379 lines
51 KiB
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379 lines
51 KiB
XML
<document ID-DOI="10.5281/zenodo.3382461" ID-GBIF-Dataset="fd03f669-c046-46cd-861a-6bf56b7fc989" ID-Handle="http://hdl.handle.net/2246/1099" ID-Zenodo-Dep="3382461" approvalRequired="468" approvalRequired_for_bibRefs="7" approvalRequired_for_document="1" approvalRequired_for_illustrations="16" approvalRequired_for_originalDoi="1" approvalRequired_for_taxonomicNames="18" approvalRequired_for_textStreams="406" approvalRequired_for_treatments="19" checkinTime="1567239673843" checkinUser="plazi" docAuthor="Sahni, Ashok" docDate="1972" docId="1A7187CFFFA31710FE78F65FEA495088" docLanguage="en" docName="B147.6.pdf" docOrigin="Bulletin of the American Museum of Natural History 147 (6)" docStyle="DocumentStyle{}" docTitle="Gypsonictops lewisi Sahni 1972, new species" docType="treatment" docVersion="22" lastPageNumber="394" masterDocId="E648FFB7FFEA175DFFBAFFBEE2785A7A" masterDocTitle="The vertebrate Fauna of the Judith River formation, Montana" masterLastPageNumber="416" masterPageNumber="319" pageNumber="390" updateTime="1673867241423" 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>The vertebrate Fauna of the Judith River formation, Montana</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>Sahni, Ashok</mods:namePart>
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</mods:name>
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<mods:typeOfResource>text</mods:typeOfResource>
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<mods:relatedItem type="host">
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<mods:titleInfo>
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<mods:title>Bulletin of the American Museum of Natural History</mods:title>
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</mods:titleInfo>
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<mods:part>
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<mods:date>1972</mods:date>
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<mods:detail type="volume">
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<mods:number>147</mods:number>
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</mods:detail>
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<mods:detail type="issue">
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<mods:number>6</mods:number>
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</mods:detail>
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<mods:extent unit="page">
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<mods:start>319</mods:start>
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<mods:end>416</mods:end>
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</mods:extent>
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</mods:part>
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</mods:relatedItem>
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<mods:classification>journal article</mods:classification>
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<mods:identifier type="DOI">10.5281/zenodo.3382461</mods:identifier>
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<mods:identifier type="GBIF-Dataset">fd03f669-c046-46cd-861a-6bf56b7fc989</mods:identifier>
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<mods:identifier type="Handle">http://hdl.handle.net/2246/1099</mods:identifier>
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<mods:identifier type="Zenodo-Dep">3382461</mods:identifier>
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</mods:mods>
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<treatment ID-DOI="http://doi.org/10.5281/zenodo.4710540" ID-GBIF-Taxon="159397365" ID-Zenodo-Dep="4710540" LSID="urn:lsid:plazi:treatment:1A7187CFFFA31710FE78F65FEA495088" httpUri="http://treatment.plazi.org/id/1A7187CFFFA31710FE78F65FEA495088" lastPageId="77" lastPageNumber="394" pageId="73" pageNumber="390">
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<subSubSection box="[450,1044,2529,2567]" pageId="73" pageNumber="390" type="nomenclature">
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<paragraph blockId="73.[450,1044,2528,2570]" box="[450,1044,2529,2567]" pageId="73" pageNumber="390">
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<taxonomicName authority="Sahni, 1972" authorityName="Sahni" authorityYear="1972" box="[450,830,2529,2567]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="73" pageNumber="390" phylum="Chordata" rank="species" species="lewisi" status="new species">
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<emphasis bold="true" box="[450,830,2529,2567]" italics="true" pageId="73" pageNumber="390">Gypsonictops lewisi</emphasis>
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</taxonomicName>
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,
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<taxonomicNameLabel box="[848,1044,2531,2566]" pageId="73" pageNumber="390" rank="species">new species</taxonomicNameLabel>
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</paragraph>
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</subSubSection>
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<subSubSection box="[671,820,2611,2643]" pageId="73" pageNumber="390" type="description">
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<paragraph blockId="73.[323,1166,2610,2781]" box="[671,820,2611,2643]" pageId="73" pageNumber="390">
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<figureCitation box="[671,820,2611,2643]" captionStart="FIG" captionStartId="75.[353,410,2387,2418]" captionTargetBox="[295,2121,347,2345]" captionText="FIG. 15. Gypsonictops lewisi, new species. A. AMNH 77426, occlusal view of right P2. B. Lingual view. C. Labial view. D. AMNH 77428, occlusal view of right P3. E. Lingual view. F. Labial view. G. AMNH 77429, occlusal view of right P4. H. Lingual view. I. Labial view. J. AMNH 77432, occlusal view of right M1. K. Lingual view. L. Labial view. M. AMNH 77434, occlusal view of left M2. N. Lingual view. 0. Labial view. P. AMNH 77438, occlusal view of left M3. Q. Lingual view. R. Labial view. S. AMNH 77442, lingual view of left P3. T. Occlusal view. U. AMNH 77451, occlusal view of right P4. V. AMNH 77452, labial view of broken right M'. W. Occlusal view. X. AMNH 77456, occlusal view of left M2. Y. AMNH 77457, occlusal view of left M3. All x 10." httpUri="https://zenodo.org/record/3382479/files/figure.png" pageId="73" pageNumber="390">Figure 15</figureCitation>
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</paragraph>
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</subSubSection>
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<subSubSection pageId="73" pageNumber="390" type="etymology">
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<paragraph blockId="73.[323,1166,2610,2781]" pageId="73" pageNumber="390">ETYMOLOGY: For Captain Meriweather Lewis, pioneer explorer of the Missouri River.</paragraph>
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</subSubSection>
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<subSubSection pageId="73" pageNumber="390" type="materials_examined">
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<paragraph blockId="73.[1245,2106,350,2786]" pageId="73" pageNumber="390">TYPE LOCALITY: Clambank Hollow, Chouteau County, Montana.</paragraph>
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</subSubSection>
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<subSubSection pageId="73" pageNumber="390" type="distribution">
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<paragraph blockId="73.[1245,2106,350,2786]" pageId="73" pageNumber="390">KNOWN DISTRIBUTION: Campanian, Judith River Formation.</paragraph>
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</subSubSection>
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<subSubSection pageId="73" pageNumber="390" type="diagnosis">
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<paragraph blockId="73.[1245,2106,350,2786]" pageId="73" pageNumber="390">
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<emphasis box="[1297,1480,538,573]" italics="true" pageId="73" pageNumber="390">DIAGNOSIS</emphasis>
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: Similar in most respects to
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<taxonomicName authorityName="Simpson" authorityYear="1927" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="73" pageNumber="390" phylum="Chordata" rank="species" species="hypoconus">
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<emphasis italics="true" pageId="73" pageNumber="390">Gypsonictops hypoconus</emphasis>
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</taxonomicName>
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and
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<taxonomicName authorityName="Lillegraven" authorityYear="1969" box="[1626,1856,582,620]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="73" pageNumber="390" phylum="Chordata" rank="species" species="illuminatus">
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<emphasis box="[1626,1656,583,620]" italics="true" pageId="73" pageNumber="390">G</emphasis>
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.
