Lepidochitona pliocinerea

Lepidochitona pliocinerea Dell’Angelo, Sosso, Prudenza & Bonfitto, 2013

Fig. 105 View FIGURE 105

Lepidochitona pliocinerea Dell’Angelo, Sosso, Prudenza & Bonfitto, 2013, p. 92, pl. 9, figs G–Z; Dell’Angelo et al. 2016, p. 84, pl. 4, figs 11–17; Dell’Angelo et al. 2020b, p. 53, tab. 9; Dell’Angelo et al. 2021b, p. 423, figs 130–133.

Lepidochitona cinerea View in CoL [non Lepidochitona cinerea ( Linnaeus, 1767) View in CoL ]; Dell’Angelo et al. 2001a, p. 148, figs 12, 15 ( partim, the valves from the Pliocene of Serre di Rapolano); Chirli 2004, pl. 3 ( partim, fig. 9); Dell’Angelo et al. 2004, p. 36, pl. 3, fig. 6 ( fide dell’Angelo et al. 2013).

Type material. Holotype: MZB 49979, intermediate valve, Figs 105F–G View FIGURE 105 . Paratypes: MZB 49977 (1 valve from Bussana); MZB 49978 (1 valve from Rio Sant’Antonino, Figs 105A–B View FIGURE 105 ); MSNG 56537 (2 valves from Bussana and Rio Sant’Antonino); private collections (4 valves): BD: (2 valves from Serre di Rapolano, Fig. 105H View FIGURE 105 ), MP (1 valve from Rio S. Antonino), MS (1 valve from from Genova Sestri).

Type locality. Bussana ( Liguria, Italy) .

Type stage. Lower Pliocene (Zanclean) .

Material examined. Lower Miocene: Italy ( Burdigalian): Piedmont: Sciolze: 1 valve ( PG). Middle Miocene : Italy ( Langhian): Piedmont: Albugnano: 1 valve ( MZB 32097 , Figs 105C–D View FIGURE 105 ). Upper Miocene : Italy ( Tortonian): Piedmont: Borelli: 5 valves ( BD 910 , MGPT PU 135299 , Fig. 105E View FIGURE 105 ), Rio di Bocca d’Asino: 21 valves ( BD 911 , MZB 32098 , Fig. 105L View FIGURE 105 , PG); Emilia-Romagna: Montegibbio: 7 valves ( BD 912 , MZB 32099 ). Lower Pliocene : Italy: Liguria: type material, plus Borzoli: 14 valves ( BD 913 ); Bussana: 10 valves ( BD 914 ); Caranchi: 4 valves ( BD 915 , MP); Garlenda: 2 valves ( MP); Genova Sestri: 2 valves ( BD 916 ); Rio Sant’Antonino : 75 valves ( BD 917 , MP). Pliocene : Italy: Tuscany: Serre di Rapolano (21 valves) ( BD 918 , Figs 105I–K View FIGURE 105 ) ; Spain: Estepona: 6 valves ( BD 919 ). Maximum width of the valves: 7.5–15– 6.2 mm .

Description. Valves solid, often remarkably thick. Head valve about one third of a circle. Intermediate valves broadly rectangular (W/L = 2.83–3.74), moderately elevated (H/W = 0.31–0.35), semicarinate in anterior profile, posterior margin almost straight, drawn out to small apex, not beaked, lateral areas not distinctly separated from central area. Tail valve elliptical (W/L = 2.04–2.35), anterior margin almost straight or slightly convex, mucro subcentral, not prominent, antemucronal and postmucronal slopes practically straight.

Tegmentum evenly sculptured all over with irregularly roundish granules (diameter up to 115 µm), arranged in somewhat irregular quincunx pattern. Each granule bearing more or less central megalaesthete and several micraesthetes (15–20) irregularly arranged along margin, also in depressions between granules.

Articulamentum with apophyses short, very wide, starting from limits of jugal area, jugal sinus straight to slightly convex, narrow about one seventh of total width. Slit formula 15–16 / 1 / 11–13, slit rays well marked, insertion teeth inaequidistant.

Remarks. Most material is represented by small fragments, whilst complete valves are rare. The material reported as Lepidochitona cinerea ( Linnaeus, 1767) from the Pliocene of Estepona (Dell’Angelo et al. 2004), and some of the valves from the Pliocene of Tuscany ( Chirli 2004, partim; Dell’Angelo et al. 2001a, partim) has been ascribed to L. pliocinerea by Dell’Angelo et al. (2013).

Comparisons. Lepidochitona pliocinerea Dell’Angelo, Sosso, Prudenza & Bonfitto, 2013 is very similar to L. cinerea ( Linnaeus, 1767) , from which it differs by the greater width and the more elongate shape of its valves, the larger apophyses starting from the limits of JA, the different slope in tail valve, the greater number of slits (slit formula 15–16 / 1 / 11–13 vs. 8–10 / 1 / 8–12 in L. cinerea ), and the more irregularly roundish granules (vs. subquadrangular and more regular in L. cinerea ).

Distribution. Lower Miocene: Proto-Mediterranean Sea (Burdigalian): N. Italy: Sciolze ( Dell’Angelo et al. 2016). Middle Miocene: Proto-Mediterranean Sea (Langhian): N. Italy: Albugnano ( Dell’Angelo et al. 2016). Late Miocene: Proto-Mediterranean Sea (Tortonian): N. Italy: Borelli, Montegibbio, Rio di Bocca d’Asino ( Dell’Angelo et al. 2016). Lower Pliocene: central Mediterranean, Italy: Liguria ( Dell’Angelo et al. 2013, 2021b). Pliocene: western Mediterranean: Spain: Estepona (Dell’Angelo et al. 2004), central Mediterranean: Italy: Tuscany: Serre di Rapolano ( Dell’Angelo et al. 2001a).