Hypolophodon Cappetta 1980
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2019
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| _version_ | 1866902314908909568 |
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| author | Ebersole, Jun A. Cicimurri, David J. Stringer, Gary L. |
| author_facet | Ebersole, Jun A. Cicimurri, David J. Stringer, Gary L. |
| contents | <p><b><i>Hypolophodon</i> s <i>ylvestris</i> (White, 1931)</b></p><p>Fig. 42 M–X</p><p><i>Hypolophus sylvestris</i> White, 1931: 30, pl. 7, figs 22–23.</p><p><i>Hypolophodon sylvestris</i> – Cappetta 1980a: pl. 39, fig. 6.</p><p><i>Dasyatis sylvestris</i> – Sahni & Mehrotra 1981: 101, pl. 3, figs 5–7. — Sharma & Patnaik 2013: 175, pl. 6a.</p><p><b>Material examined</b></p><p>UNITED STATES OF AMERICA – <b>Alabama</b> • 7 isolated teeth; Claiborne Group; MSC 35788.1 – 7.</p><p><b>Description</b></p><p>Teeth small, measure up to 5.0 mm in greatest width. Crown may have rounded six-sided outline in occlusal view; more often ovate. Crown of unworn teeth covered with smooth enameloid. Occlusal, labial, and lingual surfaces convex and smooth. Lingual crown face has a small uvula and faint enameloid wrinkling at basal margin. Root low, generally divided by single nutritive groove into two triangular lobes. Root lobes may be equidimensional or of differing size, depending on location of the nutritive groove. Two or more nutritive grooves occasionally observed.</p><p><b>Remarks</b></p><p>Based on morphological and histological criteria, Cappetta (1980b) synonymized some species that had been placed within <i>Hypolophus</i> and <i>Platyrhina</i> with his newly created genus, <i>Hypolophodon</i>. Junior synonyms included the type species, <i>H. sylvestris</i> (White, 1931), and Casier’s (1946) <i>P. ypresiensis</i>. The teeth in our sample appear to be conspecific with those of <i>H. sylvestris</i> as described and figured by Cappetta (1980a: pl. 39, fig. 6) in that they have enameloid wrinkling and a small uvula on their lingual crown face. The presence of lingual crown wrinkling separates the teeth in our sample from those of <i>H. dockeryi</i> Case, 1994, which apparently lacks this characteristic (Case 1994a; also Case <i>et al.</i> 2015: 1132, fig. 7.3). The teeth of <i>H. malembeensis</i> Murray <i>et al.</i>, 2010 can be separated from those in our sample by having numerous labial foramina on their root, sharper crown edges, and a distinct lingual concavity in profile view (see Murray <i>et al.</i> 2010: figs 2c–d). Teeth of <i>H. farreri</i> Gurr, 1962 can have a similarly angular six-sided outline, but their crown faces are vertical and flat, and they lack a lingual basal protuberance. It remains to be shown if <i>H. farreri</i> is valid, as abraded specimens in our sample lack enameloid on the underside of the crown, as well as a lingual protuberance, and this latter characteristic is also absent from larger adult teeth we examined. Casier (1967) tentatively referred a tooth to <i>H. farreri</i>, and to our knowledge this is the only other mention of the species. However, the specimen he illustrated (Casier 1967: pl. VII, fig. 24) is abraded and in our opinion compares more favorably to <i>H. sylvestris</i>.</p><p><b>Stratigraphic and geographic range in Alabama</b></p><p>The specimens in our sample were collected from the lower Tallahatta Formation at site ADl-1. Upper Ypresian to lower Lutetian, Zone NP14.</p><p>Family Gymnuridae Jordan, 1888</p> |
| format | Recurso digital |
| id | zenodo_https___doi_org_10_5281_zenodo_3664647 |
| institution | Zenodo |
