Steromphala tumida

Steromphala tumida (Montagu, 1803) (Fig. 4J 1-J 3) Trochus tumidus Montagu, 1803: 280, pl. 10, fig. 4. Trochus (Gibbula) tumidus – Harmer 1923: 733 (partim, pl. 59, fig. 11, not pl. 59, fig. 10) (Upper Pleistocene-Recent records only). Gibbula tumida – Pouwer & Wesselingh 2012: 152, fig. 4 (non Gibbula tumida Símonarson & Eiríksson in Eiríksson & Símonarson, 2021). MATERIAL AND DIMENSIONS. — Height 4.8 mm. — RGM.1310832 (1), leg. SM; n.n. (8), leg. SM. SPECIES CHARACTERISATION. — This small Steromphala species is characterised by rounded shoulders, fine and slightly irregular spiral ribbing, very strong prosocline growth-lines, a subquadrate aperture with a slight chink on the columella. DISTRIBUTION. — Lower Pleistocene: Atlantic, Selsoif, France (this paper). — Late Pleistocene: Channel region, Selsey, west coast of Scotland, Largo bay, Belfast, Livorno (Italy) and Christiana Fjord and Trondhjem in Norway (Harmer 1923). — Recent: Iceland and northern Norway to Gibraltar (Pouwer & Wesselingh 2012; Harmer 1923).