A new petroleum-degrading bacterium, designated strain GC2(T), was isolated from Bozkus 1 petroleum station in Diyarbakir, located in the southeast of Turkey. Cells were Gram-negative staining, aerobic, coccoid-rods, non-motile, non-spore-forming. The bacterium was found to degrade 100% ofn-alkanes ranging from C11 to C34 presented in the 1% crude oil after incubation of 7 days. The membrane phospholipids were 1,2 diacylglycero-3-phosphorylethanolamine (PEA), phosphatidylglycerol (PG), dipalmitoyl-sn-glycerol 1- phosphocholine (PC1), 1,2 dipalmitoyl-sn-glycero-3-phosphocholine monohydrate (PC3), cardiolipin also called diphosphatidylglycerol (CL) and l-alpha- phosphatidic acid, dipalmitoyl (AP); predominant respiratory ubiquinone was Q-8 and C16:0, C18:1 omega 9c and C16:1 were the major cellular fatty acids. The 16S rRNA sequence analysis revealed that the strain GC2(T)was a member of genusAcinetobacterand was most closely related toAcinetobacter lwoffiiDSM 2403( T)(99.79%),Acinetobacter pseudolwoffiiANC 5318( T)(98.83%) andAcinetobacter harbinensisHITLi 7( T)(98.14%). TherpoBandgyrBgene sequence analysis confirmed that the strain GC2(T)was a member of genusAcinetobacterand that the closest relative wasAcinetobacter lwoffiiDSM 2403( T)(99.08% and 100% similarity, respectively). DNA-DNA hybridization values between GC2(T)and its closest relatives ranged from 65.6% (withA. lwoffii) to 5.1% (withA. venetianus). The whole genome sequence of strain GC2(T)was obtained. The DNA G + C content of this strain was determined to be 42.9 mol %. ANI indexes, in silico estimations of DDH values and wet lab DDH values demonstrated that strain GC2(T)represents an independent genomospecies. On the basis of phenotypic characteristics, chemotaxonomic, phylogenetic data and DNA-DNA hybridization and whole genome analysis, we propose to assign strain GC2(T)as a new species of the genusAcinetobacter, for which the nameAcinetobacter mesopotamicussp. nov. is proposed. The type strain of this species is GC2(T)(DSM 26953 T = JCM 31073 T). The whole genome of strain GC2(T)has been deposited at DDBJ/ENA/GenBank under the accession JAALFF010000000.