Sea star (Clark, 1901) in the northwestern Pacific: one species or three?

Three species of the sea stars are reported from the waters of the northwestern Pacific. These species were referred by earlier authors as or . Two of them, and , were recently described from the Aleutian Islands. These species are reported for the first time from the western Pacific (southeastern Kamchatka shore, Commander Islands, and the northern Kurile Islands). The third species, sp. n. is herein described from the northern Sea of Japan. It is very likely that similar sea stars recorded in Yellow Sea and the southern Kurile Islands belong to sp. n. These three species are a part of a phylogenetic clade within the subgenus , which also includes and several undescribed species occurring in the northeastern Pacific.