Alvania sp. 1

Bouchard, Blanche, Wesselingh, Frank P., Pouwer, Ronald & Landau, Bernard, 2025, The Gelasian gastropod fauna of Selsoif (Manche, France), Geodiversitas 47 (3), pp. 39-91 : 59-60

Alvania sp. 1

( Fig. 8C 1-C 3 )

MATERIAL AND DIMENSIONS. — Maximum height 1.3 mm, width 0.8 mm. — RGM.1364985 (8), leg. ACJ ; RGM.1365091 (107), leg. AWJ ; RGM.1365090 (1), leg. AWJ ; RGM.1365089 (10), leg. AWJ ; RGM.1364987 (2), leg. ACJ .

SPECIES CHARACTERISATION. — Shell small, rissoiform.Protoconch of two smooth whorls. Three teleoconch whorls; spire whorls sculpture of four spiral cords; axial sculpture of around 16 broad orthocline ribs forming a reticulated pattern. Last whorl develops one secondary cord between suture and first cords. Base somewhat depressed, with four spiral cords; axial ribs stop at peribasal cord.

DISTRIBUTION. — Lower Pleistocene: Atlantic, Selsoif, NW France (this paper).

REMARK

The material at hand is too worn to identify with certainty. In profile and sculpture, it is similar to several Italian Pliocene species such as Alvania lanciae (Calcara, 1845) and A. thalia (De Stefani & Pantanelli, 1878) , which both have more numerous cords on the base,

Figures

FIG. 8. — 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, Alvania cf. cancellata (da Costa,1778),RGM.1364986,leg ACJ,H = 2.64 mm; B, Alvania selsoifensis n. sp. (holotype), RGM.1365286,leg ACJ,H = 1.28 mm;C, Alvania sp.1, RGM.1365090,leg AWJ,H = 1.39 mm; D, Manzonia crassa (Kanmacher,1798),RGM.1365201, leg ACJ, H = 1.68 mm; E, Onoba semicostata (Montagu, 1803), RGM.1365197, ACJ, H = 1.9 mm; F, Pusillina aff. inconspicua (Alder, 1844), RGM.1365258, leg ACJ, H = 1.3 mm. Scale bars: A, 1 mm; B-F, 500 μm.

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).