of a dentary groove does not clarify the validity of ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[583,720,708,728]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[583,720,708,728]" italics="true" pageId="3" pageNumber="3">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ or its phylogenetic position among tyrannosauroids.
|
||
</paragraph>
|
||
<paragraph blockId="3.[113,784,793,1231]" pageId="3" pageNumber="3">
|
||
<emphasis bold="true" box="[113,506,793,812]" pageId="3" pageNumber="3">
|
||
Institutional Abbreviations
|
||
<emphasis bold="true" box="[416,438,798,812]" italics="true" pageId="3" pageNumber="3">―</emphasis>
|
||
AMNH
|
||
</emphasis>
|
||
, American Museum of Natural History, New York, NY, USA;
|
||
<emphasis bold="true" box="[507,568,821,840]" pageId="3" pageNumber="3">BMRP</emphasis>
|
||
, Burpee Museum of Natural History, Rockford, IL, USA;
|
||
<emphasis bold="true" box="[462,505,849,868]" pageId="3" pageNumber="3">BYU</emphasis>
|
||
, Brigham Young University, Provo, Utah, USA;
|
||
<emphasis bold="true" box="[315,365,877,896]" pageId="3" pageNumber="3">CMN</emphasis>
|
||
, Canadian Museum of Nature, Ottawa, Ontario, Canada;
|
||
<emphasis bold="true" box="[298,364,904,923]" pageId="3" pageNumber="3">CMNH</emphasis>
|
||
, Cleveland Museum of Natural History, Cleveland, OH, USA;
|
||
<emphasis bold="true" box="[341,406,933,952]" pageId="3" pageNumber="3">FMNH</emphasis>
|
||
, Field Museum of Natural History, Chicago, IL, USA;
|
||
<emphasis bold="true" box="[285,328,960,979]" pageId="3" pageNumber="3">IGM</emphasis>
|
||
, Institute of Geology, Ulaan Baatar, Mongolia;
|
||
<emphasis bold="true" box="[113,141,988,1007]" pageId="3" pageNumber="3">LH</emphasis>
|
||
, Long Hao institute of Geology and Paleontology, Hohhot, China;
|
||
<emphasis bold="true" box="[113,164,1016,1035]" pageId="3" pageNumber="3">MOR</emphasis>
|
||
, Museum of the Rockies, Bozeman, Montana, USA;
|
||
<emphasis bold="true" box="[677,778,1016,1035]" pageId="3" pageNumber="3">NMMNHS</emphasis>
|
||
, New Mexico Museum of Natural History and Science, Albuquerque, NM, USA;
|
||
<emphasis bold="true" box="[213,250,1072,1091]" pageId="3" pageNumber="3">PIN</emphasis>
|
||
, Paleontological Institute, Moscow, Russia;
|
||
<emphasis bold="true" box="[680,735,1072,1091]" pageId="3" pageNumber="3">RMM</emphasis>
|
||
, Red Mountain Museum, McWane Center, Birmingham, Alabama, USA;
|
||
<emphasis bold="true" box="[113,164,1128,1147]" pageId="3" pageNumber="3">ROM</emphasis>
|
||
, Royal Ontario Museum, Toronto, Ontario, Canada;
|
||
<emphasis bold="true" box="[674,719,1128,1147]" pageId="3" pageNumber="3">TMP</emphasis>
|
||
, Royal Tyrrell Museum of Palaeontology, Drumheller, Alberta, Canada;
|
||
<emphasis bold="true" box="[113,176,1183,1202]" pageId="3" pageNumber="3">ZCDM</emphasis>
|
||
, Zhucheng Dinosaur Museum, Shandong, China;
|
||
<emphasis bold="true" box="[726,778,1183,1202]" pageId="3" pageNumber="3">ZPAL</emphasis>
|
||
, Instytut Paleobiologii PAN, Warsaw, Poland.
|
||
</paragraph>
|
||
<paragraph blockId="3.[113,651,1281,1300]" box="[113,651,1281,1300]" pageId="3" pageNumber="3">
|
||
<heading bold="true" box="[113,651,1281,1300]" fontSize="8" level="3" pageId="3" pageNumber="3" reason="0">
|
||
<emphasis bold="true" box="[113,651,1281,1300]" pageId="3" pageNumber="3">2. The dentary groove as a phylogenetic character</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph blockId="3.[113,783,1337,1802]" pageId="3" pageNumber="3">
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[145,508,1337,1356]" journalOrPublisher="Cretaceous Research" pageId="3" pageNumber="3" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016:26)</bibRefCitation>
|
||
insinuate that the dentary groove had yet to be ‘anatomically defined’ and only recently had been included in phylogenetic character datasets, beginning with the tyrannosauroid-specific study of
|
||
<bibRefCitation author="Brusatte, S. L. & Norell, M. A. & Carr, T. D. & Erickson, G. M. & Hutchinson, J. R. & Balanoff, A. M. & Bever, G. S. & Choiniere, J. N. & Makovicky, P. J. & Xu, X." box="[495,713,1420,1440]" journalOrPublisher="Science" pageId="3" pageNumber="3" pagination="1481 - 1485" part="329" refId="ref5508" refString="Brusatte, S. L., Norell, M. A., Carr, T. D., Erickson, G. M., Hutchinson, J. R., Balanoff, A. M., Bever, G. S., Choiniere, J. N., Makovicky, P. J., Xu, X., 2010. Tyrannosaur paleobiology: new research on ancient exemplar organisms. Science 329, 1481 - 1485." title="Tyrannosaur paleobiology: new research on ancient exemplar organisms" type="journal article" year="2010">Brusatte et al. (2010)</bibRefCitation>
|
||
. How- ever, this is incorrect. There is a long legacy of phylogenetic characters relating to the dentary groove, and it has appeared in several iterations of the Theropod Working Group (TWiG) dataset, a 20+ year project that has conducted increasingly larger and more inclusive analyses of theropod phylogeny (e.g.,
|
||
<bibRefCitation author="Norell, M. A. & Clark, J. M. & Makovicky, P. J." box="[587,775,1560,1579]" editor="Gauthier, J. & Gall, L. F." journalOrPublisher="Peabody Museum of Natural History. Yale University, New Haven, CT" pageId="3" pageNumber="3" pagination="49 - 68" refId="ref6573" refString="Norell, M. A., Clark, J. M., Makovicky, P. J., 2001. Phylogenetic relationships among coelurosaurian theropods. In: Gauthier, J., Gall, L. F. (Eds.), New Perspectives on the Origin and Early Evolution of Birds. Peabody Museum of Natural History. Yale University, New Haven, CT, pp. 49 - 68." title="Phylogenetic relationships among coelurosaurian theropods" type="book chapter" volumeTitle="New Perspectives on the Origin and Early Evolution of Birds" year="2001">Norell et al., 2001</bibRefCitation>
|
||
: character 73;
|
||
<bibRefCitation author="Turner, A. H. & Pol, D. & Clarke, J. A. & Erickson, G. M. & Norell, M. A." box="[253,438,1588,1607]" journalOrPublisher="Science" pageId="3" pageNumber="3" pagination="1378 - 1381" part="317" refId="ref6893" refString="Turner, A. H., Pol, D., Clarke, J. A., Erickson, G. M., Norell, M. A., 2007. A basal dromaeosaurid and size evolution preceding avian flight. Science 317, 1378 - 1381." title="A basal dromaeosaurid and size evolution preceding avian flight" type="journal article" year="2007">Turner et al., 2007</bibRefCitation>
|
||
: character 71;
|
||
<bibRefCitation author="Turner, A. H. & Makovicky, P. J. & Norell, M. A." box="[591,775,1588,1607]" journalOrPublisher="Bulletin of the American Museum of Natural History" pageId="3" pageNumber="3" pagination="1 - 206" part="371" refId="ref6945" refString="Turner, A. H., Makovicky, P. J., Norell, M. A., 2012. A review of dromaeosaurid systematic and paravian phylogeny. Bulletin of the American Museum of Natural History 371, 1 - 206." title="A review of dromaeosaurid systematic and paravian phylogeny" type="journal article" year="2012">Turner et al., 2012</bibRefCitation>
|
||
: character 69;
|
||
<bibRefCitation author="Brusatte, S. L. & Lloyd, G. T. & Wang, S. C. & Norell, M. A." box="[266,479,1616,1635]" journalOrPublisher="Current Biology" pageId="3" pageNumber="3" pagination="2386 - 2392" part="24" refId="ref5595" refString="Brusatte, S. L., Lloyd, G. T., Wang, S. C., Norell, M. A., 2014. Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition. Current Biology 24, 2386 - 2392." title="Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition" type="journal article" year="2014">Brusatte et al. 2014</bibRefCitation>
|
||
: character 69). Part of this confusion stems from our (Brusatte and Carr's) error in not attributing the historical usage of this character in our 2010 study.
|
||
</paragraph>
|
||
<paragraph blockId="3.[113,783,1337,1802]" lastBlockId="3.[831,1501,179,1398]" pageId="3" pageNumber="3">
|
||
The TWiG character was inspired by
|
||
<bibRefCitation author="Currie, P. J." box="[516,664,1699,1718]" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="3" pageNumber="3" pagination="72 - 81" part="7" refId="ref5961" refString="Currie, P. J., 1987. Bird-like characteristics of the jaws and teeth of troodontid theropods (Dinosauria, Saurischia). Journal of Vertebrate Paleontology 7, 72 - 81." title="Bird-like characteristics of the jaws and teeth of troodontid theropods (Dinosauria, Saurischia)" type="journal article" year="1987">Currie's (1987)</bibRefCitation>
|
||
description of the derived bird-like theropod
|
||
<taxonomicName authorityName="Leidy" authorityYear="1856" box="[457,536,1726,1746]" class="Reptilia" family="Troodontidae" genus="Troodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[457,536,1726,1746]" italics="true" pageId="3" pageNumber="3">Troodon</emphasis>
|
||
</taxonomicName>
|
||
, in which he noted that the primary neurovascular foramina on the lateral dentary were set into a groove. Additional comparisons by the TWiG team revealed that nearly all troodontids had this morphology, in which the neurovascular foramina are embedded into a sharp, dorsoventrally shallow, deeply impressed groove that is more pronounced across the middle and posterior regions of the dentary but becomes much more shallowly impressed as it dissipates anteriorly, in the symphyseal region and underneath the first several alveoli. This differs from the condition in other theropods, which early versions of the TWiG dataset described as having ‘superficial’ neurovascular foramina.
