On a new species of Chinapotamon Daiand Naiyanetr, 1994 and the first record of Chinapotamon pusillum (Song, 1984) and Songpotamon malipoense Shi, Pan & Sun, 2023 (Crustacea, Decapoda, Brachyura, Potamidae) from northern Vietnam

The presence of freshwater crabs of the genus Chinapotamon Dai & Naiyanetr, 1994 (Potamidae) in northern Vietnam was only recently established with the description of C. cf. depressum (Dai, Song, Li & Liang, 1980) from Cao Bang Province, and C. cf. pusillum (Song, 1984) and C. insulare Le, Dang & Do, 2024, from Quang Ninh Province (Le et al. 2024). Re-examination of the specimens referring to the first two species specimens in comparison with the holotypes and original descriptions of C. depressum and C. pusillum, revealed that C. cf. depressum represents a new species, herein named C. halangense sp. nov.

While C. cf. pusillum is confirmed to be C. pusillum, a recorda that represents a range extension for the latter species. Chinapotamon halangense sp. nov., can be distinguished from congeners by distinct carapace proportions and clear differences in male gonopod morphology. In addition, we report on the discovery of Songpotamon malipoense Shi, Pan & Sun, 2023, from Ha Giang Province in northern Vietnam.

As a result of these recent discoveries, Vietnam’s freshwater crab fauna now comprises 65 recognized species.