Cylichna, Loven, 1846

Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, Zootaxa 4654 (1), pp. 1-196 : 166

Cylichna ? sp. A

Figs 35 U–V

2014 Cylichna sp. A Hansen & Surlyk: tab. 3.

Material. One external mould MGUH 33320.

Occurrence. Lithified top of the Maastrichtian Højerup Member in Holtug Quarry, Stevns Klint.

Description. Shell deeply involute, inflated cylindrical with deep apical spire truncation. Aperture longer than last whorl; inner lip covered by callus. Columella with at least two columellar folds.

Teleoconch sculpture dominated by strong growth lines, crossed by sporadic, very weakly developed spiral grooves.

Measurements. The specimen MGUH 33320 is 4.3 mm high and 2.5 mm wide.

Remarks. This taxon is clearly distinguished from the other cylichniid taxa from the Danish boundary layers by the two or more columellar folds; the open spire truncation and, perhaps, by the marked growth lines.

Figures

FIGURE 35. A–B. Pseudomalaxis sp., Silicone cast of MGUH 33306. Width 4.3 mm. C–D. Climacopoma? sp., Silicone cast of MGUH 33307. Width 13.1 and 9.9 mm respectively. E–I. Mathilda dania n. sp. E. Silicone cast of holotype MGUH 33308. Width 1.9 mm. F. Silicone cast of paratype MGUH 33309. Width 2.0 mm. G. Silicone cast of paratype MGUH 33310. Width 0.8 mm. H. Silicone cast of paratype MGUH 33311. Width 0.7 mm. I. Silicone cast of paratype MGUH 33312. Width 1.7 mm. J–K. Clathrobaculus sp., Silicone cast of MGUH 33313. Width 0.5 mm. L–P. Ringicula sp. L. Silicone cast of MGUH 33314. Width 7.0 mm. M–N. Silicone cast of MGUH 33315 and a partly hidden second specimen. Width 7.3 and 6.6 mm respectively. O–P. Silicone cast of MGUH 33316. Width 5.6, 5.3 mm respectively. Q–T. Cylichna stevniensis n. sp. Q. Silicone cast of holotype MGUH 33317. Width 1.4 mm. R–S. Internal mould of paratype MGUH 33318. Width 1.5 mm. T. Internal mould of paratype MGUH 33319. Width 2.8 mm. U–V. Cylichna? sp. A. Cast of MGUH 33320. Width 2.3, 2.4 mm respectively. W–Y. Cylichna? sp. B. W. Wax cast of MGUH 33321. Width 2.4 mm. X–Y. Inner mould of MGUH 33322. Width 1.3 mm. Z–AE. Roxania sp. Cast of MGUH 33323. Width 3.2, 3.3 mm respectively.