Iridomyrmex cupreus, Heterick & Shattuck, 2011

Heterick, Brian E. & Shattuck, Steve, 2011, Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae) 2845, Zootaxa 2845 (1), pp. 1-174 : 69-70

Iridomyrmex cupreus sp. n.

( Figs 28 , 91 )

Types. Holotype worker from Blanche Cup Spring, near Coward Spring , South Australia, 18 August 1977, edge of swamp ( ANIC, ANIC32-037093 ) . Paratypes: 6 workers from William Creek , South Australia, 23 July 1956, R. S. McInnes ( ANIC, ANIC32-040968 , 3 workers; MCZC, ANIC32-040947 , 3 workers) .

Worker Description. Head. Posterior margin of head weakly concave; erect setae on posterior margin in fullface 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 below 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 convex; antennal scape surpassing posterior margin of head by 1-2 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) and longest setae elongate, flexuous and/or curved, or numerous (12 or more), short and bristly. Mesonotum sinuous, or straight. Erect mesonotal setae moderate in number (6-12), short and bristly. Mesothoracic spiracles always inconspicuous; propodeal dorsum smoothly and evenly convex; placement of propodeal spiracle posteriad and near 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 moderate in number (6-12), short and bristly. Petiole. Dorsum of node 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 dark chocolate, with dull coppery to bluish reflections. Colour of erect setae whitish.

Measurements. Worker (n = 2) — CI 86–88; EI 29–30; EL 0.20–0.21; EW 0.16–0.16; HFL 0.85–0.89; HL 0.80–0.83; HW 0.69–0.74; ML 0.97–1.01; MTL 0.60–0.65; PpH 0.11–0.14; PpL 0.41–0.42; SI 97–102; SL 0.70– 0.72.

Comments. This is yet another rather physically undistinguished and very uncommon ant. The small-medium workers can mainly be distinguished from species like I. splendens , I. mjobergi and I. coeruleus by the presence of erect setae on the tibiae, the latter species having glabrous tibiae (all in all, I. cupreus is a rather hairy ant, but the erect setae are short, thus distinguishing this species from I. spurcus ). The eye is slightly asymmetrical, and reminiscent of many workers of I. dromus . A handful of pins of this ant only are known, all collections having been made in the vicinity of Lake Eyre, South Australia.

Etymology. Latin: the name refers to the coppery appearance of the worker cuticle. Weak bluish reflections may also be seen in a few workers.

Figures

FIGURE 28. Iridomyrmex cupreus (holotype, Coward Springs, SA, ANIC32-037093): A. Front of head; B. Side of body; C. Top of body; D. Distribution of material examined.

FIGURE 91. Scape length versus head width for I. cupreus and I. macrops.