Nucella lapillus

Nucella lapillus (Linnaeus, 1758) (Fig. 12B 1-B 3, C 1-C 3, D 1-D 2) Buccinum lapillus Linnaeus, 1758: 39. Purpura lapillus – Wood 1848: 36, pl. 4, figs 6a-h. — Harmer 1914: 117, pl. 11, figs 1-5, 7-12, 14-17, 19-23. Thais (Polytropa) lapillus vulgaris – Van Regteren Altena et al. 1956: 88, pl. 11, fig. 114b. Nucella lapillus – Fretter & Graham 1984: 444, figs 314-315. — Raad et al 2021: 19, figs 25-29. MATERIAL AND DIMENSIONS. — Maximum height 54.2 mm, width 33.8 mm. — RGM.1364927 (250+), leg. WG; RGM.1365011 (230+), leg. ACJ; RGM.1365290 (1), leg. ACJ; RGM.1365267 (1), leg. AWJ; RGM.1365114 (500+), leg. AWJ; RGM.1365115 (500+), leg. AWJ; RGM.1405529 (1), leg. R. van Slageren. SPECIES CHARACTERISATION. — Shell solid broadly fusiform; protoconch paucispiral of about 1.5 smooth whorls with large, elevated nucleus.Teleoconch of about three whorls; spire whorls convex, first whorl bearing two primary cords with secondaries intercalated on second whorl; last whorl inflated, with numerous scabrous spiral cords of roughly alternating strength, shoulder and peribasal cords usually slightly stronger; aperture ovate; outer lip not thickened by varix, with internally bevelled edge, with denticles strongly developed to absent; columella thickened abapically, detached, forming medial border of umbilical chink. DISTRIBUTION. — Upper Pliocene: NSB, Red Crag, England (Wood 1848; Harmer 1914). — Pliocene and Pleistocene (indeterminate): NSB, Netherlands (Van Regteren Altena et al. 1956; Raad et al 2021). — Lower Pleistocene: NSB, England (Wood 1848; Harmer 1914), Atlantic: Selsoif, NW France (this paper). — Middle Pleistocene: Channel region England (Preece & Bates 1999). — Holocene: NSB (Strand Petersen 2004). Today this species is widely in the northern Atlantic, in the west from Greenland to Connecticut, in the east from Iceland to the Strait of Gibraltar (Fretter & Graham 1984). It inhabits rocky shores to depth of 30- 40 m. it lives between 0 and 19°C isotherms (Moore 1936). REMARKS Nucella lapillus (Linnaeus, 1758) is an exceptionally variable species both in the fossil record (Wood 1848; Harmer 1914) and in extant faunas (Berry & Crothers 1974; Rolán et al. 2004; inter alia). Some papers have associated these morphs with particular habitats (Rolán et al. 2004) and or presence/absence of predators (Crothers 1983 and others), whereas others have found no association (Berry & Crothers 1974; Crothers 2008). In the Selsoif material, the larger adult specimens usually have spiral cords (Fig. 4C), smaller but fully adult specimens judging by the thickness of their shell are smoother (Fig. 4B). The inner lip can be smooth or bear coarse denticles. Some of the juvenile specimens have an imbricated surface with raised lamellae, similar to the juvenile specimen illustrated by Fretter & Graham (1984: fig.315) as N. lapillus var. imbricata (Fig. 4D). Similar variability has been described for the size of the protoconch ranging from 800-1400 µm (Rolán et al. 2004) to 500-700 µm (Fretter & Graham 1984). A large number of juveniles are present in the Selsoif material with their protoconch preserved (npw = 1.25-1.5, dp = 740-1000 µm, hp = 730-1030 µm, n = 340-600 µm, p1 = 580-910 µm). These measurements fall between those given above for the recent populations, although the size variation of the nucleus in the Selsoif material is much greater than that reported by Rolán et al. (2004: table 1). This is a good example of the variability in protoconch size for species with paucispiral protoconchs.