Pleurotomella eurybrocha ( Dautzenberg & Fischer, 1896 )

Negri, Mauro Pietro & Corselli, Cesare, 2016, Bathyal Mollusca from the cold-water coral biotope of Santa Maria di Leuca (Apulian margin, southern Italy), Zootaxa 4186 (1), pp. 1-97 : 70

Pleurotomella eurybrocha ( Dautzenberg & Fischer, 1896)

Fig. 15 j–l

Pleurotoma eurybrocha Dautzenberg & Fischer, 1896 (p. 427, pl. 15, fig. 14).

Pleurotomella (Gymnobela) eurybrocha (Dautzenberg & H. Fischer) — Nordsieck 1968 (p. 184, pl. 31, fig. 95.65). Pleurotomella (Gymnobela) eurybrocha ( Dautzenberg & Fischer, 1896) — Nordsieck 1977 (p. 68, pl. 26, fig. 137). Pleurotomella eurybrocha ( Dautzenberg & Fischer, 1896) — Bouchet & Warén 1980 (p. 39, figs. 92, 224–225). Pleurotomella eurybrocha ( Dautzenberg and Fischer, 1896) — Poppe & Goto 1991 (p. 173, pl. I, fig. 30). Pleurotomella eurybrocha ( Dautzenberg & Fischer H., 1896) — Repetto et al. 2005 (p. 215, top right fig.).

Diagnostic characters. Fusiform shell; oval aperture; moderately long and twisted siphonal canal; rather deep anal sinus; 11 collabral ribs per whorl crossed by spiral cordlets; short recurved spines at the intersections of ribs and cordlets; stronger spines bordering the subsutural shelf. Protoconch: conical; 3.5 whorls; diameter about 480 µm (protoconch I: 250 µm); height about 630 µm; first 1.5 whorls (protoconch I) with spirally connected T-shaped granules forming a square reticulated pattern; subsequent whorls (protoconch II) with sinuous, collabral, opisthocyrt axial riblets and non-collabral prosocline riblets; the latter riblets absent in the adapical third, where only collabral riblets are present; terminal spiral keel; transition to the teleoconch at sinusigera.

Remarks. A single juvenile specimen was at hand.

Occurrence. Core BC21 (1 specimen). Height: 2 mm.

Distribution and habitat. Pleurotomella eurybrocha ranges from the northeastern Atlantic to the Azores and the Mediterranean, being a soft bottom dweller at bathyal depths, occasionally found at lower settings in the Mediterranean ( Panetta 1971; Nordsieck 1977; Bouchet & Warén 1980; Poppe & Goto 1991). It was regarded as a characteristic element of the VP (bathyal mud) biocoenosis ( Di Geronimo et al. 1982).

Fossil record. Possibly Pleistocene of Sicily ( Di Geronimo et al. 1982 as P. cf. eurybrocha ).

Figures

FIGURE 15. a – d: Drilliola loprestiana (Calcara, 1841), sample BC 05, scale bars: 1 mm (a), 0.5 mm (b – c, protoconch), 0.1 mm (d, PI detail); e – h: Mangelia nuperrima (Tiberi, 1855), samples BC 05 (e) and BC 72 (f – h), scale bars: 2 mm (e), 0.5 mm (f – g, protoconch), 0.1 mm (h, PI detail); i: Mangelia serga (Dall, 1881), sample BC 72, scale bar 2 mm; j – l: Pleurotomella eurybrocha (Dautzenberg & Fischer, 1896), sample BC 21, scale bars: 0.5 mm (j), 0.2 mm (k – l, protoconch); m – p: Teretia teres (Reeve, 1844), sample BC 72, scale bars: 1 mm (m), 0.2 mm (n – o, protoconch), 0.1 mm (p, PI detail); q – t: Pleurotomella demosia (Dautzenberg & Fischer, 1896), sample BC 71, scale bars: 2 mm (q), 0.2 mm (r – s, protoconch), 0.1 mm (t, PI detail).