Melanella, Bowdich, 1822

Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, Zootaxa 4654 (1), pp. 1-196 : 106

Melanella ? sp.

Figs 27 A–B

Material. A single external mould, MGUH 33183.

Occurrence. Lower Danian Cerithium Limestone 5–600 metres south of Harvig Stige, Stevns Klint.

Description. Shell short, broadly conical with the height corresponding to two times the width. Shell wall thick. Protoconch homeostrophic, consisting of around two convex whorls. Teleoconch whorls flat, smooth, separated by shallow sutures. Incremental scars not strongly developed. Aperture small and low, the height corresponding to 38 % of shell height on measured specimen and 1.7 times the aperture width. Outer lip slightly curved in frontal view, in lateral view strongly prosocline, describing a gently convex curve with no central projection. Inner lip curved with no parietal callus.

Measurements. Measured specimen 2.6 mm high and just over 1.2 mm wide. Aperture height 1.0 mm and width 0.6 mm. The shell consists of 6 ½ to 7 whorls, protoconch included.

Remarks. The relatively low and wide shell makes this more likely to represent a Melanella than either Eulima or Polygyreulima, both of which it also closely resembles. The relatively low spire, the flattened whorls with fairly strongly prosocline growth lines and the relatively wide aperture makes this species stand out from most related species. It shows some resemblance to the much younger Melanella (Polygyreulima) montilysensis Bałuk, 1995 from the Middle Miocene of Poland, but differs in the relatively higher aperture.

Figures

FIGURE 27. A–B. Melanella? sp., Silicone cast of MGUH 33183. Width 1.4 mm. C–E. Vermetus sp., C. Silicone cast of attached tube MGUH 33184. Largest diameter 6.6 mm. D. Inner mould of protoconch and initial teleoconch inside bryozoan ball. MGUH 33185. Protoconch 0.5 mm wide. E. Silicone cast of MGUH 33186. Width 3.5 mm. F–J. Thylacodes contendis n. sp. F. Attached holotype mould MGUH 33187. Width 2.4 mm. G–H. Silicone cast of paratype MGUH 33188. Width 2.9 mm. I. Silicone cast of paratype MGUH 33189. Width 3.0 mm. J. Silicone cast of free whorl paratype MGUH 33190. Tube diameter 1.8 mm. K–M. Thylacodes? sp., Silicone cast of MGUH 33191. Width 2.4 mm. N. Dendropoma sp., Protoconch and initial teleoconch tube of MGUH 33192. Width 1.7 mm. O. Laxispira sp., Silicone cast of MGUH 33193. Width 3.6 mm. P–R. Epetrium s.l. skeldervigensis n. sp. P. Silicone cast of holotype MGUH 33194. Width 2.4 mm. Q. Silicone cast of paratype MGUH 33195. Width 4.0 mm. R. Silicone cast of paratype MGUH 33196. Width 3.6 mm. S. Triphoridae genus et sp. indet. Sinistrally coiled protoconch MGUH 33197. Width 0.7 mm. T–W. Cerithiopsis restemlongis n. sp. T. Silicone cast of holotype MGUH 33198. Width 1.0 mm. U. Silicone cast of paratype MGUH 33199. Width 1.5 mm. V. Silicone cast of paratype protoconch MGUH 33200. Width 0.5 mm. W. Silicone cast of paratype protoconch MGUH 33201. Width 0.6 mm and height 1.1 mm. X. Cerithiopsis? sp., Silicone cast of MGUH 33202. Width 0.6 mm. Y–AE. Thereitis carlsbergi n. sp. Y–Z. Silicone cast of holotype specimen MGUH 33203. Width of protoconch 0.6 mm and teleoconch 1.4 mm. AE. Silicone cast of paratype MGUH 33204. Width 0.7 mm.