|
||
</paragraph>
|
||
<paragraph blockId="3.[831,1501,179,1398]" pageId="3" pageNumber="3">
|
||
Later TWiG studies revealed that some dromaeosaurids (
|
||
<taxonomicName authorityName="Makovicky, Apesteguia & Agnolin" authorityYear="2005" class="Reptilia" family="Dromaeosauridae" genus="Buitreraptor" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis italics="true" pageId="3" pageNumber="3">Buitreraptor</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName authorityName="Novas, Pol, Canale, Porfiri & Calvo" authorityYear="2008" box="[931,1052,457,477]" class="Reptilia" family="Dromaeosauridae" genus="Austroraptor" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[931,1052,457,477]" italics="true" pageId="3" pageNumber="3">Austroraptor</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName box="[1067,1138,457,477]" class="Reptilia" family="Dromaeosauridae" genus="Shanag" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1067,1138,457,477]" italics="true" pageId="3" pageNumber="3">Shanag</emphasis>
|
||
</taxonomicName>
|
||
), some early birds (e.g.,
|
||
<taxonomicName box="[1401,1495,457,477]" class="Reptilia" family="Pengornithidae" genus="Pengornis" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1401,1495,457,477]" italics="true" pageId="3" pageNumber="3">Pengornis</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName authorityName="Zhou & Zhang" authorityYear="2001" box="[831,915,485,505]" class="Reptilia" family="Hongshanornithidae" genus="Yanornis" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[831,915,485,505]" italics="true" pageId="3" pageNumber="3">Yanornis</emphasis>
|
||
</taxonomicName>
|
||
), the basal alvarezsauroid
|
||
<emphasis box="[1197,1323,485,505]" italics="true" pageId="3" pageNumber="3">Haplocheirus</emphasis>
|
||
, and some basal tyrannosauroids (
|
||
<emphasis box="[1014,1107,513,533]" italics="true" pageId="3" pageNumber="3">Guanlong</emphasis>
|
||
,
|
||
<emphasis box="[1124,1279,513,533]" italics="true" pageId="3" pageNumber="3">Proceratosaurus</emphasis>
|
||
,
|
||
<emphasis box="[1296,1423,513,533]" italics="true" pageId="3" pageNumber="3">Sinotyrannus</emphasis>
|
||
,
|
||
<emphasis italics="true" pageId="3" pageNumber="3">Yutyrannus</emphasis>
|
||
) also possessed the deep groove of troodontids. This led
|
||
<bibRefCitation author="Brusatte, S. L. & Norell, M. A. & Carr, T. D. & Erickson, G. M. & Hutchinson, J. R. & Balanoff, A. M. & Bever, G. S. & Choiniere, J. N. & Makovicky, P. J. & Xu, X." box="[831,1085,570,589]" journalOrPublisher="Science" pageId="3" pageNumber="3" pagination="1481 - 1485" part="329" refId="ref5508" refString="Brusatte, S. L., Norell, M. A., Carr, T. D., Erickson, G. M., Hutchinson, J. R., Balanoff, A. M., Bever, G. S., Choiniere, J. N., Makovicky, P. J., Xu, X., 2010. Tyrannosaur paleobiology: new research on ancient exemplar organisms. Science 329, 1481 - 1485." title="Tyrannosaur paleobiology: new research on ancient exemplar organisms" type="journal article" year="2010">Brusatte et al. (2010)</bibRefCitation>
|
||
to include the character in their tyrannosauroid-specific dataset, which was later merged into the larger TWiG dataset by
|
||
<bibRefCitation author="Brusatte, S. L. & Lloyd, G. T. & Wang, S. C. & Norell, M. A." box="[1071,1281,626,645]" journalOrPublisher="Current Biology" pageId="3" pageNumber="3" pagination="2386 - 2392" part="24" refId="ref5595" refString="Brusatte, S. L., Lloyd, G. T., Wang, S. C., Norell, M. A., 2014. Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition. Current Biology 24, 2386 - 2392." title="Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition" type="journal article" year="2014">Brusatte et al. (2014)</bibRefCitation>
|
||
. In doing so,
|
||
<bibRefCitation author="Brusatte, S. L. & Norell, M. A. & Carr, T. D. & Erickson, G. M. & Hutchinson, J. R. & Balanoff, A. M. & Bever, G. S. & Choiniere, J. N. & Makovicky, P. J. & Xu, X." journalOrPublisher="Science" pageId="3" pageNumber="3" pagination="1481 - 1485" part="329" refId="ref5508" refString="Brusatte, S. L., Norell, M. A., Carr, T. D., Erickson, G. M., Hutchinson, J. R., Balanoff, A. M., Bever, G. S., Choiniere, J. N., Makovicky, P. J., Xu, X., 2010. Tyrannosaur paleobiology: new research on ancient exemplar organisms. Science 329, 1481 - 1485." title="Tyrannosaur paleobiology: new research on ancient exemplar organisms" type="journal article" year="2010">Brusatte et al. (2010)</bibRefCitation>
|
||
redefined the character states so that they were more descriptive. The primitive ‘superficial’ condition, seen in most theropods, was defined as one in which the foramina are ‘distinct or set into a shallow groove posteriorly’. The derived condition, seen in troodontids and the handful of other theropods mentioned above, was defined as one in which the foramina are ‘set into a deep and sharp groove across the middle and posterior regions of the dentary’.
|
||
</paragraph>
|
||
<paragraph blockId="3.[831,1501,179,1398]" pageId="3" pageNumber="3">
|
||
Among tyrannosauroids, the derived, deeply impressed, troodontid-style groove is present only in the basal clade
|
||
<taxonomicName class="Reptilia" family="Proceratosauridae" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="family">Proceratosauridae</taxonomicName>
|
||
. It is absent in all other tyrannosauroids, and is scored that way in the
|
||
<bibRefCitation author="Brusatte, S. L. & Norell, M. A. & Carr, T. D. & Erickson, G. M. & Hutchinson, J. R. & Balanoff, A. M. & Bever, G. S. & Choiniere, J. N. & Makovicky, P. J. & Xu, X." box="[1003,1215,960,980]" journalOrPublisher="Science" pageId="3" pageNumber="3" pagination="1481 - 1485" part="329" refId="ref5508" refString="Brusatte, S. L., Norell, M. A., Carr, T. D., Erickson, G. M., Hutchinson, J. R., Balanoff, A. M., Bever, G. S., Choiniere, J. N., Makovicky, P. J., Xu, X., 2010. Tyrannosaur paleobiology: new research on ancient exemplar organisms. Science 329, 1481 - 1485." title="Tyrannosaur paleobiology: new research on ancient exemplar organisms" type="journal article" year="2010">Brusatte et al. (2010</bibRefCitation>
|
||
,
|
||
<bibRefCitation author="Brusatte, S. L. & Lloyd, G. T. & Wang, S. C. & Norell, M. A." box="[1228,1278,960,979]" journalOrPublisher="Current Biology" pageId="3" pageNumber="3" pagination="2386 - 2392" part="24" refId="ref5595" refString="Brusatte, S. L., Lloyd, G. T., Wang, S. C., Norell, M. A., 2014. Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition. Current Biology 24, 2386 - 2392." title="Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition" type="journal article" year="2014">2014</bibRefCitation>
|
||
) datasets, and in the recently published update of our tyrannosauroid dataset (
|
||
<bibRefCitation author="Brusatte, S. L. & Carr, T. D." journalOrPublisher="Scientific Reports" pageId="3" pageNumber="3" pagination="20252" part="6" refId="ref5418" refString="Brusatte, S. L., Carr, T. D., 2016. The phylogeny and evolutionary history of tyrannosauroid dinosaurs. Scientific Reports 6, 20252." title="The phylogeny and evolutionary history of tyrannosauroid dinosaurs" type="journal article" year="2016">Brusatte and Carr 2016</bibRefCitation>
|
||
). That is not to say that other tyrannosauroids do not have any type of groove on the dentary, just that they do not possess the distinctive troodontid-style condition. Indeed, many of them have shallower grooves that fall into the ‘superficial’ category.
|
||
</paragraph>
|
||
<paragraph blockId="3.[831,1501,179,1398]" pageId="3" pageNumber="3">
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[863,1197,1156,1175]" journalOrPublisher="Cretaceous Research" pageId="3" pageNumber="3" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
, on the other hand, consider some derived tyrannosauroids like
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[1220,1353,1182,1202]" class="Reptilia" family="Tyrannosauridae" genus="Albertosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1220,1353,1182,1202]" italics="true" pageId="3" pageNumber="3">Albertosaurus</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName authorityName="Cope" authorityYear="1866" box="[1373,1495,1182,1202]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1373,1495,1182,1202]" italics="true" pageId="3" pageNumber="3">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<emphasis box="[831,961,1210,1230]" italics="true" pageId="3" pageNumber="3">Dryptosaurus</emphasis>
|
||
, and putative specimens of ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[1249,1386,1210,1230]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1249,1386,1210,1230]" italics="true" pageId="3" pageNumber="3">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ to possess what they consider as a ‘dentary groove’. Their concept of a dentary groove is much more inclusive than the strictly-defined feature in the TWiG dataset, and seems to be a catch-all that combines the troodontid condition (as seen in proceratosaurids) and the more shallow grooves that are commonly seen in other tyrannosauroids (see below).
|
||
</paragraph>
|
||
<paragraph blockId="3.[831,1466,1448,1467]" box="[831,1466,1448,1467]" pageId="3" pageNumber="3">
|
||
<heading bold="true" box="[831,1466,1448,1467]" fontSize="8" level="3" pageId="3" pageNumber="3" reason="0">
|
||
<emphasis bold="true" box="[831,1466,1448,1467]" pageId="3" pageNumber="3">3. Dentary grooves are widespread among tyrannosauroids</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph blockId="3.[831,1501,1504,1802]" lastBlockId="4.[88,757,178,1984]" lastPageId="4" lastPageNumber="4" pageId="3" pageNumber="3">
|
||
We prefer to distinguish between troodontid-style grooves and shallow grooves using the TWiG definitions, and will continue to do so in our phylogenetic analyses (e.g.,
|
||
<bibRefCitation author="Brusatte, S. L. & Carr, T. D." journalOrPublisher="Scientific Reports" pageId="3" pageNumber="3" pagination="20252" part="6" refId="ref5418" refString="Brusatte, S. L., Carr, T. D., 2016. The phylogeny and evolutionary history of tyrannosauroid dinosaurs. Scientific Reports 6, 20252." title="The phylogeny and evolutionary history of tyrannosauroid dinosaurs" type="journal article" year="2016">Brusatte and Carr, 2016</bibRefCitation>
|
||
). However, in the following discussion, we employ
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[831,1183,1616,1635]" journalOrPublisher="Cretaceous Research" pageId="3" pageNumber="3" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild's (2016)</bibRefCitation>
|
||
more inclusive definition of a ‘dentary groove’, considering it as any longitudinal depression on the lateral surface of the dentary that includes a series of neurovascular foramina underneath the tooth row.
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." journalOrPublisher="Cretaceous Research" pageId="3" pageNumber="3" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
identify this type of groove in the BMRP 2002.4.1 skull of ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[1020,1159,1754,1774]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1020,1159,1754,1774]" italics="true" pageId="3" pageNumber="3">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’, and also in
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[1307,1442,1754,1774]" class="Reptilia" family="Tyrannosauridae" genus="Albertosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1307,1442,1754,1774]" italics="true" pageId="3" pageNumber="3">Albertosaurus</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<taxonomicName authorityName="Cope" authorityYear="1866" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis italics="true" pageId="3" pageNumber="3">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<emphasis box="[940,1072,1782,1802]" italics="true" pageId="3" pageNumber="3">Dryptosaurus</emphasis>
|
||
, and proceratosaurids. However, they consider it absent in all other tyrannosauroids, including
|
||
<emphasis italics="true" pageId="4" pageNumber="4">Bistahieversor</emphasis>
|
||
,
|
||
<emphasis box="[196,295,206,226]" italics="true" pageId="4" pageNumber="4">Alioramus</emphasis>
|
||
,
|
||
<taxonomicName authorityName="Maleev" authorityYear="1955" box="[315,434,206,226]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[315,434,206,226]" italics="true" pageId="4" pageNumber="4">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
, and
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[506,651,206,226]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[506,651,206,226]" italics="true" pageId="4" pageNumber="4">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
. In most cases these assessments were based on examination of published photographs, mostly of holotype specimens only, as
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016:27)</bibRefCitation>
|
||
wanted to ‘avoid controversy as to taxonomic assignment’.
|
||
</paragraph>
|
||
<caption ID-DOI="http://doi.org/10.5281/zenodo.3897671" ID-Zenodo-Dep="3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="3" pageNumber="3" targetBox="[100,1460,180,1982]" targetPageId="2">
|
||
<paragraph blockId="3.[113,1500,1876,1983]" pageId="3" pageNumber="3">
|
||
<emphasis bold="true" box="[113,158,1877,1891]" pageId="3" pageNumber="3">Fig. 1.</emphasis>
|
||
Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows).
