Takeda, 1989
Description of holotype: Carapace quadrate rather than hexagonal in its appearance, almost smooth, without hairs; dorsal surface uneven with indication of regions, but flattened as a whole; frontal region prominent, weakly convex dorsally, without median separation, being isolated from orbital region by a crescent linear furrow along orbit and from protogastric region by a transverse, shallow and wide furrow; protogastric region large, weakly convex in both directions; anterior extension of mesogastric region between protogastric regions narrow, and posterior main part small, rather depressed, not distinctly delimited from protogastric region; cardiac region transverse, bluntly ridged; branchial region provided with an obtuse low tubercle in a level of mesogastric region, weakly angulated at postero-lateral part in a level of cardiac region; posterior margin of branchial region narrowly ridged along carapacial posterior margin. Front well developed, protruded forward beyond inner angle of supraorbital margin, being only slightly less than breadth of carapace; in dorsal view its free margin almost truncated, but in oblique frontal view its submedian part is shallowly concave at each side of a median indistinct prominence. Supraorbital margin very oblique, narrowly raised laterally, with a trace of indentation at median part; external orbital angle not formed; eyestalk very short, and cornea very large, spherical, not accommodated in orbit for its most part. Lateral border of carapace only with an epibranchial tooth which is compressed and placed at anterior 2/3 and oblique as continuation of antero-lateral part of lateral border; posterior part obliquely truncated at outside of angular part of branchial region.
Antennule transversely folded in a fossa. Basal segment fills the orbital hiatus, its distal inner angle just reaching ventral prolongation of front; flagellum not excluded from orbit, its first segment just reaching inner angle of supraorbital margin. Third maxillipeds broad, completely close buccal frame; merus quadrate and not produced antero-laterally.
Male abdomen with seven distinct segments, comparatively wide, not rapidly tapering, with obtuse apex of last segment; third segment slightly less than sternal breadth between last ambulatory legs of both sides. Male genital opening sternal. First male pleopod as figured, with a branch of subdistal part recurved; second male pleopod subfiliform, as long as or slightly longer than the first.
Chelipeds comparatively heavy, similar but unequal in both sides; merus very short, its upper margin being medially armed with a blunt tubercle and rounded distally; carpus prominent, more or less compressed, with a high compressed tubercle at its inner angle; palm smooth, not long, higher distally, weakly compressed, with flattened outer surface and rounded upper margin; fingers also high, weakly curved inward, irregularly toothed on cutting edges, dark-coloured for their distal halves.
Four detached ambulatory legs slender, very sparsely fringed with hairs, microscopically granulated on margins. (Takeda, 1989)
Type locality: Oshima Passage, Amami-Oshima, Japan, 25-40 m.
Range: Japan - Amami-Oshima and Tanegashima (Takeda, 1989); 25-50 m.