[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Crustacea (Brünnich, 1772) - crustaceans see Superclass Crustacea Pennant, 1777
     Subclass Cirripedia Lamarck - barnacles and their kin see Infraclass Cirripedia Burmeister, 1834
       Superorder Thoracica Darwin, 1854
         Order Sessilia Lamarck, 1818
           Suborder Balanomorpha Pilsbry, 1916
             Superfamily Tetraclitoidea Gruvel, 1903
               Family Bathylasmatidae Newman & Ross, 1971
                 Subfamily Hexelasmatinae Newman & Ross, 1976
                   Genus Hexelasma Hoek, 1913