Spirolaxis centrifugus (Monterosato, 1890)

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 : 73-74

Spirolaxis centrifugus (Monterosato, 1890)

Fig. 16 o–q

Pseudomalaxis centrifuga Monterosato, 1890 (p. 161).

Pseudomalaxis (Spirolaxis) centrifuga ( Monterosato)—Monterosato 1913 (p. 363, lower fig. in same page); Nordsieck 1968 (p. 64, pl. 10, fig. 37.30); Taviani 1984 (p. 42, pl. 2, figs. 4–5).

Pseudomalaxis (Spirolaxis) centrifuga ( Monterosato, 1913) — Nordsieck 1972 (p. 147, pl. R XIV, fig. 10).

Spirolaxis centrifuga — Boss & Merrill 1984 (p. 362, pl. 62, fig. 2).

Spirolaxis centrifugus (Monterosato, 1890) —Melone & Taviani 1984 (p. 185, figs. 62–64).

? Spirolaxis clenchi Jaume & Borro, 1946 —Melone & Taviani 1984 (p. 188, figs. 65–67); Repetto et al. 2005 (p. 226, top right fig.).

Diagnostic characters. Planispiral shell; disjuncted first teleoconch whorl; subquadrangular aperture; four robust spiral keels placed at angles of the quadrangular whorls; thin sinuous axials forming elongated nodes on keels. Protoconch: slightly more than 2 whorls; diameter about 500 µm; surface smooth; transition to the teleoconch marked by a simple lip preceded by a narrow, slightly sinuous varix.

Remarks. The western Atlantic species S. exquisitus (Dall & Simpson, 1901) is sometimes considered a synonym of S. centrifugus (cf. Melone & Taviani 1984). The Caribbean Spirolaxis clenchi Jaume & Borro, 1946 could also be a synonym of S. centrifugus , but the relationships between the two taxa are unclear.

Occurrence. Box-corer sample BC72 (1 specimen). Diameter: 3.5 mm.

Distribution and habitat. The species is distributed on both sides of the Atlantic and in the Mediterranean, ranging in depth from circalittoral to bathyal zones (Melone & Taviani 1984).

Fossil record. Pliocene? of Italy ( Tabanelli 2008, as S. clenchi ).

Figures

FIGURE 16. a – c: Pleurotomella gibbera Bouchet & Warén, 1980, sample BC 66, scale bars: 1 mm (a), 0.2 mm (b – c, protoconch); d – f: Discotectonica discus (Philippi, 1844), sample BC 72, scale bars: 2 mm (d – e), 0.2 mm (f, protoconch); g – h: Pseudomalaxis zanclaeus (Philippi, 1844), sample BC 72, scale bar 5 mm; i – k: Solatisonax alleryi (Seguenza, 1876), sample BC 72, scale bars: 2 mm (i – j), 0.2 mm (k, protoconch); l – n: Solatisonax bannocki (Melone & Taviani, 1980), sample BC 71, scale bars: 2 mm (l – m), 0.2 mm (n, protoconch); o – q: Spirolaxis centrifugus (Monterosato, 1890), sample BC 72, scale bars: 1 mm (o – p), 0.2 mm (q, protoconch).