Key to species of genus Cryptodius Moore, 1992

(based on the characteristics of the dorsal armament of abdomen and on the structure of coxa 1)

1. Abdomen without dorsal carination (Fig. 10a)................................ Cryptodius unguidactylus Moore, 1992

- Abdomen with distinct dorsal carination (Figs. 10b, c)........................................................ 2

2. Pleonit 3 dorsal midline with gibbous hump, urosomite 1 with slight angular dorsal gibbosity, urosomite 3 bearing a single longitudional ridge on either side of the dorsal midline (Fig. 10b); coxa 1 convex anteriorly (Fig. 11i)........................................................................................... Cryptodius kelleri (Brüggen, 1907)

- Pleonite 3 and urosomite 1 with dorsal rectangular keel in posterior half of each, urosomite 3 dorsally with paired rounded keels (Fig. 10c), coxa 1 concave anteriorly (11j)....................................... Cryptodius sakhalinensis sp. nov.