Kingdom Animalia Linnaeus, 1758 - animals Phylum Arthropoda Siebold, 1848 - arthropods Superclass Tardigrada Doyère, 1840 see Phylum Tardigrada Doyère, 1840 Class Eutardigrada Richters, 1926 - naked tardigrades Class Heterotardigrada Marcus, 1927 - armored tardigrades