Columbellaria tuberculosa ( Binkhorst, 1861 )

Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, Zootaxa 4654 (1), pp. 1-196 : 101-102

Columbellaria tuberculosa ( Binkhorst, 1861)

Figs 26 L–M

1861 Pyrula tuberculosa Binkhorst : 8, pl. III, fig. 5a–b.

1861 Pyrula ? plicata —Binkhorst: 68, pl. Va.3, fig. Aa–b.

1898 Columbellaria tuberculosa (Binkhorst) —Kaunhowen: 79–80, pl. IX, figs 7–8.

1986 Columbellaria tuberculosa ( Binkhorst, 1861) —Abdel-Gawad: 111, pl. 13, figs 2–4.

Diagnosis. Low-spired and bulbous with unkeeled whorls. Sculpture of nearly smooth and sharp spiral ribs. Transverse ribs completely lacking.

Material. The present Danish material consists of specimen ØSM.10042-202-a–c and an uncatalogued external and internal apical mould from Holtug quarry (A. Rosenkrantz, 1—6/8 1940), which is deposited in the old collections at the Natural History Museum of Denmark.

Type stratum and type locality. The holotype figured by Binkhorst (1861: pl. III: 5a–b) comes from the upper Maastrichtian limestone at Limburg, Belgium.

Occurrence. In Denmark Columbellaria tuberculosa is found in the lithified top of the Maastrichtian Højerup Member at Rødvig and Holtug Quarry, Stevns Klint. Outside Denmark it is known from the Early Senonian of West Germany, the late Senonian of the Polish Lvov region and the Maastrichtian of Limburg ( Belgium), Kunrade ( Holland) and Middle Vistula Valley of Poland ( Abdel-Gawad 1986).

Description of Danish material. Protoconch with three smooth and moderately convex, slowly expanding whorls. Initial two whorls nearly planispiral. Protoconch (of ØSM.10042-202-b) 1.55 mm in width and about 0.8 mm in height.

Teleoconch low-spired with moderately convex spire whorls. Shell width corresponding to 80 % of the height. Last whorl bulbous, constituting approximately 90 % of the shell height. Base evenly rounded. Aperture narrowly elongated, height corresponding to around 70 % of shell height. Inner lip only partly preserved, wide, with at least six teeth.

Teleoconch sculpture consisting of seven narrow and sharp spiral ribs of nearly equal strength on spire whorls. Last whorl with at least 16 near equal spiral ribs and more or less completely lacking tuberculation throughout. Growth lines nearly orthogonal to slightly opisthocline.

Measurements. Specimen ØSM.10042-202 is a largely complete shell measuring about 5.9 mm in height and 5.2 mm in width.

Remarks. The rare occurrence in the Danish deposits strongly suggests that Columbariella tuberculosa ( Binkhorst, 1861) did not belong in this deep water muddy environment, but rather to a more shallow water firm-ground environment like that found in Holland, Belgium and Poland.

Figures

FIGURE 26. A–B. Alvania sp. A. Silicone cast of MGUH 33164. Width 1.5 mm. C. Alvania sp. B. Silicone cast of MGUH 33165. Width 0.8 mm. D. Zebina sp., Wax cast of MGUH 33166. Width 0.9 mm. E–H. Ceratia rodvigensis n. sp. E–F. Silicone cast of holotype MGUH 33167. Width 0.8 mm. G–H. Silicone cast of paratype MGUH 33168. Width 0.9 mm. I–J. Ceratia? sp. I. Mould of MGUH 33169. Width 0.9 mm. J. Silicone cast of MGUH 33170. Height 1.1 mm. K. Anchura sp., Silicone cast of MGUH 33171. Width 8.6 mm. L–M. Columbellaria tuberculosa (Binkhorst, 1861). Silicone cast of ØSM.10042-202-a–c. Width 5.2 mm, height 5.9 mm. N. Tylostoma? sp., inner mould MGUH 33172. Width 19.9 mm. O–P. Cassidae genus et sp. indet. Silicone cast and internal mould of ØSM.10042-315-a–b and c, respectively. Width 9.2 and 8.6 respectively. Q–U. Sassia faxense Ravn, 1933. Q. Detail of apex of MGUH 33173. Width of protoconch 1.4 mm. R. Silicone cast of MGUH 33174. Width 6.0 mm. S. Silicone cast of MGUH 33175. Width 6.5 mm. T. Silicone cast of MGUH 33176. Width 7.8 mm. U. Silicone cast of MGUH 33177. Width 5.2 mm. V–X. Hipponix sp. V–W. Internal mould MGUH 33178. Length 23.8 mm, width 19.5 mm. X. Inner mould MGUH 33179. Width 19.1 mm. Y–Z. Eulima? danica Ravn, 1933. Y. Silicone cast of MGUH 33180. Width 2.5 mm. Z. Silicone cast of MGUH 33181. Width 2.0 mm. AE. Eulima? sp., Mould MGUH 33182. Width 1.3 mm.