Abstract: This paper provides a systematic overview of the Australian Meranoplus F. Smith, 1853 fauna, estimated to contain 400 species, with the great majority undescribed. Most species occur in arid and semi-arid regions, but the genus is also very rich in the monsoonal tropics. I recognise 18 informal species groups of Australian Meranoplus, within seven putative radiations (equivalent to subgenera). All the radiations (M. diversus F. Smith, 1867, M. excavatus Clark, 1938, M. fenestratus F. Smith, 1867, M. hirsutus Mayr, 1876, M. similis Viehmeyer, 1922, M. testudineus Mcareavey, 1956 and M. group A radiations) are proposed for the first time. The M. diversus, M. dimidiatus F. Smith, 1867, M. hirsutus and M. testudineus groups are the same as those described in Andersen (2000), as are groups A, C, D, and F. Groups B and E of Andersen (2000) are now respectively referred to as complexes of the M. testudineus group and group C, and the M. mjobergi Forel, 1915 group of Andersen (2000) is now considered to be a complex within the M. fenestratus group. The M. armatus F. Smith, 1862, M. excavatus, M. froggatti Forel, 1913, M. minimus Crawley, 1922, M. puryi Forel, 1902, and M. similis groups, and groups B, E and G, are proposed for the first time. Two of the seven radiations also occur in the southern Asian and African regions, whereas the others (containing over 85 % of total species) are exclusively Australian, with occasional extensions into Papua New Guinea and eastern Indonesia. Keys are provided to informal species groups, and to species complexes within each group. More detailed, species-level information is provided for the M. diversus group of specialist seed harvesters, supplementing the recent revision by SCHÖDL (in press).