| iceland | | methanocaldococcus villosus kin24-t80 | no rank | 166 | 0 |
| india | | uncultured methanocaldococcus sp. | species | 23 | 0 |
| japan | okinawa prefecture | methanocaldococcus sp. e1885-m | species | 1 | 0 |
| nigeria | | uncultured methanocaldococcus sp. | species | 40 | 0 |
| slovakia | | uncultured methanocaldococcus sp. | species | 1 | 0 |