Early/Mid Silurian - Late Devonian | image = Dunkleosteus_terrelli_2.jpg | image_width = 200px | image_caption = Dunkleosteus attacking Gorgonichthys | regnum = Animalia | phylum = Chordata | subphylum = Vertebrata | infraphylum = Gnathostomata | classis = Placodermi | classis_authority = McCoy, 1848 | subdivision_ranks = Orders | subdivision = Antiarchi † Arthrodira † Brindabellaspida † Petalichthyida † Phyllolepida † Ptyctodontida † Rhenanida †… (More on Placodermi)