Chelicerata Heymons, 1901
Count: 2c;12o; †6o;2f;23g
   †Eurypterida Burmeister, 1843 - eurypterids
  Count: [†g] †21f;73g [26 Dec 2020]
     †Eurypterina Burmeister, 1843
    Count: [†g] †13f;42g [26 Dec 2020]
       Superfamily †Onychopterelloidea Lamsdell, 2011 [monotypic]
      Count: [†g] †1f;3g [25 Dec 2020]
         1 Family †Onychopterellidae Lamsdell, 2011
        Count: [†g] †3g [25 Dec 2020]