Sakai, 1969
The carapace is subcircular in outline, a little longer than broad. There are ten prominent tubercles around the margin of the carapace, similar to the common Japanese species Arcania undecimspinosa de Haan. The dorsal surface is thickly studded with granules and provided with fifteen tubercles, of which three are in the median line, the last one being on the intestinal region near the posterior border and the others disposed symmetrically on the hepatic and branchial regions.
The front projects strikingly anteriorly and is bilobed. Each lobe ends in a process divided by a deep V-shaped median sinus. The outer orbital tooth is moderately strong. On the subhepatic region, there is a high tubercle, which can be seen from above just below the first marginal tubercle.
The chelipeds are slender; the merus is covered with longitudinal rows of granules; the fingers are a little longer than the propodus and are finely denticulated along the prehensile edge.
The terminal segment of the male abdomen is extremely long and narrow.
Measurements: Length of carapace in the median line 10 mm, width 8.5 mm. (T. Sakai, 1969)
Type locality: Manazuru Peninsula, Japan.
Range: Japan - Manazuru Peninsula (Sakai, 1969, 1976); China - Hainan Island (Dai & Yang, 1991); Western Samoa, Fiji (Galil, 2001a); intertidal to 9m.