Trochocerithium, Cossmann & Sacco in Sacco, 1897

Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, Zootaxa 4654 (1), pp. 1-196 : 92

Trochocerithium sp.

Fig. 24R

Material. Specimen MGUH 33151 is an external mould of the spire.

Occurrence. Lower Danian Cerithium Limestone Member just south of Højerup Church, Stevns.

Description. Protoconch unknown. Teleoconch broad-spired, conical, with flat sides; whorls low, height corresponding to just over 35% of width. Whorl sculpture dominated by up to around ten weak, beaded spiral ribs and a slightly more pronounced abapical beaded spiral rib located just adjacent to abapical suture. Nearly effaced prosocline and slightly opisthocyrt striae cross the spiral ribs, resulting in a dense beading of spiral ribs. Abapical spiral rib carrying nearly 90 tubercles on sixth preserved whorl.

Measurements. Specimen MGUH 33151 measures 13.3 mm in height and 9.0 mm in width and has 8 whorls.

Remarks. The Danish specimen is easily distinguished from the Danian Trochocerithium chapuisi ( Briart & Cornet, 1873) from Belgium in the extensive spiral and transverse ribbing of the whorls and the distinct tuberculation of the primary abapical spiral rib. It may be conspecific with the Cretaceous Cerithium heberti Geinitz, 1875 from Germany

Figures

FIGURE 24. A. Tenagodus sp., Silicone cast of MGUH 33139. Tube diameter 5.6 mm. B–D. Campanile selandicum (Lundgren, 1867). B–C. Silicone cast of MGUH 33140. Width 11.4 mm. D. Silicone cast of MGUH 33141. Width 4.5 mm. E–F. Campanile sp. A. Silicone cast of MGUH 33142. Whorl height 2.1 mm. G. Campanile sp. B. Silicone cast of MGUH 33143. Height 4.2 mm. H–K. Metacerithium balticum (Ravn, 1902). H. Silicone cast of protoconch MGUH 33144. Width 0.45 mm. I. Silicone cast of MGUH 33145. Height 26.0 mm. J. Silicone cast of lectotype MGUH 91 figured by Ravn (1902, pl. I: 17). Width 11.7 mm. K. Silicone cast of MGUH 93, figured type for Cerithium sartorii Ravn, 1902. Height 7.1 mm. L. Dzikella? sp., Silicone cast of MGUH 33146. Width 6.0 mm. M–Q. Amaurellina ravni n. sp. M–N. Silicone cast of holotype MGUH 33147. Width 10.3 mm. O. The internal mould of paratype MGUH 33148. Width 13.2 mm. P. Paratype MGUH 33149, a mould with replaced shell. Height 12.8 mm. Q. Silicone cast of paratype MGUH 33150. Width of picture 3.0 mm. R. Trochocerithium sp., Silicone cast of MGUH 33151. Width 9.0 mm. S–W. Galericulus sp. S–T. Internal mould ØSM.10042-311. Length 5.8 mm. U. Internal mould MGUH 33152. Width 8.5 mm. V–W. Internal mould and external cast of MGUH 33153. Length 10.3 mm. Width of figure W 7.7 mm. X. Natica sp. A. Silicone cast of MGUH 33154. Width 7.9 mm.