Moelleria jansseni Hoeksema, Rijken & Simons, 2020

Bouchard, Blanche, Wesselingh, Frank P., Pouwer, Ronald & Landau, Bernard, 2025, The Gelasian gastropod fauna of Selsoif (Manche, France), Geodiversitas 47 (3), pp. 39-91 : 49-50

Moelleria jansseni Hoeksema, Rijken & Simons, 2020 ( Fig. 5C 1 , C 2 )

Moelleria jansseni Hoeksema, Rijken & Simons, 2020: 6 , figs 1-2.

MATERIAL AND DIMENSIONS. — Maximum height 0.61 mm, width 0.96 mm. — Holotype: RGM.1362824 , height 0.6 mm, width 0.96 mm, leg. AWJ. — Paratypes: paratype 1, RGM.1362825 , height 0.61 mm, width 0.95 mm, leg. AWJ ; paratype 2, RGM.1362630 (8), leg. AWJ .

ORIGINAL DESCRIPTION. — “Shell very small, wider than high, rather solid, opaque, depressed skeneiform, up to 2.25 whorls protoconch included. Suture deep, canaliculate. Protoconch paucispiral, ¾ whorls, smooth, D about 0.30 mm. Protoconch-teleoconch border delimited by shallow groove. Aperture prosocline and circular. Peristome sharp, simple, almost flat, continuous. Umbilicus open, deep, bordered by sharp peri-umbilical edge ( Figs 1c, 1e , 2c, 2e ). Teleoconch sculptured with ripple-like, prosocline, straight to sigmoid, flat-topped, partly dichotomous axial ribs, 40-50 on last whorl, broader than interspaces; the branched rib-parts at the periphery coalesce adapically at a short distance from the penultimate whorl and abapically on the base. Body whorl depressed, convex, weakly angled at shoulder ( Hoeksema et al. 2020: figs 1d, 2d) and in two spirals around the peri-umbilical edge ( Hoeksema et al. 2020: figs 1e, 2e). Dimensions: H up to 0.65 mm, W up to 1.00 mm.” ( Hoeksema et al. 2020: 6).

REMARKS

This species is known only from Selsoif. For full discussion see Hoeksema et al. (2020: 6).

DISTRIBUTION. — Lower Pleistocene: Atlantic, endemic to Selsoif ( Hoeksema et al. 2020).

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. 2. — Aerial photographs of the extraction site (La Sablière du Grand-Marais) with the spoil heaps visible in centre: A, photographie IGN, Mission C90SAA0491_1990_F1211- 1411_0037, cliché no. 37, 28/04/1990; B, photographie IGN, Mission CP12000422_059_12385, cliché n°12385, 26/07/2012. Width of lake in the centre c. 400 m.