Takeda & Kurata, 1977
Description of holotype: Carapace rather ovate, weakly declivous anteriorly and nearly flat laterally and posteriorly, dorsum being glabrous without fur and distinct indication of regions. Antero-lateral border convex, narrowly crested and divided into four lobes; the first confluent with external orbital angle which is not produced at all; the second as long as the first, but the following two smaller; anterior ends of second to fourth lobes angulated. Postero-lateral border not distinctly delimited from last antero-lateral lobe, but generally shorter than antero-lateral border.
Frontal border one-third as broad as carapace and nearly truncated, bearing a small median interruption. Frontal regions side by side weakly convex and surrounded laterally and posteriorly by narrow and indistinct furrows. Supraorbital border microscopically roughened, and infraorbital border more or less sinuate in the middle, slightly roughened near a notch below external orbital angle. Infraorbital inner end not produced at all. Eyestalk bulged basally and constricted at base of cornea, being tightly embedded in orbit. Antennal basal segment short and not reaching front. Antennal flagellum exceed twice the length of major diametre of orbit.
Third maxilliped broad and glabrous; inner margin of ischium sharp without fringe of hairs; merus subquadrate with weakly raised median surface and with antero-external angle ventrally curved and only slightly angulated.
Chelipeds heavy and unequal, the right being the larger. Merus short and its whole inner surface excavated and armed with several conical granules of good size both on its anterior and posterior borders. Carpus large and glabrous only with minute conical granules and short soft shaggy hairs along its inner anterior border, its inner angle being more or less tuberculated with several long stiff setae. Palm high and entirely smooth; its inner upper part weakly crested along its nearly whole length and lower border along its proximal half. Fingers stout and sharply toothed on cutting edge; in both chelae basal part of immovable finger fairly bulged; in smaller chela proximal upper part of movable finger granulated.
Ambulatory egs slender and fringed with rather sparse silky hairs of various lengths; third pair much longer than the others, and the first and fourth subequal to each other and shorter than the second. Anterior borders of meri of first to third pairs armed with series of granuliform tubercles or conical granules throughout their lengths, but in merus of last pair anterior border only indistinctly roughened proximally and nearly unarmed. Dactylus of last pair distinctly depressed and weakly curved upward near its horny tip. (Takeda & Kurata, 1977)
Type locality: Nishino-shima-shinto, Ogasawara-shoto, Japan.
Range: Japan - Ogasawara-shoto (Takeda & Kurata, 1977).