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"
             Family Hepadnaviridae
               1.1 White sucker hepatitis B virus
               1.2.1 Tibetan frog hepatitis B virus
               1.2.2 Genus Avihepadnavirus
               2.1 Bluegill hepatitis B virus
               2.2 Genus Orthohepadnavirus