Ng & Shokita, 1995
Carapace inflated laterally and longitudinally, dorsal surfaces smooth. Epigastric cristae very low; postorbital cristae distinct but not sharp, progressively stronger as it approaches lateral margin, confluent with epibranchial teeth. External orbital angle acutely triangular; separated from antero-lateral margin by distinct cleft. Antero-lateral margins strongly arcuate, epibranchial tooth distinct, blunt. Exopod of third maxilliped with vestigial flagellum. Suture between sternites 2 and 3 hardly discernible; all other sutures not visible; male abdomen reaching beyond an imaginary line joining bases of coxae of chelipeds. Male abdomen broadly triangular, telson slightly longer than segment 6. G1 relatively stout, gently sinuous; terminal segment short, ca. 0.2 times length of subterminal segment, gently curved outwards; base of terminal segment with bulbous structure on ventral surface; synovial membrane dorsal, broad. G2 with long distal segment ca. 0.3 times length of basal segment. (Ng & Shokita, 1995)
Type species: Nanhaipotamon yaeyamense Minei, 1973, by original designation.
Gender neuter.
Species treated:
Ryukyum yaeyamense (Minei, 1973)