After NCBI (National Center for Biotechnology Information)

<==o Thermoplasmata Reysenbach 2002
   `--o Thermoplasmatales Reysenbach 2002
      |-- archaebacterial symbiont RS406
      |--o Ferroplasmaceae Golyshina et al. 2000 [Ferroplasmataceae]
      |  `--o Ferroplasma Golyshina et al. 2000
      |     |--o Ferroplasma acidarmanus Dopson et al. 2004
      |     |  `-- Ferroplasma acidarmanus Fer1 
      |     |-- Ferroplasma acidiphilum Golyshina et al. 2000 [Ferromonas metallovorans]
      |     |-- Ferroplasma cyprexacervatum 
      |     |-- Ferroplasma sp. JTC3 
      |     `-- Ferroplasma sp. MT17 
      |--o Picrophilaceae Schleper et al. 1996
      |  `--o Picrophilus Schleper et al. 1996
      |     |-- Picrophilus oshimae Schleper et al. 1996
      |     `--o Picrophilus torridus Zillig et al. 1996
      |        `-- Picrophilus torridus DSM 9790 
      `--o Thermoplasmataceae Reysenbach 2002
         `--o Thermoplasma Darland et al. 1970
            |--o Thermoplasma acidophilum Darland et al. 1970 [Thermoplasma acidophila Darland et al. 1970]
            |  `-- Thermoplasma acidophilum DSM 1728 
            |--o Thermoplasma volcanium Segerer et al. 1988
            |  `-- Thermoplasma volcanium GSS1 
            |-- Thermoplasma sp. P61 
            |-- Thermoplasma sp. S01 
            |-- Thermoplasma sp. S02 
            |-- Thermoplasma sp. XT101 
            |-- Thermoplasma sp. XT102 
            |-- Thermoplasma sp. XT103 
            `-- Thermoplasma sp. XT107 

Reference(s):

• Anonymus - National Center for Biotechnology Information, Taxonomy homepage: Archaea - Thermoplasmata
  - iNet: http://www.ncbi.nlm.nih.gov/Taxonomy/