Chelicerata Heymons, 1901
   Palpigradi Thorell, 1888 - palpigrades
     1 Genus †Paleokoenenia Rowland & Sissom, 1980
     2 Family Eukoeneniidae Petrunkevitch, 1955 [monotypic]
     3 Family Prokoeneniidae Condé, 1996