Crepidula gibbosa Defrance 1818

Crepidula gibbosa Defrance, 1818 (Fig. 10B 1, B 2) Crepidula gibbosa Defrance, 1818: 397. — Chirli & Forli 2017: 53, fig. 15c. — Landau et al. 2018: 317, pl. 148, fig. 1. MATERIAL AND DIMENSIONS. — Maximum height 3.5 mm, diameter 12.3 mm. — RGM.1364917 (1), leg. WG; RGM.1364996 (2), leg. ACJ; RGM.1365101 (62), leg. AWJ; RGM.1365185 (1), leg. AWJ. SPECIES CHARACTERISATION. — Thick, low, smooth, convex shell. Aperture ovate. Concave, shallow septum covering almost 2/3 of the aperture. DISTRIBUTION. — Middle Miocene: Atlantic, Aquitaine Basin, France (Cossmann & Peyrot 1919), Loire Basin, France (Glibert 1949); Paratethys, Austria (Hörnes 1856), Poland (Bałuk 1975), Hungary (Strausz 1966); Proto-Mediterranean, Karaman Basin, Turkey (Landau et al. 2013). — Upper Miocene: Atlantic, NW France (Landau et al. 2018); Proto-Mediterranean, Italy (Sacco 1896b). — Lower Pliocene: Atlantic, NW France (Van Dingenen et al. 2016); SW Spain (González-Delgado 1988; Landau et al. 2011). — Upper Pliocene: Atlantic, Morocco (Lecointre 1952); western Mediterranean, S Spain (Landau et al. 2004); central Mediterranean, Italy (Chirli 1988; Cavallo & Repetto 1992). — Upper Pliocene-Pleistocene: NW France (Glibert 1963). — Lower Pleistocene, Atlantic, Selsoif, NW France (this paper); central Mediterranean (Chirli & Forli 2017). Today, this species occurs in the Mediterranean Sea, below low tide line, often attached to other molluscs (Poppe & Goto 1991). REMARKS Our assignment of Crepidula to C. gibbosa does not conform to its treatment in WoRMS and follows arguments provided in Landau et al. (2004: 74). In our opinion the taxonomy of European Crepidula is not resolved and requires in-depth studies that are beyond the scope of this paper.