Cultivation and description of Duncaniella dubosii sp. nov., Duncaniella freteri sp. nov. and emended description of the species Duncaniella muris

Three bacterial strains, C9, H5 and TLL-A3, were isolated from fecal pellets of conventionally raised C57BL/6J mice. Analysis of 16S rRNA genes indicated that the strains belonged to the Muribaculaceae , and shared 91.6–99.9 % sequence identity with the recently described Duncaniella muris DSM 103720 T . Genome-sequencing of the isolates was performed to compare average nucleotide identities (ANI) between strains. The ANI analysis revealed that all isolates shared highest ANI with D. muris DSM 103720 T , with strain C9 being most similar (ANI: 98.0 %) followed by strains H5 (ANI: 76.4 %) and TLL-A3 (ANI: 74.4 %). Likewise, digital DNA–DNA hybridization (dDDH) indicated high similarity of strain C9 (dDDH: 86.6 %) to D. muris DSM 103720 T , but strains H5 and TLL-A3 showed lower similarity (dDDH <35 %) to either of the three type species of the Muribaculaceae ( Muribaculum intestinale DSM 28989 T , Paramuribaculum intestinale DSM 100749 T , D. muris DSM 103720 T ). MK-10 and MK-11 were abundant in all three isolates, but concentrations varied between species. Based on genotypic, phylogenetic and phenotypic differences, the strains TLL-A3 and H5 are considered to represent novel species of the genus Duncaniella , for which the names Duncaniella freteri sp. nov., and Duncaniella dubosii sp. nov., are proposed. The respective type strains are TLL-A3 T (=DSM 108168 T =KCTC 15769 T ), and H5 T (=DSM 107170 T =KCTC 15734 T ). Strain C9 reveals limited sequence dissimilarity and minor differences in morphological properties with Duncaniella muris DSM 103720 T and is therefore proposed to belong to the same species. The respective strain is C9 (=DSM 107165=KCTC 15733).