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<emphasis box="[1681,1856,582,620]" italics="true" pageId="73" pageNumber="390">illuminatus</emphasis>
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</taxonomicName>
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, but with less molariform P3 and P2, and a more molariform P3.
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</paragraph>
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</subSubSection>
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<subSubSection lastPageId="77" lastPageNumber="394" pageId="73" pageNumber="390" type="description">
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<paragraph blockId="73.[1245,2106,350,2786]" pageId="73" pageNumber="390">
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DESCRIPTION: Lower dentition: P2; two teeth are probably P2s referable to
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<taxonomicName authorityName="Sahni" authorityYear="1972" box="[1769,1911,767,804]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="73" pageNumber="390" phylum="Chordata" rank="species" species="lewisi">
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<emphasis box="[1769,1798,768,803]" italics="true" pageId="73" pageNumber="390">G</emphasis>
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.
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<emphasis box="[1818,1911,767,804]" italics="true" pageId="73" pageNumber="390">lewisi</emphasis>
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</taxonomicName>
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. Their size and morphology sets them apart from the posterior premolars of a reconstructed dental series. Their resemblance to those of placental mammals is indicated by presence of a small metaconid that is not fully separated from the long and slender protoconid, and a shallow talonid bearing two cusps. Anterior lower premolars of Cretaceous metatherians have a protoconid that is linked to a posterior accessory cusp by a median ridge, and cingula that may be developed on either side of this ridge.
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</paragraph>
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<paragraph blockId="73.[1245,2106,350,2786]" pageId="73" pageNumber="390">A double rooted tooth, AMNH 77426 (fig. 15A-C), is smaller than P3. The specimen lacks its anterolabial part and the anterior root. The protoconid is a large cusp with a steep anterior margin. A small metaconid arises from the lingual cingulum and is not well separated from the protoconid. Buccal to the protoconid there is a well-developed labial cingulum that terminates at the labial accessory cusp of the talonid. This latter cusp is also linked to the apex of the protoconid by a shear ridge. There is at least one other cusp lingual to, and higher than, the labial accessory cusp. The talonid basin is shallow.</paragraph>
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<paragraph blockId="73.[1245,2106,350,2786]" pageId="73" pageNumber="390">
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The identification of the tooth as a P2 is based primarily on occlusal relationships and comparison with P3. Although present, the talonid is too shallow to be functional and probably occluded with a p2 which had a small protocone without root support. Unfortunately, p2 of
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<taxonomicName authorityName="Sahni" authorityYear="1972" box="[1249,1551,2242,2282]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="73" pageNumber="403" phylum="Chordata" rank="species" species="lewisi">
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<emphasis box="[1249,1443,2242,2282]" italics="true" pageId="73" pageNumber="390">Gypsonictops</emphasis>
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lewisi
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</taxonomicName>
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has not been found. P2 of
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<taxonomicName authorityName="Sahni" authorityYear="1972" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="73" pageNumber="401" phylum="Chordata" rank="species" species="lewisi">
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<emphasis box="[2059,2089,2245,2281]" italics="true" pageId="73" pageNumber="390">G</emphasis>
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. lewisi
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</taxonomicName>
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is smaller than P3, and it lacks the lingual ridge arising from the posterior side of the protoconid apex.
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</paragraph>
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<paragraph blockId="73.[1245,2106,350,2786]" box="[1289,2095,2429,2466]" pageId="73" pageNumber="390">P3; reference to specimen AMNH 77428 as</paragraph>
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<paragraph blockId="73.[1245,2106,350,2786]" lastBlockId="74.[1094,1949,350,2777]" lastPageId="74" lastPageNumber="391" pageId="73" pageNumber="390">
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P3 is based in part on the occlusal relationship of the tooth and in part on the development and degree of separation of the major cusps. This submolariform tooth has an anterior cingulum extending from the anterolingual side of the protoconid ventrally to the anterolabial side (fig. 1 5D-F). A small cuspule, more a basal swelling than a distinct cusp,
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<emphasis box="[725,749,359,391]" italics="true" pageId="74" pageNumber="391">is</emphasis>
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present at the paraconid position, and probably represents that cusp. The most proininent cusp
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<emphasis box="[914,937,451,484]" italics="true" pageId="74" pageNumber="391">is</emphasis>
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the protoconid, which is high and conical with convex anterior slopes. Two ridges arise from the posterior border of the protoconid; one extends from its lingual slope to the heel of the tooth, and the other extends more medially and joins the two major cusps of the talonid. A groove
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<emphasis box="[997,1021,726,759]" italics="true" pageId="74" pageNumber="391">is</emphasis>
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present on the posterior wall of the protoconid between the two ridges. The metaconid
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<emphasis box="[923,946,818,850]" italics="true" pageId="74" pageNumber="391">is</emphasis>
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not clearly visible, represented only by a swelling on the lingual ridge at a point one-half the height of the protoconid. The talonid is basined and deeper than that of the supposed P2. Two cusps are situated close together and probably correspond to the hypoconid-hypoconulid. A ridge bearing a small cuspule arises from the more lingual of these cusps and probably represents the entoconid. A shallow cingulum marks the posteroventral border of the tooth on the labial side. P3 of
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<taxonomicName authorityName="Sahni" authorityYear="1972" box="[332,633,1366,1402]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="74" pageNumber="403" phylum="Chordata" rank="species" species="lewisi">
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<emphasis box="[332,526,1366,1402]" italics="true" pageId="74" pageNumber="391">Gypsonictops</emphasis>
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lewisi
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</taxonomicName>
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is distinct from P3 of
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<taxonomicName baseAuthorityName="Simpson" baseAuthorityYear="1929" box="[183,369,1412,1448]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="74" pageNumber="391" phylum="Chordata" rank="species" species="petersoni">
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<emphasis box="[183,212,1412,1447]" italics="true" pageId="74" pageNumber="391">G</emphasis>
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.
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<emphasis box="[231,369,1412,1448]" italics="true" pageId="74" pageNumber="391">petersoni</emphasis>
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</taxonomicName>
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,
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<taxonomicName authorityName="Lillegraven" authorityYear="1969" box="[394,620,1412,1448]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="74" pageNumber="391" phylum="Chordata" rank="species" species="illuminatus">
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<emphasis box="[394,423,1412,1447]" italics="true" pageId="74" pageNumber="391">G</emphasis>
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.
