methanoplanus methanoplanus in taxonomy, methanoplanus is a genus of the methanomicrobiaceae, comprising three species of methanogenic, or methane-producing, archaea. the cells are irregular coccoid in shape, tend to stain gram-negative and do not form endospores. methanoplanus scientific classification domain: archaea kingdom: euryarchaeota phylum: euryarchaeota class: methanomicrobia order: methanomicrobiales family: methanomicrobiaceae genus: methanoplanuswildgruber et al. 1984 type species methanoplanus limicoluscorrig. wildgruber et al. 1984 species m. endosymbiosus m. limicolus