A novel Gram-negative, rod-shaped, motile bacterium, designated strain AK13 sup(T), was isolated from a sediment sample collected from mangrove of Namkhana, Sunderbans, West Bengal, India. Strain AK13 sup(T) was positive for oxidase, DNase and lipase activities and negative for catalase, gelatinase, ornithine decarboxylase, lysine decarboxylase, nitrate reductase, aesculinase and urease activities. The fatty acids were dominated by iso-C sub(11:0), iso-C sub(11:0) 3-OH, iso-C sub(15:0), iso- C sub(16:0), iso-C sub(17:1) omega 9c and summed feature 3 (C sub(16:1) omega 7c and/or iso-C sub(15:0) 2-OH). Strain AK13 sup(T) contained Q-8 as the major respiratory quinone and diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylserine, two unidentified aminolipids, one unidentified glycolipid and one unidentified lipid as the polar lipids. The DNA G+C content of strain AK13 sup(T) was 55.2 mol percent. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the type strain of Silanimonas lenta, of the family Xanthomonadaceae (phylum Proteobacteria), was the closest neighbour of strain AK13 sup(T), with 95.2 percent sequence similarity. Other members of the family showed sequence similarities less than 94.4 percent. Based on the phenotypic characteristics and phylogenetic inference, strain AK13 sup(T) is proposed as a member of a novel species of the genus Silanimonas, Silanimonas mangrovi sp. nov.; the type strain is AK13 sup(T) (=MTCC 11082 sup(T) =DSM 24914 sup(T)). An emended description of the genus Silanimonas is also provided.