[viruses]
   Realm Riboviria
     Order Nidovirales
       Suborder Cornidovirineae [monotypic]
         Family Coronaviridae
           Subfamily Orthocoronavirinae
             Genus Gammacoronavirus
               Subgenus Igacovirus [monotypic]
                 Avian coronavirusᵀ