Here we report a summary classification and the features of five anaerobic oral bacteria from the family Peptostreptococcaceae. Bacterial strains were isolated from human subgingival plaque. Strains ACC19a, CM2, CM5, and OBRC8 represent the first known cultivable members of “yet uncultured” human oral taxon 081; strain AS15 belongs to “cultivable” human oral taxon 377. Based on 16S rRNA gene sequence comparisons, strains ACC19a, CM2, CM5, and OBRC8 are distantly related to Eubacteriumyurii subs. yurii and Filifactor alocis, with 93.2 – 94.4 % and 85.5 % of sequence identity, respectively. The genomes of strains ACC19a, CM2, CM5, OBRC8 and AS15 are 2,541,543; 2,312,592; 2,594,242; 2,553,276; and 2,654,638 bp long. The genomes are comprised of 2277, 1973, 2325, 2277, and 2308 protein-coding genes and 54, 57, 54, 36, and 28 RNA genes, respectively. Based on the distinct characteristics presented here, we suggest that strains ACC19a, CM2, CM5, and OBRC8 represent a novel genus and species within the family Peptostreptococcaceae, for which we propose the name Peptoanaerobacter stomatis gen. nov., sp. nov. The type strain is strain ACC19aT (=HM-483T; =DSM 28705T; =ATCC BAA-2665T).