Names of classes

General remarks

As indicated by the ICNP in Rule 8, names of classes should be formed by appending -ia to the stem of the name of the type genus of the type order of the class. However, many validly published names of classes deviate from this scheme. Either other suffixes were used or the name of the class was not derived from the expected stem. Below the names of classes validly published under the ICNP are listed in groups according to the effective suffix, which is revealed by removing the expected stem from the name. Names of classes that do not contain the expected stem are marked as irregular. See also the LPSN introductory page on forming names.
It was considered to not regard Rule 8 as retroactive. If so, names of classes validly published before 1 January 2012 would not need to conform to the schema "stem and -ia". Hence the listing below indicates whether or not a name was validly published prior to 2012.

-a

AbditibacteriaEndomicrobiaLongimicrobiaPolyangiaTerrimicrobia

-a, before 2012

ClostridiaElusimicrobiaHalobacteriaIgnavibacteriaMethanobacteriaThermodesulfobacteriaThermomicrobiaThermoplasmata

-a, before 2012 (and rejected)

Acidobacteria

-ae

Kiritimatiellae

-ae, before 2012

AnaerolineaeAquificaeCaldilineaeHolophagaeOpitutaePhycisphaeraeThermotogaeVerrucomicrobiae

-ae, before 2012 (and rejected)

Chlamydiae

-alia

Hydrogenophilalia

-ea, before 2012 (and rejected)

ArchaeoglobeaPicrophilea

-es, before 2012

ActinomycetesDeferribacteres

-es, before 2012 (and rejected)

SpirochaetesStreptomycetes

-etes, before 2012

ChrysiogenetesChthonomonadetesGemmatimonadetes

-ia

AcidimicrobiiaAcidithiobacilliaActinomycetiaArdenticateniaAtribacteriaBacteriovoraciaBacteroidiaBalneoliaBdellovibrioniaBlastocatelliaChitinispirilliaChitinivibrioniaChitinophagiaChlamydiiaChloroflexia corrig.ConexivisphaeriaCoprothermobacteriaCoriobacteriiaCulicoidibacteriaCytophagiaDeferrisomatiaDehalococcoidiaDesulfarculiaDesulfobacciaDesulfobacteriaDesulfobulbiaDesulfomoniliaDesulfovibrioniaDesulfurelliaDesulfuribacilliaDesulfuromonadiaDictyoglomiaDissulfuribacteriaFibrobacteriaFimbriimonadiaFlavobacteriiaFusobacteriiaLentisphaeriaLimnochordiaMethanonatronarchaeiaMyxococciaNitriliruptoriaNitrososphaeriaOligoflexiaOligosphaeriaPlanctomycetiaRhodothermiaRubrobacteriaSaprospiriaSphingobacteriiaSpirochaetiaSyntrophiaSyntrophobacteriaSyntrophorhabdiaTepidiformiaThermoanaerobaculiaThermoflexiaThermoleophiliaTichowtungiiaVicinamibacteria

-ia, before 2012

ArmatimonadiaCaldisericiaErysipelotrichiaKtedonobacteria corrig.SynergistiaThermolithobacteria

-ia, before 2012 (and rejected)

Gloeobacteria

-i, before 2012

ArchaeoglobiBacilliDeinococciMethanococciMethanopyriThermococciThermoprotei

irregular, before 2012

AlphaproteobacteriaAnoxyphotobacteriaArchaeobacteriaBetaproteobacteriaDeltaproteobacteriaEpsilonproteobacteriaFirmibacteriaGammaproteobacteriaMollicutesNegativicutes

irregular, before 2012 (and illegitimate)

OxyphotobacteriaPhotobacteria

irregular, before 2012 (and rejected)

AlphabacteriaArabobacteriaArthrobacteriaChlorobacteriaChlorobeaChromatibacteriaChroobacteriaCrenarchaeotaDeltabacteriaEpsilobacteriaFerrobacteriaFlavobacteriaHadobacteriaHalomebacteriaHormogoneaeMethanothermeaPlanctomyceaProtoarchaeaTeichobacteriaTogobacteria