Entalina tetragona (Brocchi, 1814)

Fig. 11 d–f

Dentalium tetragonum Brocchi, 1814 (p. 627, pl. 15, fig. 26).

Entalina tetragona (Brocchi) — Caprotti 1961 (p. 356, pl. 20, figs. 7–8); Di Geronimo 1974 (p. 153); Di Geronimo & Li Gioi 1980 (pl. 1, fig. 7; pl. 3, fig. 6).

Entalina tetragona (Brocchi, 1814) — Robba 1968 (p. 505, pl. 39, fig. 6); Caprotti 1979 (p. 251, pl. 13, figs. 4–8); Pavia 1991 (p. 132, pl. 8, figs. 7–8); Barash & Danin 1992 (p. 229, fig. 233); Cossignani et al. 1992 (fig. 411); Poppe & Goto 1993 (p. 35, pl. 1, fig. 12); Petersen 2004 (p. 61, fig. 45); Repetto et al. 2005 (p. 358, bottom left fig.).

Diagnostic characters. Rather thin, regularly curved shell; anal aperture roundly quadrangular; foot aperture roundly pentagonal; four distinct longitudinal ribs on younger stages; additional slightly weaker rib developing soon after dorsally; several fine riblets appearing on older stages. Larval shell: not available.

Occurrence. Box-corer samples BC04 (8 specimens), BC05 (2), BC72 (6); cores BC04 (7), BC05 (5), BC21 (9), BC51 (4), BC72 (1). Maximum length: 8.5 mm.

Distribution and habitat. Entalina tetragona ranges from Norway to the Caribbean, Cape Verde and the Mediterranean, including the Levantine basin; it was regarded as an exclusive characteristic element of VP (bathyal mud) biocoenosis dwelling on muddy bottoms at bathyal depths, being more frequent in the 400–600 m bathymetric interval (Di Geronimo 1979[a]; Di Geronimo & Bellagamba 1985; Barash & Danin 1992; Poppe & Goto 1993; Pons-Moyà & Pons 1999; Galil 2004). In the Santa Maria di Leuca CWC biotope, it was regarded as common in Gryphus-Isidella and mollusk mud thanatofacies (Rosso et al. 2010).

Fossil record. The species appeared during Upper Miocene (Tortonian), being among the few still surviving Miocene taxa (Caprotti 1979); records are from Miocene of Italy, Poland, Hungary and Vienna basin; Pliocene of Italy ; Pleistocene of Denmark, central and southern Italy (Monterosato 1872; Robba 1968; Caprotti 1979; Di Geronimo & Li Gioi 1980; Di Geronimo & Bellagamba 1985; Pavia 1991; Di Geronimo & La Perna 1997; Petersen 2004; Di Geronimo et al. 2005).