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<emphasis box="[447,620,1412,1448]" italics="true" pageId="74" pageNumber="391">illuminatus</emphasis>
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</taxonomicName>
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, and
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<taxonomicName authorityName="Simpson" authorityYear="1927" box="[727,931,1412,1448]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="74" pageNumber="391" phylum="Chordata" rank="species" species="hypoconus">
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<emphasis box="[727,756,1413,1448]" italics="true" pageId="74" pageNumber="391">G</emphasis>
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.
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<emphasis box="[779,931,1412,1448]" italics="true" pageId="74" pageNumber="391">hypoconus</emphasis>
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</taxonomicName>
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. The Campanian specimen has a better developed and more basined talonid which bears two cusps.
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<bibRefCitation author="SIMPSON, G. G." box="[184,449,1550,1585]" journalOrPublisher="Ibid." pageId="74" pageNumber="391" pagination="1 - 19" part="1541" refId="ref63777" refString="1951. American Cretaceous insectivores. Ibid., no. 1541, pp. 1 - 19, figs. 1 - 7." title="American Cretaceous insectivores" type="journal article" year="1951">Simpson (1951</bibRefCitation>
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, pp. 10, 17) commented on the P3 "being simple and abruptly different from the molariform P4." P4; three teeth can be considered P4s on the basis of their similarity to similarly placed teeth in jaws of
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<taxonomicName authorityName="Simpson" authorityYear="1927" box="[374,734,1779,1815]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="74" pageNumber="391" phylum="Chordata" rank="species" species="hypoconus">
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<emphasis box="[374,734,1779,1815]" italics="true" pageId="74" pageNumber="391">Gypsonictops hypoconus</emphasis>
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</taxonomicName>
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from the Lance and Hell Creek formations, CM 11657, and UMVP 2316, 2317, and 2311. A distinct paraconid is present on the anterobasal cingulum in front of the groove separating the metaconid from the protoconid in AMNH 77429 (fig. 15G-I). Metaconid is not fully separated from the protoconid and in all three specimens at hand, it is a slender, conical cusp that is much smaller than the protoconid. A high ridge links the posterior wall of the protoconid to the hypoconid. An anterior ridge arises from the protoconid apex, and joins the paraconid ventrally in AMNH 77429. This is similar to the condition seen in the P4, UMVP 2311. The talonid of P4
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<emphasis box="[585,608,2468,2502]" italics="true" pageId="74" pageNumber="391">is</emphasis>
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basined and well developed, and all three cusps are represented. The hypoconulid is separated from the hypoconid, and it is only slightly smaller than the hypoconid. The entoconid is a feebly developed cusp situated on the lingual ridge of the talonid anterior to the other cusps. Labial to the crista obliqua, the crown extends ventrally, and a distinct cingulum is present on the posteroventral border.
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</paragraph>
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<paragraph blockId="74.[1094,1949,350,2777]" pageId="74" pageNumber="391">
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P4 of
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<taxonomicName authorityName="Sahni" authorityYear="1972" box="[1244,1385,493,528]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="74" pageNumber="401" phylum="Chordata" rank="species" species="lewisi">
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<emphasis box="[1244,1273,493,528]" italics="true" pageId="74" pageNumber="391">G</emphasis>
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. lewisi
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</taxonomicName>
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<emphasis box="[1403,1427,494,528]" italics="true" pageId="74" pageNumber="391">is</emphasis>
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distinguishable from that of other species because it has a stouter, broaderbased protoconid, it has less separation of the metaconid from the protoconid, and it has a less-developed talonid.
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</paragraph>
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<paragraph blockId="74.[1094,1949,350,2777]" pageId="74" pageNumber="391">M1 and M2; there are five lower molars that are either M1 or M2. The criterion used here to distinguish between molars is the tendency for the talonid to get progressively narrower (transversely) toward M3. On this basis, two teeth are probably M1s and the remainder M2s. One tooth, AMNH 77432 (fig. 16J-L), is tentatively identified as M1, and follows the basic therian pattern. Its trigonid is anteroposteriorly compressed, and its smallest cusp is the anteriorly projecting paraconid, the worn apex of which is only slightly labial to the apex of the metaconid. Its paraconid is connected to the protoconid by a ridge. A short anterobasal cingulum is present labial to the paraconid. The metaconid is a well-developed cusp and slightly smaller than the protoconid. The talonid of AMNH 77432 is basined and wide, and the hypoconid is large with a short cingulum extending down its posterior wall. The hypoconulid is well separated from the adjacent talonid cusp and is medial in position. The entoconid appears to be the highest talonid cusp. Of the two roots, at the enamel base, the anterior one is more anteroposteriorly compressed.</paragraph>
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<paragraph blockId="74.[1094,1949,350,2777]" pageId="74" pageNumber="391">M2; specimen AMNH 77434 (fig. 15M-O) is probably an M2. It differs from M1 by having a shorter, more anteroposteriorly compressed, and narrower talonid.</paragraph>
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<paragraph blockId="74.[1094,1949,350,2777]" pageId="74" pageNumber="391">M3; a possible M3 is specimen AMNH 77438 (fig. 15P-R) because its talonid is elongated anteroposteriorly and is much narrower in comparison to the trigonid width of either M1 or M2. The anterobasal cingulum flattens to form a small shelf. The trigonid is similar to those of the other molars but the talonid is very different. It narrows considerably at the point where the crista obliqua intersects the protolophid (metaconid-protoconid ridge). The three cusps of the elongate talonid are well developed, the hypoconulid and the entoconid are situated closer to each other.</paragraph>
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<paragraph blockId="74.[1094,1949,350,2777]" lastBlockId="76.[1104,1960,350,2775]" lastPageId="76" lastPageNumber="393" pageId="74" pageNumber="391">
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UPPER DENTITION: A reconstruction of the upper dentition of
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<taxonomicName authorityName="Simpson" authorityYear="1927" box="[1472,1666,2692,2730]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="74" pageNumber="391" phylum="Chordata" rank="genus">
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<emphasis box="[1472,1666,2692,2730]" italics="true" pageId="74" pageNumber="391">Gypsonictops</emphasis>
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</taxonomicName>
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was made by
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<bibRefCitation author="SIMPSON, G. G." box="[1102,1380,2737,2774]" journalOrPublisher="Ibid." pageId="74" pageNumber="391" pagination="1 - 19" part="1541" refId="ref63777" refString="1951. American Cretaceous insectivores. Ibid., no. 1541, pp. 1 - 19, figs. 1 - 7." title="American Cretaceous insectivores" type="journal article" year="1951">Simpson (1951)</bibRefCitation>
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and had been accepted until recently when doubts about the identity of P4 were expressed by
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<bibRefCitation author="McKENNA, M. C." box="[593,919,412,447]" journalOrPublisher="Univ. Calif. Publ. Geol. Sci." pageId="76" pageNumber="393" pagination="131 - 164" part="37" refId="ref61266" refString="McKENNA, M. C. 1960. The Geolabidinae, a new subfamily of early Cenozoic erinaceoid insectivores. Univ. Calif. Publ. Geol. Sci., vol. 37, no. 2, pp. 131 - 164, figs. 1 - 6." title="The Geolabidinae, a new subfamily of early Cenozoic erinaceoid insectivores" type="journal article" year="1960">McKenna (1960)</bibRefCitation>
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and
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<bibRefCitation author="SLAUGHTER, B. H." box="[187,508,458,493]" journalOrPublisher="Texas Jour. Sci." pageId="76" pageNumber="393" pagination="3 - 12" part="20" refId="ref63887" refString="1968 a. Earliest known eutherian mammals and the evolution of premolar occlusion. Texas Jour. Sci., vol. 20, pp. 3 - 12, figs. 1, 2." title="Earliest known eutherian mammals and the evolution of premolar occlusion" type="journal article" year="1968">Slaughter (1968a)</bibRefCitation>
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.
