Tectonatica tectula ( Sacco, 1890 )

Tectonatica tectula ( Sacco, 1890) View in CoL

Figs 2H View FIGURE 2 , 24C View FIGURE 24 1 –C View FIGURE 1 4 View FIGURE 4

* Natica ( Tectonatica) tectula Sacc.— Sacco 1890: 33 View in CoL .

Natica ( Tectonatica) tectula Sacc.— Sacco, 1891: 81 View in CoL , pl. 2, fig. 53.

Natica ( Tectonatica) tectula Bon.— Boettger 1902: 82 View in CoL .

Natica ( Tectonatica) tectula Bon.— Boettger 1906: 90 View in CoL .

Tectonatica tectula ( Sacco, 1890) View in CoL — Pedriali & Robba 2008a: 110, pl. 2, figs 7–9, 19, 20, pl. 3, figs 9, 22–23. Tectonatica tectula ( Sacco, 1890) View in CoL — Landau et al. 2011: 16, pl. 5, fig. 10.

Tectonatica tectula ( Sacco, 1890) View in CoL — Robba et al. 2016: 156, pl. 6, figs 13–15.

Tectonatica tectula ( Sacco, 1890) View in CoL — Landau et al. 2013: 102, pl. 11, fig. 6 ( cum syn.).

Type material. Lectotype (designated by Pedriali & Robba 2008a: 110), BS.029.04.001/01, Villalvernia ( Italy), Pliocene.

Illustrated material. SFM 366841, SL: 4.6 mm, MD: 4.2 mm, Coşteiu de Sus ( Romania), Figs 2H View FIGURE 2 , 24C View FIGURE 24 1 –C View FIGURE 1 4 View FIGURE 4 .

Revised description (based on Paratethyan material). Very small, elongate ovate to depressed ovate, glossy shell of two teleoconch whorls; slightly higher than wide ( SL /MD = ~1.1). Protoconch low turbiniform of about 2.5 convex whorls. Spire weakly elevated, broad conical with moderately to weakly convex whorls; apical angle ~110–130°. Suture linear, adpressed. Teleoconch whorls with broad, steep, almost flat subsutural ramp, delimited by rounded shoulder. Subsutural ramp with delicate spiral threads. Last whorl moderately expanding, attaining ~90–95% of total height. Regularly convex below subsutural ramp. Periphery below mid-whorl (~40%). Growth lines delicate, weakly prosocyrt in apical view, prosocline and close-set at periphery. Aperture wide, D-shaped, moderately prosocline. Position of adapical tip of aperture high (~85%), close to shoulder. Aperture attaining ~80% of total height. Columellar lip straight, solid, basal lip weakly thickened, outer lip moderately thin. Columellar angle ~15–30°. Prominent opercular ridge in outer lip. Umbilicus fully sealed by semicircular, plug-like, flattish umbilical callus. Deep, narrow umbilical chink of slightly variable width. Parietal callus long (~53%), weakly thickened, not expanding over base, with concave margin, fused with umbilical callus. Base solid, rounded. For operculum of Pliocene specimens see Pedriali et al. (2008a: 111).

Discussion. This species could be mistaken for Tectonatica distincta ( Eichwald, 1829) but differs in its wider last whorl, weakly incised suture, depressed conical spire and larger umbilical callus which leaves a narrower umbilical chink.

Distribution in Central Paratethys. Badenian (Middle Miocene): Făget Basin: Coşteiu de Sus ( Romania) ( hoc opus).

(Proto-)Mediterranean Sea. Burdigalian (Early Miocene): Colli Torinesi : Valle Ceppi ( Italy) ( Pedriali & Robba 2008a). Serravallian (Middle Miocene): Karaman Basin, Akpınar, Seyithasan ( Turkey) ( Landau et al. 2013). Tortonian (Late Miocene): Po Basin: Borelli ( Italy) ( Pedriali & Robba 2008a). Pliocene: Estepona Basin ( Spain) ( Landau et al. 2013); central Mediterranean Sea (Taly) ( Pedriali & Robba, 2008a).

Northeastern Atlantic. Serravallian (Middle Miocene): Aquitaine Basin: Orthez ( France) ( Pedriali & Robba 2008a). Pliocene: Guadalquivir Basin, Spain ( Landau et al., 2011).