Two cauliform bacteria (CM243T and CM251) isolated by J. Poindexter from the Atlantic Ocean were characterized by 16S rRNA gene sequencing, TaqI restriction fragment length polymorphism and single-strand conformation polymorphism analyses of the internally transcribed 16S-23S rDNA spacer (ITS1) region, analysis of fatty acids from cellular lipids, mass spectrometry of polar lipids and physiological properties. The two strains showed very low diversity of polar lipids with diacyl-sulfoquinovosyl glycerols as the predominant lipids. The two bacterial strains were observed to have nearly identical 16S rRNA gene sequences and could not be differentiated by their ITS1 regions. The isolates differed from species of the genus Maricaulis by their 16S rRNA gene sequences, polar lipids and fatty acid patterns. On the basis of the genotypic analyses and estimations of phylogenetic similarities, physiological and chemotaxonomic characteristics, it is proposed that the isolates represent a new genus and species, for which the name Woodsholea maritima gen. nov., sp. nov. (type strain CM243T=VKM B-1512T=LMG 21817T) is proposed.