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] Domain Bacteria Woese et al. 1990 [paraphyletic?] Phylum "Spirochaetes" Garrity and Holt 2001 [monotypic] Class Spirochaetesᵀ Cavalier-Smith 2002 [monotypic] Order Brachyspirales Gupta et al. 2014, sedis mutabilis [monotypic] Family Brachyspiraceaeᵀ Paster 2012 [monotypic] [Genus Serpulina Stanton 1992] see Genus Brachyspira Hovind-Hougen et al. 1983 [Serpulina murdochii Stanton et al. 1997] see Brachyspira murdochii (Stanton et al. 1997) Hampson and La 2006