Two new species of Dunkleosteus Lehman, 1956, from the Ohio Shale Formation (USA, Famennian) and the Kettle Point Formation (Canada, Upper Devonian), and a cladistic analysis of the Eubrachythoraci (Placodermi, Arthrodira)

New Dunkleosteus species and an explicit Eubrachythoraci matrix provide a documented sample nested within Arthrodira. The eubrachythoracid sample neither resolves all arthrodires nor sets the order's exact global first or last appearance.

Named Dunkleosteus material from the Upper Devonian formations provides a 372.15–358.86 Ma Famennian study-sample window inside Arthrodira; it does not delimit the order globally.

Two named Dunkleosteus species from Upper Devonian formations support a 372.15–358.86 Ma Famennian sample envelope; it is not an exhaustive genus-wide FAD or LAD.