|
||
<emphasis bold="true" box="[829,853,1877,1891]" pageId="3" pageNumber="3">(A)</emphasis>
|
||
<emphasis box="[857,1001,1876,1891]" italics="true" pageId="3" pageNumber="3">
|
||
<taxonomicName authorityName="Maleev" authorityYear="1955" box="[857,948,1876,1891]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">Tarbosaurus</taxonomicName>
|
||
bataar
|
||
</emphasis>
|
||
, PIN 4216/3 (image reversed);
|
||
<emphasis bold="true" box="[1239,1261,1877,1891]" pageId="3" pageNumber="3">(B)</emphasis>
|
||
<emphasis box="[1266,1410,1876,1891]" italics="true" pageId="3" pageNumber="3">
|
||
<taxonomicName authorityName="Maleev" authorityYear="1955" box="[1266,1357,1876,1891]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">Tarbosaurus</taxonomicName>
|
||
bataar
|
||
</emphasis>
|
||
, PIN 551-2/ 1;
|
||
<emphasis bold="true" box="[134,156,1899,1913]" pageId="3" pageNumber="3">(C)</emphasis>
|
||
Adult
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[208,346,1899,1914]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[208,346,1899,1914]" italics="true" pageId="3" pageNumber="3">Tyrannosaurus rex</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<materialsCitation ID-GBIF-Occurrence="2636230315" box="[355,428,1900,1914]" collectionCode="MOR" pageId="3" pageNumber="3" specimenCode="MOR 008">MOR 008</materialsCitation>
|
||
(image reversed);
|
||
<emphasis bold="true" box="[574,598,1899,1913]" pageId="3" pageNumber="3">(D)</emphasis>
|
||
Adult
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[650,788,1899,1914]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[650,788,1899,1914]" italics="true" pageId="3" pageNumber="3">Tyrannosaurus rex</emphasis>
|
||
</taxonomicName>
|
||
,
|
||
<materialsCitation ID-GBIF-Occurrence="2636230307" box="[797,987,1900,1914]" collectionCode="AMNH" pageId="3" pageNumber="3" specimenCode="AMNH 5027">AMNH FARB 5027 (cast)</materialsCitation>
|
||
;
|
||
<emphasis bold="true" box="[994,1017,1899,1913]" pageId="3" pageNumber="3">(E)</emphasis>
|
||
Juvenile
|
||
<emphasis box="[1089,1261,1899,1914]" italics="true" pageId="3" pageNumber="3">
|
||
<taxonomicName authorityName="Russell" authorityYear="1970" box="[1089,1203,1899,1914]" class="Reptilia" family="Tyrannosauridae" genus="Daspletosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">Daspletosaurus</taxonomicName>
|
||
torosus
|
||
</emphasis>
|
||
, TMP 1994.143.0001;
|
||
<emphasis bold="true" box="[1432,1453,1899,1913]" pageId="3" pageNumber="3">(F)</emphasis>
|
||
Adult
|
||
<emphasis box="[113,286,1922,1937]" italics="true" pageId="3" pageNumber="3">
|
||
<taxonomicName authorityName="Russell" authorityYear="1970" box="[113,227,1922,1937]" class="Reptilia" family="Tyrannosauridae" genus="Daspletosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">Daspletosaurus</taxonomicName>
|
||
torosus
|
||
</emphasis>
|
||
, CMN 8506 (image reversed);
|
||
<emphasis bold="true" box="[522,546,1922,1936]" pageId="3" pageNumber="3">(G)</emphasis>
|
||
Juvenile
|
||
<emphasis box="[618,777,1922,1937]" italics="true" pageId="3" pageNumber="3">Bistahieversor sealeyi</emphasis>
|
||
, NMMNHS P-25049 (image reversed);
|
||
<emphasis bold="true" box="[1080,1105,1922,1936]" pageId="3" pageNumber="3">(H)</emphasis>
|
||
Adult
|
||
<emphasis box="[1157,1317,1922,1937]" italics="true" pageId="3" pageNumber="3">Bistahieversor sealeyi</emphasis>
|
||
, NMMNHS P-27469;
|
||
<emphasis bold="true" box="[1482,1500,1922,1936]" pageId="3" pageNumber="3">(I)</emphasis>
|
||
Juvenile
|
||
<emphasis box="[180,335,1944,1960]" italics="true" pageId="3" pageNumber="3">
|
||
<taxonomicName authorityName="Cope" authorityYear="1866" box="[180,274,1944,1959]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">Gorgosaurus</taxonomicName>
|
||
libratus
|
||
</emphasis>
|
||
, ROM 1247 (image reversed);
|
||
<emphasis bold="true" box="[566,585,1945,1959]" pageId="3" pageNumber="3">(J)</emphasis>
|
||
Adult
|
||
<emphasis box="[635,789,1944,1960]" italics="true" pageId="3" pageNumber="3">
|
||
<taxonomicName authorityName="Cope" authorityYear="1866" box="[635,729,1944,1959]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">Gorgosaurus</taxonomicName>
|
||
libratus
|
||
</emphasis>
|
||
, CMNN 2120. Scale bars equal 10 cm. Scales not available for A-C because these photographs were taken of specimens on display behind glass.
|
||
</paragraph>
|
||
</caption>
|
||
<footnote pageId="3" pageNumber="3">
|
||
<paragraph blockId="3.[124,1490,2036,2110]" pageId="3" pageNumber="3">
|
||
Please cite this article in press as: Brusatte, S.L., et al., Dentary groove morphology does not distinguish ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[1163,1295,2036,2056]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1163,1295,2036,2056]" italics="true" pageId="3" pageNumber="3">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ as a valid taxon of tyrannosauroid dinosaur. Comment on: “Distribution of the dentary groove of theropod dinosaurs: Implications for theropod phylogeny and the validity of the genus
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[367,681,2089,2110]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="3" pageNumber="3" phylum="Chordata" rank="genus">
|
||
<emphasis box="[367,499,2089,2109]" italics="true" pageId="3" pageNumber="3">Nanotyrannus</emphasis>
|
||
<bibRefCitation author="Bakker, R. T. & William, M. & Currie, P." box="[505,681,2090,2110]" journalOrPublisher="Hunteria" pageId="3" pageNumber="3" pagination="1 - 28" part="1" refId="ref5336" refString="Bakker, R. T., William, M., Currie, P., 1988. Nanotyrannus, a new genus of pygmy tyrannosaur, from the Latest Cretaceous of Montana. Hunteria 1, 1 - 28." title="Nanotyrannus, a new genus of pygmy tyrannosaur, from the Latest Cretaceous of Montana" type="journal article" year="1988">Bakker et al., 1988</bibRefCitation>
|
||
</taxonomicName>
|
||
”, Cretaceous Research (2016), http://dx.doi.org/10.1016/j.cretres.2016.02.007
|
||
</paragraph>
|
||
</footnote>
|
||
<paragraph blockId="4.[88,757,178,1984]" pageId="4" pageNumber="4">
|
||
In fact, a neurovascular groove on the lateral surface of the dentary is widespread among tyrannosauroids, although often it is shallow or even very shallow (particularly anteriorly in the symphyseal region) and can easily be missed in photographs. Contra to
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[88,430,458,477]" journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
, it is present in specimens of
|
||
<emphasis box="[88,174,485,505]" italics="true" pageId="4" pageNumber="4">Raptorex</emphasis>
|
||
(LH PV18;
|
||
<bibRefCitation author="Sereno, P. C. & Tan, L. & Brusatte, S. L. & Kriegstein, H. J. & Zhao, X. - J. & Cloward, K." box="[296,494,486,506]" journalOrPublisher="Science" pageId="4" pageNumber="4" pagination="418 - 422" part="326" refId="ref6744" refString="Sereno, P. C., Tan, L., Brusatte, S. L., Kriegstein, H. J., Zhao, X. - J., Cloward, K., 2009. Tyrannosaurid skeletal design first evolved at small body size. Science 326, 418 - 422." title="Tyrannosaurid skeletal design first evolved at small body size" type="journal article" year="2009">Sereno et al., 2009</bibRefCitation>
|
||
: fig. 1),
|
||
<emphasis box="[586,757,485,505]" italics="true" pageId="4" pageNumber="4">Appalachiosaurus</emphasis>
|
||
(RMM 6670;
|
||
<bibRefCitation author="Carr, T. D. & Williamson, T. E. & Schwimmer, D. R." box="[228,394,514,533]" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="4" pageNumber="4" pagination="119 - 143" part="25" refId="ref5774" refString="Carr, T. D., Williamson, T. E., Schwimmer, D. R., 2005. A new genus and species of tyrannosauroid from the Late Cretaceous (Middle Campanian) Demopolis Formation of Alabama. Journal of Vertebrate Paleontology 25, 119 - 143." title="A new genus and species of tyrannosauroid from the Late Cretaceous (Middle Campanian) Demopolis Formation of Alabama" type="journal article" year="2005">Carr et al. 2005</bibRefCitation>
|
||
: fig. 12),
|
||
<emphasis box="[499,635,513,533]" italics="true" pageId="4" pageNumber="4">Bistahieversor</emphasis>
|
||
(
|
||
<figureCitation box="[653,709,514,533]" captionStart="Fig" captionStartId="3.[113,138,1877,1891]" captionTargetBox="[100,1460,180,1982]" captionTargetId="figure@2.[99,1462,178,1984]" captionTargetPageId="2" captionText="Fig.1. Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows). (A) Tarbosaurus bataar, PIN 4216/3 (image reversed); (B) Tarbosaurus bataar, PIN 551-2/ 1; (C) Adult Tyrannosaurus rex, MOR 008 (image reversed); (D) Adult Tyrannosaurus rex, AMNH FARB 5027 (cast); (E) Juvenile Daspletosaurus torosus, TMP 1994.143.0001; (F) Adult Daspletosaurus torosus, CMN 8506 (image reversed); (G) Juvenile Bistahieversor sealeyi, NMMNHS P-25049 (image reversed); (H) Adult Bistahieversor sealeyi, NMMNHS P-27469; (I) Juvenile Gorgosaurus libratus, ROM 1247 (image reversed); (J) Adult Gorgosaurus libratus, CMNN 2120.Scale bars equal 10 cm.Scales not available for A-C because these photographs were taken of specimens on display behind glass." figureDoi="http://doi.org/10.5281/zenodo.3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="4" pageNumber="4">Fig. 1</figureCitation>
|
||
G-H; NMMNHS P-27469, P-25049;
|
||
<bibRefCitation author="Carr, T. D. & Williamson, T. E." box="[397,676,542,561]" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="4" pageNumber="4" pagination="1 - 16" part="30" refId="ref5722" refString="Carr, T. D., Williamson, T. E., 2010. Bistahieversor sealeyi, gen. et sp. nov., a new tyrannosauroid from New Mexico and the origin of deep snouts in Tyrannosauroidea. Journal of Vertebrate Paleontology 30, 1 - 16." title="Bistahieversor sealeyi, gen. et sp. nov., a new tyrannosauroid from New Mexico and the origin of deep snouts in Tyrannosauroidea" type="journal article" year="2010">Carr and Williamson, 2010</bibRefCitation>
|
||
: fig. 1),
|
||
<emphasis box="[88,186,569,589]" italics="true" pageId="4" pageNumber="4">Alioramus</emphasis>
|
||
(IGM 100/1844;
|
||
<bibRefCitation author="Brusatte, S. L. & Carr, T. D. & Norell, M. A." box="[379,601,570,589]" journalOrPublisher="Bulletin of the American Museum of Natural History" pageId="4" pageNumber="4" pagination="1 - 197" part="366" refId="ref5449" refString="Brusatte, S. L., Carr, T. D., Norell, M. A., 2012. The osteology of Alioramus, a gracile and long-snouted tyrannosaurid (Dinosauria: Theropoda) from the Late Cretaceous of Mongolia. Bulletin of the American Museum of Natural History 366, 1 - 197." title="The osteology of Alioramus, a gracile and long-snouted tyrannosaurid (Dinosauria: Theropoda) from the Late Cretaceous of Mongolia" type="journal article" year="2012">Brusatte et al., 2012</bibRefCitation>
|
||
: fig. 32),
|
||
<emphasis italics="true" pageId="4" pageNumber="4">Teratophoneus</emphasis>
|
||
(BYU 9398;
|
||
