The freshwater crabs of Macau, with the description of a new species of Nanhaipotamon Bott, 1968 and the redescription of Nanhaipotamonwupingense Cheng, Yang, Zhong & Li, 2003 (Crustacea, Decapoda, Potamidae)

Abstract. Four species of freshwater crabs from three genera and two families (Cantopotamonhengqinense Huang, Ahyong & Shih, 2017, Nanhaipotamonguangdongense Dai, 1997, Nanhaipotamonmacausp. n., and Somanniathelphusazanklon Ng & Dudgeon, 1992) are documented from Macau for the first time. One new species, Nanhaipotamonmacausp. n., is described. The large flap on the male first gonopod terminal segment sets it apart from all other known congeners except N.wupingense Cheng, Yang, Zhong & Li, 2003, from Fujian. Characters of the carapace, male first gonopod and size, however, clearly differentiate these two species. Preliminary genetic studies also suggest that the two are not closely related. A neotype is designated for N.wupingense. The taxonomic status of Nanhaipotamonguangdongense is also discussed. Notes on the general biology and conservation status of these crabs are also included.