REORGANIZATION OF THE GENUS ERYTHROMICROBIUM - DESCRIPTION OF ERYTHROMICROBIUM-SIBIRICUM AS SANDARACINOBACTER-SIBIRICUS GEN. NOV., SP. NOV., AND OF ERYTHROMICROBIUM-URSINCOLA AS ERYTHROMONAS-URSINCOLA GEN. NOV., SP. NOV

The results of investigations on the morphology, physiology, pigment c omposition, light-harvesting antenna and reaction center organization, and electron carriers of five Erythromicrobium representatives, and o n phylogenetic relations among them, are summarized. On tbe basis of c lear phenotypic differences and distinct phylogenetic positions shown by 16S ribosomal DNA analysis, the tentative species ''Erythromicrobiu m sibiricum'' and ''Erythromicrobium ursincola'' are formally describe d as the type species of two new genera: Sandaracinobacter sibiricus g en. nov., sp. nov., and Erythromonas ursincola gen. nov., sp. nov., re spectively. The genus Erythromicrobium is at present composed of the t ypes species, E. ramosum, and two species, ''E. hydrolyticum'' and ''E . ezovicum,'' whose nomenclature is yet to be validated. All species s tudied group within the alpha-4 subclass of Proteobacteria.