Rathbun, 1909
This small species, the monotypical representative of the genus Mortensenella, is generically characteristic in having the broad third maxillipeds filling the buccal cavity, with the fused ischium and merus leaving only a faint suture line at its median part, and also with the distal three segments articulating end to end. The diagnostic features characteristic of this species are briefly noted in the following lines.
The carapace is narrowly elliptical, with the regularly convex lateral borders minutely crenulated along its whole length; the dorsal surface smooth and weakly convex in both directions, without areolation except for a median transverse furrow separating the gastric and cardiac parts. The male chelipeds of both sides are same and comparatively heavy for the small carapace, with both fingers leaving a wide gape armed with a conical tooth at each edge and meeting at the sharp horny tips. The male abdomen is seven-segmented and constricted at the fifth segment. The male first pleopod is curiously formed and of generic value, being shaped like a bean bud; the basal segment is slender with the suture on lateral margin; horny endpiece is oval and swollen, recurved towards the base along the lateral margin of basal segment, with suture inside the mesial part of the tip. (Sakai K. & Takeda, 1995: 208)
Type locality: Koh Chang, Thailand.
Range: Japan - Amami-Oshima (Sakai & Takeda, 1995); China - Hainan Island (Dai et al., 1980, Dai & Yang, 1991), Hong Kong (Manning & Morton, 1987); Thailand - Koh Chang (Rathbun, 1909).