Axinulus alleni (Carrozza, 1981)

Fig. 7 a–c

Thyasira alleni Carrozza, 1981 (p. 224, pl. 1, figs. 1–3).

Thyasira (Axinulus) alleni Carrozza, 1981 — Payne & Allen 1991 (p. 531, figs. 78–81). Thyasira alleni Carrozza, 1981 — Bonfitto et al. 1994 (p. 149, fig. 37); Repetto et al. 2005 (p. 308, mid left fig.).

Diagnostic characters. Obliquely subquadrangular shell; edentulous hinge; weak postero-dorsal radial depression; outer surface bearing growth lines only. Prodissoconch: shell type ST-2D; length about 120 µm; roundish D-shaped outline; convex profile; surface with irregular low wrinkles; rim-like shell lip barely separated from P-1; transition to the nepioconch well marked.

Occurrence. Box-corer sample BC72 (1 specimen). Height: 2.5 mm.

Distribution and habitat. Axinulus alleni ranges from NE Atlantic to West Africa (Morocco, Angola and Cape basins) and to the Mediterranean, as far east as the North Aegean Sea, dwelling on medium-fine, organic muddy sand from about 150 to over 1500 m depth (Carrozza 1981; Payne & Allen 1991; Salas 1996; Zenetos et al. 2005).

Fossil record. Upper Pleistocene of Sardinia (Bonfitto et al. 1994).