A Gram-negative, motile, non-spore-forming and moderately halophilic ellipsoid-shaped marine coccobacillus, designated strain SS011B1-4T, was isolated from benthic sediment of the South China Sea. Optimum growth occurred at 30-37 6C, pH 7.5-8.0 and 4-8% (w/v) NaCl. Strain SS011B1-4T utilized a variety of organic substrates as sole carbon sources, but did not utilize toluene, n-tetradecane or crude oil. Strain SS011B1-4T had ubiquinone-9 as the major respiratory quinone and C18: 1v9c, C16: 0 and C12: 0.3-OH as the predominant fatty acids. The genomic DNA G+C content was 62.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain SS011B1-4T belonged to the genus Marinobacter of the Gammaproteobacteria. The results of the phenotypic, phylogenetic and genomic analyses revealed that strain SS011B1-4T represents a novel species of the genus Marinobacter. The name Marinobacter segnicrescens sp. nov. is therefore proposed, with strain SS011B1-4T (5LMG 23928T5CGMCC 1.6489T) as the type strain.