PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASfflNGTON 109(3):476-48L 1996. Daipotamon minos, a new genus and species of potamid crab (Crustacea: Decapoda: Brachyura) from a cave in China Peter K. L. Ng and Peter Trontelj (PKLN) Department of Zoology, National University of Singapore, Kent Ridge, Singapore 0511, Republic of Singapore; (PT) Department of Biology, University of Ljubljana, pp 95, Vecna pot 111, 6111 Ljubljana, Slovenia Abstract. — A new genus and species of potamid freshwater crab, Daipota-mon minos, is described from a cave in Guizhou Province, China. Daipotamon, new genus, is alhed to Sinopotamon Bott, 1967, and Tenuilapotamon Dai, Song, Li, Chen, Wang & Hu, 1984, but differs distinctly in the form of the male abdomen and first male pleopods. The freshwater crab fauna of mainland China is exceptionally diverse. Some 20 species and subspecies of potamid fresh-water crabs have been reported from Guizhou Province in mainland China (Dai et al. 1984, 1985; Dai & Yuan 1988, Dai 1990), although none have been reported from caves thus far. Between February and March 1995, a Slovenian-Chinese caving expedition made explorations of the karst caves in Libo County, southeastern Guizh-ou, China. Specimens collected from one of these caves proved to belong to a new genus and species of potamid freshwater crab. The present paper describes the new taxa. The specimens are deposited in the De-partment of Biology, University of Lju-bljana, Slovenia (ULB); Zoological Ref-erence Collection, Department of Zoology, National University of Singapore (ZRC); and Academia Sinica, Beijing, China (ASB). The abbreviations Gl and G2 are used for the male first and second pleopods (gonopods) respectively. The terminology adopted here essentially follows that used by Ng (1988). The synonymy of Sinopo-tamidae Bott, 1970, and Isolapotamidae Bott, 1970, under the Potamidae Ortmann, 1896, proposed by Ng (1988), is followed here. Family Potamidae Ortmann, 1896 Daipotamon, new genus Diagnosis. — Carapace broader than long, dorsal surface smooth, gently convex; epi-branchial tooth small, blunt; external orbital tooth broadly triangular. Exopod of third maxilliped reaching to mid-length of merus, flagellum long, extending beyond width of merus. Male abdomen broadly triangular; telson subequal in length to segment 6; lat-eral margins of segment 6 concave, telson deeply concave. Gl stout, relatively short; terminal segment short, tubular, gently bent inwards towards median part of thoracic sternum. G2 subequal in length to Gl; with distinct distal segment shorter than basal segment. Type species. — Daipotamon minos, new species, by present designation. Gender neuter. Discussion. — The establishment of a new genus is necessary because the type species, Daipotamon minos, new species, cannot be assigned to any known genus. Daipotamon, new genus, appears to be closest to Sino-potamon Bott, 1967 (type species Potamon davidi Rathbun, 1904) and Tenuilapotamon Dai et al., 1984 (type species Sinopotamon joshueinse Dai et al., 1975), with regards to the general morphology of the carapace and
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