Iridomyrmex hartmeyeri

Like close relatives, this ant is largely nocturnal. It has a generally very broad distribution over much of the Australian continent, but avoids the wetter southwest and south-east corners.

Identification
Iridomyrmex hartmeyeri is a pale yellowish to dull orange ant, with large, asymmetrical compound eyes. The workers can be of a reasonable size, their proportions approaching those of a small meat ant in some populations. The large size, indented posterior margin of the head, glabrous hind tibia and glabrous or near glabrous mesosomal dorsum set this species aside from similar ants.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  hartmeyeri. Iridomyrmex hartmeyeri Forel, 1907h: 296 (w.) AUSTRALIA. See also: Heterick & Shattuck, 2011: 87.

Description
Worker Description. Head. Posterior margin of head weakly concave, or strongly concave; erect setae on posterior margin absent; sides of head noticeably convex; erect genal setae absent from sides of head in full-face view (one to a few small setae may be present near mandibular insertion). Ocelli absent; in full-face view, eyes set above midpoint of head capsule; in profile, eye set anteriad of head capsule; eye asymmetrical, curvature of inner eye margin more pronounced than its outer margin and anterior sector of eye distinctly broader than its posterior sector. Frontal carinae straight; antennal scape surpassing posterior margin of head by approximately 3 x its diameter. Erect setae on scape absent, except at tip; prominence on anteromedial clypeal margin projecting as blunt but distinct protuberance; mandible elongate triangular with oblique basal margin; long, curved setae on venter of head capsule absent. Mesosoma. Pronotum strongly inclined anteriorly. Erect pronotal setae lacking or very minute (one or two tiny setae may be present). Mesonotum sinuous, or straight. Erect mesonotal setae lacking or very minute (one or two tiny setae present). Mesothoracic spiracles always inconspicuous; propodeal dorsum protuberant, or smoothly and evenly convex; placement of propodeal spiracle mesad, more than its diameter away from propodeal declivity; propodeal angle weakly present or absent, the confluence of the dorsal and declivitous propodeal faces indicated, if at all, by an undulation. Erect propodeal setae lacking or very minute (one or two tiny setae present). Petiole. Dorsum of node convex; node thin, scale-like, orientation more-or-less vertical. Gaster. Non-marginal erect setae of gaster present or absent on first gastral tergite; marginal erect setae of gaster present on first tergite, or absent on first tergite. General characters. Allometric differences between workers of same nest present. Colour of foreparts uniformly pale yellow to medium ochre, gaster brown in darker specimens. Colour of erect setae where present, pale yellowish.

Measurements. Worker (n = 10)—CI 88–93; EI 32–38; EL 0.28–0.40; EW 0.21–0.29; HFL 1.07–2.00; HL 0.88–1.33; HW 0.78–1.20; ML 1.15–2.00; MTL 0.77–1.44; PpH 0.17–0.30; PpL 0.44–0.75; SI 106–126; SL 0.86– 1.43.

References based on Global Ant Biodiversity Informatics

 * CSIRO Collection
 * Chong C-S., L. J. Thomson, and A. A. Hoffmann. 2011. High diversity of ants in Australian vineyards. Australian Journal of Entomology 50: 7-21.
 * Fisher J., L. Beames, B. J. Rangers, N. N. Rangers, J. Majer, and B. Heterick. 2014. Using ants to monitor changes within and surrounding the endangered Monsoon Vine Thickets of the tropical Dampier Peninsula, north Western Australia. Forest Ecology and Management 318: 7890.
 * Heterick B. E., B. Durrant, and N. R. Gunawardene. 2010. The ant fauna of the Pilbara Bioregion, Western Australia. Records of the Western Australian Museum, Supplement 78: 157-167.
 * Heterick B. E., and S. Shattuck. 2011. Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae). Zootaxa 2845: 1-174.