[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990 stat. inval. see Domain Bacteria Woese et al. 2024
     Phylum "Spirochaetes" Garrity and Holt 2001 nom. inval. see Phylum Spirochaetota Garrity and Holt 2021
       Class "Spirochaetes" "Garrity and Holt 2001" nom. nud. see Class Spirochaetes Cavalier-Smith 2002 nom. rej.
         Order Spirochaetales Buchanan 1917 (Approved Lists 1980)
           Family Spirochaetaceae Swellengrebel 1907 (Approved Lists 1980)
             Genus Spirochaeta Ehrenberg 1835 (Approved Lists 1980)
               [Spirochaeta aurantia] (ex Vinzent 1926) Canale-Parola 1980
                 1 Spirochaeta aurantia subsp. aurantiaᵀ (Canale-Parola 1980) Canale-Parola 1984
                 2 Spirochaeta aurantia subsp. stricta Canale-Parola 1984