Vatopsis heinbergi, Hansen, 2019

Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, Zootaxa 4654 (1), pp. 1-196 : 122

Vatopsis heinbergi n. sp.

Figs 28 T–V

Diagnosis. Fairly broad-spired with strongly flattened whorls; periphery located close to abapical suture; transition to base sharp. Protoconch with a single spiral thread.

Derivation of name. In honour of C. Heinberg, who found the holotype and has dedicated much of his scientific effort into the study of the fauna and environments at the Danish Cretaceous-Palaeogene boundary.

Type material. The holotype MGUH 33220 is a nearly complete external mould with protoconch. Paratypes MGUH 33221 and MGUH 33222 are from the Cerithium Limestone Member at Skeldervig, Stevns Klint.

Type stratum and type locality. The lower Danian Cerithium Limestone Member at Hulerne (The Caves) near Storedal at Stevns Klint .

Occurrence. The lower Danian Cerithium Limestone at Stevns Klint.

Description. Protoconch planktotrophic turriculate, 0.85 mm high and 0.5 mm wide, consisting of around 5 ½ moderately convex whorls. Embryonic whorl slightly inflated, smooth. Second whorl too worn for a clear view of any potential sculpture. Succeeding whorls carrying 13–14 slightly opisthocline and opisthocyrt collabral threads per half whorl. The collabral threads may just cross single spiral thread appearing at periphery near abapical suture on final two whorls.

Teleoconch with flattened whorls with sharp transition to flat base. Aperture only partly preserved, appearing to have a straight columella.

Teleoconch sculpture reticulate with around 16 opisthocline transverse ribs per whorl on first teleoconch whorl. Transverse ribs crossed by three or four spiral ribs, the strongest located on keel slightly above abapical suture and succeeded by weaker abapical rib. Connecting points marked by tubercles. Base with strong spiral rib close to abaxial margin; otherwise smooth.

Measurements. The holotype MGUH 33220 is 3.3 mm high and 1.2 mm wide, consisting of five teleoconch whorls in addition to protoconch.

Remarks. The taxon appears to resemble the Bohemian Cerithium ternatum Reuss, 1845 , but differs at least by the better developed spiral and transverse ribs in contrast to the tubercle sculpture.

Figures

FIGURE 28. A. Thereitis carlsbergi n. sp., Protoconch of paratype MGUH 33205.Width of protoconch 0.4 mm. B–D. Thereitis cretacea n. sp. B. Holotype protoconch MGUH 33206. Width 0.4 mm. C. Silicone cast of paratype MGUH 33207. Width 0.9 mm. D. Silicone cast of paratype MGUH 33208. Width 1.1 mm. E. Thereitis sp., Silicone cast of MGUH 33209. Width 0.4 mm. F–I. Cerithiella moltkianum (Ravn, 1902). F–H. Silicone cast of MGUH 33210. Width of teleoconch 4.6 mm. Height of protoconch 1.0 mm. I. Silicone cast of MGUH 33211.Width 9.2 mm. J–O. Cerithiella selandica n. sp. J–K. Silicone cast of holotype MGUH 33212. Teleoconch width 2.6 mm. Preserved protoconch width 0.5 mm. L–M. Silicone cast of paratype MGUH 33213. Height 31 mm. N. Paratype protoconch MGUH 33214. Width 0.7 mm. O. Silicone cast of paratype MGUH 33215. Width 2.6 mm. P–Q. Cerithiella sp. P. Silicone cast of MGUH 33216. Width 6.7 mm. Q. Silicone cast of MGUH 33217. Width 5.1 mm. R. Eumetula sp., Silicone cast of MGUH 33218. Width 0.9 mm. S. Trituba obliquecostulata (Kaunhowen, 1898). Silicone cast of MGUH 33219. Width 1.2 mm. T–V. Vatopsis heinbergi n. sp. T. Silicone cast of holotype MGUH 33220. Width 1.2 mm. U. Silicone cast of paratype MGUH 33221. Width 3.1 mm. V. Silicone cast of paratype MGUH 33222. Width 4.0 mm. W. Vatopsis sp., Silicone cast of MGUH 33223. Width 2.5 mm. X–Y. Ageria skeldervigensis n. sp. X. Silicone cast of paratype MGUH 33224. Height 4.1 mm. Y. Silicone cast of paratype MGUH 33225. Width 7.4 mm.