Sakai, 1939
This new species differs from all other known species of this genus on account of its four-lobed antero-lateral borders, i.e. the external orbital angle is very small and followed posteriorly by three rounded lobes, the last one of which is again most inconspicuous. The dorsal surface of carapace is very feebly vaulted down near the frontal and lateral margins but the remaining posterior half is flat. The two epigastric lobes and the supraorbital ridges are obscurely demarcated; the frontal margin indistinctly bilobate. The eyestalks not much stouter and the infraorbital ridge bearing about 11 tubercles.
The exognath of the external maxillipeds is much broader than the ischium of the endognath, the merus pronouncedly auriculated and broader than long. Arm and wrist of chelipeds unarmed, the chela bears a thick tuft of hairs at the base of the outer surface as usual, the fingers much gaping at the base and their prehensile edges armed with very flat and low teeth. The terminal segment of male abdomen very narrow and moderately elongate, the penultimate segment obliquely cut on either side near the distal end. (T. Sakai, 1939: 661)
Type locality: Tan-shui, Taiwan.
Range: Japan - Sagami Bay (Sakai, 1955a, 1976), Hachijo-jima (Sakai, 1976a); Taiwan - Tan-shui (Sakai, 1939, 1976, Lin, 1949), Lan-Yü (Muraoka, 1998).