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).