Hungateiclostridium Zhang et al. 2018 Hungateiclostridium Zhang et al. 2018 Hungateiclostridium thermocellum (Viljoen et al. 1926) Zhang et al. 2018 Universal Root Woese et al. 1990 Bacteria (None 2015) Woese et al. 1990 Firmicutes (sic) Gibbons and Murray 2021 Bacillota corrig. Gibbons and Murray 2021 Firmacutes (sic) Gibbons and Murray 2021 Clostridia Rainey 2010 Clostridiales Prévot 1953 (Approved Lists 1980) Hungateiclostridiaceae Zhang et al. 2018 Hungateiclostridium Zhang et al. 2018 Hungateiclostridiaceae Zhang et al. 2018 Petroclostridium Zhang et al. 2018 Thermoclostridium Zhang et al. 2018 Ruminiclostridium Zhang et al. 2018 non Ruminiclostridium Yutin and Galperin 2013 Pseudoclostridium Zhang et al. 2018 Pseudobacteroides Horino et al. 2014 Anaerobacterium Horino et al. 2014 Ercella van Gelder et al. 2014 Fastidiosipila Falsen et al. 2005 Mageeibacillus Austin et al. 2016 Saccharofermentans Chen et al. 2010 Hungateiclostridium thermocellum (Viljoen et al. 1926) Zhang et al. 2018 Hungateiclostridium cellulolyticum (Patel et al. 1980) Zhang et al. 2018 Hungateiclostridium aldrichii (Yang et al. 1990) Zhang et al. 2018 Hungateiclostridium alkalicellulosi (Zhilina et al. 2006) Zhang et al. 2018 Hungateiclostridium clariflavum (Shiratori et al. 2009) Zhang et al. 2018 Hungateiclostridium straminisolvens (Kato et al. 2004) Zhang et al. 2018 Hungateiclostridium saccincola (Koeck et al. 2016) Zhang et al. 2018 Hungateiclostridium mesophilum Rettenmaier et al. 2019 Zhang X. Tu B. Dai L.-R. Lawson P.A. Zheng Z.-Z. Liu L.-Y. Deng Y. Zhang H. Cheng L. Petroclostridium xylanilyticum gen. nov., sp. nov., a xylan-degrading bacterium isolated from an oilfield, and reclassification of clostridial cluster III members into four novel genera in a new Hungateiclostridiaceae fam. nov. 2018 68 10 3197 3211 International Journal of Systematic and Evolutionary Microbiology Int J Syst Evol Microbiol 1466-5026 1466-5034 10.1099/ijsem.0.002966 30124399 Rettenmaier R. Gerbaulet M. Liebl W. Zverlov V.V. Hungateiclostridium mesophilum sp. nov., a mesophilic, cellulolytic and spore-forming bacterium isolated from a biogas fermenter fed with maize silage. 2019 69 11 3567 3573 International Journal of Systematic and Evolutionary Microbiology Int J Syst Evol Microbiol 1466-5026 1466-5034 10.1099/ijsem.0.003663 31429816 Acetivibrio Patel et al. 1980 emend. Tindall 2019 Tindall B.J. Replacement of the illegitimate genus name Hungateiclostridium Zhang et al. 2018 in Hungateiclostridium mesophilum Rettenmaier et al. 2019 by Acetivibrio Patel et al. 1980, creating Acetivibrio mesophilus (Rettenmaier et al. 2019). 2019 69 12 3967 3968 International Journal of Systematic and Evolutionary Microbiology Int J Syst Evol Microbiol 1466-5026 1466-5034 10.1099/ijsem.0.003810 31665099 Zhang X. Tu B. Dai L.-R. Lawson P.A. Zheng Z.-Z. Liu L.-Y. Deng Y. Zhang H. Cheng L. Petroclostridium xylanilyticum gen. nov., sp. nov., a xylan-degrading bacterium isolated from an oilfield, and reclassification of clostridial cluster III members into four novel genera in a new Hungateiclostridiaceae fam. nov. 2018 68 10 3197 3211 International Journal of Systematic and Evolutionary Microbiology Int J Syst Evol Microbiol 1466-5026 1466-5034 10.1099/ijsem.0.002966 30124399 Tindall B.J. The names Hungateiclostridium Zhang et al. 2018, Hungateiclostridium thermocellum (Viljoen et al. 1926) Zhang et al. 2018, Hungateiclostridium cellulolyticum (Patel et al. 1980) Zhang et al. 2018, Hungateiclostridium aldrichii (Yang et al. 1990) Zhang et al. 2018, Hungateiclostridium alkalicellulosi (Zhilina et al. 2006) Zhang et al. 2018, Hungateiclostridium clariflavum (Shiratori et al. 2009) Zhang et al. 2018, Hungateiclostridium straminisolvens (Kato et al. 2004) Zhang et al. 2018 and Hungateiclostridium saccincola (Koeck et al. 2016) Zhang et al. 2018 contravene Rule 51b of the International Code of Nomenclature of Prokaryotes and require replacement names in the genus Acetivibrio Patel et al. 1980. 2019 69 12 3927 3932 International Journal of Systematic and Evolutionary Microbiology Int J Syst Evol Microbiol 1466-5026 1466-5034 10.1099/ijsem.0.003685 31526446 Hungateiclostridium Zhang et al. 2018 is illegitimate because it contravenes Rule 42. By placing the nomenclatural type of Acetivibrio Patel et al. 1980 into Hungateiclostridium Zhang et al. 2018, these genera are unified. However, Acetivibrio Patel et al. 1980 has priority over Hungateiclostridium Zhang et al. 2018. Hungateiclostridium Zhang et al. 2018 is therefore a later heterotypic synonym of Acetivibrio Patel et al. 1980. Likewise, Hungateiclostridium Zhang et al. 2018 is illegitimate because it contravenes Rule 42. By placing the nomenclatural type of Herbivorax Koeck et al. 2016 into Hungateiclostridium Zhang et al. 2018, these genera are unified. However, Herbivorax Koeck et al. 2016 has priority over Hungateiclostridium Zhang et al. 2018. Hungateiclostridium Zhang et al. 2018 is therefore a later heterotypic synonym of Herbivorax Koeck et al. 2016.