(Takeda & Miyake, 1968)
Male: Carapace broader than long, hexagonal, regions relatively well defined, grooves demarcating regions relatively broad, distinct; 2F separate, 2F fused with 1M, 2M entire, 2M and 3L fused, 5L and 4L separate; dorsal surface gently convex transversely and longitudinally; regions covered with small, rounded granules, especially 2F, 1M, 2M, 3M, 2L, 3L; scattered simple and plumose soft setae present along margins of anterior regions and subbranchial regions. Antennules folding almost transversely, margins of antennulary fossae and interantennulary septum lined with small granules. Basal antennal segment large, subrectangular, distal surface gently granulated, does not enter wide orbital hiatus; flagellum directed anteriorly, not entering orbits, base normally lodged between outer lobe of frontal margin and inner supraorbital tooth. Epistome relatively broad; posterior margin strongly sinuous, trilobed; median lobe triangular, with deep median fissure, tip bifid; lateral lobes rounded, margins lined with small granules. Subhepatic suborbital and pterygostomial regions distinctly granulated; subbranchial region weakly granulated; pterygostomial, subbranchial and postero-lateral regions covered with dense, long soft setae. Frontal margin projects slightly anterior of orbits, quadrilobed, margin granulated, lined with simple and plumose setae; inner lobes broad, subtruncate, separated by deep V-shaped cleft, outer lobes acutely triangular, separated from inner lobes by broad cleft. Supraorbital margin lined with large rounded granules, with distinct median cleft and less distinct lateral cleft (sometimes obscured by granules); inner supraorbital tooth distinct, acutely triangular, forming V-shaped structure with adjoining (at base) outer frontal lobe. Infraorbital margin granulated, inner tooth well developed, acutely triangular to subtruncate, sometimes lined with accessory granules, visible when viewed from above. External orbital tooth broadly triangular, lined with granules; subhepatic region with broad, granuliform tooth which is obliquely fused with external orbital tooth, clearly visible dorsally. Rest of antero-lateral margin convex, with three teeth, separated by distinct clefts, margins lined with accessory granules; first antero-lateral tooth broadly triangular; second and third antero-lateral teeth acutely triangular, subequal in size (second tooth usually slightly smaller). Postero-lateral margin strongly converging towards almost straight posterior carapace margin.
Merus of third maxilliped squarish, surfaces gently granular, antero-external angle slightly produced; ischium rectangular, with shallow, submedian sulcus, inner margin serrated, lined with long, submarginal stiff setae; exopod relatively broad, margin subparallel, distal end almost reaching distal edge of merus, flagellum long. Endostome without trace of longitudinal ridges.
Chelipeds unequal, outer surfaces granular; with scattered long, simple and plumose soft setae which partially obscure outline; inner margins of basi-ischium and merus distinctly granular; carpus with strong rounded tooth on inner distal angle, margin proximal to basal tooth lined with one to three granules. Outer surface of larger palm, especially upper two-thirds with distinct rounded granules; fingers relatively stout, about half length of palm, cutting edges with several rounded teeth, tips with deep excavation, spoon-shaped structure distinct; both fingers completely pigmented black, with pigmentation on pollex reaching into distal one-third of inner and outer surfaces of palm; dactylus with distinct submarginal sulcus on outer margin, proximal surface with numerous small granules, inner and outer surfaces with several tufts of long setae, those along inner margin and near tip longest and densest; pollex with weak submarginal sulcus on outer margin, inner and outer surfaces with several tufts of long setae. Outer surface of smaller palm uniformly covered with rounded granules; fingers relatively stout, longer than half length of palm, cutting edges with several rounded teeth; tips with deep excavation, spoon-shaped structure distinct; both fingers completely pigmented black, with pigmentation on pollex reaching into distal half of inner and outer surfaces of palm; dactylus with submarginal sulcus on outer margin, proximal half with numerous small granules, inner and outer surfaces with several tufts of long setae; pollex with deep submarginal sulcus on outer margin which extends into palm, inner and outer margins with several tufts of long setae.
Ambulatory legs relatively short, first leg longest, outer surfaces covered with small granules to almost smooth, margins of all segments lined with long, simple and plumose soft setae which obscures outline; merus short, non-cristate, proximal ventral margin appears serrate, lined with numerous sharp granules; dorsal margins of carpus and propodus uneven but neither serrated nor distinctly granular; dactylo-propodal articulation present, formed by a large, rounded submedian extension of the lateral margin of the propodus, shaped to slide beneath a projecting button on the subproximal edge of the dactylus; dactylus gently curved, gradually tapering until sharply tapering distal part, dorsal margin lined with numerous sharp granules, non-pectinated distal spine large, pectinated spine subdistal in position, distinctly smaller than non-pectinated distal spine.
Anterior thoracic sternum relatively narrow, covered with numerous small granules, especially along margins, sutures and anterior surfaces; sternites 1 and 2 completely fused, no trace of sutures; suture between sternite 2 and 3 straight, very deep; sternites 3 and 4 separated by shallow groove, no suture line discernible; sternite 4 with distinct median longitudinal suture; male abdomen reaching to about one-third length of sternite 4. Abdominal cavity (and tip of telson) reaching to about one-third length of sternite 4.
Abdomen five-segmented, with segments 3-5 completely fused, completely immovable, without trace of sutures even laterally; segment 1 broad laterally, constricted medially; lateral surfaces gently granulated; segment 2 broadest medially, lateral margins gently granulated; surface of fused segments 3-5 smooth, with lateral parts of segment 3 gently granulated, segment 3 trapezoidal, segments 4 and 5 rectangular; segment 6 subrectangular, lateral margins gently concave; telson semicircular, shorter than segment 6, lateral margins gently convex outwards.
G1 slender, broadly C-shaped, distal part turned outwards; ventral distal margin with long plumose setae; dorsal distal margin with numerous sharp tubercles; tip with two long, simple subdistal setae. G2 relatively short, basal segment slender, broadly C-shaped; distal segment spade-like. (Ng & Yang, 1998)
Type locality: Amami-Oshima, Japan.
Range: Japan - Amami-Oshima (Takeda & Miyake, 1968d); South China Sea - Paracel Islands (Ng & Yang, 1998).