559 lines
58 KiB
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559 lines
58 KiB
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<document ID-DOI="http://dx.doi.org/10.3897/zookeys.223.2840" ID-GBIF-Dataset="b9b1f5ed-fec1-474c-a014-f0fbb309f54b" ID-PMC="PMC3491919" ID-Pensoft-Pub="1313-2970-226-1" ID-PubMed="23166462" ModsDocAuthor="" ModsDocDate="2012" ModsDocID="1313-2970-226-1" ModsDocOrigin="ZooKeys 226" ModsDocTitle="Taxonomy, morphology, masticatory function and phylogeny of heterodontosaurid dinosaurs" checkinTime="1451248705912" checkinUser="pensoft" docAuthor="Sereno, Paul C." docDate="2012" docId="B9E302B7C17C12F8A97E87344C0B00CA" docLanguage="en" docName="ZooKeys 226: 1-225" docOrigin="ZooKeys 226" docSource="http://dx.doi.org/10.3897/zookeys.223.2840" docTitle="Tianyulong confuciusi Zheng et al. 2009" docType="treatment" docVersion="4" lastPageNumber="41" masterDocId="FFFCFF9FFF9B1434FFE8FF88BA74FFB7" masterDocTitle="Taxonomy, morphology, masticatory function and phylogeny of heterodontosaurid dinosaurs" masterLastPageNumber="225" masterPageNumber="1" pageNumber="30" updateTime="1668154520870" updateUser="ExternalLinkService">
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<mods:titleInfo>
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<mods:title>Taxonomy, morphology, masticatory function and phylogeny of heterodontosaurid dinosaurs</mods:title>
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<mods:name type="personal">
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<mods:roleTerm>Author</mods:roleTerm>
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<mods:namePart>Sereno, Paul C.</mods:namePart>
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<mods:typeOfResource>text</mods:typeOfResource>
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<mods:title>ZooKeys</mods:title>
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<mods:part>
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<mods:date>2012</mods:date>
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<mods:detail type="volume">
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<mods:number>226</mods:number>
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<mods:extent unit="page">
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<mods:start>1</mods:start>
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<mods:url>http://dx.doi.org/10.3897/zookeys.223.2840</mods:url>
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<mods:classification>journal article</mods:classification>
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<mods:identifier type="DOI">http://dx.doi.org/10.3897/zookeys.223.2840</mods:identifier>
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<mods:identifier type="Pensoft-Pub">1313-2970-226-1</mods:identifier>
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<treatment ID-GBIF-Taxon="152037233" LSID="urn:lsid:plazi:treatment:B9E302B7C17C12F8A97E87344C0B00CA" httpUri="http://treatment.plazi.org/id/B9E302B7C17C12F8A97E87344C0B00CA" lastPageId="40" lastPageNumber="41" pageId="29" pageNumber="30">
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<subSubSection pageId="29" pageNumber="30" type="nomenclature">
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<paragraph pageId="29" pageNumber="30">
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<taxonomicName LSID="http://species-id.net/wiki/Tianyulong_confuciusi" authority="Zheng et al., 2009" authorityName="Zheng et al." authorityYear="2009" class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="29" pageNumber="30" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi Zheng et al., 2009</taxonomicName>
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Figs 9C2030Tables 135
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</paragraph>
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</subSubSection>
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<subSubSection pageId="29" pageNumber="30" type="reference_group">
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<paragraph pageId="29" pageNumber="30">
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="29" pageNumber="30" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
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<bibRefCitation pageId="29" pageNumber="30">Zheng et al. (2009</bibRefCitation>
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, Figs 1, 2)
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</paragraph>
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</subSubSection>
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<subSubSection pageId="29" pageNumber="30" type="holotype">
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<paragraph pageId="29" pageNumber="30">Holotype.</paragraph>
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<paragraph pageId="29" pageNumber="30">
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STMN 26-3, partial skeleton laying on its left side preserving most of the skull in left lateral view, the ventral portion of a skull and articulated skeleton lacking the mid and distal caudal vertebrae, right coracoid, left carpus, portions of the left manus, and portions of the right hindlimb (Table 3;
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<bibRefCitation pageId="29" pageNumber="30">Zheng et al. 2009</bibRefCitation>
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).
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</paragraph>
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</subSubSection>
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<subSubSection pageId="29" pageNumber="30" type="referred material">
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<paragraph pageId="29" pageNumber="30">Referred material.</paragraph>
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<paragraph pageId="29" pageNumber="30">IVPP V17090 (Fig. 20), partial skeleton laying on its left side preserving a nearly complete skull, an articulated portion of the column including the posterior dorsal vertebrae, sacral vertebrae, and proximal one-half of the tail with numerous, aligned epaxial and hypaxial ossified tendons, proximal portions of both scapulae, both coracoids, most of both forelimbs including an articulated left carpus and manus in ventral view, and both hindlimbs with right pes mostly in ventral view and left pes mostly in dorsal view (Tables 4, 5).</paragraph>
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</subSubSection>
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<subSubSection pageId="29" pageNumber="30" type="type locality">
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<paragraph pageId="29" pageNumber="30">Type locality.</paragraph>
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<paragraph pageId="29" pageNumber="30">
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Jianchang County, Liaoning Province, PRC; collected privately but localities are probably in the vicinity
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<geoCoordinate direction="north" orientation="latitude" precision="925" value="41.333332">N41°20'</geoCoordinate>
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,
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<geoCoordinate direction="east" orientation="longitude" precision="925" value="119.666664">E119°40'</geoCoordinate>
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.
