Subterranean ant nests: trace fossils past and future?

Many species of ants excavate complex, species-typical nests in soil. The basic structural units of many nests are descending tunnels connecting flattened, generally horizontal chambers of oval to lobed outline. The species-typical structure of many nests results from variation in the size, shape, number and arrangement of these basic elements. Nest architecture can be rendered by filling subterranean nests with a thin slurry of orthodontal plaster, then excavating and reconstructing the hardened cast. Photographs of such nest casts of nine species of ants from northern Florida show the range and type of variation of architecture. Preservation conditions under which ant nests could form complex trace fossils are discussed, and reports of such traces reviewed. The images presented in this paper will help to alert trace fossil specialists to the potential range of appearance of such nest fossils.