Iridomyrmex curvifrons

This is another nondescript, medium-sized brown Iridomyrmex that is known from very few specimens, although it may prove to be locally common within a limited range. All known specimens have been collected in south-east Queensland. Label data indicates that I. curvifrons tends blue butterfly larvae (Lycaenidae: Jalmenus eubulus Miskin). One series was also taken from under a rock.

Identification
Workers can be identified by a combination of erect setae on the tibiae and genae (but absent from the antennal scapes) and broadly oval head when seen in full-face view. The species is likely to be close to Iridomyrmex anceps, with which it shares its uniform brown colour and short bristly setae on the mesosoma.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  curvifrons. Iridomyrmex curvifrons Heterick & Shattuck, 2011: 70, figs. 29, 92 (w.) AUSTRALIA.

Description
Worker Description. Head. Posterior margin of head planar to weakly concave; erect setae on posterior margin in full-face view set in a row; sides of head noticeably convex; erect genal setae present on sides of head in full- face view. Ocelli absent; in full-face view, eyes set at about midpoint of head capsule; in profile, eye set anteriad of head capsule; eye semi-circular. Frontal carinae convex; antennal scape surpassing posterior margin of head by 0.2–0.5 x its length, or 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 moderately and evenly curved over its length. Erect pronotal setae numerous (12 or more), short and bristly. Mesonotum sinuous. Erect mesonotal setae numerous (12 or more), short and bristly. Mesothoracic spiracles always inconspicuous; propodeal dorsum 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 numerous (12 or more), short and bristly. Petiole. Dorsum of node acuminate, or convex; node thin, scale-like, orientation more-or-less vertical. Gaster. Non-marginal erect setae of gaster present on first gastral tergite; marginal erect setae of gaster present on first tergite. General characters. Allometric differences between workers of same nest absent. Colour uniformly brown. Colour of erect setae yellow.

Measurements. Worker (n = 4)—CI 89–93; EI 22–25; EL 0.22–0.24; EW 0.16–0.18; HFL 1.27–1.49; HL 0.97–1.17; HW 0.86–1.08; ML 1.28–1.60; MTL 0.87–1.03; PpH 0.19–0.23; PpL 0.47–0.62; SI 101–107; SL 0.92– 1.09.

Etymology
Latin: ‘curvus’ plus ‘frons’, referring to the oval appearance of the head when seen in full-face view.

References based on Global Ant Biodiversity Informatics

 * Heterick B. E., and S. Shattuck. 2011. Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae). Zootaxa 2845: 1-174.