[2] TM7x from the human oral cavity was cultivated and revealed that TM7x is an extremely small coccus (200-300 nm) and has a distinctive lifestyle not previously observed in human-associated microbes.

[5] Along with Candidate Phylum TM6,[6] it was named after sequences obtained in 1994 in an environmental study of a soil sample of peat bog in Germany where 262 PCR amplified 16S rDNA fragments were cloned into a plasmid vector, named TM clones for Torf, Mittlere Schicht (lit.

[7] It has been found in several environments since such as from activated sludges,[8][9] water treatment plant sludge[10] rainforest soil,[11] human saliva,[12][13] in association with sponges,[14] cockroaches,[15] gold mines,[16] acetate-amended aquifer sediment,[17] and other environments (bar thermophilic), making it an abundant and widespread phylum.

TM7 specific FISH probes identified species from a bioreactor sludge revealed the presence of a gram-positive cell envelopes and several morphotypes: a sheathed filament (abundant), a rod occurring in short chains, a thick filament and cocci; the former may be the cause of Eikelboom type 0041 (bulking problems of activated sludges).

[19] Using a polycarbonate membrane as a growth support and soil extract as the substrate, microcolonies of this clade were grown consisting of long filamentous rods up to 15 μm long with less than 50 cells or short rods with several hundred cells per colony, after 10 days incubation.