Concise hierarchy

(Kingdom) Bacillati - (Phylum) Actinomycetota - (Class) Actinomycetes

Current position

Actinomycetes (Class) Krassilnikov 1949 (Approved Lists 1980)

Ref: LPSN, 2020-present: [9 Dec 2025]; LPSN[9 Dec 2025].

Alternative positions

Actinobacteria (Class) Stackebrandt et al. 1997 nom. illeg.	Ref: J.P. Euzéby, 2016: [31 Aug 2017].
Actinobacteridae (Subclass) Stackebrandt et al. 1997	Ref: G.M. Garrity et al., 2007: 402.
Actinomycetes and related organisms ([unranked])	Ref: T.G. Pridham, 1982: 37.
Arthrobacteria (Class) Cavalier-Smith 2002 nom. rej.	Ref: T. Cavalier-Smith, 2002a: tbl. 1 (p. 13). [new position]
Thallobacteria (Class)	Ref: N.R. Krieg & J.G. Holt, 1984-1989

Historical positions

Actinobacteria (Class) Stackebrandt et al. 1997 nom. illeg.	Ref: J.P. Euzéby, 2016: [31 Aug 2017].
Actinobacteria (Class) Stackebrandt et al. 1997 nom. illeg.	Ref: M.A. Ruggiero et al., 2015b: table 2 (p. 6).
Actinobacteridae (Subclass) Stackebrandt et al. 1997	Ref: G.M. Garrity et al., 2007: 402.
Arthrobacteria (Class) Cavalier-Smith 2002 nom. rej.	Ref: T. Cavalier-Smith, 2002a: tbl. 1 (p. 13). [new position]
Actinobacteridae (Subclass) Stackebrandt et al. 1997	Ref: G.M. Garrity et al., 2001b: 20.
Actinobacteridae (Subclass) Stackebrandt et al. 1997	Ref: G.M. Garrity & J.G. Holt, 2001a: 163.
Thallobacteria (Class)	Ref: N.R. Krieg & J.G. Holt, 1984-1989
Actinomycetes and related organisms ([unranked])	Ref: T.G. Pridham, 1982: 37.
Actinomyceten en verwanten ([unranked])	Ref: L.J. Audus & V. Heywood, 1981: 28-29.

Number of Subtaxa

2026	Available in Systema Naturae 2000	2f;28g;67s;4ss
1989-present	Systema Naturae 2000: 20 May 2026	[2f;28g]
2016	J.P. Euzéby: [7 Sep 2017]	[20f;172g]
2007	G.M. Garrity et al.	[40f;171g;1620s;107ss]
2001b	G.M. Garrity et al.: 23	[38f;121g]
2001a	G.M. Garrity & J.G. Holt: 165	[34f;113g]
2000		34f113g
1982	T.G. Pridham	[12f49(45)g]
1981	L.J. Audus & V. Heywood	10f
1981	L.J. Audus & V. Heywood: 28	10f