methanococcus maripaludis methanococcus maripaludis methanococcus maripaludis is a species of methanogen. it is anaerobic, weakly motile, non-spore-forming, gram-negative, and a pleomorphic coccoid-rod averaging 1.2 by 1.6 μm is size. its genome has been sequenced. it has been described as an electric bacteria methanococcus maripaludis scientific classification domain: archaea kingdom: euryarchaeota phylum: euryarchaeota class: methanococci order: methanococcales family: methanococcaceae genus: methanococcus species: methanococcus maripaludisjones et al. 1984