| uncultured aquifex sp. | no rank | bacteria | environmental samples | species | 522376 |
| uncultured hydrogenobacter sp. | no rank | bacteria | environmental samples | species | 236029 |
| uncultured hydrogenobaculum sp. | no rank | bacteria | environmental samples | species | 221070 |
| uncultured thermocrinis sp. | no rank | bacteria | environmental samples | species | 158793 |