Methanocaldococcus formerly known as Methanococcus is a genus of coccoid methanogen archaea.
The latter was discovered at the base of a “white smoker” chimney at 21°N on the East Pacific Rise[2] and it was the first archaean genome to be completely sequenced, revealing many novel and eukaryote-like elements.
Overall, the name means spherical cell that produces methane at hot temperatures.
Unlike many other species within Euryarchaeota, they cannot use formate, acetate, methanol or methylamines as substrates.
[4] The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) [5] and National Center for Biotechnology Information (NCBI).