Historically, allCoriobacteriia species were placed within a single order (Coriobacteriales) and a single family (Coriobacteriaceae).[4][13][14][15][16] This view, however, was not reflective of accurate evolutionary interrelationships within the class. The current taxonomic view is justified by the presence of severalconserved signature indels (CSIs) that have been found at the different taxonomic ranks.[17] These CSIs are specific and representsynapomorphic characteristics that can be used to distinguish groups within theCoriobacteriia, both at the family and order levels.[18] The distinction of the orders within theCoriobacteriia is also supported phylogenetic tree branching and by consistent characteristics; members belonging to theCoriobacteriales are glucose-fermenting, saccharolytic species while theEggerthellales order has species that are consistently unable to ferment glucose and are asaccharolytic.[4][5][17]
CSIs have also been used to resolve the phylogenetic position of theCoriobacteriia among all bacteria where they have been found exclusively for all species within the class, delineating them from otherActinomycetota.[17] TheCoriobacteriia are an early branching lineage within the Actinomycetota phylum[5][15][16] The deep branching of the class has led to dispute over its membership within the phylum and whether or not it is a true Actinomycetota group.[13][14][15] A CSI in the form of a single amino acid insert in the enzyme deoxyuridine 59-triphosphate (dUTP) nucleotidohydrolase has been found that is shared by allCoriobacteriia members, as well as several Actinomycetota species, and absent from all other bacteria.[17] This CSI provides unambiguous support forCoriobacteriia's membership within the Actinomycetota.[17][18]
^König H (2012). "Class III.Coriobacteriia class nov.". In Goodfellow M, Kämpfer P, Trujillo ME, Ludwig W, Whitman WB (eds.).Bergey's Manual of Systematic Bacteriology. Vol. 5 (The Actinobacteria), part B (2nd ed.). New York: Springer. p. 1975.
^abcLudwig, W., Euzéby, J., Schumann, P., Busse, H. J., Trujillo, M. E.,Kämpfer, P. & Whitman, W. B. (2012). Road map of the phylum Actinobacteria. In: Bergey's Manual of Systematic Bacteriology, pp. 1–28. Eds. M. Goodfellow, P. Ka¨mpfer, H. J. Busse, M. E. Trujillo, K. Suzuki, W. Ludwig & W. B. Whitman. Springer-:New York
^abcClavel T, Lepage P & Charrier C. (2014). The family Coriobacteriaceae. In: The Prokaryotes, pp. 201-238. Springer-:Berlin Heidelberg
^abGao B, Paramanathan R, Gupta RS (2006). "Signature proteins that are distinctive characteristics ofActinobacteria and their subgroups".Antonie van Leeuwenhoek.90 (1):69–91.doi:10.1007/s10482-006-9061-2.PMID16670965.S2CID25817892.
^abcdeGupta RS, Chen WJ, Adeolu M, Chai Y (2010). "Molecular signatures for the classCoriobacteriia and its different clades; Proposal for division of the classCoriobacteriia into the emended orderCoriobacteriales, containing the emended familyCoriobacteriaceae andAtopobiaceae fam. nov., andEggerthellales ord. nov., containing the familyEggerthellaceae fam. nov".Int J Syst Evol Microbiol.63 (3):3379–97.doi:10.1099/ijs.0.048371-0.PMID23524353.
