Genus Samacar Iredale, 1936 (Bivalvia: Arcidae) with descriptions of a new subgenus and two new species from the northern Pacific

A new subgenus, Pseudoporterius, of the genus Samacar Iredale, 1936, and two new species, Samacar (Samacar) kurilensis and S. (Pseudoporterius) aleutica, are described from the Kuril (depth 170-368 m) and Aleutian (depth 70-168 m) Islands. The new subgenus has no radial sculpture; the hinge plate is strongly curved, most concave and thin under beaks, strongly widening anteriorly and posteriorly, with horizontal anterior and posterior teeth separated by a very wide edentulous gap with three ligamental grooves. A direct development is inferred for the both new species. They have a very large (length to 640 µ for S. (Samacar) kurilensis and to 790 µ for S. (Pseudoporterius) aleutica), distinctly marked, bowler-shaped prodissoconch. Expanded descriptions of Samacar (Samacar) strabo (Hedley, 1915) are also given.