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<emphasis box="[535,716,458,492]" italics="true" pageId="76" pageNumber="393">According</emphasis>
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to these authors, P4 figured by
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<bibRefCitation author="SIMPSON, G. G." box="[441,714,504,539]" journalOrPublisher="Ibid." pageId="76" pageNumber="393" pagination="1 - 19" part="1541" refId="ref63777" refString="1951. American Cretaceous insectivores. Ibid., no. 1541, pp. 1 - 19, figs. 1 - 7." title="American Cretaceous insectivores" type="journal article" year="1951">Simpson (1951)</bibRefCitation>
|
|
is most probably P3. P4, then,
|
|
<emphasis box="[427,451,553,587]" italics="true" pageId="76" pageNumber="393">is</emphasis>
|
|
probably an even more molariform tooth. McKenna based his conclusions on a fragmentary maxilla with p2, p3, and roots of P4, UCMP 51386. This specimen
|
|
<emphasis box="[719,742,695,728]" italics="true" pageId="76" pageNumber="393">is</emphasis>
|
|
currently under study by W. A. Clemens in his survey of the eutherians of the Lance Formation. The holotype maxilla of
|
|
<taxonomicName authority="Lillegraven (1969)" authorityName="Lillegraven" authorityYear="1969" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="76" pageNumber="393" phylum="Chordata" rank="species" species="illuminatus">
|
|
<emphasis box="[514,909,834,869]" italics="true" pageId="76" pageNumber="393">Gypsonictops illuminatus</emphasis>
|
|
<bibRefCitation author="LILLEGRAVEN, J. A." journalOrPublisher="Univ. Kansas Paleont. Contrib." pageId="76" pageNumber="393" pagination="1 - 122" part="50" refId="ref60830" refString="LILLEGRAVEN, J. A. 1969. Latest Cretaceous mammals of upper part of Edmonton Formation of Alberta, Canada, and review of marsupial-placental dichotomy in mammalian evolution. Univ. Kansas Paleont. Contrib., art. 50 (Vertebrata 12), pp. 1 - 122, figs. 1 - 53, tables 1 - 2 1." title="Latest Cretaceous mammals of upper part of Edmonton Formation of Alberta, Canada, and review of marsupial-placental dichotomy in mammalian evolution." type="journal article" year="1969">Lillegraven (1969)</bibRefCitation>
|
|
</taxonomicName>
|
|
, UAPC 2447, with P3 to M3, from the upper part of the Edmonton Formation, conclusively demonstrates that
|
|
<bibRefCitation author="McKENNA, M. C." journalOrPublisher="Univ. Calif. Publ. Geol. Sci." pageId="76" pageNumber="393" pagination="131 - 164" part="37" refId="ref61266" refString="McKENNA, M. C. 1960. The Geolabidinae, a new subfamily of early Cenozoic erinaceoid insectivores. Univ. Calif. Publ. Geol. Sci., vol. 37, no. 2, pp. 131 - 164, figs. 1 - 6." title="The Geolabidinae, a new subfamily of early Cenozoic erinaceoid insectivores" type="journal article" year="1960">McKenna (1960)</bibRefCitation>
|
|
and
|
|
<bibRefCitation author="SLAUGHTER, B. H." box="[421,744,1022,1057]" journalOrPublisher="Texas Jour. Sci." pageId="76" pageNumber="393" pagination="3 - 12" part="20" refId="ref63887" refString="1968 a. Earliest known eutherian mammals and the evolution of premolar occlusion. Texas Jour. Sci., vol. 20, pp. 3 - 12, figs. 1, 2." title="Earliest known eutherian mammals and the evolution of premolar occlusion" type="journal article" year="1968">Slaughter (1968a)</bibRefCitation>
|
|
are correct in their interpretation.
|
|
<taxonomicName authorityName="Simpson" authorityYear="1927" box="[569,762,1068,1106]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="76" pageNumber="393" phylum="Chordata" rank="genus">
|
|
<emphasis box="[569,762,1068,1106]" italics="true" pageId="76" pageNumber="393">Gypsonictops</emphasis>
|
|
</taxonomicName>
|
|
material from the Judith River Formation, although clearly ancestral to the Maestrichtian species, differs from them in structure of its premolars. Premolars of
|
|
<taxonomicName authorityName="Sahni" authorityYear="1972" box="[363,499,1258,1292]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="76" pageNumber="393" phylum="Chordata" rank="species" species="lewisi">
|
|
<emphasis box="[363,392,1258,1291]" italics="true" pageId="76" pageNumber="393">G</emphasis>
|
|
.
