Gracilibacteraceae Lee et al. 2010 Gracilibacteraceae Lee et al. 2010 Gracilibacter Lee et al. 2006 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 Eubacteriales Buchanan 1917 (Approved Lists 1980) emend. Tindall 2019 Gracilibacteraceae Lee et al. 2010 Eubacteriales Buchanan 1917 (Approved Lists 1980) emend. Tindall 2019 Eubacteriaceae Ludwig et al. 2010 Caldicoprobacteraceae Yokoyama et al. 2010 Christensenellaceae Morotomi et al. 2012 Clostridiaceae Pribram 1933 (Approved Lists 1980) emend. Spring 2021 Defluviitaleaceae Jabari et al. 2012 Heliobacteriaceae Asao and Madigan 2010 Lachnospiraceae Rainey 2010 Peptococcaceae Rogosa 1971 (Approved Lists 1980) emend. Lv et al. 2020 Peptostreptococcaceae Ezaki 2010 Ruminococcaceae Rainey 2010 Syntrophomonadaceae Zhao et al. 1993 emend. Zhang et al. 2019 Eubacteriineae Breed et al. 1944 (Approved Lists 1980) Oscillospiraceae Peshkoff 1940 (Approved Lists 1980) emend. Tindall 2019 Incertae sedis 723 Hitch et al. 2021 Gracilibacter Lee et al. 2006 Rainey F.A. De Vos P. Garrity G. Jones D. Krieg N.R. Ludwig W. Rainey F.A. Schleifer K.H. Whitman W.B. Order I. Clostridiales Prevot 1953 2009 3 2 736 1191 Bergey's Manual of Systematic Bacteriology Springer-Verlag New York Lee Y.J. Romanek C.S. Mills G.L. Davis R.C. Whitman W.B. Wiegel J. Gracilibacter thermotolerans gen. nov., sp. nov., an anaerobic, thermotolerant bacterium from a constructed wetland receiving acid sulfate water. 2006 56 9 2089 2093 International Journal of Systematic and Evolutionary Microbiology Int J Syst Evol Microbiol 1466-5026 1466-5034 10.1099/ijs.0.64040-0 16957104 Gerritsen J. Fuentes S. Grievink W. van Niftrik L. Tindall B.J. Timmerman H.M. Rijkers G.T. Smidt H. Characterization of Romboutsia ilealis gen. nov., sp. nov., isolated from the gastro-intestinal tract of a rat, and proposal for the reclassification of five closely related members of the genus Clostridium into the genera Romboutsia gen. nov., Intestinibacter gen. nov., Terrisporobacter gen. nov. and Asaccharospora gen. nov. 2014 64 5 1600 1616 International Journal of Systematic and Evolutionary Microbiology Int J Syst Evol Microbiol 1466-5026 1466-5034 10.1099/ijs.0.059543-0 24480908 Euzéby J. Validation List No. 132. List of new names and new combinations previously effectively, but not validly, published 2010 60 3 469 472 International Journal of Systematic and Evolutionary Microbiology Int J Syst Evol Microbiol 1466-5026 1466-5034 10.1099/ijs.0.022855-0 Lee Y.-J. Onyenwoke R.U. Wiegel J. De Vos P. Garrity G. Jones D. Krieg N.R. Ludwig W. Rainey F.A. Schleifer K.H. Whitman W.B. Family III. Gracilibacteraceae fam. nov. 2009 3 2 910 Bergey's Manual of Systematic Bacteriology Springer-Verlag New York