Iridomyrmex galbanus

Iridomyrmex galbanus is mainly confined to the Eyre Peninsula of South Australia, but scattered populations also occur in south-eastern South Australia and western Victoria. This species appears to favour certain soil types (Shattuck, 1993a).

Identification
Iridomyrmex galbanus shares with Iridomyrmex viridiaeneus greenish iridescence on the head capsule, but in the case of I. galbanus the head capsule is distinctly lighter in colour than the mesosoma (versus the same colour or only slightly lighter in I. viridiaeneus).

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  galbanus. Iridomyrmex galbanus Shattuck, 1993a: 121, fig. 10 (w.) AUSTRALIA. See also: Heterick & Shattuck, 2011: 83.

Description
Worker Description. Head. Posterior margin of head 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, or 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 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 approximately 3 x its diameter. Erect setae on scape present and abundant; prominence on anteromedial clypeal margin projecting as triangular spur; mandible elongate triangular with oblique basal margin; long, curved setae on venter of head capsule present in some workers. 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 prominent as small, vertical protuberances; 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. Petiole dorsum of node acuminate; node thick, 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 head orange, mesosoma brownish-orange, head and mesosoma with pink, green and yellow-green iridescence, gaster black with bright bluish- green and purple iridescence, legs brown. Colour of erect setae dark brown.

Measurements. Worker (n = 23)—CI 90–99; EI 17–21; EL 0.33–0.40; EW 0.21–0.26; HL 1.84–2.37; HW 1.68–2.3 1; ML 0.90–1.23; PpH 0.27–0.37; PpL 0.99–1.30; SI 87–103; SL 1.67–2.06.