Natura - nature
   actualia - actual entities
     Mundus Plinius - physical world
       naturalia - natural bodies
         Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
           Domain Bacteria Woese et al. 2024
             Kingdom Bacillatiᵀ (Gibbons and Murray 1978) Oren and Göker 2024
               Phylum Bacillotaᵀ Gibbons and Murray 2021
                 Class Negativicutes Marchandin et al. 2010
                   Order Veillonellales Campbell et al. 2015 [monotypic]
                     Family Veillonellaceaeᵀ Rogosa 1971 (Approved Lists 1980)
                       1 Genus Dialister (ex Bergey et al. 1923) Moore and Moore 1994
                       2 Genus Megasphaera Rogosa 1971 (Approved Lists 1980)
                       3 Genus Negativicoccus Marchandin et al. 2010 [monotypic]
                       4 Genus Quinella Krumholz et al. 1993 [monotypic]
                       5 Genus Veillonellaᵀ Prévot 1933 (Approved Lists 1980)
                       6 Genus "Psychrosinus" Sattley et al. 2008 nom. inval.