According to comparative analysis of 16S rRNA, this is one the most ancient group of bacteria.

[1] Thermus species can be distinguished from other genera in the family Thermaceae as well as all other bacteria by the presence of eight conserved signature indels found in proteins such as adenylate kinase and replicative DNA helicase as well as 14 conserved signature proteins that are exclusively shared by members of this genus.

[2] The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) [3] and the National Center for Biotechnology Information (NCBI).

[4][5][6] Between all its species, T. thermophilus has a special importance as a model organism for basic and applied research.

[5] Later on more isolates were obtained from several hydrothermal areas worldwide,[27] such as in Japan,[28][29] Iceland,[30] New Zealand, New Mexico or the Australian Artesian Basin.