|
|
<emphasis box="[412,499,1258,1292]" italics="true" pageId="76" pageNumber="393">lewisi</emphasis>
|
|
</taxonomicName>
|
|
are less molariform than those of later species. P3; there are seven teeth in the collection that
|
|
<taxonomicName box="[192,364,1395,1430]" class="Bivalvia" family="Inoceramidae" genus="Inoceramus" higherTaxonomySource="GBIF,CoL" kingdom="Animalia" order="Myalinida" pageId="76" pageNumber="393" phylum="Mollusca" rank="species" species="consider">I consider</taxonomicName>
|
|
to be P3 rather than
|
|
<emphasis box="[739,757,1395,1429]" italics="true" pageId="76" pageNumber="393">p</emphasis>
|
|
2 because of the occlusal relationship with the submolariform lower anterior premolars, particularly P2, and because it is unlike p2 in the
|
|
<taxonomicName authorityName="Simpson" authorityYear="1927" box="[688,879,1532,1567]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="76" pageNumber="393" phylum="Chordata" rank="genus">
|
|
<emphasis box="[688,879,1532,1567]" italics="true" pageId="76" pageNumber="393">Gypsonictops</emphasis>
|
|
</taxonomicName>
|
|
maxilla, UCMP 51386. Specimen AMNH 77442 (fig. 15S, T) is subtriangular in shape. Its most prominent cusp is the large, conical, broad-based paracone. Labial slopes of the paracone descend into a welldeveloped ectocingulum particularly in the parastylar and metastylar regions. The stylar shelf narrows at the ectoflexus where the paracone forms the buccal edge of the crown. A sharp crest, the metacrista, extends posteriorly from the apex of the paracone to the metastyle. Just anterior to the metastyle a slight swelling is present on the stylar shelf. The protocone is much smaller than the paracone with steeper lingual slopes. A definite postcingulum is present in three of the seven complete teeth and in two of these three teeth a smaller anterior cingulum is also present. Two ridges link the protocone to the paracone, but conules are absent. These three teeth have roots with rounded cross sections, and the most lingual root is placed beneath the protocone. P3 is submolariform because the paracone is undivided and has a sharp metacrista, and because the protocone has root support and lingual cingula. P3s of the later species of
|
|
<emphasis box="[1104,1207,353,389]" italics="true" pageId="76" pageNumber="393">
|
|
<emphasis box="[933,1035,2735,2764]" italics="true" pageId="76" pageNumber="393">Gypsonictops</emphasis>
|
|
</emphasis>
|
|
are more molariform, chiefly because the metacone is more separated from the paracone. Separation of the metaconid on the lingual side of the paraconid is seen in a specimen of
|
|
<taxonomicName authorityName="Simpson" authorityYear="1927" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="76" pageNumber="393" phylum="Chordata" rank="genus">
|
|
<emphasis italics="true" pageId="76" pageNumber="393">Gypsonictops</emphasis>
|
|
</taxonomicName>
|
|
, UMVP 2316, from the Hell Creek beds. P3 of
|
|
<taxonomicName authorityName="Sahni" authorityYear="1972" box="[1201,1339,583,619]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="76" pageNumber="393" phylum="Chordata" rank="species" species="lewisi">
|
|
<emphasis box="[1201,1230,584,619]" italics="true" pageId="76" pageNumber="393">G</emphasis>
|
|
.
|
|
<emphasis box="[1251,1339,583,619]" italics="true" pageId="76" pageNumber="393">lewisi</emphasis>
|
|
</taxonomicName>
|
|
is approximately at the same stage of molarization as P3.
|
|
</paragraph>
|
|
<caption httpUri="https://zenodo.org/record/3382479/files/figure.png" pageId="75" pageNumber="392" targetBox="[295,2121,347,2345]" targetPageId="75">
|
|
<paragraph blockId="75.[313,2087,2385,2675]" pageId="75" pageNumber="392">
|
|
FIG. 15.
|
|
<taxonomicName authority="Sahni, 1972" authorityName="Sahni" authorityYear="1972" box="[485,754,2385,2419]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="75" pageNumber="403" phylum="Chordata" rank="species" species="lewisi" status="new species">
|
|
<emphasis box="[485,659,2385,2419]" italics="true" pageId="75" pageNumber="392">Gypsonictops</emphasis>
|
|
lewisi
|
|
</taxonomicName>
|
|
,
|
|
<taxonomicNameLabel box="[773,955,2386,2418]" pageId="75" pageNumber="392" rank="species">new species</taxonomicNameLabel>
|
|
. A. AMNH 77426, occlusal view of right P2. B. Lingual view.
|
|
<emphasis box="[1938,1966,2386,2418]" italics="true" pageId="75" pageNumber="392">C</emphasis>
|
|
. Labial view. D. AMNH 77428, occlusal view of right P3. E. Lingual view. F. Labial view. G. AMNH 77429, occlusal view of right P4. H. Lingual view. I. Labial view. J. AMNH 77432, occlusal view of right M1. K. Lingual
|
|
<emphasis box="[2004,2080,2469,2501]" italics="true" pageId="75" pageNumber="392">view</emphasis>
|
|
. L. Labial view. M. AMNH 77434, occlusal view of left M2. N. Lingual view. 0. Labial
|
|
<emphasis box="[1709,1785,2511,2543]" italics="true" pageId="75" pageNumber="392">view</emphasis>
|
|
. P. AMNH 77438, occlusal view of left M3. Q. Lingual view. R. Labial view. S. AMNH 77442, lingual view of left P3. T. Occlusal view. U. AMNH 77451, occlusal view of right P4. V. AMNH 77452, labial view of broken right M'. W. Occlusal view. X. AMNH 77456, occlusal view of left M2. Y. AMNH 77457, occlusal view of left M3. All x 10.
|
|
</paragraph>
|
|
</caption>
|
|
<paragraph blockId="76.[1104,1960,350,2775]" pageId="76" pageNumber="393">
|
|
P4; there is only one tooth, AMNH 77451 (fig. 15U), that is considered P4. The reasons for this are not its similarity to P4 of
|
|
<taxonomicName authorityName="Simpson" authorityYear="1927" box="[1697,1898,764,803]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="76" pageNumber="393" phylum="Chordata" rank="species" species="hypoconus">
|
|
<emphasis box="[1697,1726,766,802]" italics="true" pageId="76" pageNumber="393">G</emphasis>
|
|
.
|
|
<emphasis box="[1745,1898,764,803]" italics="true" pageId="76" pageNumber="393">hypoconus</emphasis>
|
|
</taxonomicName>
|
|
, as identified by
|
|
<bibRefCitation author="SIMPSON, G. G." box="[1355,1632,811,849]" journalOrPublisher="Ibid." pageId="76" pageNumber="393" pagination="1 - 19" part="1541" refId="ref63777" refString="1951. American Cretaceous insectivores. Ibid., no. 1541, pp. 1 - 19, figs. 1 - 7." title="American Cretaceous insectivores" type="journal article" year="1951">Simpson (1951)</bibRefCitation>
|
|
(now considered to be P3), but because of its degree of molarization relative to P3 and Ml, and because of its occlusal relationship to P4. This specimen, AMNH 77451, lacks the area lingual to the paracone and metacone. A trace of a paraconule was present but during preparation this region broke away and thus the protoconule is not visible in the illustration. The tooth is more molariform than P3, as indicated by the greater separation of the paracone from the metacone. These cusps, however, are undivided at the base and only a narrow valley separates their apexes. Absence of a prominent ectoflexus and less transverseness also imply that it is less molariform than the upper molars. A small protocone with root support, a paraconule, and both precingulum and postcingulum must have been originally present. P4 of
|
|
<taxonomicName authorityName="Sahni" authorityYear="1972" box="[1590,1743,1639,1675]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="76" pageNumber="401" phylum="Chordata" rank="species" species="lewisi">
|
|
<emphasis box="[1590,1619,1639,1674]" italics="true" pageId="76" pageNumber="393">G</emphasis>
|
|
. lewisi
|
|
</taxonomicName>
|
|
closely resembles P3 of
|
|
<taxonomicName authorityName="Simpson" authorityYear="1927" box="[1349,1550,1686,1721]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="76" pageNumber="393" phylum="Chordata" rank="species" species="hypoconus">
|
|
<emphasis box="[1349,1378,1686,1721]" italics="true" pageId="76" pageNumber="393">G</emphasis>
|
|
.
