Clathrobaculus Cossmann 1912

Clathrobaculus sp. Figs 35 J–K Material. MGUH 33313 and an external mould with the informal sample number SR.938, collected in connection with this study. Occurrence. Upper 15 centimetres of the upper Maastrichtian Højerup Member at Rødvig, Stevns Klint. Description. Protoconch smooth, apparently hy...

Full description

Bibliographic Details
Main Author: Hansen, Thomas
Format: Text
Language:unknown
Published: Zenodo 2019
Subjects:
Online Access:https://dx.doi.org/10.5281/zenodo.5582995
https://zenodo.org/record/5582995
Description
Summary:Clathrobaculus sp. Figs 35 J–K Material. MGUH 33313 and an external mould with the informal sample number SR.938, collected in connection with this study. Occurrence. Upper 15 centimetres of the upper Maastrichtian Højerup Member at Rødvig, Stevns Klint. Description. Protoconch smooth, apparently hyperstrophic, but only last quarter of a whorl preserved. Transition to teleoconch sharp. Teleoconch thick-shelled, very slender with relatively high, convex, keeled whorls; keel located just abapical to whorl center; whorl height corresponding to approximately 80 % of the width. Suture very faint. First teleoconch whorl with three spiral ribs, a weak adapical one and two stronger spiral ribs located on keel and halfway between keel and abapical suture. A fourth, weak spiral rib is added between spiral rib 1 and keel on second teleoconch whorl. Spiral ribs crossed by faint transverse, largely orthocline transverse ribs numbering around 20 per half whorl on the fourth teleoconch whorl. Measurements. MGUH 33313 is 1.8 mm high and 0.5 mm wide, consisting of part of the protoconch and the first 5 ½ teleoconch whorls. Remarks. Clathrobaculus sp. is the youngest taxon so far, which with any degree of confidence may be assigned to this genus (see Kaim 2004: p. 140). There are, though, two taxa from the slightly younger middle Danian deposits of Denmark that may belong here, but at present their protoconchs are unknown (Lauridsen & Schnetler 2014: pp. 109–110). The Danish specimen strongly resembles the Early Cretaceous Clathrobaculus sp. 1 sensu Kaim (2004) from Poland, but differs by the higher number of transverse ribs, which appear weaker and by the later appearance of spiral rib 2. : Published as part of Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, pp. 1-196 in Zootaxa 4654 (1) on pages 164-165, DOI: 10.11646/zootaxa.4654.1.1, http://zenodo.org/record/3365803 : {"references": ["Lauridsen, B. W. & Schnetler, K. I. (2014) A catalogue of Danian gastropods from the Baunekule facies, Faxe Formation, Denmark. Geological Survey of Denmark and Greenland Bulletin, 32, 117 pp."]}