Revision of Yarepotamon Dai & Turkay, 1997 (Brachyura: Potamidae), freshwater crabs endemic to southern China, with descriptions of two new genera and four new species

The systematics of the poorly studied potamid genus Yarepotamon Dai & Turkay, 1997 is reviewed based on morphological and molecular data. The species in this genus are assigned to three separate genera: Yarepotamon sensu stricto, Qianguimon n. gen., and Eurusamon n. gen. Yarepotamon is restricted to Y. breviflagellum Dai & Turkay, 1997, Y. gracilipa (Dai, Song, Li & Liang, 1980), and two new species. Yuexipotamon arcophallus Huang, Mao & Huang, 2014 is revealed to be a junior synonym of Yarepotamon breviflagellum. Consequently, Yuexipotamon Huang, Mao & Huang, 2014 is also synonymized with Yarepotamon. A new genus, Qianguimon n. gen., is proposed for the clade that includes Yarepotamon aflagellum (Dai, Song, Li & Liang, 1980) and two new species described herein. A new monotypic genus, Eurusamon n. gen., is proposed for Yarepotamon guangdongense Dai & Turkay, 1997. Crabs of these three genera differ in the combination of character (third maxilliped, male pleon, male first gonopod, and vulvae) and adult size. Genetic data derived from the mitochondrial 16S rDNA support the monophyly of the six new taxa.