aquificaceae aquificaceae the aquificaceae family are bacteria that live in harsh environmental settings such as hot springs, sulfur pools, and hydrothermal vents. although they are true bacteria as opposed to the other inhabitants of extreme environments, the archaea, aquificaceae genera are an early phylogenetic branch. aquificaceae scientific classification domain: bacteria phylum: aquificota order: aquificales family: aquificaceaereysenbach 2002 genera aquifex hydrogenivirga hydrogenobacter thermocrinis phylogeny the currently accepted taxonomy is based on the list of prokaryotic names with standing in nomenclature (lpsn) and national center for biotechnology information (ncbi) 16s rrna based ltp_01_2022 120 marker proteins based gtdb 07-rs207 hydrogenobaculum acidophilum (shima & suzuki 1993) stohr et al. 2001 hydrogenobacter h. hydrogenophilus (kryukov et al. 1984) stöhr et al. 2001 h. thermophilus kawasumi et al. 1984 (type sp.) thermocrinis minervae huber et al. 1999 hydrogenobacter subterraneus takai et al. 2001 thermothrix azorensis caldwell et al. 1981 thermocrinis t. jamiesonii dodsworth et al. 2015 t. ruber huber et al. 1999 (type sp.) thermocrinis albus eder and huber 2002 aquifex pyrophilus huber and stetter 1992 (type sp.) hydrogenivirga h. calditorris nakagawa et al. 2004 (type sp.) h. okinawensis nunoura et al. 2008 "hydrogenobaculaceae" hydrogenobaculum acidophilum aquificaceae aquifex pyrophilus hydrogenivirga calditorris thermocrinis minervae hydrogenobacter h. hydrogenophilus h. thermophilus thermocrinis t. albus t. ruber unassigned species: "aquifex aeolicus" huber and stetter 2001