<bibRefCitation author="Carr, T. D. & Williamson, T. E. & Britt, B. B. & Stadtman, K." box="[327,484,598,617]" journalOrPublisher="Naturwissenschaften" pageId="4" pageNumber="4" pagination="241 - 246" part="98" refId="ref5827" refString="Carr, T. D., Williamson, T. E., Britt, B. B., Stadtman, K., 2011. Evidence for high taxonomic and morphologic tyrannosauroid diversity in the Late Cretaceous (Late Campanian) of the American Southwest and a new short-skulled tyrannosaurid from the Kaiparowits Formation of Utah. Naturwissenschaften 98, 241 - 246." title="Evidence for high taxonomic and morphologic tyrannosauroid diversity in the Late Cretaceous (Late Campanian) of the American Southwest and a new short-skulled tyrannosaurid from the Kaiparowits Formation of Utah" type="journal article" year="2011">Carr et al., 2011</bibRefCitation>
|
||
: fig. 2;
|
||
<bibRefCitation author="Loewen, M. A. & Irmis, R. B. & Sertich, J. J. W. & Currie, P. J. & Sampson, S. D." box="[561,749,598,617]" journalOrPublisher="PLoS One" pageId="4" pageNumber="4" pagination="e 79420" part="8" refId="ref6494" refString="Loewen, M. A., Irmis, R. B., Sertich, J. J. W., Currie, P. J., Sampson, S. D., 2013. Tyrant dinosaur evolution tracks the rise and fall of Late Cretaceous oceans. PLoS One 8 (11), e 79420. http: // dx. doi. org / 10.1371 / journal. pone. 0079420." title="Tyrant dinosaur evolution tracks the rise and fall of Late Cretaceous oceans" type="journal article" year="2013">Loewen et al. 2013</bibRefCitation>
|
||
: fig. 3),
|
||
<taxonomicName authorityName="Russell" authorityYear="1970" box="[167,314,624,644]" class="Reptilia" family="Tyrannosauridae" genus="Daspletosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[167,314,624,644]" italics="true" pageId="4" pageNumber="4">Daspletosaurus</emphasis>
|
||
</taxonomicName>
|
||
(
|
||
<figureCitation box="[334,391,626,645]" captionStart="Fig" captionStartId="3.[113,138,1877,1891]" captionTargetBox="[100,1460,180,1982]" captionTargetId="figure@2.[99,1462,178,1984]" captionTargetPageId="2" captionText="Fig.1. Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows). (A) Tarbosaurus bataar, PIN 4216/3 (image reversed); (B) Tarbosaurus bataar, PIN 551-2/ 1; (C) Adult Tyrannosaurus rex, MOR 008 (image reversed); (D) Adult Tyrannosaurus rex, AMNH FARB 5027 (cast); (E) Juvenile Daspletosaurus torosus, TMP 1994.143.0001; (F) Adult Daspletosaurus torosus, CMN 8506 (image reversed); (G) Juvenile Bistahieversor sealeyi, NMMNHS P-25049 (image reversed); (H) Adult Bistahieversor sealeyi, NMMNHS P-27469; (I) Juvenile Gorgosaurus libratus, ROM 1247 (image reversed); (J) Adult Gorgosaurus libratus, CMNN 2120.Scale bars equal 10 cm.Scales not available for A-C because these photographs were taken of specimens on display behind glass." figureDoi="http://doi.org/10.5281/zenodo.3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="4" pageNumber="4">Fig. 1</figureCitation>
|
||
E-F; MN 8506; TMP 1994.143.001;
|
||
<bibRefCitation author="Currie, P. J." box="[88,211,653,673]" journalOrPublisher="Acta Palaeontologica Polonica" pageId="4" pageNumber="4" pagination="191 - 226" part="48" refId="ref5996" refString="Currie, P. J., 2003. Cranial anatomy of tyrannosaurid dinosaus from the Late Cretaceous of Alberta, Canada. Acta Palaeontologica Polonica 48, 191 - 226." title="Cranial anatomy of tyrannosaurid dinosaus from the Late Cretaceous of Alberta, Canada" type="journal article" year="2003">Currie, 2003</bibRefCitation>
|
||
: fig. 33),
|
||
<taxonomicName authorityName="Maleev" authorityYear="1955" box="[306,424,652,672]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[306,424,652,672]" italics="true" pageId="4" pageNumber="4">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
(
|
||
<figureCitation box="[437,489,653,673]" captionStart="Fig" captionStartId="3.[113,138,1877,1891]" captionTargetBox="[100,1460,180,1982]" captionTargetId="figure@2.[99,1462,178,1984]" captionTargetPageId="2" captionText="Fig.1. Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows). (A) Tarbosaurus bataar, PIN 4216/3 (image reversed); (B) Tarbosaurus bataar, PIN 551-2/ 1; (C) Adult Tyrannosaurus rex, MOR 008 (image reversed); (D) Adult Tyrannosaurus rex, AMNH FARB 5027 (cast); (E) Juvenile Daspletosaurus torosus, TMP 1994.143.0001; (F) Adult Daspletosaurus torosus, CMN 8506 (image reversed); (G) Juvenile Bistahieversor sealeyi, NMMNHS P-25049 (image reversed); (H) Adult Bistahieversor sealeyi, NMMNHS P-27469; (I) Juvenile Gorgosaurus libratus, ROM 1247 (image reversed); (J) Adult Gorgosaurus libratus, CMNN 2120.Scale bars equal 10 cm.Scales not available for A-C because these photographs were taken of specimens on display behind glass." figureDoi="http://doi.org/10.5281/zenodo.3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="4" pageNumber="4">Fig. 1</figureCitation>
|
||
A-B; e.g., PIN 551-2/1, 551- 12/1, 4216/3, 4216/1; ZPAL MgD-I/75, I/5), and
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[613,757,680,700]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[613,757,680,700]" italics="true" pageId="4" pageNumber="4">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
(
|
||
<figureCitation box="[96,149,709,728]" captionStart="Fig" captionStartId="3.[113,138,1877,1891]" captionTargetBox="[100,1460,180,1982]" captionTargetId="figure@2.[99,1462,178,1984]" captionTargetPageId="2" captionText="Fig.1. Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows). (A) Tarbosaurus bataar, PIN 4216/3 (image reversed); (B) Tarbosaurus bataar, PIN 551-2/ 1; (C) Adult Tyrannosaurus rex, MOR 008 (image reversed); (D) Adult Tyrannosaurus rex, AMNH FARB 5027 (cast); (E) Juvenile Daspletosaurus torosus, TMP 1994.143.0001; (F) Adult Daspletosaurus torosus, CMN 8506 (image reversed); (G) Juvenile Bistahieversor sealeyi, NMMNHS P-25049 (image reversed); (H) Adult Bistahieversor sealeyi, NMMNHS P-27469; (I) Juvenile Gorgosaurus libratus, ROM 1247 (image reversed); (J) Adult Gorgosaurus libratus, CMNN 2120.Scale bars equal 10 cm.Scales not available for A-C because these photographs were taken of specimens on display behind glass." figureDoi="http://doi.org/10.5281/zenodo.3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="4" pageNumber="4">Fig. 1</figureCitation>
|
||
C-D; e.g.,
|
||
<materialsCitation ID-GBIF-Occurrence="2636230301" box="[247,358,709,728]" collectionCode="CM" pageId="4" pageNumber="4" specimenCode="CM 9380">CMN 9380</materialsCitation>
|
||
;
|
||
<materialsCitation ID-GBIF-Occurrence="2636230305" box="[370,469,709,728]" collectionCode="MOR" pageId="4" pageNumber="4" specimenCode="MOR 008">MOR 008</materialsCitation>
|
||
;
|
||
<materialsCitation ID-GBIF-Occurrence="2636230314" box="[481,668,709,728]" collectionCode="AMNH" pageId="4" pageNumber="4" specimenCode="AMNH 5027">AMNH FARB 5027</materialsCitation>
|
||
;
|
||
<bibRefCitation author="Osborn, H. F." journalOrPublisher="Memoirs of the American Museum of Natural History" pageId="4" pageNumber="4" pagination="1 - 54" part="1" refId="ref6651" refString="Osborn, H. F., 1912. Cranial of Tyrannosaurus and Allosaurus; and integument of the iguanodont dinosaur Trachodon. Memoirs of the American Museum of Natural History 1 (1 - 2), 1 - 54." title="Cranial of Tyrannosaurus and Allosaurus; and integument of the iguanodont dinosaur Trachodon" type="journal article" year="1912">Osborn, 1912</bibRefCitation>
|
||
: pl. 1, although we do concur with
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild [2016]</bibRefCitation>
|
||
that some
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[278,421,764,784]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[278,421,764,784]" italics="true" pageId="4" pageNumber="4">Tyrannosaurus</emphasis>
|
||
</taxonomicName>
|
||
specimens like
|
||
<materialsCitation ID-GBIF-Occurrence="2636230318" box="[595,757,765,785]" collectionCode="FMNHN" pageId="4" pageNumber="4" specimenCode="FMNH PR 2081">FMNH PR 2081</materialsCitation>
|
||
have such a shallow groove that it is essentially absent). We have personally observed and studied all of these specimens, and photographs of some of the more salient ones are shown in
|
||
<figureCitation box="[658,709,849,868]" captionStart="Fig" captionStartId="3.[113,138,1877,1891]" captionTargetBox="[100,1460,180,1982]" captionTargetId="figure@2.[99,1462,178,1984]" captionTargetPageId="2" captionText="Fig.1. Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows). (A) Tarbosaurus bataar, PIN 4216/3 (image reversed); (B) Tarbosaurus bataar, PIN 551-2/ 1; (C) Adult Tyrannosaurus rex, MOR 008 (image reversed); (D) Adult Tyrannosaurus rex, AMNH FARB 5027 (cast); (E) Juvenile Daspletosaurus torosus, TMP 1994.143.0001; (F) Adult Daspletosaurus torosus, CMN 8506 (image reversed); (G) Juvenile Bistahieversor sealeyi, NMMNHS P-25049 (image reversed); (H) Adult Bistahieversor sealeyi, NMMNHS P-27469; (I) Juvenile Gorgosaurus libratus, ROM 1247 (image reversed); (J) Adult Gorgosaurus libratus, CMNN 2120.Scale bars equal 10 cm.Scales not available for A-C because these photographs were taken of specimens on display behind glass." figureDoi="http://doi.org/10.5281/zenodo.3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="4" pageNumber="4">Fig. 1</figureCitation>
|
||
. The groove is also present on the tyrannosaurids
|
||
<taxonomicName box="[565,662,875,895]" class="Reptilia" family="Tyrannosauridae" genus="Lythronax" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[565,662,875,895]" italics="true" pageId="4" pageNumber="4">Lythronax</emphasis>
|
||
</taxonomicName>
|
||
(
|
||
<bibRefCitation author="Loewen, M. A. & Irmis, R. B. & Sertich, J. J. W. & Currie, P. J. & Sampson, S. D." journalOrPublisher="PLoS One" pageId="4" pageNumber="4" pagination="e 79420" part="8" refId="ref6494" refString="Loewen, M. A., Irmis, R. B., Sertich, J. J. W., Currie, P. J., Sampson, S. D., 2013. Tyrant dinosaur evolution tracks the rise and fall of Late Cretaceous oceans. PLoS One 8 (11), e 79420. http: // dx. doi. org / 10.1371 / journal. pone. 0079420." title="Tyrant dinosaur evolution tracks the rise and fall of Late Cretaceous oceans" type="journal article" year="2013">Loewen et al., 2013</bibRefCitation>
|
||
: fig. 2) and
|
||
<taxonomicName box="[348,527,903,923]" class="Reptilia" family="Tyrannosauridae" genus="Zhuchengtyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[348,527,903,923]" italics="true" pageId="4" pageNumber="4">Zhuchengtyrannus</emphasis>
|
||
</taxonomicName>
|
||
(ZCDM V0031;
|
||
<bibRefCitation author="Hone, D. W. E. & Wang, K. & Sullivan, C. & Zhao, X. - J. & Chen, S. & Li, D. & Ji, S. & Ji, Q. & Xu, X." journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="495 - 503" part="32" refId="ref6321" refString="Hone, D. W. E., Wang, K., Sullivan, C., Zhao, X. - J., Chen, S., Li, D., Ji, S., Ji, Q., Xu, X., 2011. A new, large tyrannosaurine theropod from the Upper Cretaceous of China. Cretaceous Research 32, 495 - 503." title="A new, large tyrannosaurine theropod from the Upper Cretaceous of China" type="journal article" year="2011">Hone et al., 2011</bibRefCitation>
|
||
: fig. 3), which were not considered by
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
.