|
|
<emphasis box="[1398,1550,1686,1721]" italics="true" pageId="76" pageNumber="393">hypoconus</emphasis>
|
|
</taxonomicName>
|
|
. The parastylar area is more prominent than the metastylar area and no ectoflexus is present. The apex of the metacone is separated from the larger paracone by a short centrocrista and is connected to the metastyle by a metacrista.
|
|
</paragraph>
|
|
<paragraph blockId="76.[1104,1960,350,2775]" lastBlockId="77.[1240,2106,364,2804]" lastPageId="77" lastPageNumber="394" pageId="76" pageNumber="393">
|
|
M1; three teeth have been identified as Mls. They are more molariform than the supposed P4, less transverse, with less prominent lingual cingula than M2. The stylar shelf extends above the entire labial margin of the crown in AMNH 77452 (fig. 15V, W), and the parastylar area is well developed with a prominent parastyle connected to the paracone by a short, low ridge. The metastyle is joined to the metacone by a metacrista. The paracone is taller than the metacone and separated from it by a deep valley. Conules are present, the preparaconular wing of the paraconule is bounded anteriorly by a ridge extending anterobuccally, and a prominent premetaconular wing is also present. The protocone is a narrow, thin cusp with nearly vertical lingual slopes. The preprotocrista and the postprotocrista join the paraconule and the metaconule, respectively. The postcingulum is larger than the precingulum and bears a worn area representing the hypocone. M1 of
|
|
<taxonomicName authorityName="Sahni" authorityYear="1972" box="[482,623,508,544]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="77" pageNumber="394" phylum="Chordata" rank="species" species="lewisi">
|
|
<emphasis box="[482,511,508,544]" italics="true" pageId="77" pageNumber="394">G</emphasis>
|
|
.
|
|
<emphasis box="[535,623,508,544]" italics="true" pageId="77" pageNumber="394">lewisi</emphasis>
|
|
</taxonomicName>
|
|
is similar to the upper molar, USNM 5044, figured by
|
|
<bibRefCitation author="SIMPSON, G. G." box="[758,1016,552,591]" journalOrPublisher="Ibid." pageId="77" pageNumber="394" pagination="1 - 19" part="1541" refId="ref63777" refString="1951. American Cretaceous insectivores. Ibid., no. 1541, pp. 1 - 19, figs. 1 - 7." title="American Cretaceous insectivores" type="journal article" year="1951">Simpson (1951</bibRefCitation>
|
|
, fig. 2b). M2; there is only one worn but complete M2 (AMNH 77456, fig. 15X). It is distinguished from M1 by having a narrower stylar shelf with a more anterobucally expanded parastylar region, by being shorter and more transverse, and by fuller development of the precingulum and the postcingulum. The paracone and metacone are set buccally, and the precingulum is better developed than on M1 and extends from a point just ventral to the paraconule, to the anterolingual side of the protocone. The postcingulum, bearing a hypocone, is even larger than the precingulum, extending from a point ventral to the base of the metacone, and terminating on the posterolingual side of the protocone. The tooth is three rooted, and its lingual root is very compressed anteroposteriorly. Its labial roots are small in comparison and have rounded cross sections. M3; the third upper molar is known by a lingual fragment, AMNH 77457 (fig. 15Y). Its paracone is missing, but the metacone is a small, conical cusp. The paraconule is better developed than the metaconule, and the postcingulinm is broken in the specimen.
|
|
<emphasis box="[371,564,1756,1791]" italics="true" pageId="77" pageNumber="394">DISCUSSION</emphasis>
|
|
:
|
|
<bibRefCitation author="PATTERSON, BRYAN" box="[591,907,1751,1789]" journalOrPublisher="Ibid., Geol." pageId="77" pageNumber="394" pagination="1 - 105" part="13" refId="ref62538" refString="1956. Early Cretaceous mammals and the evolution of mammalian molar teeth. Ibid., Geol., no. 13, pp. 1 - 105, figs. 1 - 17." title="Early Cretaceous mammals and the evolution of mammalian molar teeth" type="journal article" year="1956">Patterson's (1956)</bibRefCitation>
|
|
description of mammals at the eutherian-metatherian grade has greatly increased our knowledge about placental origins. Mammal remains recovered from the Trinity Sandstone of Texas, of Albian age (Lower Cretaceous), indicate that they had already differentiated into placental and marsupial types, as based on presence or absence of submolariform premolars. Submolariform premolars indicate a specialization unknown in marsupials (
|
|
<bibRefCitation author="SLAUGHTER, B. H." box="[561,870,2216,2253]" journalOrPublisher="Texas Jour. Sci." pageId="77" pageNumber="394" pagination="3 - 12" part="20" refId="ref63887" refString="1968 a. Earliest known eutherian mammals and the evolution of premolar occlusion. Texas Jour. Sci., vol. 20, pp. 3 - 12, figs. 1, 2." title="Earliest known eutherian mammals and the evolution of premolar occlusion" type="journal article" year="1968">Slaughter, 1968a</bibRefCitation>
|
|
,
|
|
<bibRefCitation author="SLAUGHTER, B. H." box="[908,1010,2216,2252]" journalOrPublisher="Science" pageId="77" pageNumber="394" pagination="254 - 255" part="162" refId="ref63923" refString="1968 b. Earliest known marsupials. Science, vol. 162, pp. 254 - 255, fig. 1." title="Earliest known marsupials" type="journal article" year="1968">
|
|
1968
|
|
<bibRefCitation author="SLAUGHTER, B. H." box="[989,1153,2216,2252]" journalOrPublisher="Ibid." pageId="77" pageNumber="394" pagination="1306" part="162" refId="ref63946" refString="1968 c. Holoclemensia instead of Clemensia. Ibid., vol. 162, p. 1306." title="Holoclemensia instead of Clemensia" type="journal article" year="1968">b, 1968c</bibRefCitation>
|
|
</bibRefCitation>
|
|
). The next record of eutherians in North America is during the Campanian, and the new material from the Judith River Formation is the principal source of this information. During the Maestrichtian, placentals increased in diversity in various western states of North America, and at the close of the Cretaceous represent the orders:
|
|
<taxonomicName authority=", Deltatheriidia" authorityName="Deltatheriidia" box="[334,808,2585,2622]" class="Mammalia" higherTaxonomySource="GBIF" kingdom="Animalia" order="Insectivora" pageId="77" pageNumber="394" phylum="Chordata" rank="order">Insectivora, Deltatheriidia</taxonomicName>
|
|
(
|
|
<emphasis box="[851,930,2583,2620]" italics="true" pageId="77" pageNumber="394">sensu</emphasis>
|
|
<bibRefCitation author="VAN VALEN, L." journalOrPublisher="Bull. Amer. Mus. Nat. Hist." pageId="77" pageNumber="394" pagination="1 - 126" part="132" refId="ref64909" refString="VAN VALEN, L. 1966. Deltatheridia, a new order of mammals. Bull. Amer. Mus. Nat. Hist., vol. 132, pp. 1 - 126, figs. 1 - 17, pls. 1 - 8." title="Deltatheridia, a new order of mammals" type="journal article" year="1966">Van Valen, 1966</bibRefCitation>
|
|
), Condylarthra, and Primates (Sloan and
|
|
<bibRefCitation author="VAN VALEN, L. & R. E. SLOAN" box="[333,639,2674,2711]" journalOrPublisher="Science" pageId="77" pageNumber="394" pagination="743 - 745" part="150" refId="ref64995" refString="VAN VALEN, L., AND R. E. SLOAN 1965. The earliest primates. Science, vol. 150, pp. 743 - 745, fig. 1, table 1." title="The earliest primates" type="journal article" year="1965">Van Valen, 1965</bibRefCitation>
|
|
; Van Valen and
|
|
<bibRefCitation author="SLOAN, R. E. & L. VAN VALEN" box="[945,1156,2673,2710]" journalOrPublisher="Sci- ence" pageId="77" pageNumber="394" pagination="220 - 227" part="148" refId="ref64076" refString="SLOAN, R. E., AND L. VAN VALEN 1965. Cretaceous mammals from Montana. Sci- ence, vol. 148, pp. 220 - 227, figs. 1 - 7." title="Cretaceous mammals from Montana" type="journal article" year="1965">Sloan, 1965</bibRefCitation>
|
|
).
