A Gram-negative, non-motile, rod-shaped bacterium, strain SS011B1-20T, was isolated from sediments of the South China Sea. Growth occurred at NaCl concentrations between 0 and 10% and at temperatures between 10 and 37 6C. Strain SS011B1-20T contained Q-10 as the major respiratory quinone and C18: 1v7c (81.2%), C16: 0 (7.0%) and C18: 1 methyl (4.3%) as the predominant fatty acids. The G+C content of the genomic DNA was 64.7 mol%. A phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain SS011B1-20T belonged to a clade within the genus Oceanicola in the Alphaproteobacteria, the highest sequence similarities being found with respect to Oceanicola batsensis (96.3%) and with Oceanicola granulosus (94.9%). Strain SS011B1-20T could be clearly distinguished from other Oceanicola species on the basis of the genotypic, phenotypic and phylogenetic data. Thus, it is proposed that strain SS011B1-20T represents a novel species of the genus Oceanicola, with the name Oceanicola nanhaiensis sp. nov. The type strain is SS011B1-20T (=LMG 23508T=CGMCC 1.6293T).