Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         [crown] Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           ?"viruses"
             Order Ortervirales
               Family Retroviridae
                 Subfamily Orthoretrovirinae
                   Genus Deltaretrovirus
                     1 Bovine leukemia virusᵀ
                     2 Primate T-lymphotropic virus 1
                     3 Primate T-lymphotropic virus 2
                     4 Primate T-lymphotropic virus 3