Anchura, Conrad, 1860

Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, Zootaxa 4654 (1), pp. 1-196 : 101

Anchura sp.

Fig. 26K

Material. Specimen MGUH 33171 is an external mould of parts of the last two whorls.

Occurrence. Lithified top of the Maastrichtian Højerup Member of the Tor Formation at Holtug Quarry, Stevns.

Description. Whorls relatively high and moderately convex, the height corresponding to half the width. Suture very narrow. Second last whorl with two moderately strong central rows of tubercles and an abapical tuberculated spiral rib situated just above suture. The stronger rows or ribs intercalated by two narrow and weak spiral threads. Last whorl sculpture consisting of two weak adapical rows of tubercles, succeeded abapically by two strong and sharp peripheral ribs carrying tubercles. Base of whorl covered by at least eight strong to weaker spiral rows of tubercles, five located above the canal. The peripheral two ridges and the slightly less developed adapical rib or row of tubercles on the base diverge at transition to apertual wing.

Measurements. Preserved diameter of last whorl 8.1 mm.

Remarks. The specimen somewhat resembles the contemporaneous A. baptos Elder & Saul, 1996 from the North American Pacific Slope, but differs by the finer and slightly less developed spiral ribs and in the slightly lower location of the two strong peripheral spiral ribs on the last whorl. It is distinguished from the Late Cretaceous A. securifera ( Forbes, 1846) from Cameroon as redescribed by Kiel & Bandel (2002b) in the weaker sculpture and the presence of two nearly equally strong peripheral spiral ribs on the last whorl.

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.