sp. nov., isolated from a cave, and proposals that is a later synonym of , and are later synonyms of , and and are later synonyms of .

Two novel actinobacterial strains, designated C9-5 and C3-43, were isolated from soil samples of a cave in Jeju Island, Republic of Korea, and subjected to taxonomic study by a polyphasic approach. The organisms exhibited a typical rod-coccus developmental cycle during growth and grew at 10-30 °C, pH 5-9 and 0-3 % (w/v) NaCl. In 92 single-copy core gene sequence analysis, strain C9-5 was loosely associated with , albeit sharing low 16S rRNA gene sequence similarity (97.4 %). A combination of morphological and chemotaxonomic characteristics supported assignment with the genus . With respect to 16S rRNA gene sequence similarity, the novel isolates showed the highest identity to the type strain of (98.7 % sequence similarity), followed by (98.5 %) and (98.4 %).The average nucleotide identity and digital DNA-DNA hybridization values between strain C9-5 and members of the genus were ≤81.5 and ≤37.1 %, respectively. A set of physiological and chemotaxonomic properties together with overall genomic relatedness differentiated the novel isolates from members of the genus , for which the name sp. nov. is proposed. The type strain is C9-5 (=KACC 19822=DSM 107558). Based on genome analysis performed here, it is also proposed that Su . 2015 is a later heterotypic synonym of Yoon . 2000, Xu . 2007 and Li . 2004 are later heterotypic synonyms of (Gray and Thornton 1928) Goodfellow and Alderson 1979 (Approved Lists 1980), and Briglia . 1996 and Ghosh . 2006 are later heterotypic synonyms of Klatte . 1995.