Dacrydium hyalinum (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 : 24

Dacrydium hyalinum (Monterosato, 1875)

Fig. 4 g–i

Mytilus (Dacrydium) hyalinus Monterosato, 1875 [a] (p. 10).

Dacrydium hyalinum (Monterosato, 1875) — Nordsieck 1969 (p. 30); Mattson & Warén 1977 (p. 1, figs. 3, 9); Salas & Gofas 1997 (p. 266, figs. 20–24); Önen & Doğan 2007 (p. 236, fig. 3).

Dacrydium cf. hyalinum Monterosato, 1875 — Salas 1996 (p. 53, figs. 91–93).

Dacrydium hyalinum Monterosato, 1875 — Giannuzzi-Savelli et al. 2001 (p. 132, figs. 236–238); Repetto et al. 2005 (p. 294, mid right fig.); Peñas et al. 2006 (p. 140, figs. 389–395).

Diagnostic characters. Much higher than long, bean-shaped shell; small beaks; very short anterior side; convex antero-ventral margin nearly parallel to the postero-dorsal one. Prodissoconch: shell type ST-2D; length about 170 µm; roundish D-shaped outline; convex profile; P-1 surface pitted, with roughly commarginal, irregular wrinkles; rim-like metamorphic lip barely separated from P-1; transition to the nepioconch well marked.

Occurrence. Box-corer sample BC72 (4 specimens); core BC72 (2). Maximum height: 2 mm.

Distribution and habitat. Dacrydium hyalinum appears to be endemic of the Mediterranean Sea, from the western basin to Turkey, although similar forms have been reported from some North Atlantic seamounts; it occurs on circalittoral to bathyal hard bottoms (frequently corals), as well as on mud and sand ( Nordsieck 1969; Salas & Gofas 1997; Önen & Doğan 2007).

Fossil record. Bathyal Pleistocene of Sardinia ( Di Geronimo & Bellagamba 1985).

Figures

FIGURE 4. a – c: Bathyarca pectunculoides (Scacchi, 1835); RV (a, b) and LV (c), sample BC 72, scale bars: 1 mm (a – b), 0.1 mm (c, prodissoconch); d – f: Bathyarca philippiana (Nyst, 1848); LV, sample BC 04, scale bars: 2 mm (d – e), 0.1 mm (f, prodissoconch); g – i: Dacrydium hyalinum (Monterosato, 1875); LV, sample BC 72, scale bars: 1 mm (g – h), 0.1 mm (i, prodissoconch); j – m: Pseudamussium peslutrae? (Linnaeus, 1771); LV, sample BC 67, scale bars: 2 mm (j – k), 0.1 mm (l, prodissoconch), 0.05 mm (m, P – 1 detail); n – q: Karnekampia sulcata (Müller, 1776); RV (o – q) and LV (n), sample BC 72, scale bars: 5 mm (n – p), 0.1 mm (q, prodissoconch).