|
||
</paragraph>
|
||
<paragraph blockId="4.[88,757,178,1984]" pageId="4" pageNumber="4">
|
||
In some of these cases, we are considering the same specimens as
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[113,435,1016,1035]" journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
but our observations are at odds (e.g.,
|
||
<emphasis box="[149,234,1043,1063]" italics="true" pageId="4" pageNumber="4">Raptorex</emphasis>
|
||
,
|
||
<emphasis box="[255,426,1043,1063]" italics="true" pageId="4" pageNumber="4">Appalachiosaurus</emphasis>
|
||
,
|
||
<emphasis box="[446,581,1043,1063]" italics="true" pageId="4" pageNumber="4">Bistahieversor</emphasis>
|
||
,
|
||
<emphasis box="[601,699,1043,1063]" italics="true" pageId="4" pageNumber="4">Alioramus</emphasis>
|
||
,
|
||
<emphasis italics="true" pageId="4" pageNumber="4">Teratophoneus</emphasis>
|
||
). The most likely explanation is that all
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
scored all of these taxa based on figures in published literature, which often do not clearly convey the extent and morphology of shallow grooves. In other cases, however, our disagreements have to do with
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[412,757,1183,1202]" journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild's (2016)</bibRefCitation>
|
||
strategy of targeting holotypes or small samples of taxa known from many specimens. For example, they score
|
||
<taxonomicName authorityName="Maleev" authorityYear="1955" box="[606,724,1238,1258]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[606,724,1238,1258]" italics="true" pageId="4" pageNumber="4">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
as lacking the groove based on a photograph of a single specimen (MPC-D 107/7) with either an absent or very shallow groove, whereas we have examined numerous other specimens in the Warsaw (ZPAL) and Moscow (PIN) collections that have grooves of varying morphology, from very shallow to deeply impressed (
|
||
<figureCitation box="[96,146,1407,1426]" captionStart="Fig" captionStartId="3.[113,138,1877,1891]" captionTargetBox="[100,1460,180,1982]" captionTargetId="figure@2.[99,1462,178,1984]" captionTargetPageId="2" captionText="Fig.1. Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows). (A) Tarbosaurus bataar, PIN 4216/3 (image reversed); (B) Tarbosaurus bataar, PIN 551-2/ 1; (C) Adult Tyrannosaurus rex, MOR 008 (image reversed); (D) Adult Tyrannosaurus rex, AMNH FARB 5027 (cast); (E) Juvenile Daspletosaurus torosus, TMP 1994.143.0001; (F) Adult Daspletosaurus torosus, CMN 8506 (image reversed); (G) Juvenile Bistahieversor sealeyi, NMMNHS P-25049 (image reversed); (H) Adult Bistahieversor sealeyi, NMMNHS P-27469; (I) Juvenile Gorgosaurus libratus, ROM 1247 (image reversed); (J) Adult Gorgosaurus libratus, CMNN 2120.Scale bars equal 10 cm.Scales not available for A-C because these photographs were taken of specimens on display behind glass." figureDoi="http://doi.org/10.5281/zenodo.3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="4" pageNumber="4">Fig.1</figureCitation>
|
||
A-B). Therefore, by looking primarily at holotypes rather than larger hypodigms,
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[279,612,1435,1454]" journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
minimize the chance of recognizing variation in this trait. To effectively demonstrate this trait exists in only one state within a species (i.e., that it does not vary by ontogeny, sexual dimorphism, individual variation, or other causes), one needs to examine a larger number of individuals.
|
||
</paragraph>
|
||
</subSubSection>
|
||
<subSubSection pageId="4" pageNumber="4" type="nomenclature">
|
||
<paragraph blockId="4.[88,757,178,1984]" pageId="4" pageNumber="4">
|
||
Our identification of a dentary groove in a wide variety of tyrannosauroids, including
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[371,555,1628,1648]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[371,555,1628,1648]" italics="true" pageId="4" pageNumber="4">Tyrannosaurus rex</emphasis>
|
||
</taxonomicName>
|
||
, falsifies two main conclusions of
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[238,566,1658,1677]" journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
: that the presence of a groove differentiates ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[357,494,1684,1704]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[357,494,1684,1704]" italics="true" pageId="4" pageNumber="4">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ from
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[564,617,1684,1705]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[564,574,1684,1704]" italics="true" pageId="4" pageNumber="4">T</emphasis>
|
||
.
|
||
<emphasis box="[587,617,1684,1704]" italics="true" pageId="4" pageNumber="4">rex</emphasis>
|
||
</taxonomicName>
|
||
, and that the groove is unusually shared between ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[478,615,1712,1732]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[478,615,1712,1732]" italics="true" pageId="4" pageNumber="4">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ and albertosaurines (
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[186,319,1740,1760]" class="Reptilia" family="Tyrannosauridae" genus="Albertosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[186,319,1740,1760]" italics="true" pageId="4" pageNumber="4">Albertosaurus</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<taxonomicName authorityName="Cope" authorityYear="1866" box="[371,493,1740,1760]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[371,493,1740,1760]" italics="true" pageId="4" pageNumber="4">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
) to the exclusion of other taxa. Instead, the groove is a common character of tyrannosauroids, and indeed theropods in general, that all of these taxa plesiomorphically retain from their distant ancestors. Simple presence or absence of a groove appears to have no bearing on tyrannosauroid phylogeny, although as discussed above, the presence of a troodontid-style deep, sharp groove is a proceratosaurid synapomorphy (
|
||
<bibRefCitation author="Brusatte, S. L. & Norell, M. A. & Carr, T. D. & Erickson, G. M. & Hutchinson, J. R. & Balanoff, A. M. & Bever, G. S. & Choiniere, J. N. & Makovicky, P. J. & Xu, X." box="[354,556,1937,1956]" journalOrPublisher="Science" pageId="4" pageNumber="4" pagination="1481 - 1485" part="329" refId="ref5508" refString="Brusatte, S. L., Norell, M. A., Carr, T. D., Erickson, G. M., Hutchinson, J. R., Balanoff, A. M., Bever, G. S., Choiniere, J. N., Makovicky, P. J., Xu, X., 2010. Tyrannosaur paleobiology: new research on ancient exemplar organisms. Science 329, 1481 - 1485." title="Tyrannosaur paleobiology: new research on ancient exemplar organisms" type="journal article" year="2010">Brusatte et al., 2010</bibRefCitation>
|
||
,
|
||
<bibRefCitation author="Brusatte, S. L. & Lloyd, G. T. & Wang, S. C. & Norell, M. A." box="[566,618,1937,1956]" journalOrPublisher="Current Biology" pageId="4" pageNumber="4" pagination="2386 - 2392" part="24" refId="ref5595" refString="Brusatte, S. L., Lloyd, G. T., Wang, S. C., Norell, M. A., 2014. Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition. Current Biology 24, 2386 - 2392." title="Gradual assembly of avian body plan culminated in rapid rates of evolution across the dinosaur-bird transition" type="journal article" year="2014">2014</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Brusatte, S. L. & Carr, T. D." journalOrPublisher="Scientific Reports" pageId="4" pageNumber="4" pagination="20252" part="6" refId="ref5418" refString="Brusatte, S. L., Carr, T. D., 2016. The phylogeny and evolutionary history of tyrannosauroid dinosaurs. Scientific Reports 6, 20252." title="The phylogeny and evolutionary history of tyrannosauroid dinosaurs" type="journal article" year="2016">Brusatte and Carr, 2016</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
</subSubSection>
|
||
<subSubSection lastPageId="5" lastPageNumber="5" pageId="4" pageNumber="4" type="discussion">
|
||
<paragraph blockId="4.[805,1342,179,226]" pageId="4" pageNumber="4">
|
||
<heading bold="true" fontSize="8" level="3" pageId="4" pageNumber="4" reason="0">
|
||
<emphasis bold="true" pageId="4" pageNumber="4">4. Dentary grooves are ontogenetically variable in tyrannosauroids</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph blockId="4.[805,1475,263,1984]" pageId="4" pageNumber="4">
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[837,1194,263,282]" journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016:31)</bibRefCitation>
|
||
also argue that the dentary groove is an ontogenetically invariant feature in tyrannosauroids, meaning that juveniles and adults of the same taxon would have the same condition (presence or absence of the groove). This is based on two points: 1) their identification of the groove as absent in juvenile, subadult, and adult specimens of
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[1286,1469,401,421]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[1286,1469,401,421]" italics="true" pageId="4" pageNumber="4">Tyrannosaurus rex</emphasis>
|
||
</taxonomicName>
|
||
, and 2) a philosophical argument that a ‘dramatic change’ like ‘metamorphosis’ would be needed to explain the loss of the groove as an individual matured, because the groove corresponds to a system of nerves that they assume to be developmentally conservative.
|
||
</paragraph>
|
||
<paragraph blockId="4.[805,1475,263,1984]" pageId="4" pageNumber="4">
|
||
In fact, the morphology of the groove is highly ontogenetically variable in tyrannosauroids, and in some taxa clearly changes from a deeply-inset and pronounced structure in juveniles to a shallow and sometimes nearly indistinguishable sulcus in adults. This can be seen in the growth series of two tyrannosauroids. A remarkably preserved juvenile specimen of
|
||
<taxonomicName authorityName="Maleev" authorityYear="1955" box="[1141,1259,708,728]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1141,1259,708,728]" italics="true" pageId="4" pageNumber="4">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
that died at two or three years of age has a deep, well-pronounced dentary groove (
|
||
<bibRefCitation author="Tsuihiji, T. & Watabe, M. & Togtbaatar, K. & Tsubamoto, T. & Barsbold, R. & Suzuki, S. & Lee, A. H. & Ridgely, R. C. & Kawahara, Y. & Witmer, L. M." box="[813,1006,765,785]" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="4" pageNumber="4" pagination="497 - 517" part="31" refId="ref6802" refString="Tsuihiji, T., Watabe, M., Togtbaatar, K., Tsubamoto, T., Barsbold, R., Suzuki, S., Lee, A. H., Ridgely, R. C., Kawahara, Y., Witmer, L. M., 2011. Cranial osteology of a juvenile specimen of Tarbosaurus bataar from the Nemegt Formation (Upper Cretaceous) of Bugin Tsav, Mongolia. Journal of Vertebrate Paleontology 31, 497 - 517." title="Cranial osteology of a juvenile specimen of Tarbosaurus bataar from the Nemegt Formation (Upper Cretaceous) of Bugin Tsav, Mongolia" type="journal article" year="2011">Tsuihiji et al., 2011</bibRefCitation>
|
||
: fig. 3). Much larger, subadult and adult
|
||
<taxonomicName authorityName="Maleev" authorityYear="1955" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis italics="true" pageId="4" pageNumber="4">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
retain dentary grooves, but they are much more shallowly impressed (
|
||
<figureCitation box="[924,977,821,840]" captionStart="Fig" captionStartId="3.[113,138,1877,1891]" captionTargetBox="[100,1460,180,1982]" captionTargetId="figure@2.[99,1462,178,1984]" captionTargetPageId="2" captionText="Fig.1. Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows). (A) Tarbosaurus bataar, PIN 4216/3 (image reversed); (B) Tarbosaurus bataar, PIN 551-2/ 1; (C) Adult Tyrannosaurus rex, MOR 008 (image reversed); (D) Adult Tyrannosaurus rex, AMNH FARB 5027 (cast); (E) Juvenile Daspletosaurus torosus, TMP 1994.143.0001; (F) Adult Daspletosaurus torosus, CMN 8506 (image reversed); (G) Juvenile Bistahieversor sealeyi, NMMNHS P-25049 (image reversed); (H) Adult Bistahieversor sealeyi, NMMNHS P-27469; (I) Juvenile Gorgosaurus libratus, ROM 1247 (image reversed); (J) Adult Gorgosaurus libratus, CMNN 2120.Scale bars equal 10 cm.Scales not available for A-C because these photographs were taken of specimens on display behind glass." figureDoi="http://doi.org/10.5281/zenodo.3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="4" pageNumber="4">Fig. 1</figureCitation>
|
||
A-B; PIN 551-2/1, 551-12/1, 4216/3, 4216/1; ZPAL MgD-I/75, I/5). In the same vein, a juvenile
|
||
<emphasis box="[1237,1373,847,867]" italics="true" pageId="4" pageNumber="4">Bistahieversor</emphasis>
|
||
specimen has a deep groove across the middle and posterior portion of its dentary, which approaches the troodontid-condition in having well-defined dorsal and ventral margins that completely enclose the neurovascular foramina (
|
||
<figureCitation box="[1098,1170,960,979]" captionStart="Fig" captionStartId="3.[113,138,1877,1891]" captionTargetBox="[100,1460,180,1982]" captionTargetId="figure@2.[99,1462,178,1984]" captionTargetPageId="2" captionText="Fig.1. Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows). (A) Tarbosaurus bataar, PIN 4216/3 (image reversed); (B) Tarbosaurus bataar, PIN 551-2/ 1; (C) Adult Tyrannosaurus rex, MOR 008 (image reversed); (D) Adult Tyrannosaurus rex, AMNH FARB 5027 (cast); (E) Juvenile Daspletosaurus torosus, TMP 1994.143.0001; (F) Adult Daspletosaurus torosus, CMN 8506 (image reversed); (G) Juvenile Bistahieversor sealeyi, NMMNHS P-25049 (image reversed); (H) Adult Bistahieversor sealeyi, NMMNHS P-27469; (I) Juvenile Gorgosaurus libratus, ROM 1247 (image reversed); (J) Adult Gorgosaurus libratus, CMNN 2120.Scale bars equal 10 cm.Scales not available for A-C because these photographs were taken of specimens on display behind glass." figureDoi="http://doi.org/10.5281/zenodo.3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="4" pageNumber="4">Fig. 1G</figureCitation>
|
||
; NMMNHS P-25049;
|
||
<bibRefCitation author="Carr, T. D. & Williamson, T. E." journalOrPublisher="Journal of Vertebrate Paleontology" pageId="4" pageNumber="4" pagination="1 - 16" part="30" refId="ref5722" refString="Carr, T. D., Williamson, T. E., 2010. Bistahieversor sealeyi, gen. et sp. nov., a new tyrannosauroid from New Mexico and the origin of deep snouts in Tyrannosauroidea. Journal of Vertebrate Paleontology 30, 1 - 16." title="Bistahieversor sealeyi, gen. et sp. nov., a new tyrannosauroid from New Mexico and the origin of deep snouts in Tyrannosauroidea" type="journal article" year="2010">Carr and Williamson, 2010</bibRefCitation>
|
||
: fig. 1B). An adult, by contrast, has a much shallower groove that is better defined ventrally than dorsally. The neurovascular foramina are larger and channel upwards, breaching the dorsal margin of the groove and thus making the groove appear as a less discrete structure (
|
||
<figureCitation box="[1094,1167,1100,1119]" captionStart="Fig" captionStartId="3.[113,138,1877,1891]" captionTargetBox="[100,1460,180,1982]" captionTargetId="figure@2.[99,1462,178,1984]" captionTargetPageId="2" captionText="Fig.1. Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows). (A) Tarbosaurus bataar, PIN 4216/3 (image reversed); (B) Tarbosaurus bataar, PIN 551-2/ 1; (C) Adult Tyrannosaurus rex, MOR 008 (image reversed); (D) Adult Tyrannosaurus rex, AMNH FARB 5027 (cast); (E) Juvenile Daspletosaurus torosus, TMP 1994.143.0001; (F) Adult Daspletosaurus torosus, CMN 8506 (image reversed); (G) Juvenile Bistahieversor sealeyi, NMMNHS P-25049 (image reversed); (H) Adult Bistahieversor sealeyi, NMMNHS P-27469; (I) Juvenile Gorgosaurus libratus, ROM 1247 (image reversed); (J) Adult Gorgosaurus libratus, CMNN 2120.Scale bars equal 10 cm.Scales not available for A-C because these photographs were taken of specimens on display behind glass." figureDoi="http://doi.org/10.5281/zenodo.3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="4" pageNumber="4">Fig. 1H</figureCitation>
|
||
; NMMNHS P-27469;
|
||
<bibRefCitation author="Carr, T. D. & Williamson, T. E." journalOrPublisher="Journal of Vertebrate Paleontology" pageId="4" pageNumber="4" pagination="1 - 16" part="30" refId="ref5722" refString="Carr, T. D., Williamson, T. E., 2010. Bistahieversor sealeyi, gen. et sp. nov., a new tyrannosauroid from New Mexico and the origin of deep snouts in Tyrannosauroidea. Journal of Vertebrate Paleontology 30, 1 - 16." title="Bistahieversor sealeyi, gen. et sp. nov., a new tyrannosauroid from New Mexico and the origin of deep snouts in Tyrannosauroidea" type="journal article" year="2010">Carr and Williamson, 2010</bibRefCitation>
|
||
: fig. 1A).
