An antibiotic-producing, obligate anaerobic, Gram-stain-negative, catalase- and oxidase-negative strain (JC271T) was isolated from a marine habitat and identified, based on 16S rRNA gene sequence analysis, as a novel member of the family Desulfovibrionaceae. The closest phylogenetic relatives of strain JC271T were found to be Desulfovibrio marinisediminis C/L2T (99.2 %), Desulfovibrio acrylicus W218T (98.7 %), Desulfovibrio desulfuricans subsp. aestuarii (98.6 %), Desulfovibrio oceani subsp. oceani (98.0 %), Desulfovibrio oceani subsp. galatae (98.0 %) and other members of the genus Desulfovibrio (≤91.9 %). To resolve its full taxonomic position, the genomic sequence of strain JC271T was compared to available genomes of the most closely related phylogenetic members. Average Nucleotide Identity scores and DNA-DNA hybridization values confirmed that strain JC271T represents a novel genomic species. Iso-C17 : 0, iso-C17 : 1ω9c, and iso-C15 : 0 were found to be the major (comprising >10 % of the total present) fatty acids of strain JC271T. Phosphatidylglycerol, phosphatidylethanolamine and unidentified lipids (L1-8) were the polar lipids identified. The G+C content of strain JC271T was 46.2 mol%. Integrated genomic and phenotypic data supported the classification of strain JC271T as a representative of a novel genus, for which the name Halodesulfovibrio spirochaetisodalis gen. nov., sp. nov. is proposed. The type strain is JC271T (=KCTC 15474T=DSM 100016T). It is also proposed that Desulfovibrio acrylicus W218T is the latter heterotypic synonym of Desulfovibrio desulfuricans subsp. aestuarii Sylt 3T. Desulfovibrio desulfuricans subsp. aestuarii Sylt 3T should also be elevated as Halodesulfovibrio aestuarii comb. nov. and Desulfovibrio marinisediminisreclassified as Halodesulfovibrio marinisediminis comb. nov. Desulfovibrio oceani subsp. oceanishould be reclassified as Halodesulfovibrio oceani subsp. oceani comb. nov. and Desulfovibrio oceani subsp. galateae as Halodesulfovibrio oceani subsp. galateae comb. nov.