Methanocaldococcus

Methanocaldococcus formerly known as Methanococcus is a genus of coccoid methanogen archaea. They are all thermophiles, including M. infernus and the hyperthermophilic M. jannaschii. The latter was discovered at the base of a “white smoker” chimney at 21°N on the East Pacific Rise and it was the first archaean genome to be completely sequenced, revealing many novel and eukaryote-like elements.