[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Phylum Tardigrada Doyère, 1840 - tardigrades
     Order Heterotardigrada Marcus, 1927 see Class Heterotardigrada Marcus, 1927
       Family Stygarctidae Schulz, 1951
         1 Genus Megastygarctides McKirdy et al., 1976
         2 Genus Mesostygarctus Renaud-Mornant, 1979
         3 Genus Neoarctus Grimaldi de Zio et al., 1992
         4 Genus Parastygarctus Renaud-Debyser, 1965
         5 Genus Stygarctus Schulz, 1951