Abstract

Seven species of ampithoid amphipods are reported from subtidal macroalgae living in Port Jackson, Sydney, Australia. In the genus Ampithoe the Indo–West Pacific species Ampithoe kava Myers, 1985, is recorded for the first time from Australia, and two new species, A. caddi, sp. nov. and A. ngana, sp. nov., are described. One new species ofCymadusa,C. munnu, sp. nov., is described. The genera Exampithoe (Melanesius), Peramphithoe and Plumithoe are recorded for the first time from Australian waters. The new species E. (M.) kutti, sp. nov. and Peramphithoe parmerong, sp. nov. are described, and Plumithoe quadrimana (Haswell, 1879b), comb. nov. is redescribed and a neotype is selected. New ecological and behavioural information is presented for these species. A new key and diagnoses for all known genera of Ampithoidae are presented. Paradusa Ruffo, 1969 is synonomised with Cymadusa Savigny, 1816.Exampithoe (Melanesius) gracilipes Ledoyer, 1984 is transferred to Exampithoe (Exampithoe) and Cymadusa uncinata Stout, 1912 and C. variata Sheard, 1936 are transferred to Paragrubia.