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</paragraph>
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</subSubSection>
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<subSubSection pageId="29" pageNumber="30" type="horizon">
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<paragraph pageId="29" pageNumber="30">Horizon.</paragraph>
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<paragraph pageId="29" pageNumber="30">
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Probably from the Lujiatun Beds of the Yixian Formation, Jehol Group; Lower Cretaceous (Barremian-Aptian), ca. 125 Ma (
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<bibRefCitation author="Xu, X" journalOrPublisher="Geological Journal" pageId="164" pageNumber="165" pagination="419 - 437" title="Non-avian dinosaur fossils from the Lower Cretaceous Jehol Group of western Liaoning, China." url="10.1002/gj.1044" volume="41" year="2006">Xu and Norell 2006</bibRefCitation>
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;
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<bibRefCitation pageId="29" pageNumber="30">Gradstein and Ogg 2009</bibRefCitation>
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).
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</paragraph>
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</subSubSection>
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<subSubSection pageId="29" pageNumber="30" type="revised diagnosis">
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<paragraph pageId="29" pageNumber="30">Revised diagnosis.</paragraph>
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<paragraph pageId="29" pageNumber="30">Heterodontosaurid with (1) only two premaxillary teeth, (2) rectangular dentary ramus with parallel dorsal and ventral margins, (3) extremely reduced forelimb that is less than 30% the length of the hindlimb, (4) manual digit III and metacarpal 3 shorter than manual digit II and metacarpal 2, respectively, (5) tail increased in length, (6) subtriangular chevrons in mid caudal vertebrae, and (7) numerous parallel ossified epaxial and hypaxial ossified tendons in the mid and distal regions of the tail.</paragraph>
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</subSubSection>
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<subSubSection pageId="29" pageNumber="30" type="comments">
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<paragraph pageId="29" pageNumber="30">Comments.</paragraph>
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<paragraph pageId="29" pageNumber="30">
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The holotype is a mature skeleton as evidenced by fusion of sacral centra, fusion or tight articulation of the neural arch and centrum of all other preserved vertebrae, and fusion between the tibia and proximal tarsals and between the bases of the metatarsals. The stratigraphic origin and geological age of
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="29" pageNumber="30" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
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remain uncertain, because all currently known specimens were collected privately (X. Xu, pers. comm.). The initial description of
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="29" pageNumber="30" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
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only reported a general area ("Jianchang County, Liaoning Province") and horizon ("Jehol Group, Early Cretaceous") (
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<bibRefCitation pageId="29" pageNumber="30">Zheng et al. 2009</bibRefCitation>
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: 333). Upper Jurassic formations underlying the Jehol Group also have yielded specimens with integument preservation and a similar taphonomic attributes (
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<bibRefCitation author="Hu, D" journalOrPublisher="Nature" pageId="162" pageNumber="163" pagination="640 - 643" title="A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus." url="10.1038/nature08322" volume="461" year="2009">Hu et al. 2009</bibRefCitation>
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), and so the assignment of
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="29" pageNumber="30" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
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to the Yixian Formation with a Lower Cretaceous (Barremian-Aptian) age awaits confirmation.
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</paragraph>
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</subSubSection>
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<subSubSection lastPageId="30" lastPageNumber="31" pageId="29" pageNumber="30" type="description">
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<paragraph pageId="29" pageNumber="30">Description.</paragraph>
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<paragraph lastPageId="30" lastPageNumber="31" pageId="29" pageNumber="30">
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The following brief description is based on two skeletons, the holotype (STMN 26-3; Fig. 9C) and a referred specimen (IVPP V17090; 20-30). Four additional skeletons of varying completeness are catalogued in the collections of the Shandong Tianyu Museum of Nature. Further preparation and study of all
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<pageBreakToken pageId="30" pageNumber="31" start="start">of</pageBreakToken>
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these specimens of
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="30" pageNumber="31" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
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is needed before attempting a reliable skull reconstruction. The present description focuses on the most important features, culminating in a skeletal reconstruction (Fig. 30) and a set of comparative measurements (Tables 3-5).
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</paragraph>
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</subSubSection>
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<subSubSection lastPageId="31" lastPageNumber="32" pageId="30" pageNumber="31" type="cranium">
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<paragraph pageId="30" pageNumber="31">Cranium.</paragraph>
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<paragraph pageId="30" pageNumber="31">
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The cranium is well represented in the holotype and referred specimens, although several portions remain poorly understood (Figs 20-23). Little is known of the posterodorsal portion of the cranium, which is broken away in the holotype (STMN 26-3;
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<bibRefCitation pageId="30" pageNumber="31">Zheng et al. 2009</bibRefCitation>
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; Fig. 9C) and disarticulated and only partially prepared in the referred specimen (Fig. 21). Likewise, virtually nothing is known about the palate and braincase. The shape of the skull is similar to that in
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="30" pageNumber="31" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
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; both are subtriangular in lateral view with a gently concave roof over the antorbital region. Both crania also are preserved in a similar manner, with jaws in occlusion and the premaxilla and predentary in close approximation (Fig. 21).
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</paragraph>
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<caption pageId="30" pageNumber="31">
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<paragraph pageId="30" pageNumber="31">
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Figure 20. Partial skeleton of the heterodontosaurid
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="30" pageNumber="31" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
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from the Lower Cretaceous Jehol Group of China. Partial skeleton mainly in right lateral view (IVPP V17090). Enlargements of subsequent figures are shown in red. Scale bar equals 10 cm.
