(de Man, 1895)
Male: Carapace trapezoidal, surfaces smooth; regions well defined; entire surface rugose to finely granulated; surface adjacent to antero- and postero-lateral margins lined with strong, oblique striae; antero-median surface with distinct Y-shaped groove. Front strongly deflexed downwards, margin bilobed, each lobe broadly convex, separated by shallow cleft. Supraorbital margin entire, separated from external orbital tooth by small but distinct cleft. Antero-lateral margin entire, with no trace of tooth. Postero-lateral margin strongly converging towards gently concave posterior carapace margin.
Ischium of third maxillipeds with shallow submedian sulcus; merus subovate with distinct median ridge which extends to antero-external angle of ischium; exopod slender, with long flagellum.
P1 unequal. Outer surface of larger chela strongly rugose, granulose and squamate; inner surface rugose, gently convex, not distinctly raised; dorsal margin of palm granuliform but without trace of ridge; fingers short, distinctly shorter than palm; dorsal margin of dactylus with row of 13-21 low but distinct transversely subrectangular granules, most distinct medially, blending with granuliform proximal part of finger and becoming very low and indistinctive distally, cutting edge with 3 submolariform teeth; propodus with 3 teeth; tips of fingers not pectinated, distinctly spatulate, inner surface deeply excavated. Smaller chela with outer surface strongly rugose, granulose, and squamate; fingers shorter than palm; cutting edges of both fingers with 3 teeth and numerous denticles, dorsal margin of dactylus with row of 13-21 low but distinct transversely subrectangular granules; tips of fingers not pectinated, distinctly spatulate, inner surface deeply excavated, margins slightly expanded. Outer surface of carpus squamiform to rugose; inner distal angle not distinctly produced, margins granulated. Outer margin of merus strongly convex, sublamelliform, granulated; inner margin strongly expanded distally, lamelliform margins lined with sharp granules of varying sizes, distal part visible from dorsal view even when chelipeds are apposed tightly against carapace; inner surface with oblique row of stiff setae. Basis and ischium separated by distinct suture. Ambulatory legs short, 2nd pair longest. Outer surfaces of merus, carpus, and propodus rugose to slightly squamate. Propodi glabrous or only with scattered long, simple setae. Meri laterally flattened, foliaceous, margins finely granulated; with sharp, subdistal dorsal spine; outer part of postero-distal margin strongly expanded, inner surface with deep concavity. Outer surface of corpus with 2 distinct carinae, lowest on the 4th carpus. Base of dactylus of all legs with 2 swollen lobes which fit swollen rounded knobs on posterior margin of propodus. Inner surface of coxae of 1st to 3rd ambulatory legs with ring of short to long setae; antero-ventral margin of 2nd and 3rd coxae with dense tuft of long setae.
Sutures and margins of anterior thoracic sternites strongly setose. Sternites 1 and 2 completely fused. Sternites 2 and 3 separated by suture which is distinct, interrupted medially, distinctly concave toward buccal cavity. Sternites 3 and 4 completely fused, relatively broad, abdominal cavity extending to just before anterior margin of fused sternites 2-4.
Abdomen triangular. Telson subcircular, lateral margins gently convex, tip rounded. Segment 6 with strongly arcuate latero-distal margins, proximal part almost straight.. Segment 3-5 progressively more trapezoidal. Segments 2 and 3 subequal in width. G1 almost straight from ventral view, relatively stout; distal part bent at about 45° outwards, pectinated. (Ng & Liu, 1999: 234)
Type locality: Banda Aceh, Sumatra.
Range: Sumatra - Banda Aceh (de Man, 1895b, 1898); Taiwan.