Blastococcus saxobsidens sp. nov., and emended descriptions of the genus Blastococcus Ahrens and Moll 1970 and Blastococcus aggregatus Ahrens and Moll 1970.

Ten Gram-positive, aerobic bacterial strains with coccoid cells occurring singly, in pairs, tetrads and small aggregates were isolated from the surface of marble and calcareous stones. The peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. The major menaquinone was MK-9(H4). The cellular fatty acid pattern consisted mainly of iso-branched chain components. According to their phylogenetic position, the organisms are members of the family Geodermatophilaceae, clustering close to Blastococcus aggregatus DSM 4725T. Based on a combination of phenotypic, chemotaxonomic and genotypic characteristics, strain BC444T and seven relatives group apart from strains BC412 (=DSM 44517) and BC521 (=DSM 44518), which themselves form two individual lineages. DNA-DNA reassociation studies revealed that members of the three lineages were only remotely related to B. aggregatus DSM 4725T; as the strain-rich cluster containing BC444T shared low DNA similarity values with strains BC412 and BC521, it will be described as a novel species of Blastococcus, for which the name Blastococcus saxobsidens sp. nov. is proposed. The type strain is BC444T (=DSM 44509T=NRRL 24246T).