The systematics of the freshwater crabs (Decapoda: Brachyura: Potamidae) of southern China, and freshwater zoogeography of China

Freshwater crabs make up close to 20% of brachyuran diversity with over 1300 species. China is the most species rich country for freshwater crabs with two families, 49 genera and 321 species, yet there are still large areas that are unsurveyed for them. To fill in these blanks, multiple field surveys have been carried out during the last few years which have resulted in the accumulation of new distribution records and the discovery of 13 new species (Calcipotamon puglabrum, Cantopotamon hengqinense, Cantopotamon shangchuanense, Cantopotamon yangxiense, Cantopotamon zhuhaiense, Diyutamon cereum, Luteomon spinapodum, Megapleonum ehuangzhang, Nanhaipotamon macau, Qianguimon elongatum, Qianguimon splendidum, Yarepotamon meridianum, Yarepotamon fossor) and the establishment of seven new genera (Calcipotamon, Cantopotamon, Diyutamon, Eurusamon, Luteomon, Megapleonum, Qianguimon). These new taxa have since been described and are included herein. Freshwater crabs are also good candidates for biogeographical research due to their very limited dispersal abilities. The large scale freshwater zoogeographic bioregionalisation studies of China were revised. In order to study the freshwater zoogeographical areas of mainland China, a dataset of close to ten thousand distributional records of freshwater animals that covers 80% of the amphibians, 60% of the freshwater fish and 90% of the freshwater crab species of mainland China was compiled. According to the results from cluster analysis and network analysis, four subregions, three dominions and five provinces were found, of which one dominion and two provinces were newly proposed. In addition, the endemic areas of each animal group were individually studied and were all found to reflect the bioregionalisation at the subregion level but differed from each other in the dominion and province levels. The first quantitative, multi-taxon based bioregionalisation of the freshwater zoogeographic areas of mainland China is herein proposed