Kingdom Animalia Linnaeus, 1758 - animals Phylum Tardigrada Doyère, 1840 - tardigrades 1 Class Heterotardigrada Marcus, 1927 - armored tardigrades 2 Class Mesotardigrada Rahm, 1937, nom. dub. [monotypic] 3 Class Eutardigrada Richters, 1926 - naked tardigrades