Revision of the Chinese freshwater crab genus Tenuipotamon Dai, 1990 (Decapoda: Brachyura: Potamidae), with the description of a new genus from southwestern China

The taxonomy of the potamiscine freshwater crab genus Tenuipotamon Dai, 1990, which contains seven species, is revised. According to a concurrent molecular phylogenetic study, Tenuipotamon is paraphyletic, and is composed of two lineages. In this study, Tenuipotamon sensu stricto is restricted to its type species, T. purpura Dai, 1990, while a new genus, Pusillamongen. nov., is established to accommodate the remaining six species placed previously in Tenuipotamon sensu stricto (T. baishuiense Chen, 1993, T. huaningense Dai & Bo, 1994, T. panxiense Chen, 1993, T. tonghaiense Chen, 1993, T. xinpingense Chen, 1993, and T. yuxiense Chen, 1993). Diagnoses are provided for the two genera, which are both endemic to the topographically complex Hengduan Mountains Region of southwestern China.