Sveltella Cossmann 1889
Sveltella sp. Figs 33 I–L Material. Two fragmentary moulds, MGUH 33291 and MGUH 33292. Occurrence. Cerithium Limestone Member at Skeldervig and Højerup, Stevns Klint. Description. Protoconch poorly preserved, 0.85 mm high and 1.0 mm wide, low conical, consisting of between 2 and 2 ½ smooth whorls wi...
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| Format: | Other/Unknown Material |
| Language: | unknown |
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2019
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| Online Access: | https://zenodo.org/record/5582963 https://doi.org/10.5281/zenodo.5582963 |
| Summary: | Sveltella sp. Figs 33 I–L Material. Two fragmentary moulds, MGUH 33291 and MGUH 33292. Occurrence. Cerithium Limestone Member at Skeldervig and Højerup, Stevns Klint. Description. Protoconch poorly preserved, 0.85 mm high and 1.0 mm wide, low conical, consisting of between 2 and 2 ½ smooth whorls with fairly weak sutural angle. Teleoconch slender, ranellid-like with moderately convex whorls separated by fairly deep suture. Whorls moderately low, their height corresponding to 40 % of the width. Whorl periphery located approximately 2/3 of height from adapical suture. Varix strongly developed. Aperture with straight columella carrying two strong columellar folds. Teleoconch sculpture on initial two whorls dominated by 13 to 14 moderately sharp, strong, slightly prosocline transverse ribs, narrower than the interspaces. Number of ribs increasing with size. Transverse ribs crossed by fine spiral threads numbering 5 to 6 on spire whorls and with 12 from suture to mid-way on the base on last whorl. Growth lines sigmoid. Measurements. Specimen MGUH 33292 is 4.4 mm high and 3.1 mm wide, consisting of protoconch and 2 ½ teleoconch whorls, the last whorl lacking base and canal. Remarks. The taxon resembles Sveltella multistriata (Ravn, 1939) from the Danish Selandian, although the whorls are less convex and the shell slightly more slender in outline. It also shows a strong affinity to the Danian Sveltella tobiasseni Schnetler & Petit, 2010 from Greenland, but has only up to 2 ½ protoconch whorls and not 2 ¾; the protoconch suture is less deep and the shell more slender. Published as part of Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, pp. 1-196 in Zootaxa 4654 (1) on page 155, DOI:10.11646/zootaxa.4654.1.1, http://zenodo.org/record/3365803 |
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