A novel Gram-stain-positive, coccoid, non-motile bacterium, designated strain AMV4T, was isolated from a soil sample collected from a mud volcano located in the Andaman Islands, India. The colony was pale orange. Strain AMV4Twas positive for oxidase, aesculinase, lysine decarboxylase and ornithine decarboxylase activities and negative for amylase, catalase, cellulase, protease, urease and lipase activities. 16S rRNA gene sequence analysis indicated that strain AMV4Twas a member of the orderActinomycetalesand was closely related toAquipuribacter hungaricuswith a sequence similarity of 97.13 % (pairwise alignment). Phylogenetic analyses showed that strain AMV4Tclustered withAquipuribacter hungaricusand was distantly related to the other genera of the familyIntrasporangiaceae. DNA–DNA hybridization between strains AMV4TandAquipuribacter hungaricusIV-75Tshowed a relatedness of 28 %. The predominant cellular fatty acids were iso-C15 : 0(6.9 %), anteiso-C15 : 0(25.3 %), C16 : 0(12.9 %), anteiso-C16 : 0(5.6 %), C18 : 1ω9c(19.8 %) and C18 : 3ω6,9,12c(9.1 %). The diagnostic diamino acid in the cell-wall peptidoglycan of strain AMV4Twasmeso-diaminopimelic acid. Strain AMV4Tcontained MK-10(H4) as the predominant respiratory quinone. The polar lipids consisted of phosphatidylglycerol, one unidentified glycolipid, two unidentified phospholipids and five unidentified lipids. The DNA G+C content of strain AMV4Twas 74.3 mol%. Based on data from this taxonomic study using a polyphasic approach, it is proposed that strain AMV4Trepresents a novel species of the genusAquipuribacter, with the suggested nameAquipuribacter nitratireducenssp. nov. The type strain is AMV4T( = CCUG 58430T = DSM 22863T = NBRC 107137T).