Onychomyrmex hedleyi

I took two small companies of this ant, unaccompanied by larvae or females, Oct. 24 and 28, evidently on foraging expeditions in the heart of rotten logs. One of the companies comprised a dozen, the other about two dozen workers. Later Mr. Dodd sent me eight workers which he had taken in the same locality. The ants moved rather slowly and were easily captured. (Wheeler 1916)

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Biology
Workers of O. hedleyi did not dismember prey but recruited nestmates to conduct group retrieval. If the prey was too large or too heavy to retrieve, the entire colony moved from the bivouac site to the prey site (Miyata et al. 2009). Colonies were nomadic and the relocation distance was up to 150 cm (mean +/-􏰀 SD, 74.4 +/- 45.0 cm). Retinues guarded a queen who moved to a new bivouac site in the early phase of relocation. Colony size was 850 +/- 341 workers (Miyata et al. 2003).

Castes
Data about ergatoid queens are given in Miyata et al. (2003)

Nomenclature

 *  hedleyi. Onychomyrmex hedleyi Emery, 1895g: 350, fig. 2 (w.) AUSTRALIA. Forel, 1915b: 4 (m.); Wheeler, G.C. & Wheeler, J. 1964b: 454 (l.). See also: Wheeler, W.M. 1916a: 50.

Type Material
Syntype workers from Mt. Bellenden Ker, Queensland (3 in, 2 pins in , 1 worker in ).



Worker
Wheeler (1916) - Length 3.5-4 mm.

Head about 1 1/4 times as long as broad, subrectangular, a little broader in front than behind, with straight sides and posterior border and rounded posterior corners. Clypeus with the anterior border slightly flattened, arcuately rounded in the middle, sinuate at the sides, its edge beset with about 20 minute, regular teeth. Eyes with about 6-8 minute ommatidia, situated 3/5 the length of the head from the anterior margin. Mandibles with long, abruptly incurved apical tooth and seven basal teeth of different sizes, the two in the middle of the series largest and directed backward. Antennae slender, scapes fully 4/5 as long as the head, first and last funicular joints twice as long as broad, remaining joints about l ½ times as long as broad. Thoracic sutures all strongly impressed; pronotum convex above, especially in front, with convex sides, a little longer than broad; mesonotum nearly twice as broad as long; epinotum longer and narrower than the pronotum, longer than broad, with feebly convex sides and separated in dorsal view from the pronotum by a pronounced impression on each side. In profile the thorax is distinctly impressed at the mesonotum, the base of the epinotum is nearly twice as long as the straight declivity into which it passes through an obtuse angle. Node of petiole in profile with rather straight anterior slope and convex summit, slightly concave at the posterior border; from above the node is as long as broad, rounded in front, with straight posterior border; ventral projection long and blunt, compressed and somewhat translucent. Postpetiole as long as broad, first gastric segment a little longer than the postpetiole. Legs slender.

Very smooth and shining; mandibles, clypeus, and cheeks subopaque, the mandibles finely striated, the clypeus and cheeks finely rugulose-punctate. Body with fine,' sparse, piligerous punctures, which are most numerous on the head, especially on its sides.

Hairs delicate, pale yellowish, short, suberect, covering not only the whole body, legs, and antennal scapes but also the funiculi; somewhat longer and sparser on the thorax, abdomen, and legs than on the head and antennae.

Black; thoracic sutures, sides and terminal segments of abdomen, clypeus, cheeks, and anterior portion of gula reddish castaneous, mandibles, except their teeth, antennae, and legs paler, brownish red, middle portions of femora and tibiae more or less infuscated.

References based on Global Ant Biodiversity Informatics

 * Brown W. L., Jr. 1960. Contributions toward a reclassification of the Formicidae. III. Tribe Amblyoponini (Hymenoptera). Bull. Mus. Comp. Zool. 122: 143-230.
 * King J. R., A. N. Andersen, and A. D. Cutter. 1998. Ants as bioindicators of habitat disturbance: validation of the functional goup model for Australi's humid tropics. Biodiversity and Conservation 7: 1627-1638.
 * Taylor R. W. 1987. A checklist of the ants of Australia, New Caledonia and New Zealand (Hymenoptera: Formicidae). CSIRO (Commonwealth Scientific and Industrial Research Organization) Division of Entomology Report 41: 1-92.
 * Wheeler W. M. 1916. The Australian ants of the genus Onychomyrmex. Bulletin of the Museum of Comparative Zoology 60: 45-54.