[Phylum] [Arthropoda] Siebold, 1848 - arthropods Chelicerata Heymons, 1901 Euchelicerata Weygoldt & Paulus, 1979 Pantetrapulmonata Shultz, 2007 [Order] Schizomida Petrunkevitch, 1945 - schizomids Family †Calcitronidae Petrunkevitch, 1945 [monotypic] 1 Genus †Calcitro Petrunkevitch, 1945