Sakai, 1969
Related to Leucosia obtusifrons de Haan, but this species may be easily distinguished from the former by its smaller size, the peculiarity of the colour markings of the carapace, and the different form of the anterior pleopod of the male. The outline of the carapace is typically circular and the dorsal surface evenly convex. On either side of the gastric portion, there is a pair of dark purplish markings of a rounded trilobular shape, in each of which there are three spots of light yellow, arranged fore and aft. The anterior spot is very small, the other two large and rimmed with much darker colouration.
The front is short, its anterior edge cut obtusely. The antero-lateral margins are rounded, obscurely lined with depressed granules near the junction of the antero- and postero-lateral borders. The thoracic sinus is very simple and circular, rimmed with about six beaded tubercles, its base pubescent, not tuberculated.
The anterior male pleopod is thickened near the distal portion and obtusely pointed, curved inwards and furnished with hairs on outer surface. (Sakai, 1976)
Type locality: Mimase, Tosa Bay, Japan.
Range: Japan - Mimase, Tosa Bay (Sakai, 1969).