Ceratia rodvigensis Hansen 2019, n. sp.
Ceratia rodvigensis n. sp. Figs 26 E–H Diagnosis. Shell slender with slowly expanding and relatively flat whorls; apex blunt with low, obtusely conical protoconch and first teleoconch whorl; aperture distinctly lenticular. Teleoconch with very weak spiral striation. Derivation of name. Refers to the...
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Zenodo
2019
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| Online Access: | https://dx.doi.org/10.5281/zenodo.5582825 https://zenodo.org/record/5582825 |
| Summary: | Ceratia rodvigensis n. sp. Figs 26 E–H Diagnosis. Shell slender with slowly expanding and relatively flat whorls; apex blunt with low, obtusely conical protoconch and first teleoconch whorl; aperture distinctly lenticular. Teleoconch with very weak spiral striation. Derivation of name. Refers to the type locality Rødvig at the southern end of Stevns Klint, Denmark. Type material. Holotype MGUH 33167 is an external and internal mould from 10 to 20 cm below the top of the Cerithium Limestone Member at Rødvig. Paratype MGUH 33168 is an external and internal mould from the same locality and stratigraphic horizon as the holotype. Additional material. ØSM.10042-108 and 16 external and internal moulds in the inofficially catalogued samples SH.140.A–B, SH.274.B, SH.416, SH.456.A–B, SH.479, SS.211.A–B, SR.152.A, SR.275, SR.395, SR.518, SR.591, SR.620.A, SR.628, SR.630 and SR.696.B–C are known from the Cerithium Limestone Member of Stevns Klint. A specimen in sample DN.28.A–B comes from the contemporaneous ‘dead layer’ in Dania Quarry, Northern Jutland. Additionally a single specimen, ØSM.10042-70, from the hardground about two metres above the base of the Korsnaeb Member at Stevns Klint was examined. Type stratum and type locality. Uppermost part of the lower Danian Cerithium Limestone Member at Rødvig, Stevns Klint. Occurrence. Ranges from 30 cm above the Cretaceous to the top of the lower Danian Cerithium Limestone Member at Rødvig and up to the hardground in the lower part of the succeeding Korsnaeb Member at Stevns Klint. It is furthermore found in the lower Danian ‘dead layer’ at Dania quarry, Northern Jutland. Description. Spire blunt with smooth and obtusely conical protoconch consisting of 1 ½ convex whorls; transition to teleoconch rather gradual. Teleoconch with very finely spirally striated and fairly high whorls, the first rather weakly convex, the following becoming more convex with increasingly steeply inclined flanks. Growth lines weak, slightly opisthocline. Suture distinct but not deep. Measurements. Minute gastropod, the largest specimen from sample SR.628 being just over 2 mm high and 0.95 mm wide and consisting of approximately 6 ½ whorls, protoconch included. Remarks. Ceratia rodvigensis n. sp. is distinguished from most species belonging to this genus by the low, obtusely conical apex, the relatively flat whorls and the fairly slow whorl expansion. This species may superficially resemble the Palaeocene Ceratia sp. 2 and C . sp. 3 sensu Kollmann & Peel (1983) from Greenland but for the blunt apex and the less deep suture. : Published as part of Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, pp. 1-196 in Zootaxa 4654 (1) on page 100, DOI: 10.11646/zootaxa.4654.1.1, http://zenodo.org/record/3365803 : {"references": ["Kollmann, H. A. & Peel, J. S. (1983) Paleocene gastropods from Nugssuaq, West Greenland. GrOnlands Geologiske UndersOgelse, Bulletin, 146, 1 - 115."]} |
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