A Gram-negative, aerobic, motile rod strain, designated Ma-20(T), was isolated from a pool of marine Spirulina platensis cultivation, Sanya, China, and was subjected to a polyphasic taxonomy study. Strain Ma-20(T) can grow in the presence of 0.5-11 % (w/v) NaCl, 10-43 °C and pH 6-10, and grew optimally at 30 °C, pH 7.5-9.0 in natural seawater medium. The polar lipids were composed of phosphatidylethanolamine, three unidentified phospholipids and three unidentified polar lipids. The respiratory quinone was ubiquinone 8 (Q-8) and the major fatty acids were C18:1ω6c/C18:1ω7c (summed feature 8, 32.84 %), C16:1ω6c/C16:1ω7c (summed feature 3, 30.76 %), C16:0 (13.54 %), C12:03-OH (4.63 %), and C12:0 (4.09 %). The DNA G+C content of strain Ma-20(T) was 58 mol %. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Ma-20(T) belonging to Gammaproteobacteria, it shared 88.46-91.55 and 89.21-91.26 % 16S rRNA gene sequence similarity to the type strains in genus Hahella and Marinobacter, respectively. In addition to the large 16S rRNA gene sequence difference, Ma-20(T) can also be distinguished from the reference type strains Hahella ganghwensis FR1050(T) and Marinobacter hydrocarbonoclasticus sp. 17(T) by several phenotypic characteristics and chemotaxonomic properties. On the basis of phenotypic, chemotaxonomic and phylogenetic properties, strain Ma-20(T) is suggested to represent a novel species of a new genus in Gammaproteobacteria, for which the name Nonhongiella spirulinensis gen. nov., sp. nov. is proposed. The type strain is Ma-20(T) (=KCTC 32221(T)=LMG 27470(T)).