Aturobatis Adnet 2006
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2019
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| _version_ | 1866902314855432192 |
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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>Aturobatis</i> aff. <i>A</i>. <i>aquensis</i> Adnet, 2006</b></p><p>Fig. 41</p><p><i>Aturobatis aquensis</i> Adnet, 2006: 111, pl. 39, figs 3a–5b.</p><p><b>Material examined</b></p><p>UNITED STATES OF AMERICA – <b>Alabama</b> • 2 isolated teeth; Claiborne Group; MSC 37687, MSC 38464.</p><p><b>Description</b></p><p>Large teeth approaching 4.0 mm in mesiodistal width. Occlusal outline of crown is rhomboidal, wider than long, with sharp labial, lingual and lateral angles. Oral surface flat and diamond-shaped, subparallel to basal plane of crown. Sharp medial vertical ridge of labial face flanked by concave faces, with indistinct transverse ridge near the crown foot. Crown is weakly concave on each side of the vertical ridge. Lingual crown face slightly higher than labial face, inclined, straight, weakly concave on either side of lingual angle. Lingual crown foot developed into distinctive shelf-like projection, forming acute angle with lingual face. All crown faces smooth. Base of crown overhangs root labially and laterally. Root narrow, distally located under lingual part of crown, bilobed with a shallow medial nutritive groove. Root lobes rather elongate, with oblique labial face, extending just past lingual crown foot.</p><p><b>Remarks</b></p><p>The gross morphology of MSC 37687 and MSC 38464 is similar to other the Dasyatidae teeth in our sample, but the teeth are much larger and lack crown ornamentation.These teeth are also morphologically similar to the lateral teeth of members of the Myliobatidae, however, the lack of labial and lingual ornament on vertical crown faces and narrow, distally located root are inconsistent with our observations of Lisbon Formation Myliobatidae (see below). Teeth of <i>Aturobatis</i> are not to be confused with <i>Hypolophodon</i>, which has a weakly convex occlusal surface, much less angular appearance in occlusal and profile views, and a wide, centrally located root (Dartevelle & Casier 1959; Murray <i>et al.</i> 2010: figs 2c–d; Cappetta 2012: fig. 412).</p><p>Adnet <i>et al.</i> (2010) and Cappetta (2012) mentioned the occurrence of <i>Aturobatis</i> in Ypresian strata in the Atlantic Coastal Plain of the USA, and a younger, potentially new species has been noted from the Priabonian of Morocco (Adnet <i>et al.</i> 2010). Only the type species, <i>A. aquensis</i>, has been described and illustrated, and the two teeth in our Lisbon Formation sample, although much larger, are comparable to the Lutetian teeth reported by Adnet (2006). However, as <i>A. aquensis</i> is based on only four teeth and the range of variation is not known, we tentatively assign our two teeth to this species. Discovery of additional specimens will help determine if the Lisbon taxon is distinct or conspecific with <i>A. aquensis</i>.</p><p><b><i>Stratigraphic and geographic range in Alabama</i></b></p><p>The two specimens in our sample were collected from the basal Lisbon Formation at site ACov-11. Lower Lutetian, Zone NP15.</p> |
| format | Recurso digital |
| id | zenodo_https___doi_org_10_5281_zenodo_3664661 |
| institution | Zenodo |
| language | |
| publishDate | 2019 |
| publisher | Zenodo |
| record_format | zenodo |
| spellingShingle | Aturobatis Adnet 2006 Ebersole, Jun A. Cicimurri, David J. Stringer, Gary L. Biodiversity Taxonomy Animalia Chordata Chondrichthyes Myliobatiformes Aturobatis <p><b><i>Aturobatis</i> aff. <i>A</i>. <i>aquensis</i> Adnet, 2006</b></p><p>Fig. 41</p><p><i>Aturobatis aquensis</i> Adnet, 2006: 111, pl. 39, figs 3a–5b.</p><p><b>Material examined</b></p><p>UNITED STATES OF AMERICA – <b>Alabama</b> • 2 isolated teeth; Claiborne Group; MSC 37687, MSC 38464.</p><p><b>Description</b></p><p>Large teeth approaching 4.0 mm in mesiodistal width. Occlusal outline of crown is rhomboidal, wider than long, with sharp labial, lingual and lateral angles. Oral surface flat and diamond-shaped, subparallel to basal plane of crown. Sharp medial vertical ridge of labial face flanked by concave faces, with indistinct transverse ridge near the crown foot. Crown is weakly concave on each side of the vertical ridge. Lingual crown face slightly higher than labial face, inclined, straight, weakly concave on either side of lingual angle. Lingual crown foot developed into distinctive shelf-like projection, forming acute angle with lingual face. All crown faces smooth. Base of crown overhangs root labially and laterally. Root narrow, distally located under lingual part of crown, bilobed with a shallow medial nutritive groove. Root lobes rather elongate, with oblique labial face, extending just past lingual crown foot.</p><p><b>Remarks</b></p><p>The gross morphology of MSC 37687 and MSC 38464 is similar to other the Dasyatidae teeth in our sample, but the teeth are much larger and lack crown ornamentation.These teeth are also morphologically similar to the lateral teeth of members of the Myliobatidae, however, the lack of labial and lingual ornament on vertical crown faces and narrow, distally located root are inconsistent with our observations of Lisbon Formation Myliobatidae (see below). Teeth of <i>Aturobatis</i> are not to be confused with <i>Hypolophodon</i>, which has a weakly convex occlusal surface, much less angular appearance in occlusal and profile views, and a wide, centrally located root (Dartevelle & Casier 1959; Murray <i>et al.</i> 2010: figs 2c–d; Cappetta 2012: fig. 412).</p><p>Adnet <i>et al.</i> (2010) and Cappetta (2012) mentioned the occurrence of <i>Aturobatis</i> in Ypresian strata in the Atlantic Coastal Plain of the USA, and a younger, potentially new species has been noted from the Priabonian of Morocco (Adnet <i>et al.</i> 2010). Only the type species, <i>A. aquensis</i>, has been described and illustrated, and the two teeth in our Lisbon Formation sample, although much larger, are comparable to the Lutetian teeth reported by Adnet (2006). However, as <i>A. aquensis</i> is based on only four teeth and the range of variation is not known, we tentatively assign our two teeth to this species. Discovery of additional specimens will help determine if the Lisbon taxon is distinct or conspecific with <i>A. aquensis</i>.</p><p><b><i>Stratigraphic and geographic range in Alabama</i></b></p><p>The two specimens in our sample were collected from the basal Lisbon Formation at site ACov-11. Lower Lutetian, Zone NP15.</p> |
| title | Aturobatis Adnet 2006 |
| topic | Biodiversity Taxonomy Animalia Chordata Chondrichthyes Myliobatiformes Aturobatis |
| url | https://doi.org/10.5281/zenodo.3664661 |