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Petrunkevitch, A. I.
1949.

A study of Palaeozoic Arachnida. Transactions of the Connecticut Academy of Arts and Sciences, 37, 69-315.




Comments:

Petrunkevitch's scheme was based primarily on whether the prosoma-opisthosoma junction was broad (Latigastra), narrow (Caulogastra) or variable (Soluta) and the orientation of the chelicerae which hang down in one subclass (Stethostomata). He did not propose relationships between the orders. This scheme is significant as the fossil order Trigonotarbida makes its first appearance here, but its subclass Soluta can be criticised for being defined on what he believed to be a variable character (in fact it is restricted in all trigonotarbids).

Class ARACHNIDA

Subclass LATIGASTRA

Order SCORPIONES
Order PSEUDOSCORPIONES
Order OPILIONES
Order ARCHITARBI (=Phalangiotarbida)
Order ACARI

Subclass STETHOSTOMATA

Order HAPTOPODA
Order ANTHRACOMARTI

Subclass SOLUTA

Order TRIGONOTARBI

Subclass CAULOGASTRA

Branch LATISTERNA

Order PALPIGRADI

Branch CAMAROSTOMATA

Order THELYPHONIDA
Order KUSTARACHNAE (=opilionids)

Branch LABELLATA

Order PHRYNCHNIDIA (=Amblypygi)
Order ARANEAE

Branch CUCULLIFERA

Order RICINULEI

Branch ROSTRATA

Order SOLIFUGAE

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