|
|
<taxonomicName authorityName="Simpson" authorityYear="1927" box="[376,569,2719,2756]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="77" pageNumber="394" phylum="Chordata" rank="genus">
|
|
<emphasis box="[376,569,2719,2756]" italics="true" pageId="77" pageNumber="394">Gypsonictops</emphasis>
|
|
</taxonomicName>
|
|
was first described by
|
|
<bibRefCitation author="SIMPSON, G. G." journalOrPublisher="Amer. Mus. Novitates" pageId="77" pageNumber="394" pagination="1 - 7" part="267" refId="ref63475" refString="SIMPSON, G. G. 1927 a. Mammalian fauna of the Hell Creek Formation of Montana. Amer. Mus. Novitates, no. 267, pp. 1 - 7, figs. 1 - 6." title="Mammalian fauna of the Hell Creek Formation of Montana" type="journal article" year="1927">Simpson (1927a)</bibRefCitation>
|
|
on the basis of isolated upper teeth from the Lance Formation. These teeth had originally been assigned by
|
|
<bibRefCitation author="MARSH, O. C." box="[1556,1813,413,449]" journalOrPublisher="Ibid." pageId="77" pageNumber="394" pagination="249 - 262" part="43" refId="ref61735" refString="1892 c. Discovery of Cretaceous Mammalia. Pt. 3. Ibid., ser. 3, vol. 43, pp. 249 - 262, pls. 5 - 11." title="Discovery of Cretaceous Mammalia. Pt. 3." type="journal article" year="1892">Marsh (1892c)</bibRefCitation>
|
|
to
|
|
<taxonomicName authorityName="Marsh" authorityYear="1892" box="[1880,2007,414,449]" class="Mammalia" family="Cimolestidae" genus="Batodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Cimolesta" pageId="77" pageNumber="394" phylum="Chordata" rank="genus">
|
|
<emphasis box="[1880,2007,414,449]" italics="true" pageId="77" pageNumber="394">Batodon</emphasis>
|
|
</taxonomicName>
|
|
and
|
|
<taxonomicName authorityName="Marsh" authorityYear="1892" box="[1247,1403,460,496]" class="Mammalia" family="Cimolestidae" genus="Telacodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Cimolesta" pageId="77" pageNumber="394" phylum="Chordata" rank="genus">
|
|
<emphasis box="[1247,1403,460,496]" italics="true" pageId="77" pageNumber="394">Telacodon</emphasis>
|
|
</taxonomicName>
|
|
.
|
|
<bibRefCitation author="SIMPSON, G. G." box="[1443,1736,459,496]" journalOrPublisher="Ibid." pageId="77" pageNumber="394" pagination="1 - 19" part="1541" refId="ref63777" refString="1951. American Cretaceous insectivores. Ibid., no. 1541, pp. 1 - 19, figs. 1 - 7." title="American Cretaceous insectivores" type="journal article" year="1951">Simpson (1951)</bibRefCitation>
|
|
brought together previous information on this Cretaceous insectivore and made a hypothetical reconstruction of its dentition. This reconstruction was based partly on upper teeth assigned to
|
|
<taxonomicName authorityName="Simpson" authorityYear="1927" box="[1893,2089,643,679]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="77" pageNumber="394" phylum="Chordata" rank="genus">
|
|
<emphasis box="[1893,2089,643,679]" italics="true" pageId="77" pageNumber="394">Gypsonictops</emphasis>
|
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</taxonomicName>
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|
and partly on lower teeth assigned to
|
|
<taxonomicName class="Mammalia" genus="Euangelistes" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="77" pageNumber="394" phylum="Chordata" rank="genus">
|
|
<emphasis italics="true" pageId="77" pageNumber="394">Euangelistes</emphasis>
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</taxonomicName>
|
|
. Later, it was found that probably two different species were involved, because the dimensions of the lower teeth were considerably larger than those of the upper teeth. Two species were thus retained,
|
|
<taxonomicName authorityName="Simpson" authorityYear="1927" box="[1693,1902,922,957]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="77" pageNumber="394" phylum="Chordata" rank="species" species="hypoconus">
|
|
<emphasis box="[1693,1722,922,957]" italics="true" pageId="77" pageNumber="394">G</emphasis>
|
|
.
|
|
<emphasis box="[1749,1902,922,957]" italics="true" pageId="77" pageNumber="394">hypoconus</emphasis>
|
|
</taxonomicName>
|
|
, based on the smaller upper molars, and
|
|
<taxonomicName baseAuthorityName="Simpson" baseAuthorityYear="1929" box="[1786,1970,968,1004]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="77" pageNumber="394" phylum="Chordata" rank="species" species="petersoni">
|
|
<emphasis box="[1786,1815,968,1003]" italics="true" pageId="77" pageNumber="394">G</emphasis>
|
|
.
|
|
<emphasis box="[1831,1970,968,1004]" italics="true" pageId="77" pageNumber="394">petersoni</emphasis>
|
|
</taxonomicName>
|
|
, based on the larger lower molars.
