| methanobrevibacter gottschalkii | species | archaea | bacteria | species | 190974 |
| methanobrevibacter ruminantium | species | archaea | bacteria | species | 83816 |
| methanobrevibacter smithii | species | archaea | bacteria | species | 2173 |
| methanobrevibacter sp. | no rank | archaea | bacteria | species | 66852 |
| uncultured methanobrevibacter sp. | no rank | archaea | environmental samples | species | 253161 |