Zebina, H. Adams & A. Adams, 1854

Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, Zootaxa 4654 (1), pp. 1-196 : 98

Zebina sp.

Fig. 26D

Material. Specimen MGUH 33166 is an external mould.

Occurrence. The specimen was found in the Cerithium Limestone Member , 52–62 cm above the K-Pg boundary at Rødvig, Stevns Klint.

Description. Spire blunt with smooth and flatly dome-shaped protoconch consisting of 1 ½ convex whorls; transition to teleoconch rather gradual. Teleoconch with fairly high whorls, the first being rather weakly convex, the following becoming more convex with increasingly steeply inclined flanks. Suture distinct but not deep. Aperture narrow, obliquely lenticular with a weakly developed anterior apertural channel; aperture height approximating 40 % of shell height, the width corresponding to just over 60 % of height.

Measurements. Minute gastropod, MGUH 33166 is 2.0 mm high and 0.9 mm wide and consists of approximately 5 ½ whorls, protoconch included.

Remarks. Zebina sp. is distinguished from most species belonging to this genus by the unusually well developed anterior apertural channel and strongly rounded base. It has a passing resemblance to the Early Cretaceous Zebina dziki Kaim, 2004 from Poland, but differs by the thinner shell, the rounded base and the narrow aperture. It differs from the mid Danian Zebina sp. 1 and Zebina sp. 2 sensu Lauridsen & Schnetler (2014) from Denmark by the relatively broader apex and narrow aperture with developed channel.

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.