living organisms
 see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
  
 Superkingdom Eukaryotae
 see Domain Eukaryota Chatton, 1925
    
 Kingdom Animalia Linnaeus, 1758 - animals
      
 Subkingdom Eumetazoa Butschli, 1910
 see [unranked] Eumetazoa Bütschli, 1910
        
 Phylum Nemata Cobb, 1919
 see Phylum Nematoda Gegenbaur, 1859
          
 Class Secernentea Von Linstow, 1905
            
 Subclass Spiruria
 see Subclass Plectia Hodda, 2007
              
 Order Spirurida Railliet, 1914
                
 Suborder Spirurina Railliet & Henry, 1915
                  
 Superfamily Physalopteroidea Railliet, 1893
 see Superfamily Camallanoidea Railliet & Henry, 1915
                    
 1 Family Physalopteridae Railliet, 1893
                    
 2 Family Gnathostomatidae Railliet, 1895