Onychomyrmex

These uncommon ants have an army-ant life style. They alternate between temporary bivouacs in protected sites on the ground and semi-permanent nests in soil or in rotten logs. Groups of workers forage by forming distinct raiding columns across the surface of the ground. Some species are known to be specialist predators on centipedes. Queens have greatly extended gasters (they are dichthadiiform), and new colonies are formed by the division of established colonies.

Identification
The mandibles are long and slender, with numerous (always more than 3) teeth which vary greatly in size and are scattered along the inner margins, and with a sharp, pointed tooth at their tips which is at least 4 times longer than the next longest tooth. The frontal lobes extend only slightly forward of the antennal sockets and do not cover the clypeus when viewed from the front. The petiole has distinct front and upper faces but lacks a rear face, and its attachment to the gaster is broad and approximately the same height as the petiole so that the upper surfaces of the petiole and gaster are separated by at most a shallow impression. The tibiae of the hind legs usually lack spurs at their tips, but when present they are small, straight and not comb-like (pectinate) (best viewed from the front).

Onychomyrmex workers are most often confused with workers of Amblyopone. However, they differ in having the tooth at the tip of the mandible much longer and in lacking a comb-like spur on the hind tibia.

Additional References

 * Brown, W. L., Jr. (1950) Morphological, taxonomic, and other notes on ants. Wasmann Journal of Biology, 8: 241–250.
 * Brown, W. L., Jr. (1960) Contributions toward a reclassification of the Formicidae. III. Tribe Amblyoponini (Hymenoptera). Bulletin of the Museum of Comparative Zoology, 122: 143–230.
 * Emery, C. (1895) Descriptions de quelques fourmis nouvelles d'Australie. Annales de la Société Entomologique de Belgique, 39: 345–358.
 * Hölldobler, B., Engel, H., Taylor, R. W. (1982) A new sternal gland in ants and its function in chemical communication. Naturwissenschaften, 69: 90–91.
 * Hölldobler, B., Palmer, J. M. (1989) A new tarsal gland in ants and the possible role in chemical communication. Naturwissenschaften, 76: 385–386.