Terebratulina crossei Davidson, 1882

Davidson, 1882: 106, pl. 7, fig. 1; Konzhukova, 1957: 17–19, text-figs. 10–11, pl. 1, figs. 6–11.

Description. Shells are up to 46 mm in length, yellowish or cream, drop-shaped in plan, length is more than the maximum width. Anterior commissure of the valves is from rectimarginate (straight) to uniplicate (convex to brachial valve). Deltidial plates are narrow and disjunct to form open foramen. Cardinal process is large fun-shaped and overhangs anteriorly. Loop of brachial skeleton forms a ring stretching transversely with transversal band convexed to pedal valve. Numerous ribs are flat and their width is larger than the width of furrows between them.

Distribution. Widely distributed boreal Pacific species. It is known from the Gulf of Anadyr to Kii Strait (Japan) and to the Newport Bay (USA). A single specimen was found in the Sea of Japan: near Sakhalin coast at 49° N (Konzhukova, 1957).

Ecological data. The species lives at the depths of 110–375 m.

Remarks. Terebratulina crossei differs from two other far-eastern species (T. unguicola and T. kiiensis) in yellow or cream colour of the shells and in flat ribs.

References:

The World Register of Marine Species