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</paragraph>
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</caption>
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<caption pageId="30" pageNumber="31">
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<paragraph pageId="30" pageNumber="31">
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Figure 21. Skull of the heterodontosaurid
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="30" pageNumber="31" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
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from the Lower Cretaceous Jehol Group of China. Skull in right lateral view (IVPP V17090). Enlargements of subsequent figures are shown in red. Scale bar equals 2 cm.
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</paragraph>
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</caption>
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<caption pageId="30" pageNumber="31">
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<paragraph pageId="30" pageNumber="31">
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Figure 22. Anterior portion of skull of the heterodontosaurid
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="30" pageNumber="31" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
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from the Lower Cretaceous Jehol Group of China. Snout in right lateral view (IVPP V17090). Scale bar equals 5 mm.
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</paragraph>
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</caption>
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<caption pageId="30" pageNumber="31">
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<paragraph pageId="30" pageNumber="31">
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Figure 23. Anterior portion of skull of the heterodontosaurid
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="30" pageNumber="31" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
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from the Lower Cretaceous Jehol Group of China. Snout in right lateral view (IVPP V17090). Hatching indicates broken bone; dashed lines indicate estimated edges; tone indicates matrix. Scale bar equals 5 mm. Abbreviations: ad1 alveolus of dentary tooth 1 antfe antorbital fenestra be buccal emargination d dentary d1, 5, 9 dentary tooth 1, 5, 9 en external naris fo foramen l left m maxilla m4, 9 maxillary tooth 4, 9 n nasal nf narial fossa pd predentary pm premaxilla pm1, 2 premaxillary tooth 1, 2 r right.
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</paragraph>
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</caption>
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<paragraph pageId="31" pageNumber="32">
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<pageBreakToken pageId="31" pageNumber="32" start="start">In</pageBreakToken>
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both skulls the alveolar margin of the premaxilla is tilted slightly anteroventrally and is positioned ventral to the maxillary tooth row (Figs 22, 23). A horizontal line along the maxillary crowns at mid height passes above the premaxillary alveolar margin and closer to the ventral margin of the external naris. Approximately 60% of the length of the premaxillary alveolar margin is edentulous, the posterior 40% of its length accommodating two premaxillary teeth. In both skulls the posterior end of the alveolar margin curves posterodorsally, exposing a portion of the root of the caniniform second premaxillary tooth. Dorsal to this root, the premaxilla forms the anterior portion of an inset, arched diastema for the large dentary caniniform tooth. The narial fossa extends ventrally near the alveolar margin, and the external naris is dorsoventrally elongate as in
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="31" pageNumber="32" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
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. The posterolateral process of the premaxilla also is very similar in shape and articular contacts to that in
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="31" pageNumber="32" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
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. This process expands in width above the caniniform tooth and then tapers to a narrow tip, which in the holotype appears to establish point contact with the anterior tip of the lacrimal (STMN 26-3;
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<bibRefCitation pageId="31" pageNumber="32">Zheng et al. 2009</bibRefCitation>
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).
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</paragraph>
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<paragraph pageId="31" pageNumber="32">
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The subtriangular maxilla forms the posterior portion of the inset, arched diastema (Fig. 9C). Most of the lateral aspect of the maxilla is occupied by the subtriangular antorbital fossa, which is bordered ventrally by a sharp, slightly arched rim. The buccal emargination ventral to this rim is narrow compared to that in
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<taxonomicName class="Reptilia" family="Scutellosauridae" genus="Echinodon" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Echinodon" order="Ornithischia" pageId="31" pageNumber="32" phylum="Chordata" rank="genus">Echinodon</taxonomicName>
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and
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Lycorhinus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Lycorhinus" order="Ornithischia" pageId="31" pageNumber="32" phylum="Chordata" rank="genus">Lycorhinus</taxonomicName>
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. The jugal appears to lack the horn and flange that characterizes
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="31" pageNumber="32" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
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and
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Manidens" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Manidens" order="Dinosauria" pageId="31" pageNumber="32" phylum="Chordata" rank="genus">Manidens</taxonomicName>
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.
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</paragraph>
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</subSubSection>
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<subSubSection pageId="31" pageNumber="32" type="lower jaw">
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<paragraph pageId="31" pageNumber="32">Lower jaw.</paragraph>
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<paragraph pageId="31" pageNumber="32">
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The predentary is a small, wedge-shaped bone that lacks discrete processes (Figs 22, 23). The predentary had been shown with a long ventral process (
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<bibRefCitation pageId="31" pageNumber="32">Zheng et al. 2009</bibRefCitation>
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: fig. 1d; Fig. 9C), but a portion of this process is actually the ventral margin of the dentary. All but the posterodorsal corner of the predentary is positioned anterior to the premaxillary caniniform tooth.
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</paragraph>
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<paragraph pageId="31" pageNumber="32">
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The dentary ramus is straight and parallel-sided for most of its length (Fig. 21) in contrast to most heterodontosaurids, which exhibit a posterior deepening of the ramus. At its anterior end, a ventral protuberance is present in both the holotypic and referred skulls (Figs 22, 23). Anterior to the protuberance, the dentary end is strongly beveled as in
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<taxonomicName class="Reptilia" family="Scutellosauridae" genus="Echinodon" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Echinodon" order="Ornithischia" pageId="31" pageNumber="32" phylum="Chordata" rank="genus">Echinodon</taxonomicName>
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(Fig. 17). The ventral rim of the well developed buccal emargination is marked by diverging impressed vessel tracts (Figs 22, 23).