|
||
</paragraph>
|
||
<paragraph blockId="4.[805,1475,263,1984]" pageId="4" pageNumber="4">
|
||
The ontogenetic trend from a deeply impressed to a shallow and indistinct groove is also seen in three taxa that were discussed by
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[909,1237,1211,1230]" journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
. First, in
|
||
<taxonomicName authorityName="Cope" authorityYear="1866" box="[1329,1452,1210,1230]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1329,1452,1210,1230]" italics="true" pageId="4" pageNumber="4">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
, a taxon they consider as possessing the groove, juveniles have sharp and well-defined grooves whereas adults have less discrete and shallower grooves just like those of adult
|
||
<taxonomicName authorityName="Maleev" authorityYear="1955" box="[1307,1426,1294,1314]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1307,1426,1294,1314]" italics="true" pageId="4" pageNumber="4">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<emphasis box="[805,943,1322,1342]" italics="true" pageId="4" pageNumber="4">Bistahieversor</emphasis>
|
||
(
|
||
<figureCitation box="[962,1020,1323,1342]" captionStart="Fig" captionStartId="3.[113,138,1877,1891]" captionTargetBox="[100,1460,180,1982]" captionTargetId="figure@2.[99,1462,178,1984]" captionTargetPageId="2" captionText="Fig.1. Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows). (A) Tarbosaurus bataar, PIN 4216/3 (image reversed); (B) Tarbosaurus bataar, PIN 551-2/ 1; (C) Adult Tyrannosaurus rex, MOR 008 (image reversed); (D) Adult Tyrannosaurus rex, AMNH FARB 5027 (cast); (E) Juvenile Daspletosaurus torosus, TMP 1994.143.0001; (F) Adult Daspletosaurus torosus, CMN 8506 (image reversed); (G) Juvenile Bistahieversor sealeyi, NMMNHS P-25049 (image reversed); (H) Adult Bistahieversor sealeyi, NMMNHS P-27469; (I) Juvenile Gorgosaurus libratus, ROM 1247 (image reversed); (J) Adult Gorgosaurus libratus, CMNN 2120.Scale bars equal 10 cm.Scales not available for A-C because these photographs were taken of specimens on display behind glass." figureDoi="http://doi.org/10.5281/zenodo.3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="4" pageNumber="4">Fig. 1</figureCitation>
|
||
I-J; juvenile condition: TMP 1986.144.0001 and ROM 1247, adult condition: CMN 2120). Second, the trend is seen in
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[896,1031,1377,1397]" class="Reptilia" family="Tyrannosauridae" genus="Albertosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[896,1031,1377,1397]" italics="true" pageId="4" pageNumber="4">Albertosaurus</emphasis>
|
||
</taxonomicName>
|
||
(juvenile condition: TMP 1986.064.0001, adult condition: TMP 1999.050.0021). It is also worth noting that some non-ontogenetic variation is also seen in
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[1299,1428,1433,1453]" class="Reptilia" family="Tyrannosauridae" genus="Albertosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1299,1428,1433,1453]" italics="true" pageId="4" pageNumber="4">Abertosaurus</emphasis>
|
||
</taxonomicName>
|
||
and
|
||
<taxonomicName authorityName="Cope" authorityYear="1866" box="[805,928,1461,1481]" class="Reptilia" family="Tyrannosauridae" genus="Gorgosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[805,928,1461,1481]" italics="true" pageId="4" pageNumber="4">Gorgosaurus</emphasis>
|
||
</taxonomicName>
|
||
, as some adults have a deep groove like that of juveniles (TMP 2000.045.0084, AMNH FARB 5458, respectively). Third, although
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[976,1318,1518,1537]" journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
argue that no specimens of
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[949,1003,1545,1566]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[949,959,1545,1565]" italics="true" pageId="4" pageNumber="4">T</emphasis>
|
||
.
|
||
<emphasis box="[973,1003,1545,1565]" italics="true" pageId="4" pageNumber="4">rex</emphasis>
|
||
</taxonomicName>
|
||
possess the groove, we disagree and instead identify
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[893,947,1573,1593]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[893,903,1573,1593]" italics="true" pageId="4" pageNumber="4">T</emphasis>
|
||
.
|
||
<emphasis box="[917,947,1573,1593]" italics="true" pageId="4" pageNumber="4">rex</emphasis>
|
||
</taxonomicName>
|
||
as undergoing the same ontogenetic trajectory as other tyrannosauroids. Our observations show that a groove is seen on the left side of the juvenile specimen
|
||
<materialsCitation ID-GBIF-Occurrence="2636230303" box="[1273,1400,1630,1649]" collectionCode="LACM" pageId="4" pageNumber="4" specimenCode="LACM 28471">LACM 28471</materialsCitation>
|
||
, contra to
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[837,1183,1658,1677]" journalOrPublisher="Cretaceous Research" pageId="4" pageNumber="4" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
, but heavy damage to the external bone surface obscures its depth, easily making it appear absent in photographs. There is also a groove in adult
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[1417,1474,1712,1732]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[1417,1474,1712,1732]" italics="true" pageId="4" pageNumber="4">T. rex</emphasis>
|
||
</taxonomicName>
|
||
specimens (
|
||
<figureCitation box="[930,986,1741,1761]" captionStart="Fig" captionStartId="3.[113,138,1877,1891]" captionTargetBox="[100,1460,180,1982]" captionTargetId="figure@2.[99,1462,178,1984]" captionTargetPageId="2" captionText="Fig.1. Lateral views of tyrannosauroid dentaries with a lateral groove (indicated by arrows). (A) Tarbosaurus bataar, PIN 4216/3 (image reversed); (B) Tarbosaurus bataar, PIN 551-2/ 1; (C) Adult Tyrannosaurus rex, MOR 008 (image reversed); (D) Adult Tyrannosaurus rex, AMNH FARB 5027 (cast); (E) Juvenile Daspletosaurus torosus, TMP 1994.143.0001; (F) Adult Daspletosaurus torosus, CMN 8506 (image reversed); (G) Juvenile Bistahieversor sealeyi, NMMNHS P-25049 (image reversed); (H) Adult Bistahieversor sealeyi, NMMNHS P-27469; (I) Juvenile Gorgosaurus libratus, ROM 1247 (image reversed); (J) Adult Gorgosaurus libratus, CMNN 2120.Scale bars equal 10 cm.Scales not available for A-C because these photographs were taken of specimens on display behind glass." figureDoi="http://doi.org/10.5281/zenodo.3897671" httpUri="https://zenodo.org/record/3897671/files/figure.png" pageId="4" pageNumber="4">Fig. 1</figureCitation>
|
||
C-D;
|
||
<materialsCitation ID-GBIF-Occurrence="2636230304" box="[1042,1235,1741,1761]" collectionCode="AMNH" pageId="4" pageNumber="4" specimenCode="AMNH 5027">AMNH FARB 5027</materialsCitation>
|
||
;
|
||
<materialsCitation ID-GBIF-Occurrence="2636230316" box="[1250,1348,1742,1761]" collectionCode="CM" pageId="4" pageNumber="4" specimenCode="CM 9380">CM 9380</materialsCitation>
|
||
;
|
||
<materialsCitation ID-GBIF-Occurrence="2636230319" box="[1362,1463,1742,1761]" collectionCode="MOR" pageId="4" pageNumber="4" specimenCode="MOR 008">MOR 008</materialsCitation>
|
||
), which is shallow, weakly inset, and houses large foramina that course dorsally, just as in other adult tyrannosaurids. The well- defined grooves of the two purported ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[1215,1354,1824,1844]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1215,1354,1824,1844]" italics="true" pageId="4" pageNumber="4">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ specimens (
|
||
<materialsCitation ID-GBIF-Occurrence="2636230302" box="[811,939,1853,1872]" collectionCode="CMNH" pageId="4" pageNumber="4" specimenCode="CMNH 7541">CMNH 7541</materialsCitation>
|
||
;
|
||
<materialsCitation ID-GBIF-Occurrence="2636230306" box="[949,1103,1853,1873]" collectionCode="BMRP" pageId="4" pageNumber="4" specimenCode="BMRP 2002.4.1">BMRP 2002.4.1</materialsCitation>
|
||
) are thus expected for juvenile
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[1423,1474,1852,1873]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[1423,1433,1852,1872]" italics="true" pageId="4" pageNumber="4">T</emphasis>
|
||
.
|
||
<emphasis box="[1444,1474,1852,1872]" italics="true" pageId="4" pageNumber="4">rex</emphasis>
|
||
</taxonomicName>
|
||
filling an ontogenetic gap between the very small
|
||
<materialsCitation ID-GBIF-Occurrence="2636230313" box="[1344,1474,1881,1900]" collectionCode="LACM" pageId="4" pageNumber="4" specimenCode="LACM 28471">LACM 28471</materialsCitation>
|
||
and adults.
