Takeda, 1977
Description of holotype: Carapace broader than long, with lateral expansions, being not so markedly convex; dorsum nearly smooth to unaided eye, but with enlargement quite thickly paved by minute, flat vesicular granules; regions barely traceable except for intestinal region which is moderately convex; a small prominence on protogastric part; median gastric and cardiac parts traceable, but not distinct, being shallowly separated from intestinal region; hepatic region indistinctly surrounded by a shallow wide depression, but not convex dorsally as well as laterally.
Frontal region moderately raised and weakly convex dorsally, without median sulcas; its free margin nearly truncated in dorsal view, but on close examination median part very weakly concave, and in frontal view this concave median part perpendicularly deflexed as an anterior part of antennular septum, being not pointed distally.
Antero-external end of buccal frame more or less angulated. Pterygostomial margin armed with a small conical protuberance. Margin between antero-external angle of buccal frame and pterygostomial protuberance more or less ridge-like and forms true margin of carapace in dorsal view. Margin behind pterygostomial protuberance weakly concave and then convex as anterior slope of lateral expansion of carapace; tip of lateral expansion convex, but not sharp; posterior slope of lateral expansion weakly concave, ending in a postero-lateral dorsal convexity; margin behind this convexity about half the length of posterior slope of lateral expansion, being rapidly convergent. Antero-lateral border of posterior margin of carapace nearly as long as margin behind the convexity mentioned above, directing toward epimeron; lateral end of posterior border rather rounded, and posterior border almost straight.
Orbit shallow, with two supraorbital and one infraorbital small notches. Third maxilliped thickly covered with minute pearly granules; inner margin of ischium only slightly longer than merus, and slightly wider than exopod; a small protuberance at distal end of ischium, and a similar one at proximal end of merus; in natural position merus convex ventrally as a whole at its proximal half.
Left cheliped, left second and fourth, and right third and fourth ambulatory legs missing. Right cheliped rather slender and wholly covered with vesicular granules so as to be somewhat scabrous. Merus armed with a conical tubercle at proximal one-third on anterior margin and three at median part on posterior margin, and distal end of posterior margin weakly angulated. Carpus small and weakly convex at the middle of outer margin. Palm moderately inflated proximally, with a longitudinal shallow furrow along outer margin. Fingers as long as palm and straight, but immovable finger not in a straight line with palm; cutting edges minutely, sharply and irregularly toothed throughout their length.
Ambulatory legs slender, roughly granulated and more or less scabrous except for dactyli, being unarmed at all. In each pair dactylus as long as propodus. Only three pieces of abdomen observable; first linear segment may be hidden under carapace; terminal segment more or less oblong, with subacute apex, nearly reaching tip of sternum between third maxillipeds of both sides.
Unfortunately, all the chelipeds and ambulatory legs are missing in the female paratype which is larger than the holotype. In general the carapace agrees with that of the holotype, but a minute protuberance is traceable at the posterior part of the median gastric region, and the antero-external part of the buccal frame and the pterygostomial margin are not angulated at all.
In each of the juvenile specimens, the carapace is uneven with the more accentuated prominences. In the female two protogastric and one median gastric prominences are rather tuberculated. In the female and the smaller male, but not in the larger male, an additional prominence is present on the branchial region, and on the contrary a prominence is present on the intestinal region in the larger male, but not in the female and the smaller male. In all the juvenile specimens the hepatic margin is more or less ridge-like, but not protruded beyond the angulated pterygostomial margin in dorsal view.
In the female and the smaller male the lateral expansion is rather angulated as in the adult, but that of the larger male is sharper and armed with a spinule which is curved dorsally. The male abdomen is comparatively wide, with four pieces; a transverse prominence at the fused segment is very small; the terminal segment is not long, being about one-fourth the length of the fused segment. The first and second male pleopods may be not fully developed, but the second is without doubt filiform and longer than the first.
In life, the carapace, chelipeds and ambulatory legs are entirely white except for the smaller juvenile male which is brownish. (Takeda, 1977d)
Type locality: Ogasawara-shoto, Japan.
Range: Japan - Ogasawara-shoto (Takeda, 1977d).