[organisms] see Clade Biota Wagner 2004 [Wiemann, de Queiroz, Rowe, Planavsky, Anderson, Gogarten, Turner & Gauthier 2020]
   Domain "Archaea" Woese et al. 1990
     Phylum "Euryarchaeota" Garrity and Holt 2001
       Class Methanococci Boone 2002
         Order Methanococcales Balch and Wolfe 1981
           Family Methanococcaceae Balch and Wolfe 1981
             Genus Methanothermococcus Whitman 2002
               1 Methanothermococcus thermolithotrophicus (Huber et al. 1984) Whitman 2002
               2 Methanothermococcus okinawensis Takai et al. 2002