A new monotypic Phyllophoridae (Phyllophorinae) genus Phyllostauros, with author O’Loughlin, is erected for Thyone vercoi Joshua and Creed. We raise Phyllophorella Heding and Panning (subgenus of Phyllophorus Grube) to generic rank. The holotype and three paratypes of Phyllophorus ventripes Joshua and Creed are conspecific with Thyone vercoi Joshua and Creed. We make Phyllophorus ventripes Joshua and Creed a subjective junior synonym of Thyone vercoi Joshua and Creed. One paratype of Phyllophorus ventripes Joshua and Creed is conspecific with Phyllophorus thyonoides H. L. Clark. We reject the synonymy of Thyone okeni Bell with Thyone venusta Selenka. Twelve new species of Phyllophoridae are described for southern Australia, with author O’Loughlin: Lipotrapeza eichleri, Lipotrapeza litusi,Massinium melanieae, Massinium vimsi, Massinium watsonae, Phyllophorella notialis, Thyone flindersi, Thyone joshuai, Thyone kerkosa, Thyone spenceri, Thyone tourvillei, Thyonidiella kungi. Phyllophoridae species reported previously for southern Australia are reviewed: Lipotrapeza ventripes (Joshua and Creed); Lipotrapeza vestiens (Joshua); Neothyonidium dearmatum (Dendy and Hindle); Phyrella thyonoides (H. L. Clark); Thyone nigra Joshua and Creed; Thyone okeni Bell; Thyone vercoi Joshua and Creed. Species Phyrella thyonoides (H. L. Clark) is re-assigned to genus Phyllophorella Heding and Panning. A key is provided for the southern Australian species of Phyllophoridae. We acknowledge the rejection for nomenclatorial purposes by the ICZN (Opinion 417) of the publication by Oken 1815, and hence the current invalid statusof genus Thyone Oken. A petition has been sent to the ICZN for re-validation of Thyone Oken and we retain the use of Thyone Oken provisionally. The petition includes a similar request for re-validation of Psolus Oken.