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</paragraph>
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<paragraph pageId="31" pageNumber="32">
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The sutures between the postdentary bones are poorly preserved in the two available specimens. The coronoid process rises well above the level of the dentary crowns as in
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="31" pageNumber="32" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
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, but the jaw articulation is not dropped relative to the occlusal plane (Figs 9C, 21). As best seen in the holotypic skull, a line drawn through the zone of occlusion between the cheek tooth rows passes just ventral to the jaw articulation (Fig. 9C). The coronoid process of the dentary was shown as a deep ramus rather than a more slender process (
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<bibRefCitation pageId="31" pageNumber="32">Zheng et al. 2009</bibRefCitation>
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), an interpretation that may have incorporated portions of the adjacent surangular (Fig. 9C). An external mandibular fenestra appears to have been present (
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<bibRefCitation pageId="31" pageNumber="32">Zheng et al. 2009</bibRefCitation>
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). There is no evidence for the presence of an external mandibular fossa around the fenestra or for an incised vessel tract to a large anterior surangular foramen, both of which characterize
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Lycorhinus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Lycorhinus" order="Ornithischia" pageId="31" pageNumber="32" phylum="Chordata" rank="genus">Lycorhinus</taxonomicName>
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,
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Manidens" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Manidens" order="Dinosauria" pageId="31" pageNumber="32" phylum="Chordata" rank="genus">Manidens</taxonomicName>
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and
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="31" pageNumber="32" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
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.
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</paragraph>
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</subSubSection>
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<subSubSection lastPageId="32" lastPageNumber="33" pageId="31" pageNumber="32" type="premaxillary teeth">
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<paragraph pageId="31" pageNumber="32">Premaxillary teeth.</paragraph>
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<paragraph lastPageId="32" lastPageNumber="33" pageId="31" pageNumber="32">
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There are two premaxillary teeth, the first a small tooth known only from its broken base and the second a large caniniform tooth (Figs 22,
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<pageBreakToken pageId="32" pageNumber="33" start="start">23</pageBreakToken>
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). The caniniform premaxillary tooth, the base of which is better preserved in the holotype skull, has a gentle posterior recurvature. Mesial and distal carinae are present, at least the latter with serrations. Only the larger distal premaxillary tooth was shown in the initial drawing of the holotypic skull (Fig. 9C). As in all heterodontosaurids and neornithischians, there is a substantial edentulous border preceding the first premaxillary tooth.
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</paragraph>
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</subSubSection>
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<subSubSection lastPageId="34" lastPageNumber="35" pageId="32" pageNumber="33" type="dentary teeth">
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<paragraph pageId="32" pageNumber="33">Dentary teeth.</paragraph>
|
|
<paragraph lastPageId="33" lastPageNumber="34" pageId="32" pageNumber="33">
|
|
The total number of dentary teeth in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="32" pageNumber="33" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
|
|
cannot be established with certainty based on the holotype, although referred skulls suggest there are 10 dentary teeth. An enlarged caniniform is the first tooth in the dentary series; no trace of a leading rudimentary crown is present. The dentary caniniform tooth is followed by a postcaniniform crown without a significant intervening gap, similar to the condition in
|
|
<taxonomicName class="Reptilia" family="Scutellosauridae" genus="Echinodon" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Echinodon" order="Ornithischia" pageId="32" pageNumber="33" phylum="Chordata" rank="genus">Echinodon</taxonomicName>
|
|
and
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Fruitadens" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Fruitadens" order="Ornithischia" pageId="32" pageNumber="33" phylum="Chordata" rank="genus">Fruitadens</taxonomicName>
|
|
. The first postcaniniform tooth in the holotypic skull can be seen in the photographs slightly dislodged toward the caniniform
|
|
<pageBreakToken pageId="33" pageNumber="34" start="start">tooth</pageBreakToken>
|
|
(
|
|
<bibRefCitation pageId="33" pageNumber="34">Zheng et al. 2009</bibRefCitation>
|
|
: fig. 1e). It was omitted in a drawing of the holotypic skull (Fig. 9C), leaving the impression that a postcaniniform diastema may be present in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="33" pageNumber="34" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
|
|
. The first dentary tooth has a subconical crown that is slightly smaller than that of more distal dentary teeth. This differs from the substantially smaller tooth immediately distal to the caniniform tooth in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Fruitadens" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Fruitadens" order="Ornithischia" pageId="33" pageNumber="34" phylum="Chordata" rank="genus">Fruitadens</taxonomicName>
|
|
(Fig. 9A). A referred specimen in the Shandong Tianyu Museum of Nature collections confirms the morphology, size and position of the first postcaniniform dentary tooth.
|
|
</paragraph>
|
|
<paragraph pageId="34" pageNumber="35">
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|
<pageBreakToken pageId="34" pageNumber="35" start="start">Successive</pageBreakToken>
|
|
dentary crowns 3-10 become slightly larger in the holotypic and referred skulls. In these postcaniniform dentary teeth, the bulbous cingulum has well-defined margins, a cingular ectoloph raised above the remainder of the crown surface including the primary ridge. The cingulum curves apically, terminating mesially and distally in prominent apically projecting denticles. Toward the posterior end of the dentary series, the prominence of the apical, mesial and distal basal denticles gives the crown a tricuspid appearance. The penultimate tooth, dentary tooth 9, is the largest in the series. The most distal tooth, dentary tooth 10, has a considerably smaller crown, as seen in several referred skulls.
