[Phylum] [Arthropoda] Siebold, 1848 - arthropods
   Chelicerata Heymons, 1901
     Euchelicerata Weygoldt & Paulus, 1979
       Pantetrapulmonata Shultz, 2007
         [Order] †Haptopoda Pocock, 1911 [monotypic]
           Family †Plesiosironidae Pocock, 1911 [monotypic]
             1 Genus †Plesiosiro Pocock, 1911