Chelicerata Heymons, 1901
Count: 2c;12o; †6o;2f;23g
   01 Pycnogonida Latreille, 1810 - pycnogonids
  Count: -
   02.1 Genus †Sanctacaris Briggs & Collins, 1988
  Count: -
   02.2 Euchelicerata Weygoldt & Paulus, 1979
  Count: [†g] †5g
   03 Xiphosura s. lat. Latreille, 1802 - horseshoe crabs see Class Xiphosura Latreille, 1802
  Count: 1c; †2f;13g
   04 †Chasmataspidida Caster & Brooks, 1956
  Count: [†g] †2f;10g [24 Dec 2020]
   05 †Eurypterida Burmeister, 1843 - eurypterids
  Count: [†g] †21f;73g [26 Dec 2020]
   06 Scorpiones Koch, 1837 - scorpions
  Count: [g†g] 15f;5g; †43f;92g [27 Dec 2020]
   07 Opiliones Sundevall, 1833 - harvestmen
  Count: [g†g] 49f;17g; †4f;22g [25 Jan 2021]
   08 †Phalangiotarbida Haase, 1890
  Count: [†g] †5f;19g [24 Dec 2020]
   09 Pseudoscorpiones De Geer, 1778
  Count: [g†g] 26f;22g; †1f;13g [8 Jan 2021]
   10 Solifugae Sundevall, 1833
  Count: [g†g] 12f; †6g [24 Dec 2020]
   11 Palpigradi Thorell, 1888 - palpigrades
  Count: [g†g] 2f; †2g [24 Dec 2020]
   12 Acari Leach, 1817 - mites and ticks
  Count: 2o
   13 Ricinulei Thorell, 1876 [monotypic] - ricinuleids
  Count: [g†g] 1f; †5f;7g [24 Dec 2020]
   14 Arachnida and/or Pantetrapulmonata Shultz, 2007
  Count: [†g] †4g
   15 †Trigonotarbida Petrunkevitch, 1949
  Count: [†g] †9f;37g [24 Dec 2020]
   16 †Uraraneida Selden & Shear, 2008
  Count: [†g] †1f;2g [23 Dec 2020]
   17 Araneae Clerck, 1757 - spiders
  Count: -
   18 †Haptopoda Pocock, 1911 [monotypic]
  Count: [†g] †1f;1g [23 Dec 2020]
   19 Amblypygi Thorell, 1883 - whip spiders
  Count: [g†g] 5f;1g; †1f;6g [23 Dec 2020]
   20 Uropygi Thorell, 1882 [monotypic] - whip scorpions see [unranked] Uropygi Thorell, 1882
  Count: [g†g] 1f; †7g [23 Dec 2020]
   21 Schizomida Petrunkevitch, 1945 - schizomids
  Count: [g†g] 2f;2g; †1f;4g [23 Dec 2020]