NOMEN: Opiliones Sundevall 1833: 12 [C.J. Sundevall. Conspectus Arachnidem. – Londini Gothorum, typus excudit C.F. Berling, Universitatis typographus, 1833: 1-39]
ORIGINAL LISTED MEMBERSHIP (Sundevall
1833):
Gonoleptes + Mitobater + Phalangium + Trogulus
+ Caeculus 
JUNIOR CIRCUMSCRIPTIONAL SYNONYM:
= Opilionina Siebold 1848
TYPIFIED NAME IN BASIC FORMAT: Phalangium/fg (sine Siro)
TYPIFIED NAMES IN USE:
MODERN
STATUS: 
the
oldest name of a holophyletic taxon.
Systematic position and classification of Opiliones:
| Phalangium/fg1 Anepignathi (or Siro/fg1) Temperophthalmi (or Siro/fg2) Tropicophthalmi (or Stylocellus/fg1) Opiliones (or Phalangium/fg2) Plagiostheti (or Phalangium/fg3) Eupnoi (or Phalangium/fg4) Dyspnoi (or Trogulus/fg1) Laniatores (or Gonyleptis/fg1) Insidiatores (or Travunia/f=Abasola/g1) Grassatores (or Gonyleptis/fg2) |
COMMENTS. The name Opiliones is often wrongly used for a wider taxon, which unites Opiliones with Anepignathi (or Siro/fg); actually, in the original publication (Sundevall 1833) the genus Siro was attributed not to the order Opiliones, but to the order Solifugae.
Some authors use the name Opiliones as a typified one: they change its ending and circumscription, retaining authorship. Indeed, the order Opiliones includes the genus Opilio, so the name Opiliones Sundevall 1833 looks as a typified name formed from Opilio/fg [f: Opilioninae Koch 1839; g: Opilio Herbst 1798, typus Phalangium parietinum De Geer 1778 (design. Simon 1879)]. However, Sundevall (1833) in his comprehensive revision of arachnid genera did not mention the genus Opilio; this means that he did not know this generic name (which was regarded to be a synonym of Phalangium) and formed the name Opiliones from the species name opilio Linnaeus 1758 [Phalangium]. If the name Opiliones would be a typified name formed from Opilio/fg, it would be regarded to be wrong, because the taxon under consideration includes the type of the older name – Phalangium/fg. As the name Opiliones is non-typified, it should be used as a circumscriptional one and, thus, applied only to a taxon Phalangium/fg2 (sine Siro), but not to Phalangium/fg1 (incl. Siro) – i.e. to a taxon which includes Eupnoi, Dispnoi and Laniatores, but not Anepignathi.