Cheliomyrmex

Cheliomyrmex is a rarely encountered genus of New World army ants that is a mostly subterranean predator with likely a specialized diet.

Identification
Diagnosis. Worker. Workers of Cheliomyrmex can be recognized by a combination of propodeal spiracle positioned high on the propodeum, propodeal declivity simple and not armed with cuticular ridges or denticles, abdominal segment III small but broad posteriorly and thus waist appearing one-segmented, pygidium small and armed with at most a pair of modified setae, and pretarsal claws armed with a tooth. Cheliomyrmex is perhaps most similar to Labidus and certain Neivamyrmex but it is unique among New World army ants in having abdominal segment III broadly attached to segment IV (i.e. it has a uninodal waist) and thus easily told apart from all other army ant genera in this region.

Species richness
Species richness by country based on regional taxon lists (countries with darker colours are more species-rich). View Data



Biology
Ants in this lineage have been rarely observed or collected. The raids and emigrations of these ants are mostly subterranean, only occasionally seen above ground. Raids have been observed mostly under stones or rotting wood (Wheeler 1921, Gotwald 1971). A diverse fauna of associates was reported from an emigration column of C. morosus, including phorid flies, staphylinid beetles, silverfish and mites (Berghoff and Franks 2007). The 2007 study and the only other published observation of a Cheliomyrmex emigration (C. megalonyx; Wheeler 1921), described galleries of soil built by the ants to cover the areas where the ant columns had to proceed on the surface. Wheeler also reported a behavior where stationary major workers were guarding the emigration columns and compared it to that of African Dorylus, although this behavior is also known in Labidus (Rettenmeyer 1963). As Wheeler observed only larvae being carried by the workers, it has been postulated that brood production is synchronized (Rettenmeyer 1963). Cheliomyrmex andicola has been observed feeding on a dead snake and actively pursuing and killing a giant earthworm in Ecuador (O’Donnell et al. 2005). Given that no other prey has been observed for this genus, combined with the specialized mandibular morphology and potent sting, O’Donnell et al. (2005) proposed that Cheliomyrmex are specialized predators of large subterranean invertebrates or maybe even vertebrates.

Nomenclature

 *  CHELIOMYRMEX [Ecitoninae: Cheliomyrmecini]
 * Cheliomyrmex Mayr, 1870b: 968. Type-species: Cheliomyrmex nortoni (junior synonym of Labidus morosus), by monotypy.