Phorcus, Risso, 1826

Hansen, Thomas, 2019, Gastropods from the Cretaceous-Palaeogene boundary in Denmark, Zootaxa 4654 (1), pp. 1-196 : 72

Phorcus sp.

Figs 21U , 22A

Material. Specimen MGUH 33109, an external mould of the spire.

Occurrence. Lithified top of the Maastrichtian Tor Formation at Holtug Quarry.

Description. Protoconch smooth, weakly convex with flattened whorls. Transition to teleoconch gradual. Teleoconch with low cyrtoconoid spire and weakly convex whorls separated by distinct suture. Whorls in cross-section broadly rounded without keel; smooth. Aperture and abapical side of whorl not known.

Measurements. Specimen MGUH 33109 is 3.1 mm high.

Remarks. Phorcus sp. differs from the middle Danian Phorcus carinatus ( Ravn, 1933) from Denmark by the lack of a carination on the whorls and a relatively higher teleoconch shell. It differs from the two Paleocene species of Phorcus from Greenland, presented under the names Osilinus sp. 1 and 2 by Kollmann & Peel (1983), by the higher shell and lack of spiral striation.

Figures

FIGURE 21. A–B. Leptomaria meyeri Pacaud, 2004. Silicone cast and inner mould of MGUH 33097. Width of cast 14.5. Width of inner mould 11.4 mm. C–H. Bathrotomaria jakobseni n. sp. C–F. Silicone cast and inner mould of holotype MGUH 33098. Width of exposed shell 21.3, 21.3, 15.6, 17.3 mm respectively. G. Outer mould of paratype MGUH 33099. Preserved radius 4.4 mm. H. Silicone cast of last whorl of paratype MGUH 33100. Width 16.2 mm. I. Bathybembix? sp., Silicone cast of MGUH 33101. Width 3.65 mm. J–K. Danilia sp., Silicone cast of MGUH 33102. Width 1.25 mm. L–Q. Chilodonta rudis (Binkhorst, 1861). L–M. Silicone cast of MGUH 33103. Width 6.0 mm for complete specimen, 0.25 mm for protoconch. N–O. Silicone cast of MGUH 33104. Width 7.35 mm. P. Silicone cast of aperture MGUH 33105. Height 4.8 mm. Q. Silicone cast of MGUH 33106. Width 4.65 mm. R–T. Eucycloscala gracilicostatus n. sp. R. Silicone cast of paratype MGUH 33107. Width of fragment 1.3 mm. S–T. Silicone cast of holotype MGUH 33108. Width 2.3 mm. U. Phorcus sp., Silicone cast of MGUH 33109. Height 3.2 mm, exposed width 2.2 mm.

FIGURE 22. A. Phorcus sp., Silicone cast of MGUH 33109. Exposed width 2.2 mm. B–C. Stomatella sp., External mould of MGUH 33110. Figure B has been colour inverted and mirrored to show it in positive. Width 1.5 mm. D–F. Solariella sp. D–E. Silicone cast of MGUH 33111. Width 6.2 mm. F. Silicone cast of aperture of MGUH 33112. Width 5.95 mm. G–I. Skenea sp. G–H. Inner mould of MGUH 33113. Width 5.2 mm. I. Inner mould of MGUH 33114. Width 10.2 mm. J–K. Leucorhynchia sp., Silicone cast of MGUH 33115. Width 2.4 mm. L–N. Tectus? indecorus n. sp., L. Umbilical view of inner mould of paratype ØSM.10042-327-b. Width 19.7 mm. M–N. Silicone cast of holotype MGUH 33116. Width 1.7 mm. O–P. Homalopoma sp., Silicone cast and inner mould of MGUH 33117. Width 9.6, 6.9 mm respectively. Q. Calliomphalus (Calliomphalus) sp., Silicone cast of MGUH 33118. Width 3.1 mm. R–U. Arene jakobseni n. sp. R–T. Silicone cast of holotype MGUH 33119. Width 8.6 mm. U. Silicone cast of paratype MGUH 33120. Width of aperture 4.8 mm.