Summary A strain of the Cytophaga-like bacterium (CLB), Nano-1, was isolated from the 0.2 μm-filtrate of natural seawater. Both cellular fatty acid and 16S rDNA sequence analyses indicated that Nano-1 is closely affiliated to the marine gliding CLB genus, Microscilla. Nano-1 was observed to undergo cyclic morphological change typical of the genus Microscilla, and sub-0.2-μm cells were formed in the late stationary phase. The sub-0.2-μm cells were repeatedly revived and subcultured. Formation of the sub-0.2-μm cells seems to be adaptive for oligotrophic growth and starvation survival.