[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain Bacteria Woese et al. 1990
     Phylum Firmicutes corrig. Gibbons and Murray 1978 (Approved Lists 1980)
       Class "Bacilli" Garrity et al. 2001 nom. ined. see Class Bacilli Ludwig et al. 2010
         Order "Lactobacillales" Garrity and Holt 2001 nom. nud. see Order Lactobacillales Ludwig et al. 2010
           Family Streptococcaceae Deibel and Seeley 1974 (Approved Lists 1980)
             Genus Streptococcus Rosenbach 1884 (Approved Lists 1980)
               [Streptococcus equi] Sand and Jensen 1888 (Approved Lists 1980)
                 1 Streptococcus equi subsp. equiᵀ (Sand and Jensen 1888) Farrow and Collins 1985
                 2 Streptococcus equi subsp. ruminatorum Fernández et al. 2004
                 3 Streptococcus equi subsp. zooepidemicus (ex Frost and Englebrecht 1936) Farrow and Collins 1985