Four new genera of leucosiid crabs (Crustacea: Brachyura: Leucosiidae) for three new species and nine species previously in the genus Randallia Stimpson, 1857, with a redescription of the type species, R-ornata (Randall, 1939)

A study of the leucosiid genus Randallia Stimpson, 1857, led to the description of four new genera: Tanaoa, for R. distincta Rathbun, 1893, R. pustulosa Wood-Mason, in Wood-Mason & Alcock, 1891, and a new species, T. nanus; Tokoyo for R. eburnea Alcock, 1896, and a new species, T. cirrata; Toru for R. granuloides Sakai, 1961, R. trituberculata Sakai, 1961, R. pila Tan, 1996, R. mesjatzevi Zarenkov, 1990, and a new species, T. septimus; and Urashima, for R. lamellidentata Wood-Mason, 1892, and R. pustuloides Sakai, 1961. Randallia is restricted to its type species, R. ornata (Randall, 1839), and provisionally 12 other species currently placed in this genus pending further revision. All new genera are diagnosed and species assigned to them described or redescribed and illustrated; extended synonymies are given, and a key for species identification is provided. The type species, R. ornata, is redescribed.