Nature 398, 701–704 (1999).

We reported in this Letter that, on the basis of its cell-wall chemistry, the bacterium associated with the fungus-growing ant Acromyrmex octospinosus is in the genus Streptomyces (Streptomycetaceae: Actinomycetes). It has been brought to our attention by Nature that R. Wirth, T. Wagner, C. Kost, I. Böttcher, W.-R. Arendholz and M. Redenbach (manuscript submitted) do not find evidence of a specialized relationship between bacteria in the genus Streptomyces and fungus-growing ants in the genus Acromyrmex. Our ongoing molecular phylogenetic analyses reveal that the specialized symbiotic bacterium associated with Acromyrmex is not a species of Streptomyces, but is instead in the actinomycetous family Pseudonocardiaceae (C.R.C. and M. Cafaro, manuscript in preparation). This genus-level misidentification does not affect our other conclusions.