[viruses]
   Realm Riboviria
     Order Nidovirales
       Suborder Arnidovirineae [monotypic]
         Family Arteriviridae
           Subfamily Simarterivirinae
             Genus Thetaarterivirus
               1 Subgenus Kaftartevirus [monotypic]
               2 Subgenus Mitartevirus [monotypic]