Cyclopecten hoskynsi ( 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 : 28

Cyclopecten hoskynsi ( Forbes, 1844)

Fig. 5 h–l

Pecten hoskynsi Forbes, 1844 (p. 192).

Amussium hoskynsi Forbes—Jeffreys 1879 (p. 562).

Propeamussium (Cyclopecten) hoskynsi hoskynsi (Forbes, 1846) — Nordsieck 1969 (p. 46, pl. 7, fig. 30.15).

Propeamussium hoskynsi (Forbes) — Di Geronimo & Panetta 1973 (p. 99, pl. 3, fig. 13); Di Geronimo & Li Gioi 1980 (pl. 3, figs. 1–2).

Cyclopecten hoskynsi (Forbes, 1846) — Poppe & Goto 1993 (p. 71, pl. 10, fig. 9).

Cyclopecten hoskynsi ( Forbes, 1844) — Giannuzzi-Savelli et al. 2001 (p. 172, fig. 324); Repetto et al. 2005 (p. 300, bottom left fig); Oliver et al. 2016 (online resource).

Cyclopecten hoskynsi (Forbes) —Rosso et al. 2010 (fig. 10 E).

Diagnostic characters. Flattened, subrounded shell; moderately long right anterior auricle with 7–8 radial ribs and deep byssal notch; subequal left auricles with concentric lamellae; right valve with crowded concentric cordlets and about 15 inner radial ribs sometimes restricted to the peripheral area; left valve with sparse radial rows of moon-shaped, recurved lamellar nodes. Prodissoconch: shell type ST-2D; length about 150 µm; roundish D-shaped outline; low convex profile; P-1 surface pitted; P-2 replaced by narrow metamorphic lip; transition to the nepioconch well marked.

Occurrence. Box-corer samples BC04 (5 specimens), BC05 (7), BC41 (1), BC66 (12), BC67 (9), BC71 (27), BC72 (146); cores BC04 (1), BC05 (5), BC21 (11), BC51 (8), BC52 (1), BC67 (1), BC72 (17). Maximum height: 6 mm.

Distribution and habitat. The species is distributed all along the western margin of the Atlantic (from Greenland to Cape Verde) and in the Mediterranean, where it thrives on soft sediments from shelf edge to bathyal depths ( Nordsieck 1969; Oliver et al. 2016). It was regarded as a typical element of VP (bathyal mud) biocoenosis ( Di Geronimo et al. 1982). In the Santa Maria di Leuca CWC biotope, it was regarded as abundant in mollusk mud, and common in coral rubble and Gryphus-Isidella thanatofacies (Rosso et al. 2010).

Fossil record. Pliocene of Sicily ( Monterosato 1872); bathyal Pleistocene of central and southern Italy ( Di Geronimo & Li Gioi 1980; Di Geronimo & Bellagamba 1985; Barrier et al. 1987; Di Geronimo & La Perna 1997; Di Geronimo et al. 2005).

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).