A polyphasic taxonomic study was performed on a strain, designated FHC16(T), which was isolated from surface seawater collected from the South China Sea. Cells of strain FHC16(T) are Gram stain-negative, oxidase- and catalase-positive and non-motile rods. Growth was observed at 15-37 °C (optimum, 25-30 °C), at pH 6.0-9.0 (optimum, pH 7.0) and in the presence of 0-5 % (w/v) NaCl (optimum, 3%). 16S rRNA gene sequence analysis showed that strain FHC16(T) is most closely related to Tamlana sedimentorum JCM 19808(T) (98.2% sequence similarity). The ANI value between strain FHC16(T) and T. sedimentorum JCM 19808(T) was found to be 81.82-81.81%. The DNA-DNA hybridization estimated value between strain FHC16(T) and T. sedimentorum JCM 19808(T) was determined to be 25.8 ± 2.41%. The principal fatty acids (>5% of the total) were found to be iso-C(15:0), iso G-C(15:1), iso-C(17:0) 3-OH, iso-C(15:0) 3-OH and summed feature 3 (comprising C(16:1)ω7c/C(16:1)ω6c). The strain was found to have MK-6 as the major respiratory menaquinone, which is consistent with the other three recognized Tamlana species, T. sedimentorum, Tamlana crocina and Tamlana agarivorans. The polar lipids were found to comprise phosphatidylethanolamine, one unidentified aminophospholipid, two unidentified aminolipids and seven unidentified lipids. The G+C content of the chromosomal DNA was determined to be 34.2 mol%. On the basis of phenotypic, chemotaxonomic and molecular data, strain FHC16(T) is considered to represent a novel species of the genus Tamlana, for which the name Tamlana nanhaiensis sp. nov. is proposed. The type strain is FHC16(T) (.LMG 27420(T) = CGMCC 1.12469(T) = MCCC 1A06648(T)).