Delectopecten vitreus ( Gmelin, 1791 )

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

Delectopecten vitreus ( Gmelin, 1791)

Fig. 5 a–d

Ostrea vitrea Gmelin, 1791 (p. 3328).

Pecten vitreus Chemnitz—Jeffreys 1879 (p. 561).

Chlamys vitrea Chemnitz—Hidalgo 1917 (p. 240).

Chlamys (Delectopecten) vitrea (Gmelin) — Tebble 1966 (p. 64, text-figs. 27a–b).

Delectopecten vitreus vitreus (Gmelin, 1789) — Nordsieck 1969 (p. 47, pl. 7, fig. 31.10).

Delectopecten vitreus (Gmelin) — Di Geronimo & Li Gioi 1980 (pl. 4, figs. 1–2); Di Geronimo & Bellagamba 1985 (pl. 3, fig. 3); Rosso et al. 2010 (fig. 5 C).

Delectopecten vitreus ( Gmelin, 1791) — Thomsen & Vorren 1986 (pl. 5, fig. C); Barash & Danin 1992 (p. 254, fig. 272); Poppe & Goto 1993 (p. 65, pl. 9, fig. 7); Giannuzzi-Savelli et al. 2001 (p. 172, fig. 326); Petersen 2004 (p. 70, fig. 59); Repetto et al. 2005 (p. 297, top right fig); Mastrototaro et al. 2010 (fig. 5 h); Oliver et al. 2016 (online resource).

Delectopecten vitreus — Ceregato et al. 2007 (fig. 3.8).

Diagnostic characters. Subrounded, thin shell; moderately long anterior right auricle with 5/6 densely rugose radial riblets; deep byssal notch; left valve with subequal auricles; thin and slightly wavy commarginal lamellae; few radial rows of small nodes on the very anterior part of the shell and on the posterior auricles. Prodissoconch: shell type ST-2A; length about 220 µm (P-1 about 70 µm); P-2 roundish, weakly inequilateral (anterior side shorter); convex profile; P-1 surface rough; P-1/P-2 boundary ill-defined; P-2 with commarginal lines; transition to the nepioconch well marked.

Occurrence. Box-corer samples BC04 (5 specimens), BC05 (6), BC10 (1), BC11 (11), BC22 (3), BC41 (4), BC66 (38), BC67 (18), BC70 (3), BC71 (243), BC72 (165); cores BC04 (2), BC05 (25), BC21 (13), BC51 (7), BC67 (5), BC72 (42). Maximum height: 12 mm.

Distribution and habitat. Delectopecten vitreus is regarded as a cosmopolitan species, usually ranging from about 30 to 600 m but occasionally down to 3000 m water depth; it is more common in cold-water coral biotopes, where it lives attached by byssus to coral branches and hardgrounds (eventually on mud), becoming dominant in hypoxic conditions ( Buhl-Mortensen & Høisaeter 1993; Poppe & Goto 1993; Ceregato et al. 2007; Oliver et al. 2016). The species was previously regarded as an exclusive characteristic element of the VP (bathyal mud) biocoenosis ( Pérès & Picard 1964; Di Geronimo 1979[a]; Di Geronimo & Bellagamba 1985). In the Santa Maria di Leuca CWC biotope, it was found on living and dead colonies of Madrepora oculata (Mastrototaro et al. 2010) , being common of framework-building coral, mollusk mud and foraminifer mud thanatofacies (Rosso et al. 2010).

Fossil record. D. vitreus is a common taxon in Pliocene and Pleistocene associations, often characterizing local paleocommunities along with other bathyal species, e.g. Kelliella miliaris ( Ceregato et al. 2007) ; it is frequently recovered from Pleistocene bathyal deposits of central and southern Italy ( Di Geronimo & Li Gioi 1980; Di Geronimo & Bellagamba 1985; 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).