A novel actinobacterial strain, MKSP12(T), was isolated from coastal sediment of a crater lake in central Anatolia, Turkey. The taxonomic position of the strain was clarified using a polyphasic approach. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain MKSP12(T) is closely related to Streptomyces specialis GW 41-1564(T) with 97.1% sequence similarity. The strain produces aerial hyphae that differentiate into spiral chains of smooth surfaced spores and grows over a temperature range of 20-37 A degrees C, at pH 7-11 and in the presence of 3% (w/v) sodium chloride. The cell wall amino acid is LL-diaminopimelic acid and the whole cell sugars are glucose and ribose. The polar lipids profile consists of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, an unidentified aminophospholipid, two unidentified phospholipids, an unidentified glycophospholipid and eight unidentified glycolipids; iso-C-16:0, iso-C-16:1 G, anteiso-C-17:0 and anteiso-C-17:1 omega 9c were identified as the predominant cellular fatty acids (> 10%). Based on morphological and chemotaxonomic characteristics, and phylogenetic analyses, the strain is considered to represent a novel species in the genus Streptomyces, for which the name Streptomyces sediminis sp. nov. is proposed with the type strain MKSP12(T) (= DSM 100692(T) = KCTC 39613(T)).