Rissoella Chira Siadén & Wakeman & Webb & Hasegawa & Kajihara 2019

Rissoella sp. 1 (Figs 3J, 3K) Material examined. Two mature specimens: ICHUM RSH 4001, RSH 4002; Shakotan, Hokkaido, Japan, 43°18′06.2″N 140°35′55.6″E, 25 August 2017. Both specimens were used for DNA extraction. For further information on specimens collection locality and GenBank accession numbers see Table 1. Remarks. Shell minute, thin, fragile, translucent or whitish, elongate. Head–foot translucent white; with very short round oral lobes, long cephalic tentacles with tapering tip, translucent as well. Mantle pigmented in light brown with three or four big yellowish asymmetrical patches. Big black patch, with few small whitish blotches inside, centrally placed on the dorsal portion of body whorl. Visceral mass dark brown to black, with several elongate whitish blotches (Figs. 3J, K). Distribution and microhabitat. Found in Shakotan, Hokkaido, Japan; in the subtidal zone on red algae Gelidium spp.