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|
</paragraph>
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|
</subSubSection>
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<subSubSection pageId="34" pageNumber="35" type="maxillary teeth">
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<paragraph pageId="34" pageNumber="35">Maxillary teeth.</paragraph>
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|
<paragraph pageId="34" pageNumber="35">
|
|
The total number of maxillary teeth is currently unknown given the available evidence in the holotypic and referred skulls. In the right maxillary series of the holotypic skull, the crowns of the smallest teeth just behind the caniniform dentary tooth are broken at their bases (Fig. 9C). This pair is followed by three crowns, a gap for a missing sixth maxillary tooth, and a final set of three teeth, all of which have crowns that are progressively larger in size (
|
|
<bibRefCitation pageId="34" pageNumber="35">Zheng et al. 2009</bibRefCitation>
|
|
: fig. 1d). Probably at least two additional teeth with progressively smaller crowns were present at the distal end of the maxillary series. Taking these two into account, a total of 11 maxillary teeth likely were present in the holotypic skull.
|
|
</paragraph>
|
|
<paragraph pageId="34" pageNumber="35">
|
|
Maxillary and dentary crowns are subtriangular, the dentary crowns somewhat deeper than opposing maxillary crowns as in
|
|
<taxonomicName class="Reptilia" family="Scutellosauridae" genus="Echinodon" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Echinodon" order="Ornithischia" pageId="34" pageNumber="35" phylum="Chordata" rank="genus">Echinodon</taxonomicName>
|
|
. All have similar features in labial view (Fig. 24). The bulbous cingulum is well-defined from the remainder of the crown surface as in the largest crowns in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Fruitadens" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Fruitadens" order="Ornithischia" pageId="34" pageNumber="35" phylum="Chordata" rank="genus">Fruitadens</taxonomicName>
|
|
, and the root is tapered rather than swollen. The cingulum curves apically as a prominent cingular ectoloph along the mesial and distal crowns edges, terminating in prominent basal denticles mesially and distally. Arching of the alveolar margins is not pronounced as in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Abrictosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Abrictosaurus" order="Ornithischia" pageId="34" pageNumber="35" phylum="Chordata" rank="genus">Abrictosaurus</taxonomicName>
|
|
and
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="34" pageNumber="35" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
. The dentary alveolar margin is straight; the opposing maxillary margin is gently arched in both holotypic and referred skulls (Figs 22, 23).
|
|
</paragraph>
|
|
<caption pageId="34" pageNumber="35">
|
|
<paragraph pageId="34" pageNumber="35">
|
|
Figure 24. Maxillary dentition of the heterodontosaurid
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="34" pageNumber="35" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
|
|
from the Lower Cretaceous Jehol Group of China. Right maxillary teeth?6-9 in lateral view (IVPP V17090). Hatching indicates broken bone; dashed lines indicate estimated edges; tone indicates matrix. Scale bar equals 3 mm. Abbreviations: cel cingular ectoloph ci cingulum m69 maxillary tooth 6 9 ne neck pri primary ridge rt root.
|
|
</paragraph>
|
|
</caption>
|
|
</subSubSection>
|
|
<subSubSection lastPageId="37" lastPageNumber="38" pageId="34" pageNumber="35" type="axial skeleton">
|
|
<paragraph pageId="34" pageNumber="35">Axial skeleton.</paragraph>
|
|
<paragraph lastPageId="35" lastPageNumber="36" pageId="34" pageNumber="35">
|
|
Theholotype preserves the posterior one-half of the cervical series (C5-9), and much of the dorsal column is preserved in the referred skeleton. Centrum length is nearly constant, measuring approximately 5 mm (Fig. 30;
|
|
<pageBreakToken pageId="35" pageNumber="36" start="start">Table</pageBreakToken>
|
|
4). In
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="35" pageNumber="36" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
, in contrast, centrum length decreases in posterior cervical vertebrae by approximately 20% (Fig. 72, Table 7). Posterior dorsal centra have deeply concave sides and join as a gently arched series (Fig. 20). Their hatchet-shaped neural spines are longer than deep and nearly touch at their anterior and posterior extremities (IVPP V17090). In
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="35" pageNumber="36" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
, in contrast, the neural spines of the posterior dorsal vertebrae are deeper than long and well separated (Fig. 72). The sacral vertebrae are fused in IVPP V17090, and it is possible to measure only the centrum length of S1 (Table 4).
|
|
</paragraph>
|
|
<paragraph lastPageId="37" lastPageNumber="38" pageId="36" pageNumber="37">
|
|
<pageBreakToken pageId="36" pageNumber="37" start="start">The</pageBreakToken>
|
|
proximal one-half of the caudal series is preserved in the holotypic skeleton and nearly as much in the referred skeleton (Fig. 25). The tail is very long, exceeding the length of the precaudal column by the twentieth caudal vertebra (Fig. 30). Caudal centra increase in length by approximately 40% from the first to the tenth caudal vertebra. By the seventh caudal vertebra, the neural arch is low and hatchet-shaped and the opposing chevrons subtriangular rather than strap-shaped (Fig. 25). At this point in
|
|
<pageBreakToken pageId="37" pageNumber="38" start="start">the</pageBreakToken>
|
|
tail, a sheath of parallel ossified tendons are present spanning the neural spines and chevrons. By the thirteenth caudal vertebra, the neural spines are reduced to a ridge, and the chevrons are boat-shaped (Fig. 25). Although a few epaxial ossified tendons are present near the neural arches of the posterior dorsal, sacral and anterior caudal vertebrae (IVPP V17090), the sheath of ossified tendons starting around the seventh caudal vertebra would have stiffened mid and distal portions of the tail. The caudal structure in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="37" pageNumber="38" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
|
|
is remarkably similar to that in dromaeosaurid theropods (
|
|
<bibRefCitation author="Ostrom, JH" journalOrPublisher="Bulletin of the Peabody Museum of Natural History" pageId="163" pageNumber="164" pagination="1 - 165" title="Osteology of Deinonychus antirrhopus, an unusual theropod from the Lower Cretaceous of Montana." volume="30" year="1969">Ostrom 1969</bibRefCitation>
|
|
), the neural spines and chevrons changing in a similar manner distally and the parallel sheath of ossified tendons equivalent to the parallel, attenuated processes of the prezygapophyses and chevrons. Probably the more mobile tail base and stiffened mid and distal tail functioned in a similar manner as a balancing beam to enhance maneuverability.
