The taxonomic position of seven soil actinomycetes provisionally assigned to the genus Amycolatopsis was established in a polyphasic study. The isolates, which had identical 16S rRNA gene sequences, had closest similarity to the type strain of Amycolatopsis orientalis. A representative isolate, strain GY080T, had chemotaxonomic properties that were typical of the genus Amycolatopsis and could be distinguished from the type strain of A. orientalis using DNA–DNA relatedness data. All of the isolates shared a phenotypic profile that distinguished them from representatives of phylogenetically closely related species. Amplified rDNA restriction analysis showed that the isolates formed a homogeneous group that was distinctly separate from single-membered groups consisting of representative Amycolatopsis type strains, including that of A. orientalis. Based on the combined genotypic and phenotypic evidence, it is proposed that the seven isolates be classified as representatives of a novel species for which the name Amycolatopsis regifaucium sp. nov. is proposed. The type strain is GY080T (=DSM 45072T =NCIMB 14277T).

The taxonomic position of a group of mesophilic actinomycetes isolated from arid Australian soils was determined using a polyphasic approach. The organisms shared chemical and morphological markers typical of members of the genus Amycolatopsis. They had identical 16S rRNA gene sequences and formed a distinct phyletic line in the Amycolatopsis mediterranei clade, being most closely related to A. mediterranei. In addition, they shared a range of phenotypic properties that distinguished them from representatives of all of the species classified in this clade. The combined genotypic and phenotypic data indicate that the strains merit species status within the genus Amycolatopsis. The name proposed for the novel species is Amycolatopsis australiensis sp. nov.; the type strain is GY048 T (=DSM 44671 T =NCIMB 14142 T ).