Dikoleps cutleriana ( Clark, 1849 )

Bouchard, Blanche, Wesselingh, Frank P., Pouwer, Ronald & Landau, Bernard, 2025, The Gelasian gastropod fauna of Selsoif (Manche, France), Geodiversitas 47 (3), pp. 39-91 : 49

Dikoleps cutleriana ( Clark, 1849)

( Fig. 5B 1-B 3 )

Skenea cutleriana Clark, 1849: 424 .

Dikoleps cutleriana – Ceulemans et al. 2016: 73, pl. 10, fig. 1. — Landau et al. 2017: 142, pl. 66, fig. 1.

For more, see synonymy list in Ceulemans et al. (2016).

MATERIAL AND DIMENSIONS. — Maximum height 5.4 mm, width 3.9 mm. — RGM.1365319 (47), leg. AWJ ; RGM.1365303 (1), leg. AWJ ; RGM.1365300 (2), leg. AWJ ; RGM.1365301 (29), leg. AWJ ; RGM.1365302 (15), leg. AWJ .

SPECIES CHARACTERISATION. — Small depressed skeneimorph shell; protoconch of one smooth whorl; teleoconch of two whorls separated by deep suture; sculpture of fine spiral cords that continues inside the deep umbilicus.

DISTRIBUTION. — Upper Miocene: Atlantic, NW France ( Landau et al. 2017). — Lower Pliocene: NSB, Luchtbal Member, Belgium (Marquet & Landau 2006); Atlantic, NW France ( Ceulemans et al. 2016). — Lower Pleistocene: Atlantic, Selsoif, France (this paper). Today this species is present from the Atlantic SW England ( Fretter & Graham 1977) to southwards into the Mediterranean, Corsica ( Van Aartsen et al. 1984).

REMARKS

There is some variation in shape in the specimen from Selsoif, some slightly more depressed than others and in some specimens the last portion of the last whorl is slightly disjunct. Dikoleps marianae Rubio, Dantart & Luque, 1998 , from the Mediterranean Sea resembles D. cutleriana in having the teleoconch covered in fine spirals, even finer than those of D. cutleriana (40 vs 30; fide Rubio et al. 2004: 131) but the protoconch is rugose rather than smooth.

Figures

FIG. 5. — Gastropods from Selsoif. All illustrated specimens are collected from the Sablière du Grand Marais, Selsoif, France and come from the Early Pleistocene Saint-Nicolas de Pierrepont Formation (continuation):A, Calliostoma normanensis n. sp.(paratype 1),RGM.1365210,leg.WG,L = 5.2 mm;B, Dikoleps cutleriana (Clark, 1849) RGM.1365303, leg AWJ, H = 700 μm; C, Moelleria jansseni Hoeksema, Rijken & Simons, 2020 (holotype), RGM.1362824, H = 580 μm; D, Tricolia pullus picta (da Costa, 1778), RGM.1365082, leg AWJ, H = 2.3 mm; E, Petaloconchus intortus (Lamarck, 1818), RGM.1365216, leg AWJ, H = 5.1 mm; F, Bittium rubanocinctum Glibert, 1958, RGM.1365268, leg ACJ, H = 3.3 mm; G, Bittium jadertinum (Brusina, 1865), RGM.1365269, leg AWJ, H = 3.7 mm; H, Haustator incrassata (Sowerby, 1814), RGM.1365285, leg AWJ, H = 18.3 mm; I, Haustator incrassata (Sowerby, 1814), RGM.1365217, leg WG, H = 3.75 mm; J, Marshallora cf. adversa (Montagu, 1803), RGM.1365280, leg AWJ, H = 3.7 mm. Scale bars: A, E, 2 mm; B, C, 200 μm; D, F, G, I, J, 1 mm; H, 5 mm.

FIG. 1. — Simplified geological map of the Normandy region (after Dugué et al. 2000 and Pareyn 1987) showing the location of Selsoif:1, Precambrian-Palaeozoic basement; 2, Permo-Mesozoic Paris Basin fill; 3, Neogene-Quaternary subbasins.

FIG. 3. — Simplified biographic map of South-West of Europe (after Landau et al. 2011).