Sakai, 1939
In general this new species is closely related to Pinnotheres tsingtaoensis Shen from Tsingtao, what is interesting, this species is found in freshwater bivalves, Yamato-sizimi or Corbicula japonica from Kagoshima Province.
The carapace is broad and roundish, the lateral borders are subparallel but the shoulders are weakly angular and the posterior border slightly convex. The front is moderately produced and the eyes may be observed in dorsal aspect. The external maxilliped has the dactylus slender and much exceeding the tip of propodus (in tsingtaoensis, this segment is distally broadened).
The immovable finger has four or five denticles near the base, the movable finger has a stout tooth near the base and its apex is strongly curved inwards. The anterior three pairs of ambulatory legs are subequal in length, the last pair conspicuously smaller. The anterior and posterior borders of all pairs are fringed with longish hairs but the carpus is not crossed by an oblique row of hairs contrary to Pinnotheres pholadis, which is also the nearest kin of this species. I could not examine the male specimen, but its seventh segment seems to be triangular according to Urita, who referred this species erroneously to P. pholadis. (T. Sakai, 1939: 591)
Type locality: Sendai-gawa, Kagoshima, Japan.
Range: Japan - Sendai-gawa, Satsuma (Urita, 1926a), Nagasaki (Sakai, 1939), Sendai-gawa, Kagoshima and Kikuchi-gawa, Kumamoto (Sakai, 1976a).