Euarthropoda †Lamellipedia see Superclass Lamellipedia Hou & Bergström, 1997 †Artiopoda Hou & Bergström, 1997 see Subphylum Artiopoda Hou & Bergström, 1997 †Conciliterga see Subclass Conciliterga Hou & Bergström, 1997 Genus †Helmetia Walcott, 1918 1 †Helmetia expansa Walcott, 1918