Iridomyrmex rubriceps Forel, 1902

Heterick, Brian E. & Shattuck, Steve, 2011, Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae) 2845, Zootaxa 2845 (1), pp. 1-174 : 130-131

Iridomyrmex rubriceps Forel , stat. n.

( Fig. 67 )

Iridomyrmex gracilis rubriceps Forel, 1902: 468 .

Types. Syntypes from Mackay , Queensland ( ANIC, 2 workers, examined; BMNH, 5 workers, examined; MCZC, 2 workers, examined; MHNG, 8 workers, examined; NHMB, 1 worker) .

Worker Description. Head. Posterior margin of head weakly convex to planar; erect setae on posterior margin in full-face view set in a row; sides of head convergent anteriad; erect genal setae absent from sides of head in fullface 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 absent, except at tip; prominence on anteromedial clypeal margin projecting as triangular spur; mandible elongate triangular with oblique basal margin; long, curved setae on venter of head capsule absent. Mesosoma. Pronotum weakly undulant or almost straight. Erect pronotal setae numerous (12 or more), short and bristly. Mesonotum straight. Erect mesonotal setae moderate in number (6–12), 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 moderate in number (6–12), short and bristly. Petiole. Dorsum of node convex, or planar; 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, pronotum brownish-orange, rest of body brown. Colour of erect setae pale, depigmented yellow.

Measurements. Worker (n = 3)— CI 81–82; EI 24–24; EL 0.29–0.29; EW 0.22–0.23; HFL 2.26–2.28; HL 1.47–1.51; HW 1.20–1.23; ML 2.00–2.06; MTL 1.58–1.63; PpH 0.23–0.24; PpL 0.72–0.74; SI 123–124; SL 1.49– 1.52.

Comments. Iridomyrmex rubriceps is the sister species to I. agilis , and can be distinguished from it as described in ‘Comments’ under the former species. Iridomyrmex rubriceps also differs in its habitat preferences, being an ant of the rainforest and wet sclerophyll forests of the Australian east coast. The taxon has been recorded from Queensland and New South Wales (including one record from the Bogan River in central New South Wales). There is also one South Australia record that requires verification. This species appears to have different requirements to its sister species, various label data indicating that colonies have been located under rocks or stones rather than in the open ground preferred by I. agilis . Workers have also been taken from termite nests around logs in Castlereagh SF (New South Wales), and have been found foraging on low vegetation (Tamborine, Queensland) and tending lycaenid larvae ( Jalmenus evagoras ) (Maryborough, Queensland).

Figures

FIGURE 67. Iridomyrmex rubriceps (syntype, Port of Mackay, Qld, ANIC32-038937): A. Front of head; B. Side of body; C. Top of body; D. Distribution of material examined.