Abstract A new minute anthurid isopod, 2.7 mm long, is described. It is notable ina uropod with almost cylindrical terminal rami, lacking the typical anthuroid uropodal structure in which the flattened exopod is attached to the peduncle dorsolaterally and more proximal to the terminal endopod. The species has all the other features of Anthuroidea (cylindrical body, mandibular spine row absent or evident as lamina dentata, maxilla 2 fused with the lower lip as a hypopharynx) and many features of the family Anthuridae (paired statocysts, fused pleonites, compact mandible, pereopods 2 and 3 propodus with single palmar robust seta) and is placed in this family as a new genus and species, Leipanthura casuarina, close to Anthura, Exallanthura and Ptilanthura. Leipanthura casuarina is also unusual in lacking pereopod 7 in the adult.