The taxonomic positions of three thermophilic actinomycetes isolated from arid soil samples were established by using a polyphasic approach. The organisms had chemical and morphological features that were consistent with their classification in the genus
. 16S rRNA gene sequence data supported the classification of the isolates in the genus
and showed that they formed distinct branches in the
subclade. DNA–DNA relatedness studies between the isolates and their phylogenetic neighbours showed that they belonged to distinct genomic species. The three isolates were readily distinguished from one another and from the type strains of species classified in the
subclade based on a combination of phenotypic properties and by genomic fingerprinting. Consequently, it is proposed that the three isolates be classified in the genus
as representatives of Amycolatopsis granulosa sp. nov. (type strain GY307T = NCIMB 14709T = NRRL B-24844T), Amycolatopsis ruanii sp. nov. (type strain NMG112T = NCIMB 14711T = NRRL B-24848T) and Amycolatopsis thermalba sp. nov. (type strain SF45T = NCIMB 14705T = NRRL B-24845T).