| language | |
| publishDate | 2019 |
| publisher | Zenodo |
| record_format | zenodo |
| spellingShingle | Hypolophodon Cappetta 1980 Ebersole, Jun A. Cicimurri, David J. Stringer, Gary L. Biodiversity Taxonomy Animalia Chordata Elasmobranchii Myliobatiformes Dasyatidae Hypolophodon <p><b><i>Hypolophodon</i> s <i>ylvestris</i> (White, 1931)</b></p><p>Fig. 42 M–X</p><p><i>Hypolophus sylvestris</i> White, 1931: 30, pl. 7, figs 22–23.</p><p><i>Hypolophodon sylvestris</i> – Cappetta 1980a: pl. 39, fig. 6.</p><p><i>Dasyatis sylvestris</i> – Sahni & Mehrotra 1981: 101, pl. 3, figs 5–7. — Sharma & Patnaik 2013: 175, pl. 6a.</p><p><b>Material examined</b></p><p>UNITED STATES OF AMERICA – <b>Alabama</b> • 7 isolated teeth; Claiborne Group; MSC 35788.1 – 7.</p><p><b>Description</b></p><p>Teeth small, measure up to 5.0 mm in greatest width. Crown may have rounded six-sided outline in occlusal view; more often ovate. Crown of unworn teeth covered with smooth enameloid. Occlusal, labial, and lingual surfaces convex and smooth. Lingual crown face has a small uvula and faint enameloid wrinkling at basal margin. Root low, generally divided by single nutritive groove into two triangular lobes. Root lobes may be equidimensional or of differing size, depending on location of the nutritive groove. Two or more nutritive grooves occasionally observed.</p><p><b>Remarks</b></p><p>Based on morphological and histological criteria, Cappetta (1980b) synonymized some species that had been placed within <i>Hypolophus</i> and <i>Platyrhina</i> with his newly created genus, <i>Hypolophodon</i>. Junior synonyms included the type species, <i>H. sylvestris</i> (White, 1931), and Casier’s (1946) <i>P. ypresiensis</i>. The teeth in our sample appear to be conspecific with those of <i>H. sylvestris</i> as described and figured by Cappetta (1980a: pl. 39, fig. 6) in that they have enameloid wrinkling and a small uvula on their lingual crown face. The presence of lingual crown wrinkling separates the teeth in our sample from those of <i>H. dockeryi</i> Case, 1994, which apparently lacks this characteristic (Case 1994a; also Case <i>et al.</i> 2015: 1132, fig. 7.3). The teeth of <i>H. malembeensis</i> Murray <i>et al.</i>, 2010 can be separated from those in our sample by having numerous labial foramina on their root, sharper crown edges, and a distinct lingual concavity in profile view (see Murray <i>et al.</i> 2010: figs 2c–d). Teeth of <i>H. farreri</i> Gurr, 1962 can have a similarly angular six-sided outline, but their crown faces are vertical and flat, and they lack a lingual basal protuberance. It remains to be shown if <i>H. farreri</i> is valid, as abraded specimens in our sample lack enameloid on the underside of the crown, as well as a lingual protuberance, and this latter characteristic is also absent from larger adult teeth we examined. Casier (1967) tentatively referred a tooth to <i>H. farreri</i>, and to our knowledge this is the only other mention of the species. However, the specimen he illustrated (Casier 1967: pl. VII, fig. 24) is abraded and in our opinion compares more favorably to <i>H. sylvestris</i>.</p><p><b>Stratigraphic and geographic range in Alabama</b></p><p>The specimens in our sample were collected from the lower Tallahatta Formation at site ADl-1. Upper Ypresian to lower Lutetian, Zone NP14.</p><p>Family Gymnuridae Jordan, 1888</p> |
| title | Hypolophodon Cappetta 1980 |
| topic | Biodiversity Taxonomy Animalia Chordata Elasmobranchii Myliobatiformes Dasyatidae Hypolophodon |
| url | https://doi.org/10.5281/zenodo.3664647 |