Previously known as candidate phylum OP10 and was comprised solely of environmental 16S rRNA

16S ribosomal RNA

16S ribosomal RNA is a component of the 30S subunit of prokaryotic ribosomes. It is approximately 1.5kb in length...

 gene clone sequences, however recently three strains were formally described two of which are in press at the International Journal of Systematic and Evolutionary Microbiology

International Journal of Systematic and Evolutionary Microbiology

The International Journal of Systematic and Evolutionary Microbiology is a peer-reviewed scientific journal in the field of microbial systematics, first published in 1951...

, thus nearing validation as formal species.

Armatimonas rosea an aerobic chemoheterotrophic bacterium, strain YO-36T, isolated from rhizoplane of an aquatic plant (a reed, Phragmites australis) inhabiting a freshwater lake in Japan. Chthonomonas calidirosea an aerobic, saccharolytic, obligately thermophilic, motile, nonspore-forming bacterium, strain T49(T), was isolated from geothermally heated soil at Hell's Gate, Tikitere, New Zealand. Both of which are differentiated sufficiently enough to warrant placing in separate classes.

Phylogeny

The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LSPN)

and the phylogeny is based on 16S rRNA-based LTP release 106 by The All-Species Living Tree Project 
Notes:

♠ Strains found at the National Center for Biotechnology Information

National Center for Biotechnology Information

The National Center for Biotechnology Information is part of the United States National Library of Medicine , a branch of the National Institutes of Health. The NCBI is located in Bethesda, Maryland and was founded in 1988 through legislation sponsored by Senator Claude Pepper...

 (NCBI) but not listed in the List of Prokaryotic names with Standing in Nomenclature (LSPN)