A novel actinobacterium, designated isolate B204(T), was isolated from a marine ascidian Didemnum sp., collected from São Paulo, Brazil, and its taxonomic position established using data from a polyphasic study. The organism showed a combination of chemotaxonomic and morphological characteristics consistent with its classification in the genus Gordonia and formed a distinct phyletic line in the Gordonia 16S rRNA gene tree. It was closely related to Gordonia terrae DSM 43249(T) (99.9 % 16S rRNA gene sequence similarity) and Gordonia lacunae DSM 45085(T) (99.3 % 16S rRNA gene sequence similarity) but was distinguished from these strains by a moderate level of DNA-DNA relatedness (63.0 and 54.7 %) and discriminatory phenotypic properties. Based on the data obtained, the isolate B204(T) (=CBMAI 1069(T) = DSM 46679(T)) should therefore be classified as the type strain of a novel species of the genus Gordonia, for which the name Gordonia didemni sp. nov. is proposed.
Keywords: Gordonia didemni; Marine ascidium; Polyphasic taxonomy; São Paulo state.