Parvamussium fenestratum ( Forbes, 1844 )

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 : 26-28

Parvamussium fenestratum ( Forbes, 1844)

Fig. 5 e–g

Pecten fenestratus Forbes, 1844 (p. 192).

Amussium fenestratum Forbes—Jeffreys 1879 (p. 561).

Propeamussium fenestratum ( Forbes, 1843) — Nordsieck 1969 (p. 45).

Propeamussium fenestratum (Forbes) — Di Geronimo & Panetta 1973 (p. 98, pl. 3, fig. 11).

Propeamussium fenestratum ( Forbes, 1844) — Cossignani et al. 1992 (fig. 283); Poppe & Goto 1993 (p. 70, pl. 10, fig. 5); Repetto et al. 2005 (p. 300, bottom right fig.).

Parvamussium fenestratum ( Forbes, 1844) — Giannuzzi-Savelli et al. 2001 (p. 170, fig. 323); Beck et al. 2006 (p. 99, top fig.).

Diagnostic characters. Rounded shell; subequal auricles; several orders of radial riblets crossed by raised commarginal lamellae; spiny projections at the intersections, more so on crossing the main ribs. Prodissoconch: shell type ST-2D; length about 170 µm; roundish D-shaped outline; convex profile; P-1 surface smooth; P-2 absent; transition to the nepioconch well marked, somewhat step-like.

Occurrence. Box-corer samples BC66 (1 specimen), BC67 (3), BC70 (1), BC71 (3), BC72 (4); cores BC67 (1), BC72 (1). Maximum height: 7.5 mm.

Distribution and habitat. The species is distributed from off the New England coast to Britain, the Azores, the Canaries and the Mediterranean, from about 50 to 2000 m depth, reaching 4000 m in the Azores waters ( Nordsieck 1969; Poppe & Goto 1993). It was recovered among the Abra-Nucula biocoenosis in the bathyal of Taranto ( Di Geronimo & Panetta 1973). In the Santa Maria di Leuca CWC biotope, it was found on muddy bottoms around coral colonies (Mastrototaro et al. 2010).

Fossil record. Pliocene of the Mediterranean ( Monterosato 1872).

Figures

FIGURE 5. a – d: Delectopecten vitreus (Gmelin, 1791); RV (a, c, d) and LV (b), sample BC 72, scale bars: 5 mm (a – b), 1 mm (c, juvenile), 0.1 mm (d, prodissoconch); e – g: Parvamussium fenestratum (Forbes, 1844); LV, samples BC 70 (e – f) and BC 72 (g), scale bars: 5 mm (e – f), 0.1 mm (g, prodissoconch); h – l: Cyclopecten hoskynsi (Forbes, 1844); RV (h, i, l) and LV (j, k), sample BC 72, scale bars: 5 mm (h – k), 0.1 mm (l, prodissoconch); m – o: Similipecten similis (Laskey, 1811); RV (n, o) and LV (m), sample BC 72, scale bars: 1 mm (m – n), 0.05 mm (o, prodissoconch).