|
||
</paragraph>
|
||
<paragraph blockId="4.[805,1475,263,1984]" lastBlockId="5.[113,783,179,505]" lastPageId="5" lastPageNumber="5" pageId="4" pageNumber="4">
|
||
The dentary groove, therefore, can be added to the list of features that are ontogenetically variable in large-bodied tyrannosauroids, which have been outlined in detail by
|
||
<bibRefCitation author="Carr, T. D." box="[670,783,179,198]" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="5" pageNumber="5" pagination="497 - 520" part="19" refId="ref5650" refString="Carr, T. D., 1999. Craniofacial ontogeny in Tyrannosauridae (Dinosauria, Coelurosauria). Journal of Vertebrate Paleontology 19, 497 - 520." title="Craniofacial ontogeny in Tyrannosauridae (Dinosauria, Coelurosauria)" type="journal article" year="1999">Carr (1999)</bibRefCitation>
|
||
and
|
||
<bibRefCitation author="Carr, T. D. & Williamson, T. E." box="[158,441,207,226]" journalOrPublisher="Zoological Journal of the Linnean Society" pageId="5" pageNumber="5" pagination="479 - 523" part="142" refId="ref5679" refString="Carr, T. D., Williamson, T. E., 2004. Diversity of late Maastrichtian Tyrannosauridae (Dinosauria: Theropoda) from western North America. Zoological Journal of the Linnean Society 142, 479 - 523." title="Diversity of late Maastrichtian Tyrannosauridae (Dinosauria: Theropoda) from western North America" type="journal article" year="2004">Carr and Williamson (2004)</bibRefCitation>
|
||
. Many of these other ontogenetic transformations in skull shape, robusticity, ornamentation, and sinuses are much more extreme than a shallowing of the neuro- vascular groove on the dentary, so there is no need to invoke biologically implausible mechanisms like metamorphosis to explain the latter. With that said,
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[489,547,345,366]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[489,499,345,365]" italics="true" pageId="5" pageNumber="5">T</emphasis>
|
||
.
|
||
<emphasis box="[517,547,345,365]" italics="true" pageId="5" pageNumber="5">rex</emphasis>
|
||
</taxonomicName>
|
||
did undergo a major transformation as it grew from a tiny hatchling into a multi-ton, 13- meter-long, bone-crunching adult (
|
||
<bibRefCitation author="Erickson, G. M. & Makovicky, P. J. & Currie, P. J. & Norell, M. A. & Yerby, S. A. & Brochu, C. A." box="[481,696,402,422]" journalOrPublisher="Nature" pageId="5" pageNumber="5" pagination="772 - 775" part="430" refId="ref6057" refString="Erickson, G. M., Makovicky, P. J., Currie, P. J., Norell, M. A., Yerby, S. A., Brochu, C. A., 2004. Gigantism and comparative life-history parameters of tyrannosaurid dinosaurs. Nature 430, 772 - 775." title="Gigantism and comparative life-history parameters of tyrannosaurid dinosaurs" type="journal article" year="2004">Erickson et al., 2004</bibRefCitation>
|
||
). Subtle alterations in its neurovascular ornamentation were some of the least impressive changes as
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[427,486,457,478]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[427,437,457,477]" italics="true" pageId="5" pageNumber="5">T</emphasis>
|
||
.
|
||
<emphasis box="[456,486,457,477]" italics="true" pageId="5" pageNumber="5">rex</emphasis>
|
||
</taxonomicName>
|
||
and other tyrannosauroids matured.
|
||
</paragraph>
|
||
<footnote pageId="4" pageNumber="4">
|
||
<paragraph blockId="4.[98,1464,2036,2110]" pageId="4" pageNumber="4">
|
||
Please cite this article in press as: Brusatte, S.L., et al., Dentary groove morphology does not distinguish ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[1137,1269,2036,2056]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1137,1269,2036,2056]" italics="true" pageId="4" pageNumber="4">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ as a valid taxon of tyrannosauroid dinosaur. Comment on: “Distribution of the dentary groove of theropod dinosaurs: Implications for theropod phylogeny and the validity of the genus
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[341,656,2089,2110]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="4" pageNumber="4" phylum="Chordata" rank="genus">
|
||
<emphasis box="[341,473,2089,2109]" italics="true" pageId="4" pageNumber="4">Nanotyrannus</emphasis>
|
||
<bibRefCitation author="Bakker, R. T. & William, M. & Currie, P." box="[479,656,2090,2110]" journalOrPublisher="Hunteria" pageId="4" pageNumber="4" pagination="1 - 28" part="1" refId="ref5336" refString="Bakker, R. T., William, M., Currie, P., 1988. Nanotyrannus, a new genus of pygmy tyrannosaur, from the Latest Cretaceous of Montana. Hunteria 1, 1 - 28." title="Nanotyrannus, a new genus of pygmy tyrannosaur, from the Latest Cretaceous of Montana" type="journal article" year="1988">Bakker et al., 1988</bibRefCitation>
|
||
</taxonomicName>
|
||
”, Cretaceous Research (2016), http://dx.doi.org/10.1016/j.cretres.2016.02.007
|
||
</paragraph>
|
||
</footnote>
|
||
<paragraph blockId="5.[113,581,542,561]" box="[113,581,542,561]" pageId="5" pageNumber="5">
|
||
<heading bold="true" box="[113,581,542,561]" fontSize="8" level="3" pageId="5" pageNumber="5" reason="0">
|
||
<emphasis bold="true" box="[113,581,542,561]" pageId="5" pageNumber="5">5. Key characters and phylogenetic analysis</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph blockId="5.[113,784,598,1984]" pageId="5" pageNumber="5">
|
||
Even if
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[235,584,598,617]" journalOrPublisher="Cretaceous Research" pageId="5" pageNumber="5" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
were correct and ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[118,255,624,644]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">
|
||
<emphasis box="[118,255,624,644]" italics="true" pageId="5" pageNumber="5">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ and
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[316,370,624,645]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[316,326,624,644]" italics="true" pageId="5" pageNumber="5">T</emphasis>
|
||
.
|
||
<emphasis box="[340,370,624,644]" italics="true" pageId="5" pageNumber="5">rex</emphasis>
|
||
</taxonomicName>
|
||
had different conditions of the dentary groove, it is unclear what this difference would mean systematically and phylogenetically. A common dictum of modern phyloge- netics is that all possible relevant evidence should be used to construct a phylogenetic hypothesis
|
||
<emphasis box="[473,495,742,756]" italics="true" pageId="5" pageNumber="5">―</emphasis>
|
||
the ‘total evidence’ approach (e.g.,
|
||
<bibRefCitation author="Kluge, A. G." box="[167,284,765,784]" journalOrPublisher="Systematic Zoology" pageId="5" pageNumber="5" pagination="7 - 25" part="38" refId="ref6396" refString="Kluge, A. G., 1989. A concern for evidence and a phylogenetic hypothesis of relationships among Epicrates (Boidae, Serpentes). Systematic Zoology 38, 7 - 25." title="A concern for evidence and a phylogenetic hypothesis of relationships among Epicrates (Boidae, Serpentes)" type="journal article" year="1989">Kluge, 1989</bibRefCitation>
|
||
). Individual characters can have patchy distributions between (and within) taxa, so it is the weight of total character evidence that is the best test of phylogenetic relationships.
|
||
</paragraph>
|
||
<paragraph blockId="5.[113,784,598,1984]" pageId="5" pageNumber="5">
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[145,479,849,868]" journalOrPublisher="Cretaceous Research" pageId="5" pageNumber="5" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
do conduct a broader phylogenetic analysis, by including the
|
||
<materialsCitation ID-GBIF-Occurrence="2636230312" box="[469,622,877,896]" collectionCode="BMRP" pageId="5" pageNumber="5" specimenCode="BMRP 2002.4.1">BMRP 2002.4.1</materialsCitation>
|
||
skull of ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">
|
||
<emphasis italics="true" pageId="5" pageNumber="5">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ in the cladistic dataset of
|
||
<bibRefCitation author="Brusatte, S. L. & Norell, M. A. & Carr, T. D. & Erickson, G. M. & Hutchinson, J. R. & Balanoff, A. M. & Bever, G. S. & Choiniere, J. N. & Makovicky, P. J. & Xu, X." box="[469,679,905,924]" journalOrPublisher="Science" pageId="5" pageNumber="5" pagination="1481 - 1485" part="329" refId="ref5508" refString="Brusatte, S. L., Norell, M. A., Carr, T. D., Erickson, G. M., Hutchinson, J. R., Balanoff, A. M., Bever, G. S., Choiniere, J. N., Makovicky, P. J., Xu, X., 2010. Tyrannosaur paleobiology: new research on ancient exemplar organisms. Science 329, 1481 - 1485." title="Tyrannosaur paleobiology: new research on ancient exemplar organisms" type="journal article" year="2010">Brusatte et al. (2010)</bibRefCitation>
|
||
. Although this exercise is much preferable to arguments based on single characters, the methodology of
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[446,783,960,979]" journalOrPublisher="Cretaceous Research" pageId="5" pageNumber="5" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
has its flaws. First, they scored ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[457,594,987,1007]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">
|
||
<emphasis box="[457,600,987,1007]" italics="true" pageId="5" pageNumber="5">Nanotyrannus’</emphasis>
|
||
</taxonomicName>
|
||
based on cranial characters only (except for a single character relating to the forelimbs), even though there are ample postcranial data for
|
||
<materialsCitation ID-GBIF-Occurrence="2636230310" collectionCode="BMRP" pageId="5" pageNumber="5" specimenCode="BMRP 2002.4.1">BMRP 2002.4.1</materialsCitation>
|
||
. Second, the phylogenetic dataset of
|
||
<bibRefCitation author="Brusatte, S. L. & Norell, M. A. & Carr, T. D. & Erickson, G. M. & Hutchinson, J. R. & Balanoff, A. M. & Bever, G. S. & Choiniere, J. N. & Makovicky, P. J. & Xu, X." box="[573,783,1072,1091]" journalOrPublisher="Science" pageId="5" pageNumber="5" pagination="1481 - 1485" part="329" refId="ref5508" refString="Brusatte, S. L., Norell, M. A., Carr, T. D., Erickson, G. M., Hutchinson, J. R., Balanoff, A. M., Bever, G. S., Choiniere, J. N., Makovicky, P. J., Xu, X., 2010. Tyrannosaur paleobiology: new research on ancient exemplar organisms. Science 329, 1481 - 1485." title="Tyrannosaur paleobiology: new research on ancient exemplar organisms" type="journal article" year="2010">Brusatte et al. (2010)</bibRefCitation>
|
||
was designed to test the relationships of taxa using adult specimens. It includes many ontogenetically variable characters, and because of the complex interplay between ontogeny and phylogeny, it scores taxa for the adult condition. In unavoidable cases, taxa without known adult specimens are included in the dataset, the best example being
|
||
<emphasis box="[339,424,1238,1258]" italics="true" pageId="5" pageNumber="5">Raptorex</emphasis>
|
||
. However, although it possesses numerous features of derived tyrannosaurines,
|
||
<emphasis box="[586,671,1266,1286]" italics="true" pageId="5" pageNumber="5">Raptorex</emphasis>
|
||
falls out as a basal non-tyrannosaurid, which is surely the result of the juvenile condition of holotype (see discussion in
|
||
<bibRefCitation author="Fowler, D. W. & Woodward, H. N. & Freedman, E. A. & Larson, P. L. & Horner, J. R." box="[529,714,1323,1342]" journalOrPublisher="PLoS One" pageId="5" pageNumber="5" pagination="e 21376" part="6" refId="ref6117" refString="Fowler, D. W., Woodward, H. N., Freedman, E. A., Larson, P. L., Horner, J. R., 2011. Reanalysis of " Raptorex kriegsteini ": a juvenile tyrannosaurid dinosaur from Mongolia. PLoS One 6 (6), e 21376." title="Reanalysis of " Raptorex kriegsteini ": a juvenile tyrannosaurid dinosaur from Mongolia" type="journal article" year="2011">Fowler et al., 2011</bibRefCitation>
|
||
, and a similar case concerning juvenile
|
||
<taxonomicName authorityName="Maleev" authorityYear="1955" box="[439,557,1350,1370]" class="Reptilia" family="Tyrannosauridae" genus="Tarbosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">
|
||
<emphasis box="[439,557,1350,1370]" italics="true" pageId="5" pageNumber="5">Tarbosaurus</emphasis>
|
||
</taxonomicName>
|
||
in
|
||
<bibRefCitation author="Tsuihiji, T. & Watabe, M. & Togtbaatar, K. & Tsubamoto, T. & Barsbold, R. & Suzuki, S. & Lee, A. H. & Ridgely, R. C. & Kawahara, Y. & Witmer, L. M." box="[586,770,1351,1370]" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="5" pageNumber="5" pagination="497 - 517" part="31" refId="ref6802" refString="Tsuihiji, T., Watabe, M., Togtbaatar, K., Tsubamoto, T., Barsbold, R., Suzuki, S., Lee, A. H., Ridgely, R. C., Kawahara, Y., Witmer, L. M., 2011. Cranial osteology of a juvenile specimen of Tarbosaurus bataar from the Nemegt Formation (Upper Cretaceous) of Bugin Tsav, Mongolia. Journal of Vertebrate Paleontology 31, 497 - 517." title="Cranial osteology of a juvenile specimen of Tarbosaurus bataar from the Nemegt Formation (Upper Cretaceous) of Bugin Tsav, Mongolia" type="journal article" year="2011">Tsuihiji et al., 2011</bibRefCitation>
|
||
). In that regard, the placement of ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[443,580,1377,1397]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">
|
||
<emphasis box="[443,580,1377,1397]" italics="true" pageId="5" pageNumber="5">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ as phylogenetically distant from
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[246,297,1405,1426]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[246,256,1405,1425]" italics="true" pageId="5" pageNumber="5">T</emphasis>
|
||
.
