Order – Pseudoscorpionida (British Species)
There are 29 species in Britain & Ireland. They are an extremely under-recorded and difficult to identify group.
Family – Chthoniidae
Chthonius ischnocheles (Common Chthoniid)
Kewochthonius haiberti (Halbert’s Chthoniid)
Chthonius halberti (Kew’s Chthoniid)
Chthonius tetrachelatus (Dimpled-clawed Chthonid)
Chthonius tenuis (Dark-clawed Chthoniid)
Chthonius orthodactylus (Straight-fingered Chthoniid)
Microbisium brevifemoratum (Bog Neobisiid)
Neobisium carcinoides (Moss Neobisiid) ✓
Neobisium carpenteri (Carpenter’s Neobisiid)
Neobisium maritimum (Shore Neobisiid)
Roncus lubricus (Reddish Two-eyed Neobisiid)
Roncocreagris cambridgei (Cambridge’s Two-eyed Chelifer)
Neobisium simile (Quarry Neobisiid)
Family – Cheiridiidae
Cheiridium museorum (Book Chelifer)
Family – Chernetiidae
Lamprochernes nodosus (Knotty Shining Claw)
Lamprochernes savignyi (Savigny’s Shining Claw)
Lamprochernes chyzeri (Chyzer’s Shining Claw)
Chernes cimicoides (Common Tree-Chernes)
Dendrochernes cyrneus (Large Tree-Chernes)
Dinocheirus panzeri (Terrible-Clawed Chernes)
Pselaphochernes scorpioides (Compost Chernes)
Pselaphochernes dubius (Small Chernes)
Allochernes powelli (Powell’s Chernes)
Allochernes wideri (Wider’s Tree-Chernes)
Family – Cheliferiidae
Chelifer cancroides (House Chelifer)
Dactylochelifer latreillii (Marram Grass Chelifer)
Larca lata (Oak-tree Chelifer)
Withius piger (Lazy Chelifer).
The above list is from https://www.chelifer.com/?page_id=81