Diagnosis (emended after Lehman, 1956: 25–26). A genus of Dunkleosteidae characterized by its large size, well-developed orbit, a skull roof where the marginal and central plates are in direct contact with each other, the development of a concave posterior border on the nuchal plate, an externally visible shallow embayment of the central plate by the postorbital plate, and a complex ginglymoid articulation between the paranuchal plate of the skull roof and the anterior dorsolateral plate of the thoracic armour. A lack of sensory line grooves on the anterior median ventral and anterior ventrolateral plates, and a small spinal plate that is strongly bent, are characteristic of the thoracic armour. The gnathal plates consist of an inferognathal, with a well-developed anterior cusp and acute posterior occlusal region, and paired anterior superognathals that articulate with the parasphenoid bone (following Dunkle & Bungart, 1946, i.e. their terrelli group). The anterior superognathal– parasphenoid contact is expanded to include two styles of articulation on the parasphenoid bone: either contact surfaces (with a reinforced thickening of the prehypophysial region) or transverse facets.