|
||
<emphasis box="[267,297,1405,1425]" italics="true" pageId="5" pageNumber="5">rex</emphasis>
|
||
</taxonomicName>
|
||
in
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[331,674,1407,1426]" journalOrPublisher="Cretaceous Research" pageId="5" pageNumber="5" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild's (2016)</bibRefCitation>
|
||
analysis is most likely an artifact of its juvenile status. This is how we would interpret the results of
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[343,667,1462,1481]" journalOrPublisher="Cretaceous Research" pageId="5" pageNumber="5" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
analysis, as it follows our interpretation of the placement of the juvenile
|
||
<emphasis italics="true" pageId="5" pageNumber="5">Raptorex</emphasis>
|
||
in our published studies (
|
||
<bibRefCitation author="Brusatte, S. L. & Norell, M. A. & Carr, T. D. & Erickson, G. M. & Hutchinson, J. R. & Balanoff, A. M. & Bever, G. S. & Choiniere, J. N. & Makovicky, P. J. & Xu, X." box="[435,642,1518,1538]" journalOrPublisher="Science" pageId="5" pageNumber="5" pagination="1481 - 1485" part="329" refId="ref5508" refString="Brusatte, S. L., Norell, M. A., Carr, T. D., Erickson, G. M., Hutchinson, J. R., Balanoff, A. M., Bever, G. S., Choiniere, J. N., Makovicky, P. J., Xu, X., 2010. Tyrannosaur paleobiology: new research on ancient exemplar organisms. Science 329, 1481 - 1485." title="Tyrannosaur paleobiology: new research on ancient exemplar organisms" type="journal article" year="2010">Brusatte et al., 2010</bibRefCitation>
|
||
;
|
||
<bibRefCitation author="Brusatte, S. L. & Carr, T. D." journalOrPublisher="Scientific Reports" pageId="5" pageNumber="5" pagination="20252" part="6" refId="ref5418" refString="Brusatte, S. L., Carr, T. D., 2016. The phylogeny and evolutionary history of tyrannosauroid dinosaurs. Scientific Reports 6, 20252." title="The phylogeny and evolutionary history of tyrannosauroid dinosaurs" type="journal article" year="2016">Brusatte and Carr, 2016</bibRefCitation>
|
||
).
|
||
</paragraph>
|
||
<paragraph blockId="5.[113,784,598,1984]" lastBlockId="5.[831,1501,179,282]" pageId="5" pageNumber="5">
|
||
Phylogenetic analyses can only determine the relationships among taxa. They cannot, on their own, determine if two specimens belong to the same species, although they can provide topologies that are consistent or inconsistent with such a hypothesis. The ultimate arbiter of whether ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[398,535,1684,1704]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">
|
||
<emphasis box="[398,535,1684,1704]" italics="true" pageId="5" pageNumber="5">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ is a distinct species is whether it possesses unique diagnostic features that are not seen in
|
||
<emphasis box="[113,296,1740,1760]" italics="true" pageId="5" pageNumber="5">
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[113,256,1740,1760]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">Tyrannosaurus</taxonomicName>
|
||
rex
|
||
</emphasis>
|
||
, particularly
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[435,489,1740,1761]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[435,445,1740,1760]" italics="true" pageId="5" pageNumber="5">T</emphasis>
|
||
.
|
||
<emphasis box="[459,489,1740,1760]" italics="true" pageId="5" pageNumber="5">rex</emphasis>
|
||
</taxonomicName>
|
||
specimens of the same size and ontogenetic stage of the purported ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[542,679,1768,1788]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">
|
||
<emphasis box="[542,679,1768,1788]" italics="true" pageId="5" pageNumber="5">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ material.
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[113,474,1797,1816]" journalOrPublisher="Cretaceous Research" pageId="5" pageNumber="5" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016:31)</bibRefCitation>
|
||
state that
|
||
<bibRefCitation author="Larson, P." box="[584,723,1797,1817]" editor="Parrish, J. M. & Molnar, R. E. & Currie, P. J. & Koppelhus, E. B." journalOrPublisher="Indiana University Press, Bloomington, Indiana" pageId="5" pageNumber="5" pagination="14 - 53" refId="ref6431" refString="Larson, P., 2013. The case for Nanotyrannus. In: Parrish, J. M., Molnar, R. E., Currie, P. J., Koppelhus, E. B. (Eds.), Tyrannosaurid Paleobiology. Indiana University Press, Bloomington, Indiana, pp. 14 - 53." title="The case for Nanotyrannus" type="book chapter" volumeTitle="Tyrannosaurid Paleobiology" year="2013">Larson (2013)</bibRefCitation>
|
||
identified ‘more than 30 other skeletal characters as evidence’ to separate ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[209,346,1852,1872]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">
|
||
<emphasis box="[209,346,1852,1872]" italics="true" pageId="5" pageNumber="5">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ and
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[401,452,1852,1873]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[401,411,1852,1872]" italics="true" pageId="5" pageNumber="5">T</emphasis>
|
||
.
|
||
<emphasis box="[422,452,1852,1872]" italics="true" pageId="5" pageNumber="5">rex</emphasis>
|
||
</taxonomicName>
|
||
. However, as has been shown by
|
||
<bibRefCitation author="Carr, T. D." box="[113,229,1881,1900]" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="5" pageNumber="5" pagination="497 - 520" part="19" refId="ref5650" refString="Carr, T. D., 1999. Craniofacial ontogeny in Tyrannosauridae (Dinosauria, Coelurosauria). Journal of Vertebrate Paleontology 19, 497 - 520." title="Craniofacial ontogeny in Tyrannosauridae (Dinosauria, Coelurosauria)" type="journal article" year="1999">Carr (1999)</bibRefCitation>
|
||
and
|
||
<bibRefCitation author="Carr, T. D. & Williamson, T. E." box="[282,569,1881,1900]" journalOrPublisher="Zoological Journal of the Linnean Society" pageId="5" pageNumber="5" pagination="479 - 523" part="142" refId="ref5679" refString="Carr, T. D., Williamson, T. E., 2004. Diversity of late Maastrichtian Tyrannosauridae (Dinosauria: Theropoda) from western North America. Zoological Journal of the Linnean Society 142, 479 - 523." title="Diversity of late Maastrichtian Tyrannosauridae (Dinosauria: Theropoda) from western North America" type="journal article" year="2004">Carr and Williamson (2004)</bibRefCitation>
|
||
, the vast majority of these features are ontogenetically variable, and therefore not reliable indicators of taxonomic separation. The monographic description of
|
||
<materialsCitation ID-GBIF-Occurrence="2636230311" box="[264,417,1965,1984]" collectionCode="BMRP" pageId="5" pageNumber="5" specimenCode="BMRP 2002.4.1">BMRP 2002.4.1</materialsCitation>
|
||
and its inclusion in a phylogenetic analysis that minimizes the effects of ontogenetic variation, both of which are underway by one of us (TDC) and have been presented in abstract form (
|
||
<bibRefCitation author="Carr, T. D. & Henderson, M. & Erickson, G. M. & Peterson, J. & Williams, S. & Currie, P. & Scherer, R. & Harrison, B." box="[979,1134,235,255]" journalOrPublisher="Journal of Vertebrate Paleontology" pageId="5" pageNumber="5" pagination="101 A" part="35" refId="ref5894" refString="Carr, T. D., Henderson, M., Erickson, G. M., Peterson, J., Williams, S., Currie, P., Scherer, R., Harrison, B., 2015. A subadult Tyrannosaurus rex and its bearing on the Nanotyrannus hypothesis. Journal of Vertebrate Paleontology 35, 101 A." title="A subadult Tyrannosaurus rex and its bearing on the Nanotyrannus hypothesis" type="journal article" year="2015">Carr et al., 2015</bibRefCitation>
|
||
), will go a long way in clarifying the systematics of the long-controversial ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[1216,1353,262,282]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1216,1353,262,282]" italics="true" pageId="5" pageNumber="5">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’.
|
||
</paragraph>
|
||
<paragraph blockId="5.[831,989,328,347]" box="[831,989,328,347]" pageId="5" pageNumber="5">
|
||
<heading bold="true" box="[831,989,328,347]" fontSize="8" level="3" pageId="5" pageNumber="5" reason="0">
|
||
<emphasis bold="true" box="[831,989,328,347]" pageId="5" pageNumber="5">6. Conclusions</emphasis>
|
||
</heading>
|
||
</paragraph>
|
||
<paragraph blockId="5.[831,1501,384,682]" pageId="5" pageNumber="5">
|
||
Contrary to
|
||
<bibRefCitation author="Schmerge, J. D. & Rothschild, B. M." box="[996,1341,384,403]" journalOrPublisher="Cretaceous Research" pageId="5" pageNumber="5" pagination="26 - 33" part="61" refId="ref6693" refString="Schmerge, J. D., Rothschild, B. M., 2016. Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988. Cretaceous Research 61, 26 - 33." title="Distribution of the dentary groove of theropod dinosaurs: implications for theropod phylogeny and the validity of the genus Nanotyrannus Bakker et al., 1988" type="journal article" year="2016">Schmerge and Rothschild (2016)</bibRefCitation>
|
||
, neurovascular grooves on the lateral surface of the dentary are common features among tyrannosauroids, and they become more shallowly inset and less distinct during ontogeny. The groove in one putative specimen of ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[966,1103,494,514]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">
|
||
<emphasis box="[966,1103,494,514]" italics="true" pageId="5" pageNumber="5">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ does not differentiate it from
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[1420,1472,494,515]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[1420,1430,494,514]" italics="true" pageId="5" pageNumber="5">T</emphasis>
|
||
.
|
||
<emphasis box="[1442,1472,494,514]" italics="true" pageId="5" pageNumber="5">rex</emphasis>
|
||
</taxonomicName>
|
||
or link it to albertosaurines. Rather, the pronounced condition of the groove is entirely consistent with the identification of this specimen as a juvenile
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[1023,1076,578,598]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[1023,1033,578,598]" italics="true" pageId="5" pageNumber="5">T</emphasis>
|
||
.
|
||
<emphasis box="[1046,1076,578,598]" italics="true" pageId="5" pageNumber="5">rex</emphasis>
|
||
</taxonomicName>
|
||
. We reaffirm that the most parsimonious explanation of all observations is that ‘
|
||
<taxonomicName authority="Bakker et al., 1988" authorityName="Bakker et al." authorityYear="1988" baseAuthorityName="Gilmore" baseAuthorityYear="1946" box="[1211,1348,606,626]" class="Reptilia" family="Tyrannosauridae" genus="Nanotyrannus" higherTaxonomySource="GBIF" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="genus">
|
||
<emphasis box="[1211,1348,606,626]" italics="true" pageId="5" pageNumber="5">Nanotyrannus</emphasis>
|
||
</taxonomicName>
|
||
’ is not a pygmy tyrannosaur, but a young
|
||
<taxonomicName authorityName="Osborn" authorityYear="1905" box="[1094,1146,634,654]" class="Reptilia" family="Tyrannosauridae" genus="Tyrannosaurus" kingdom="Animalia" order="Dinosauria" pageId="5" pageNumber="5" phylum="Chordata" rank="species" species="rex">
|
||
<emphasis box="[1094,1104,634,654]" italics="true" pageId="5" pageNumber="5">T</emphasis>
|
||
.
|
||
<emphasis box="[1116,1146,634,654]" italics="true" pageId="5" pageNumber="5">rex</emphasis>
|
||
</taxonomicName>
|
||
that has yet to grow into its adult frame.
|
||
</paragraph>
|
||
</subSubSection>
|
||
</treatment>
|
||
</document> |