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A taxonomic study was carried out to clarify the status of a Gram-negative, heterotrophic mesophile that was isolated from the marine sponge Halichondria okadai. The strain, designated HOact23T, was a non-motile, rod-shaped (0.44–0.53×0.65–0.79 μm) bacterium. The strain produced squalene and a red–pink carotenoid pigment. The cell-wall peptidoglycan contained meso-diaminopimelic acid, glutamic acid and alanine. The G+C content of the genomic DNA was 52.4 mol%. The major fatty acids were iso-C14 : 0 (43.1 %), iso-C16 : 0 (20.6 %) and anteiso-C15 : 0 (18.1 %), and the major isoprenoid quinone was MK-9 (90.8 %). Based on 16S rRNA gene sequence data, the strain formed a distinct group within subdivision 1 in the phylum ‘Verrucomicrobia’. It showed a range of phenotypic properties that distinguished it from its closest relative, Rubritalea marina Pol012T (94.3 % 16S rRNA gene sequence similarity). On the basis of polyphasic taxonomic evidence, it was concluded that strain HOact23T should be classified within a novel species in the genus Rubritalea. The name proposed for the taxon is Rubritalea squalenifaciens sp. nov., with the type strain HOact23T (=MBIC08254T=DSM 18772T).