Discotectonica discus (Philippi, 1844)

Fig. 16 d–f

Solarium discus Philippi, 1844 (p. 225, pl. 28, fig. 12).

Solarium discus, Ph. — Monterosato 1873 (p. 4, figs. 1–4).

Solarium discus Philippi—Hidalgo 1917 (p. 644).

Philippia pseudoperspectiva (Brocchi) — Nordsieck 1968 (p. 64, pl. 10, fig. 37.40).

Discotectonica discus (Philippi, 1844) —Melone & Taviani 1984 (p. 152, figs. 1–10); Repetto et al. 2005 (p. 224, bottom left fig.); Peñas et al. 2006 (p. 128, figs. 282–284); Mastrototaro et al. 2010 (fig. 5 b).

Diagnostic characters. Low conical, almost discoidal shell; very low spire; rounded aperture with weak adaxial and abaxial angulation; deep and wide umbilicus bordered by 2 rows of elongated knobs; robust peripheral keel; spiral rows of squarish nodes ceasing on the mid-base; dense axial striation on base. Protoconch: heterostrophic; about 2 whorls, the first immersed; diameter about 680 µm; surface smooth; transition to the teleoconch marked by a thread-like varix.

Occurrence. Box-corer samples BC67 (2 specimens), BC70 (1), BC71 (2), BC72 (17). Maximum diameter: 6.5 mm.

Distribution and habitat. Discotectonica discus is distributed from the Lusitanic province to West Africa and the Mediterranean, as well as in the Caribbean area; it is a rare species dwelling on circalittoral to bathyal mud (Melone & Taviani 1984; Poppe & Goto 1991). In the Santa Maria di Leuca CWC biotope, it was found on living colonies of Madrepora oculata (Mastrototaro et al. 2010) .

Fossil record. Pleistocene of Ischia, southern Italy (Melone & Taviani 1984).