Also,
Methanothermobacter crinale Tm2T and Methanobacterium
thermaggregans DSM 3266T were found to be closely related
to strain RMAST (98.7 and 95.7% sequence similarity,
respectively); however, we did not include them for comparative analysis because Methanothermobacter crinale Tm2T was not validly described at the time of writing (Cheng et al., 2011) and the purity of the culture of Methanobacterium thermaggregans DSM 3266T is considered doubtful, owing to its purification procedure (Blotevogel & Fischer, 1985), and the reported data are difficult to interpret (Boone et al., 2001).