A taxonomic study was carried out on strain 22II-S11g(T), which was isolated from the surface seawater of the Atlantic Ocean. The bacterium was found to be Gram-negative, rod shaped without flagellum, oxidase positive and weakly catalase positive. Growth was observed at NaCl concentrations of 0.5-9 % and at temperatures of 10-41 °C. The isolate was incapable of gelatin hydrolysis and unable to reduce nitrate to nitrite, degrade aesculin and Tween 80. On the basis of 16S rRNA gene sequence similarity, strain 22II-S11g(T) was found to be most closely related to Oceanicola batsensis HTCC2597(T) (97.26 %), followed by Oceanicola nitratireducens JLT1210(T) (96.39 %), whilst other species of genus Oceanicola shared 94.00-96.34 % sequence similarity. However, it showed low similarity to Oceanicola granulosus HTCC2516(T) (94.79 %), the type species of the genus Oceanicola. Phylogenetic analysis showed that strain 22II-S11g(T) formed a clade with six species currently classified in the genus Oceanicola, but strain O. granulosus HTCC2516(T) and strain O. litoreus M-M22(T) clustered with two other genera respectively. The ANI values between strain 22II-S11g(T) and two type strains (O. batsensis HTCC2597(T) and O. granulosus HTCC2516(T)) are 91.86 and 91.81 % respectively. The digital DNA-DNA hybridization estimate values between strain 22II-S11g(T) and two type strains (O. batsensis HTCC2597(T) and O. granulosus HTCC2516(T)) are 23.4 ± 2.4 and 20.0 ± 2.3 %, respectively. The principal fatty acids were identified as summed feature 8 (C18:1 ω7c/ω6c), C16:0, C18:1 ω7c11-methyl and C12:0 3OH. The G+C content determined from the draft genome sequence is 64.1 mol%. The respiratory quinone was determined to be Q-10 (100 %). Phosphatidylethanolamine, phosphatidylglycerol, an aminolipid, phosphatidylcholine, a phospholipid and three lipids were identified in the polar lipids. The combined genotypic and phenotypic data also show that strain 22II-S11g(T) should not be assigned to the genus Oceanicola; consequently strain 22II-S11g(T) is concluded to represent a novel species of a novel genus in the family Rhodobacteraceae, for which the name Pseudooceanicola atlanticus gen. nov., sp. nov. is proposed (type strain 22II-S11g(T) = KCTC 42004(T) = LMG 27424(T) = MCCC 1A09160(T)). Six misclassified species should be transferred to the novel genus Pseudooceanicola as follows: O. batsensis should be transferred to the genus Pseudooceanicola as Pseudooceanicola batsensis comb. nov. (type strain HTCC2597(T) = ATCC BAA-863(T) = DSM 15984(T) = KCTC 12145(T)); Oceanicola marinus should be transferred to the genus Pseudooceanicola as Pseudooceanicola marinus comb. nov. (type strain AZO-C(T) = LMG 23705(T) = BCRC 17591(T)); O. nitratireducens should be transferred to the genus Pseudooceanicola as Pseudooceanicola nitratireducens comb. nov. (type strain JLT1210(T) = LMG 24663(T) = CGMCC 1.7292(T)); Oceanicola nanhaiensis should be transferred to the genus Pseudooceanicola as Pseudooceanicola nanhaiensis comb. nov. (type strain SS011B1-20(T) = LMG 23508(T) = CGMCC 1.6293(T)); Oceanicola antarcticus should be transferred to the genus Pseudooceanicola as Pseudooceanicola antarcticus comb. nov. (type strain Ar-45(T) = CGMCC 1.12662(T) = LMG 27868(T)); and Oceanicola flagellatus should be transferred to the genus Pseudooceanicola as Pseudooceanicola flagellatus comb. nov. (type strain DY470(T) = CGMCC 1.12664(T) = LMG 27871(T)).