Patella rustica Linnaeus 1758

Patella rustica Linnaeus, 1758 (Fig. 4A 1, A 2) Patella rustica Linnaeus, 1758: 783. MATERIAL AND DIMENSIONS. — Maximum height 9.1 mm, diameter 28.2 mm. — RGM.1364897 (2), leg. WG; RGM.1364961 (5), leg. ACJ; RGM.1365058 (18), leg. AWJ; RGM.1365190 (1), leg. AWJ. SPECIES CHARACTERISATION. — Low patelliform shell; apex placed two-thirds distance from anterior margin. Sculpture of about 34 low, narrow, scabrous primary ribs with single secondary intercalated in interspaces. Edge finely crenulated. DISTRIBUTION. — Fossils records are scarce. Pliocene (indeterminate): Calabria and Modena, Italy (Bucquoy et al. 1886: 471). — Early Pleistocene: Atlantic, Selsoif, France (this paper). — Middle/Late Pleistocene: Italy (Buccheri et al. 2014). Today this species occurs in the Atlantic south of Bay of Biscay, Strait of Gibraltar, to the coast of North Africa, including the Macaronesian Islands (Zegaoula et al. 2016), and into the Mediterranean Sea from Spain (Gofas et al. 2011) to the Aegean Sea (Öztürk et al. 2014). It inhabits upper midlittoral rocky environments (Bensettiti et al. 2004: 112). Patella rustica lives highest on the shore of all extant co-occurring European Patella species: just at the high tide line, generally on rocks in exposed zones with strong splash. Even at localities where the species is common, empty shells are rarely found between the rocks or on adjoining beaches. Therefore, it is surprising to find it well represented at Selsoif. REMARKS Separation of Patella species based on the shell alone is problematic (Côrte-Real et al. 1996). The specimens from Selsoif probably represent P. rustica Linnaeus, 1758. This species has been considered conspecific or a separate species from P.piperata Gould, 1846 although soft tissue and molecular data suggest separation at species/subspecies level (Côrte-Real et al. 1996). Patella rustica can also be confused with P. depressa Pennant, 1777, but that species tends to be more pointed posteriorly, have coarser, more irregular ribs and a less scabrous surface.