Marinobacter hydrocarbonoclasticus Gauthier et al. 1992 and Marinobacter aquaeolei Nguyen et al. 1999 are heterotypic synonyms.

The genus Marinobacter was described with a single species, Marinobacter hydrocarbonoclasticus Gauthier et al. 1992, to place a hydrocarbon-degrading marine bacterium belonging to the gamma-subclass of the Proteobacteria. Marinobacter aquaeolei Nguyen et al. 1999, the second described species of the genus, was proposed for a strain isolated from an oil-producing well on an offshore platform in southern Vietnam, on the basis of differences in the whole-cell protein pattern and lipopolysaccharide composition, although its phenotypic and genotypic characteristics were very similar to those of the type species, M. hydrocarbonoclasticus. In the present paper, literature data concerning the two species were reviewed. Fatty acid composition, G+C content and DNA-DNA hybridization studies were performed in order to clarify the taxonomic positions of these two species. Based on the results obtained in this study and phenotypic and phylogenetic traits available from the literature, it is proposed that the two species should be united under the same name; according to the rules of priority, M. hydrocarbonoclasticus, the first described species, is the earlier synonym and M. aquaeolei is the later synonym.