|
|
</paragraph>
|
|
<caption pageId="37" pageNumber="38">
|
|
<paragraph pageId="37" pageNumber="38">
|
|
Figure 25. Tail of the heterodontosaurid
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="37" pageNumber="38" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
|
|
from the Lower Cretaceous Jehol Group of China. Anterior caudal vertebrae and ossified tendons in left lateral view, from the seventh to the thirteenth caudal vertebra. Hatching indicates broken bone; dashed lines indicate estimated edges; tone indicates matrix. Scale bar equals 1 cm. Abbreviations: CA caudal ch chevron epot epaxial ossified tendons hyot hypaxial ossified tendons ns neural spine poz postzygapophyses prz prezygapohpysis.
|
|
</paragraph>
|
|
</caption>
|
|
</subSubSection>
|
|
<subSubSection lastPageId="38" lastPageNumber="39" pageId="37" pageNumber="38" type="pectoral girdle">
|
|
<paragraph pageId="37" pageNumber="38">Pectoral girdle.</paragraph>
|
|
<paragraph pageId="37" pageNumber="38">
|
|
Both scapulocoracoids are preserved in opposition in the referred skeleton (Fig. 20; IVPP V17090). The right forelimb is disarticulated dorsally, the humerus displaced from its articulation in the glenoid. The proximal end of the right humerus is exposed, the remainder of the bone damaged or embedded as it crosses a crack in the slab to a small corner of bone, the medial epicondyle. The right humerus has an estimated length of 28 mm. The left humerus, with an estimated length of 26 mm, lies in articulation with the glenoid of the scapulocoracoid proximally and the remainder of the left forelimb distally. The holotypic skeleton preserves both scapulocoracoids and humeri but little of the distal forelimb (
|
|
<bibRefCitation pageId="37" pageNumber="38">Zheng et al. 2009</bibRefCitation>
|
|
: suppl. info.). Overlapping limb bone measurements suggest that the holotypic skeleton (STMN 26-3) is approximately 15% larger than the referred skeleton (IVPP V17090; Table 3).
|
|
</paragraph>
|
|
<paragraph pageId="38" pageNumber="39">
|
|
<pageBreakToken pageId="38" pageNumber="39" start="start">Proximally</pageBreakToken>
|
|
, the scapula broadens gradually to the acromial process as in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="38" pageNumber="39" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
(Santa Luca 1984). The neck is narrow as is most of the slender, straight strap-shaped blade (STMN 26-3;
|
|
<bibRefCitation pageId="38" pageNumber="39">Zheng et al. 2009</bibRefCitation>
|
|
: suppl. info.). The distal end of the blade is not well exposed in either specimen. Expansion in width of the distal end of the blade, if present, would be proportionately less than in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="38" pageNumber="39" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
. The coracoid has a subquadrate body and a prominent hook-shaped posterior process (STMN 26-3).
|
|
</paragraph>
|
|
</subSubSection>
|
|
<subSubSection lastPageId="39" lastPageNumber="40" pageId="38" pageNumber="39" type="forelimb">
|
|
<paragraph pageId="38" pageNumber="39">Forelimb.</paragraph>
|
|
<paragraph pageId="38" pageNumber="39">
|
|
The humerus, which is best preserved in STMN 26-3, has a bulbous head, prominent deltopectoral crest, gently curved shaft and prominent distal condyles as in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="38" pageNumber="39" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
. The olecranon process of the ulna, also best exposed in STMN 26-3, is very prominent proximally as in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="38" pageNumber="39" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
. The radius tapers at mid-shaft and expands distally as in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="38" pageNumber="39" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
to broadly contact a well ossified, but poorly preserved, carpus (Figs 26, 27).
|
|
</paragraph>
|
|
<paragraph pageId="39" pageNumber="40">
|
|
<pageBreakToken pageId="39" pageNumber="40" start="start">The</pageBreakToken>
|
|
manus probably retained all five digits as in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
, although only fragments of digits IV and V remain (Figs 26, 27; Table 5; IVPP V17090). The proportions of the manual digits are most unusual among ornithischians including
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
. Digit II and metacarpal 2 are longer than digit III and metacarpal 3. This mismatch in length is due to the shortening of all bones in digit III, as metacarpal 1 is also longer than metacarpal 3 (Figs 26, 27). The block-shaped bases and divided distal condyles of metacarpals 1-3 are well exposed. Metacarpal 1 has a particularly broad base as in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
. The phalangeal formula 2-3-4-?-? is typical for the inner three digits of basal dinosaurs and archosaurs in general.
|
|
</paragraph>
|
|
<paragraph pageId="39" pageNumber="40">
|
|
The two phalanges of manual digit I diverge medially from the others. The nonungual phalanges have proximal intercondylar processes articulating between paired distal condyles with well-formed collateral ligament pits as in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
. The penultimate phalanges in digits II and III, in addition, are longer than the preceding phalanges, suggesting an enhanced grasping function for the manus in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
|
|
as in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
. The unguals are transversely compressed and trenchant, that on digit I longer than those on digits II and III (Figs 26, 27).
