Euarthropoda †Lamellipedia see Superclass Lamellipedia Hou & Bergström, 1997 †Artiopoda Hou & Bergström, 1997 see Subphylum Artiopoda Hou & Bergström, 1997 †Xenopoda see Subclass Xenopoda Raymond, 1935 Genus †Sidneyia Walcott, 1911 †Sidneyia inexpectans Walcott, 1911