Unrecorded crabs (Crustacea: Decapoda: Brachyura) from Taiwan and Tungsha Islands, with description of a new genus and species of Xanthidae. Zoological Studies 36(4): 261-276. The taxonomy of 20 species of brachyuran crabs representing 8 families from Taiwan and the Tungsha Islands (Prattas Islands) are reported. Of these, 16 are new records for this area: Paromola japonica Parisi, 1915, P. macrochira Sakai, 1961, Latreillopsis bispinosa Henderson, 1888 (Homolidae); Arcania elongata (Yokoya, 1933), Heteronucia laminata (Doflein, 1904) (Leucosiidae); Izanami curtispina (Sakai, 1961) (Calappidae); Heikea arachnoides (Manning and Holthuis, 1986), Ethusa sexdentata (Stimpson, 1858) (Dorippidae); Platymaia bartschi Rathbun, 1916. Cyrtomaia curviceros Bouvier, 1915, C. murrayi Miers, 1886 (Majidae); Cancer nadaensis Sakai, 1969 (Cancridae); Zalasius sakaii Balss, 1938, Forestia scabra (Odhner, 1925), Etisus splendidus Rathbun, 1906 (Xanthidae); and Ommatocarcinus pulcher (Barnard, 1950) (Goneplacidae). The taxonomy of 3 other species: Matuta victor (Fabricius, 1781), Ashtoret maculata (Miers, 1877) (Calappidae), and Platymaia remifera Rathbun, 1916 (Majidae) is clarified. One new genus and 1 new species (Pulchratis reticulatus) of Xanthidae are also described.