|
|
</paragraph>
|
|
<caption pageId="39" pageNumber="40">
|
|
<paragraph pageId="39" pageNumber="40">
|
|
Figure 26. Forearm and manus of the heterodontosaurid
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
|
|
from the Lower Cretaceous Jehol Group of China. Left ulna, radius and manus for the most part in anterior or ventral view. Scale bar equals 5 mm.
|
|
</paragraph>
|
|
</caption>
|
|
<caption pageId="39" pageNumber="40">
|
|
<paragraph pageId="39" pageNumber="40">
|
|
Figure 27. Forearm and manus of the heterodontosaurid
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
|
|
from the Lower Cretaceous Jehol Group of China. Left ulna, radius and manus for the most part in anterior or ventral view. Hatching indicates broken bone; dashed lines indicate estimated edges; tone indicates matrix. Scale bar equals 5 mm. Abbreviations: I-III digits I-III mc1-5 metacarpal 1-5 ph phalanx ra radius ul ulna un ungual.
|
|
</paragraph>
|
|
</caption>
|
|
</subSubSection>
|
|
<subSubSection pageId="39" pageNumber="40" type="pelvic girdle">
|
|
<paragraph pageId="39" pageNumber="40">Pelvic girdle.</paragraph>
|
|
<paragraph pageId="39" pageNumber="40">
|
|
Little can be said about the ilium, which is poorly preserved in both skeletons. The ischia and pubes are preserved in lateral view (STMN 26-3;
|
|
<bibRefCitation pageId="39" pageNumber="40">Zheng et al. 2009</bibRefCitation>
|
|
: suppl. Info). The ischial shaft is gently dorsally bowed, a curve not present in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
. The ischial shaft is transversely compressed and lacks any flanges or processes, including the lateral flange of
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
(Santa Luca 1984) or the obturator process present in many ornithischians.
|
|
</paragraph>
|
|
<paragraph pageId="39" pageNumber="40">
|
|
Of the pubis, only the postpubic process is preserved (STMN 26-3;
|
|
<bibRefCitation pageId="39" pageNumber="40">Zheng et al. 2009</bibRefCitation>
|
|
). Its shaft is rod-shaped and very slender as in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
but only one-half its length. The process tapers to a slender tip just beyond the midpoint of the ischial shaft.
|
|
</paragraph>
|
|
</subSubSection>
|
|
<subSubSection lastPageId="40" lastPageNumber="41" pageId="39" pageNumber="40" type="hindlimb">
|
|
<paragraph pageId="39" pageNumber="40">Hindlimb.</paragraph>
|
|
<paragraph lastPageId="40" lastPageNumber="41" pageId="39" pageNumber="40">
|
|
The femoral head is large and round, and the femoral shaft is robust with a proximally placed pendant fourth trochanter (IVPP V17090). Whether the anterior trochanter is separate as in the Kayenta heterodontosaurid and
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Abrictosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Abrictosaurus" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Abrictosaurus</taxonomicName>
|
|
or fused with the greater trochanter as in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Fruitadens" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Fruitadens" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Fruitadens</taxonomicName>
|
|
cannot be determined. The tibia is extremely elongate, measuring more than 140% the length of the femur (Table 3). The cnemial crest is lower than in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="39" pageNumber="40" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
, so that in medial view the anterior margin of the proximal end of the tibia is straight rather than convex (Fig. 20).
|
|
<pageBreakToken pageId="40" pageNumber="41" start="start">The</pageBreakToken>
|
|
posterior condyles expand farther away from the central axis of the shaft. A fibular crest on the tibia supports the proximal end of the fibula, which has a swollen anterior trochanter (STMN 26-3;
|
|
<bibRefCitation pageId="40" pageNumber="41">Zheng et al. 2009</bibRefCitation>
|
|
: suppl. info.). Distally, the fibula tapers to a slender rod. The tibia, fibula and proximal tarsals appear fused as a tibiotarsus as in most specimens of
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
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. The distal tarsals are dislodged on one side of the referred skeleton and thus may not have coossified with the metatarsus.
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</paragraph>
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<paragraph pageId="40" pageNumber="41">
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In the pes, the proximal ends of metatarsal 1-4 appear to be coossified. Pedal digit I is very short, the tip of its ungual extending just beyond the condyles of metatarsal 2 (Figs 28, 29). That ungual, however, is quite large, equaling the length of the ungual on digit II and exceeding the length of the ungual on digit IV. Pedal digit III, in contrast, is slightly longer relative to pedal digits II and IV, a proportion that fits with other cursorial adaptations of the hindlimb. There is no trace of pedal digit V, which may owe its absence in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
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|
to postmortem loss. The unguals are transversely compressed and taper to slender tips (Table 5). Several of the unguals preserve portions of the keratinous claw sheath (Figs 28, 29).
|
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</paragraph>
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<caption pageId="40" pageNumber="41">
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<paragraph pageId="40" pageNumber="41">
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Figure 28. Pes of the heterodontosaurid
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
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|
from the Lower Cretaceous Jehol Group of China. Left pedal phalanges (left) in dorsal and medial views; right pedal phalanges (right) in ventral and lateral views. Scale bar equals 1 cm.
|
|
</paragraph>
|
|
</caption>
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<caption pageId="40" pageNumber="41">
|
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<paragraph pageId="40" pageNumber="41">
|
|
Figure 29. Pes of the heterodontosaurid
|
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<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
|
|
from the Lower Cretaceous Jehol Group of China. Left pedal phalanges (left) in dorsal and medial views; right pedal phalanges (right) in ventral and lateral views. Hatching indicates broken bone; dashed lines indicate estimated edges; tone indicates matrix. Scale bar equals 1 cm. Abbreviations: I-IV digits I-IV csh claw sheath mc1-4 metacarpal 1-4 ph phalanx un ungual.
