Sakai, 1963
(Single species of genus, thus characters of genus are repeated:)
Carapace subquadrangular in shape, slightly longer than wide, surface convex, granulate, well areolated; individual areolae each having one or two low conical tubercles. Lateral carapace margins well defined, subparallel and armed with irregular teeth. Narrow frontal groove split in two posteriorly; cervical, postcervical grooves evident. Frontal carapace margin well produced anteriorly, cut into three teeth; median tooth small; lateral teeth broad and cristate; eyestalks short; eyes protected by well defined orbits. Sternal sutures 7/8 of female end well apart on low tubercles behind bases of second walking legs.
Antennule can be concealed inside orbit at base of eyestalk. Antennal flagella shorter than half of carapace width. All articles of antenna movable; first article (urinal) beaked medially and second article has an exopod firmly fixed. Third maxillipeds opercular, completely covering buccal cavern, separated at their bases by a plate at the same level as the sternum; basis and ischium of endopod fused but joint always marked by a shallow groove. Crista dentata present. Chelipeds robust, equal, stouter than walking legs. Last pair of legs very reduced; dactyl rudimentary, forming an obsolete chelate mechanism with an extension of propodus only in female. Branchial formula 19 gills + 7 epipods.
Abdomen of six segments and telson folded loosely under thorax; uropods comparatively small; effective abdominal locking mechanism absent. Both sexes have five pairs of pleopods, first pair vestigial in female, last three pairs rudimentary in male. First pair of male pleopods consist of a stout, setose semi-rolled tube with an apical plate; second pair needle-like bearing a linear row of tiny inset spines along anterior surface. (after McLay, 1999)
Type locality: west of Jogashima Light, Sagami Bay, Japan, 85 m.
Range: Gulf of Aden (McLay, 1999); Japan - off Jogashima (Sakai, 1963a, 1965b, 1976a), Misaki and Kii Minabe (Sakai, 1976a); Guam (McLay, 1999); Indonesia - Kepulauan Kai and Tanimbar (McLay, 1999); Chesterfield Islands (McLay, 1999); New Caledonia (McLay, 1999); Loyalty Islands (McLay, 1999); Norfolk Ridge (Guinot, 1993a); 1.5-402 m.