Three strains of gliding bacteria, 24(T), 62 and 71, isolated from a marine sponge and algae from the southern coastline of Thailand, were studied using a polyphasic approach to clarify their taxonomic positions. A phylogenetic analysis based on 16S rRNA gene sequences showed that the three isolates formed a distinct lineage within the family 'Saprospiraceae' of the phylum Bacteroidetes and were related to members of the genus Saprospira. The G+C contents of the isolates were in the range 38-39 mol%. The major respiratory quinone was MK-7. The predominant cellular fatty acids were 20 : 4omega6c (arachidonic acid), 16 : 0 and iso-17 : 0. On the basis of morphological, physiological and chemotaxonomic characteristics, together with DNA-DNA hybridization data and 16S rRNA gene sequences, the isolates represent a novel species of a novel genus, for which the name Aureispira marina gen. nov., sp. nov. is proposed. The type strain of Aureispira marina is 24(T) (=IAM 15389(T)=TISTR 1719(T)).