The cladtstic framework for the description of arthrodires is further revised, and a new genus of eubrachythoracid, Torosteus gen. nov, is described from the Upper Devonian Gogo Formation of Western Australia. The structure and relationships of the genus are discussed. The two species T. tuberculatus sp. nov and T. pulchellus sp. nov. are placed in the new family Torosteidae which is the sister group of the Camuropiscidae + Incisoscutum.