Diodora graeca

Diodora graeca (Defrance, 1820) (Fig. 4D 1, D 2) Patella graeca Linnaeus, 1758: 784. Diodora graeca – Landau et al. 2003: 26, pl. 4, fig. 4; 2017: 80, pl. 3, figs 1-4. — Chirli & Linse 2011: 35, pl. 4, fig. 5. — Ceulemans et al. 2016: 54, pl. 1, figs 5, 6. — Chirli & Forli 2017: 24, fig. 5a. For more, see synonymy list in Landau et al. (2003, 2017) and Ceulemans et al. (2016). MATERIAL AND DIMENSIONS. — Maximum height 23.5 mm, diameter 11.9 mm. — RGM.1364899 (3), leg. WG; RGM.1364964 (7), leg. ACJ; RGM.1365061 (24), leg. AWJ; RGM.1365174 (1), leg. AWJ; RGM.1365062 (1), leg. AWJ. SPECIES CHARACTERISATION. — Patelliform shell with ovate profile; apical perforation two-third distance from anterior margin; sculpture of primary to tertiary ribs differentiated to a variable degree. DISTRIBUTION. — Middle Miocene: Paratethys (Strausz 1966; Bałuk 1975). — Upper Miocene: NW France (Ceulemans et al. 2016); Proto-Mediterranean (Sacco 1896a). — Lower Pliocene: NW France (Ceulemans et al. 2016), Coralline Crag, England (Harmer 1923), Belgium (Marquet & Landau 2006); central Mediterranean (Chirli 2004). — Upper Pliocene: Red, Crag, England (Harmer 1923); western and central Mediterranean (Landau et al. 2003; Malatesta 1974; Caprotti 1976; Cavallo & Repetto 1992); France (Chirli & Richard 2008). — Lower Pleistocene: NW France (Brébion 1964), Selsoif (this paper); central Mediterranean (Cerulli-Irelli 1916; Malatesta 1960; Chirli & Forli 2017); eastern Mediterranean, Rhodes Island (Chirli & Linse 2011). — Upper Pleistocene: England (Harmer 1923), Netherlands (Wesselingh & Pouwer 2011); western Mediterranean, Balearic Islands (Cuerda Barceló 1987). Today this species occurs from the Atlantic British Isles to Canaries, Mediterranean and Black Sea on rocky shores under stones and rocks, especially where a little silt occurs, living near sponges, on which it feeds (Poppe & Goto 1991). REMARKS This species is highly variable in height and the differentiation between the primary to tertiary ribs (see discussion in Ceulemans et al. 2016: 55). Some of the Selsoif specimens have weaker primaries than seen in some Mediterranean fossil material.