Volutomitra cf. quinqueplicata Ravn, 1902

Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, Zootaxa 4654 (1), pp. 1-196 : 144

Volutomitra cf. quinqueplicata Ravn, 1902

Fig. 31O

Material. MGUH 33269, consisting of mould and replaced shell, is the only available specimen from the studied interval.

Occurrence. The described specimen comes from the Cerithium Limestone Member at Holtug Quarry, Stevns Klint. Undoubted Volutomitra quinqueplicata Ravn is known from the middle Danian Coral Limestone of Faxe in Denmark ( Fig. 31P ).

Description. Shell very slender, turriculid with high flattened whorls, whorl height corresponding to approximately 70 % of the width. Suture narrow but distinct. Transition to weakly convex base very gradual.

Teleoconch surface smooth except for nearly orthogonal, very weakly opisthocyrt growth lines.

Measurements. MGUH 33269 consists of the last 2 ½ teleoconch whorls and measures 30.9 mm in height and at least 11.6 mm in width.

Remarks. The very fragmentary material lacking apex and aperture makes the assignment somewhat tentative. The large and slender shell with its fairly weakly convex and smooth whorls covered by nearly orthogonal growth lines is on the other hand fairly distinctive for at least this genus among the early Palaeocene gastropods of Denmark.

Figures

FIGURE 31. A–C. Vexillum tenestolidum n. sp. A–B. Silicone cast of holotype MGUH 33259. Width of protoconch 0.7 mm. Width of last whorl 3.4 mm. C. Silicone cast of paratype MGUH 33260. Width 5.8 mm. D–G. Vexillum? rosenkrantzi n. sp. D–E. Silicone cast and inner mould of holotype MGUH 33261. Width 1.9 and 1.6 mm respectively. F. Silicone cast of paratype MGUH 33262. Width 3.2 mm. G. Silicone cast of paratype MGUH 33263. Width 2.9 mm. H. Vexillum? sp. Silicone cast of MGUH 33264. Width 3.5 mm. I. Columbarium heberti (Briart & Cornet, 1880). Silicone cast of last whorl MGUH 33265. Width 7.7 mm. Photograph by S.L. Jakobsen. J. Columbarium sp. Silicone cast of MGUH 33266. Width 13.3 mm. K–N. Conomitra glabra (Ravn, 1902). K. Silicone cast of MGUH 33267. Width 3.6 mm. L–M. Silicone cast of MGUH 33268. Width 3.6 and 3.9 mm respectively. N. External cast of syntype MGUH 116. Height 8.2 mm. Photograph by S.L. Jakobsen. O. Volutomitra cf. quinqueplicata Ravn, 1902. Silicone cast of MGUH 33269. Width 11.6 mm. P. Volutomitra quinqueplicata Ravn, 1902. External cast representing last whorl of type specimen MGUH 117. Middle Danien Faxe Formation, Denmark. Height 38.6 mm. Photograph by S.L. Jakobsen. Q–R. Spirancilla milthersii (Ravn, 1902). Q. Silicone cast of holotype MGUH 33270. Width 3.3 mm. R. Silicone cast of MGUH 33271. Width 3.1 mm. S–T. Exilia sp., Silicone cast of MGUH 33272. Width 1.6 mm. U–W. Latiromitra? sp. External cast and inner mould of MGUH 33273. Width 4.6 mm for casts and 4.0 mm for mould.