|
|
</paragraph>
|
|
<paragraph blockId="77.[1240,2106,364,2804]" pageId="77" pageNumber="394">
|
|
Although the hazards of such a hypothetical reconstruction were obvious to
|
|
<bibRefCitation author="SIMPSON, G. G." box="[1802,2083,1107,1144]" journalOrPublisher="Ibid." pageId="77" pageNumber="394" pagination="1 - 19" part="1541" refId="ref63777" refString="1951. American Cretaceous insectivores. Ibid., no. 1541, pp. 1 - 19, figs. 1 - 7." title="American Cretaceous insectivores" type="journal article" year="1951">Simpson (1951)</bibRefCitation>
|
|
, subsequent finds have shown that, at least in the association of upper and lower dentitions, he was correct, but owing to misidentification of P3 as P4 and of P4 as an upper molar Simpson was led to believe that
|
|
<taxonomicName authorityName="Simpson" authorityYear="1927" box="[1517,1711,1339,1375]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="77" pageNumber="394" phylum="Chordata" rank="genus">
|
|
<emphasis box="[1517,1711,1339,1375]" italics="true" pageId="77" pageNumber="394">Gypsonictops</emphasis>
|
|
</taxonomicName>
|
|
possessed simple, not incipiently molariform, pl_p3.
|
|
</paragraph>
|
|
<paragraph blockId="77.[1240,2106,364,2804]" pageId="77" pageNumber="394">
|
|
The placental mammal,
|
|
<taxonomicName authorityName="Sahni" authorityYear="1972" box="[1753,1905,1430,1467]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="77" pageNumber="394" phylum="Chordata" rank="species" species="lewisi">
|
|
<emphasis box="[1753,1782,1431,1466]" italics="true" pageId="77" pageNumber="394">G</emphasis>
|
|
.
|
|
<emphasis box="[1813,1905,1430,1467]" italics="true" pageId="77" pageNumber="394">lewisi</emphasis>
|
|
</taxonomicName>
|
|
, from the Judith River Formation, is represented by about 45 teeth, comprising slightly over 5 per cent of the total mammal teeth recovered, and a calcaneum quite similar to that of
|
|
<taxonomicName authority="(Szalay, 1966)" authorityName="Szalay" authorityYear="1966" baseAuthorityName="Szalay" baseAuthorityYear="1966" class="Mammalia" family="Leptictidae" genus="Prodiacodon" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="77" pageNumber="394" phylum="Chordata" rank="genus">
|
|
<emphasis box="[1908,2095,1616,1651]" italics="true" pageId="77" pageNumber="394">Prodiacodon</emphasis>
|
|
(
|
|
<bibRefCitation author="SZALAY, F. S." box="[1262,1501,1662,1699]" journalOrPublisher="Amer. Mus. Novitates" pageId="77" pageNumber="394" pagination="1 - 13" part="2267" refId="ref64657" refString="SZALAY, F. S. 1966. The tarsus of the Paleocene leptictid Prodiacodon (Insectivora, Mammalia). Amer. Mus. Novitates, no. 2267, pp. 1 - 13, figs. 1 - 4." title="The tarsus of the Paleocene leptictid Prodiacodon (Insectivora, Mammalia)" type="journal article" year="1966">Szalay, 1966</bibRefCitation>
|
|
)
|
|
</taxonomicName>
|
|
. It probably belongs to
|
|
<taxonomicName authorityName="Simpson" authorityYear="1927" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="77" pageNumber="394" phylum="Chordata" rank="genus">
|
|
<emphasis italics="true" pageId="77" pageNumber="394">Gypsonictops</emphasis>
|
|
</taxonomicName>
|
|
and
|
|
<emphasis box="[1447,1471,1710,1745]" italics="true" pageId="77" pageNumber="394">is</emphasis>
|
|
currently under study by W. Nelson. The majority of the isolated teeth are broken or worn. None of the edentulousjaws can be referred with any certainty to the species. Still, by comparison with other eutherian material in the Maestrichtian of Alberta and Montana, it has been possible to identify the series of teeth, P2 to M3, and P3 to M3. Teeth anterior to P2 and P3 may be present in the collection, but are as yet unidentified. If the reconstruction of the dentition of
|
|
<taxonomicName authorityName="Sahni" authorityYear="1972" box="[1826,1970,2170,2207]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="77" pageNumber="394" phylum="Chordata" rank="species" species="lewisi">
|
|
<emphasis box="[1826,1855,2172,2207]" italics="true" pageId="77" pageNumber="394">G</emphasis>
|
|
.
|
|
<emphasis box="[1881,1970,2170,2207]" italics="true" pageId="77" pageNumber="394">lewisi</emphasis>
|
|
</taxonomicName>
|
|
proves to be correct, then the Campanian species differs from those of the Maestrichtian, at least at the species level.
|
|
</paragraph>
|
|
<paragraph blockId="77.[1240,2106,364,2804]" pageId="77" pageNumber="394">
|
|
Absence of
|
|
<taxonomicName authorityName="Marsh" authorityYear="1889" box="[1509,1665,2356,2391]" class="Mammalia" family="Cimolestidae" genus="Cimolestes" higherTaxonomySource="GBIF" kingdom="Animalia" order="Cimolesta" pageId="77" pageNumber="394" phylum="Chordata" rank="genus">
|
|
<emphasis box="[1509,1665,2356,2391]" italics="true" pageId="77" pageNumber="394">Cimolestes</emphasis>
|
|
</taxonomicName>
|
|
and other members of the
|
|
<taxonomicName authorityName="Winge" authorityYear="1917" box="[1344,1601,2401,2438]" class="Mammalia" family="Palaeoryctidae" higherTaxonomySource="GBIF" kingdom="Animalia" order="Cimolesta" pageId="77" pageNumber="394" phylum="Chordata" rank="family">Palaeoryctidae</taxonomicName>
|
|
from the Judith River Formation lends some credence to the viewpoint that deltatheridians were an immigrant group that invaded the coastal plains east of the rising Rocky Mountains sometime during the Maestrichtian.
|
|
<taxonomicName authorityName="Simpson" authorityYear="1927" box="[1443,1637,2632,2667]" class="Mammalia" family="Gypsonictopidae" genus="Gypsonictops" higherTaxonomySource="GBIF" kingdom="Animalia" order="Pilosa" pageId="77" pageNumber="394" phylum="Chordata" rank="genus">
|
|
<emphasis box="[1443,1637,2632,2667]" italics="true" pageId="77" pageNumber="394">Gypsonictops</emphasis>
|
|
</taxonomicName>
|
|
is considered here to be a primitive placental and, by virtue of its presence in pre-Maestrichtian sediments, is a likely ancestor for some later North American eutherians.
|
|
</paragraph>
|
|
</subSubSection>
|
|
</treatment>
|
|
</document> |