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|
</paragraph>
|
|
</caption>
|
|
</subSubSection>
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<subSubSection pageId="40" pageNumber="41" type="skeletal reconstruction">
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<paragraph pageId="40" pageNumber="41">Skeletal reconstruction.</paragraph>
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<paragraph pageId="40" pageNumber="41">
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
|
|
has very unusual skeletal proportions that differ from those in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
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|
and, to the extent that comparisons are possible, other heterodontosaurids (Figs 30, 72; Tables 3-9). The skull is proportionately very large and the hindlimbs are very long, whereas the neck and trunk are proportionately small and the forelimbs are reduced in length. Using
|
|
<taxonomicName class="Aves" family="Archaeopterygidae" genus="Archaeopteryx" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Archaeopteryx" order="Archaeopterygiformes" pageId="40" pageNumber="41" phylum="Chordata" rank="genus">Archaeopteryx</taxonomicName>
|
|
for initial comparison (
|
|
<bibRefCitation author="Wellnhofer, P" journalOrPublisher="Archaeopteryx" pageId="164" pageNumber="165" pagination="1 - 48" title="Das siebte Exemplar von Archaeopteryx aus den Solnhofener Schichten." volume="11" year="1993">Wellnhofer 1993</bibRefCitation>
|
|
), the skull of
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
|
|
is 25% longer than in the
|
|
<normalizedToken originalValue="Eichstätt">Eichstaett</normalizedToken>
|
|
specimen, which has a nearly identical femoral length (Table 5). The tibiofemoral ratio in this specimen of
|
|
<taxonomicName class="Aves" family="Archaeopterygidae" genus="Archaeopteryx" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Archaeopteryx" order="Archaeopterygiformes" pageId="40" pageNumber="41" phylum="Chordata" rank="genus">Archaeopteryx</taxonomicName>
|
|
is high (140%), although still slightly lower than in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="genus">Tianyulong</taxonomicName>
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|
(143%). The humerus, in contrast, is approximately 48% the length of that in
|
|
<taxonomicName class="Aves" family="Archaeopterygidae" genus="Archaeopteryx" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Archaeopteryx" order="Archaeopterygiformes" pageId="40" pageNumber="41" phylum="Chordata" rank="genus">Archaeopteryx</taxonomicName>
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. As discussed further below (see Discussion, Body size and proportions), these unusual proportions give this small-bodied heterodontosaurid the appearance of a large-headed, short-armed, long-legged dwarf (Fig. 30) with very different proportions than in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
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|
(Fig. 72).
|
|
</paragraph>
|
|
<caption pageId="40" pageNumber="41">
|
|
<paragraph pageId="40" pageNumber="41">
|
|
Figure 30. Skeleton of the heterodontosaurid
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
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|
from the Lower Cretaceous Jehol Group of China. Silhouette skeletal reconstruction in lateral view showing preserved bones and integumental fibers (based on IVPP V17090). Distal most caudal vertebrae unknown.
|
|
</paragraph>
|
|
</caption>
|
|
<caption ID-Table-UUID="508E51271127B8B8CEFE4B9E2F64599D" httpUri="http://table.plazi.org/id/508E51271127B8B8CEFE4B9E2F64599D" pageId="40" pageNumber="41">
|
|
<paragraph pageId="40" pageNumber="41">
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|
Table 4. Measurements (mm) of the cranium and axial skeleton of the Early Cretaceous heterodontosaurid
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
|
|
(IVPP V17090). Parentheses indicate estimated measurement. Identification of dorsal vertebral number based on the vertebral count in
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Heterodontosaurus" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Heterodontosaurus" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="genus">Heterodontosaurus</taxonomicName>
|
|
.;
|
|
</paragraph>
|
|
</caption>
|
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<paragraph pageId="40" pageNumber="41">
|
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<table pageId="40" pageNumber="41">
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<tr pageId="40" pageNumber="41">
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<th colspan="1" pageId="40" pageNumber="41" rowspan="1">Region</th>
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<th colspan="1" pageId="40" pageNumber="41" rowspan="1">Measurement</th>
|
|
</tr>
|
|
</table>
|
|
</paragraph>
|
|
<caption pageId="40" pageNumber="41">
|
|
<paragraph pageId="40" pageNumber="41">
|
|
Table 5. Measurements (mm) of the girdles and limb bones of the Early Cretaceous heterodontosaurid
|
|
<taxonomicName class="Reptilia" family="Heterodontosauridae" genus="Tianyulong" higherTaxonomySource="GBIF" kingdom="Animalia" lsidName="Tianyulong confuciusi" order="Ornithischia" pageId="40" pageNumber="41" phylum="Chordata" rank="species" species="confuciusi">Tianyulong confuciusi</taxonomicName>
|
|
(IVPP V17090). Measurements are from the right side for paired bones except as indicated. Parentheses indicate estimated measurement.
|
|
</paragraph>
|
|
</caption>
|
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<paragraph pageId="40" pageNumber="41">
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<table pageId="40" pageNumber="41">
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">Structure</td>
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">Measurement</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
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<tr pageId="40" pageNumber="41">
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<td colspan="1" pageId="40" pageNumber="41" rowspan="1">1</td>
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</tr>
|
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</table>
|
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</paragraph>
|
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</subSubSection>
|
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</treatment>
|
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</document> |