Sakai, 1969
One male specimen obtained from the Yoron Island, which was formerly reported by the author as N. richtersi de Man (loc. cit.) seems to be a distinct new species. The author examined the typical N. richtersi from Bikini Island by courtesy of Dr. J. S. Garth at the Allan Hancock Foundation, Los Angeles, and several male and female specimens from the Hawaiian Islands idenfitied by Edmondson, by courtesy of Dr. D. M. Devaney at the Bernice P. Bishop Museum, Honolulu.
The carapace is appreciably broader than long and the dorsal surface is thickly studded with granules of various sizes. The antero-lateral borders are well arched and distinctly cristate, cut into four teeth, of which the first and second are long and lobular, obscurely divided by an indistinct incision, while the third and fourth are dentiform, the former as long as the third and the latter very short. In typical N. richtersi, the antero-lateral borders are not arcuate but slender, the first and second teeth entirely united and the third and fourth are short. The margins of these teeth are studded with sharp granules and the crest is very narrow.
The frontal and upper orbital margins are also distinctly cristate, while in N. richtersi, they are not cristate at all.
The chelipeds resemble those of N. richtersi as does the black color of the immovable finger which extends onto the surface of the propodus, enclosing the distal portion of that segment.
The colouration of the fresh specimen is yellow as in N. richtersi, having a number of whitish spots of various sizes on the carapace.
The anterior male pleopod also resembles that of N. richtersi, having eight long and two or three shorter hairs at the distal portion.
Measurements: Length of carapace 12.5 mm, width of same 24.0 mm. (T. Sakai, 1969)
Type locality: Yoron-jima, Amami-shoto, Japan.
Range: Mauritius (Serène, 1984); Japan - Yoron-jima and Ishigaki-jima; shallow waters.