Four strictly anaerobic, Gram-stain-positive, urease-, oxidase- and catalase-negative, rod-shaped strains (zg-886T/zg-887 and zg-1050T/zg-1084) were isolated from Marmota himalayana. Comparison analysis of 16S rRNA genes showed that the two strain pairs belong to the family
Eggerthellaceae
: zg-1050T and zg-1084 were most closely related to
Berryella intestinalis
68-1-3T (97.2 %), while zg-886T/zg-887 had the highest similarity to
Slackia piriformis
YIT 12062T (91.6 %), followed by
Paraeggerthella hongkongensis
DSM 16106T (91.4 %) and
Gordonibacter urolithinfaciens
DSM 27213T (91.4 %). Phylogenetic analyses based on 16S rRNA genes and genomes showed that the two strain pairs represent two different lineages within the family
Eggerthellaceae
. The genomic G+C contents of strains zg-886T and zg-1050T were 63.0 and 66.3 mol%, respectively. The values of digital DNA–DNA hybridization, average nucleotide identity, average amino acid identity and the percentage of conserved proteins between the two new type strains and members of the family
Eggerthellaceae
were lower than the respective thresholds for delineation of a species or genus. In contrast to the absence of any known quinones in strain zg-1050T, strain zg-886T contained MK-6 (42.5 %), MMK-6 (25.0 %) and DMMK-6 (32.5 %). The four strains grew optimally at pH 7.0, 37 ºC and 0.5 % NaCl (w/v). According to these polyphasic analyses, two new members within the family
Eggerthellaceae
are proposed, Xiamenia xianingshaonis gen. nov., sp. nov. (zg-886T=JCM 34097T=GDMCC 1.1710T) and Berryella wangjianweii sp. nov. (zg-1050T=GDMCC 1.2426T=JCM 34748T).