Procaryotic Genera
   Domain "Bacteria" Woese et al. 1990
     Phylum Planctomycetes Garrity and Holt 2001 [monotypic]
       Class "Planctomycetacia" [monotypic]
         Order Planctomycetales Schlesner and Stackebrandt 1987 [monotypic]
           Family Planctomycetaceae Schlesner and Stackebrandt 1987
             Genus Pirellula Schlesner and Hirsch 1987