Description:
<jats:p>The faecal microbiota of muskoxen (<jats:italic>n</jats:italic>=3) pasturing on Ryøya (69° 33′ N 18° 43′ E), Norway, in late September was characterized using high-throughput sequencing of partial 16S rRNA gene regions. A total of 16 209 high-quality sequence reads from bacterial domains and 19 462 from archaea were generated. Preliminary taxonomic classifications of 806 bacterial operational taxonomic units (OTUs) resulted in 53.7–59.3 % of the total sequences being without designations beyond the family level. <jats:italic>Firmicutes</jats:italic> (70.7–81.1 % of the total sequences) and <jats:italic>Bacteroidetes</jats:italic> (16.8–25.3 %) constituted the two major bacterial phyla, with uncharacterized members within the family <jats:italic>Ruminococcaceae</jats:italic> (28.9–40.9 %) as the major phylotype. Multiple-library comparisons between muskoxen and other ruminants indicated a higher similarity for muskoxen faeces and reindeer caecum (<jats:italic>P</jats:italic>>0.05) and some samples from cattle faeces. The archaeal sequences clustered into 37 OTUs, with dominating phylotypes affiliated to the methane-producing genus <jats:italic>Methanobrevibacter</jats:italic> (80–92 % of the total sequences). UniFrac analysis demonstrated heterogeneity between muskoxen archaeal libraries and those from reindeer and roe deer (<jats:italic>P</jats:italic>=1.0e-02, Bonferroni corrected), but not with foregut fermenters. The high proportion of cellulose-degrading <jats:italic>Ruminococcus</jats:italic>-affiliated bacteria agrees with the ingestion of a highly fibrous diet. Further experiments are required to elucidate the role played by these novel bacteria in the digestion of this fibrous Artic diet eaten by muskoxen.</jats:p>