Turbonilla micans (Monterosato, 1875)

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 : 78

Turbonilla micans (Monterosato, 1875)

Fig. 18 a–c

Odostomia (Turbonilla) micans Monterosato, 1875 [a] (p. 33).

Odostomia attenuata Jeffreys, 1884 [b] (p. 360, pl. 27, fig. 4).

Turbonilla micans, Monts. —Monterosato 1884 (p. 92).

Turbonilla guernei Dautzenberg, 1889 (p. 60, pl. 4, fig. 6).

Turbonilla (Cylindriturbonilla) guernei Dautzenberg, 1889 — Nordsieck 1972 (p. 127, pl. P V, fig. 31). Turbonilla attenuata (Jeffreys, 1884) — Van Aartsen 1981 (p. 72. fig. 28).

Turbonilla micans (Monterosato, 1875) — Sbrana 1999 (p. 9, top figures); Repetto et al. 2005 (p. 248, mid right fig.).? Turbonilla aff. micans (Monterosato, 1875) — Beck et al. 2006 (p. 86, bottom fig).

Not Turbonilla (Cylindriturbonilla) micans (Monterosato, 1875) — Nordsieck 1972 (p. 127, pl. P V, fig. 30). Not Turbonilla cf. micans (Monterosato, 1875) Nordsieck, 1972 — Van Aartsen 1981 (p. 75, fig. 29). Not Turbonilla guernei Dautzenberg, 1889 — Sbrana 1999 (p. 7, bottom figures).

Diagnostic characters. Turreted, very slender shell; gently convex teleoconch whorls; 14 opisthocline axial ribs per whorl. Protoconch: heterostrophic, globose/helicoid; coiling at about 130° to the teleoconch; 2.25 whorls; diameter about 350 µm; surface smooth; transition to the teleoconch marked by a simple, thin lip.

Remarks. The attribution to Monterosato’s species is provisional, since the type material was not examined. Nevertheless, it is of note that protoconch and shell features of the present specimens match very well the description and figure of T. attenuata (Jeffreys, 1884) reported by Van Aartsen (1981), who examined specimens from the Jeffreys’ Collection in Washington ( United States National Museum, Smithsonian Institution); Monterosato himself (1884) regarded T. attenuata to represent a junior synonym of his taxon. In our opinion, Nordsieck (1972) published a misleading figure of T. micans , with nearly flat whorl profile and a protruding protoconch. Turbonilla guernei Dautzenberg, 1889 is currently regarded as a junior synonym of T. micans (fide CLEMAM 2016), although the current iconography of this species appears to be discrepant (cf. Nordsieck 1972, Sbrana 1999).

Occurrence. Cores BC21 (1 specimen), BC51 (2). Maximum height: 2.5 mm.

Distribution and habitat. Turbonilla micans seems to be a bathyal species distributed in the Atlantic (southward to the Azores) and across the Mediterranean, sometimes on seamounts and knolls ( Dautzenberg 1889; Nordsieck 1972; Galil 2004).

Fossil record. Possibly Pliocene of Calabria ( Vazzana 1996, as T. attenuata ).

Figures

FIGURE 18. a – c: Turbonilla micans (Monterosato, 1875), sample BC 51, scale bars: 0.5 mm (a), 0.2 mm (b – c, protoconch); d – f: Graphis gracilis (Monterosato, 1874), sample BC 72, scale bars: 0.5 mm (d), 0.2 mm (e – f, protoconch); g – i: Crenilabium exile (Jeffreys, 1870), samples BC 67 (g) and BC 04 (h – i), scale bars: 2 mm (g), 0.2 mm (h – i, protoconch); j – l: Japonacteon pusillus (MacGillivray, 1843), sample BC 72, scale bars: 2 mm (j), 0.2 mm (k – l, protoconch); m – o: Callostracon thyrrenicum (Smriglio & Mariottini, 1996), sample BC 71, scale bars: 1 mm (m), 0.2 mm (n – o, protoconch).