Iridomyrmex rufoinclinus Shattuck, 1322

Heterick, Brian E. & Shattuck, Steve, 2011, Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae) 2845, Zootaxa 2845 (1), pp. 1-174 : 132-133

Iridomyrmex rufoinclinus Shattuck

( Fig. 68 )

Iridomyrmex rufoinclinus Shattuck, 1993b: 1322 , figs 34, 35, 37.

Types. Holotype worker from Edith Falls, Katherine Gorge National Park , 14°10'57"S 132°11'13"E, Northern Territory ( ANIC, ANIC32-000062 , examined) . Paratypes: same data as holotype ( ANIC, ANIC32-000061 , 28 workers, examined; BMNH, 1 worker; MCZC, 1 worker) .

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 at about midpoint of head capsule; in profile, eye set anteriad of head capsule; eye more-or-less circular. Frontal carinae concave; antennal scape barely attaining posterior margin of head, or surpassing it by less than 1 x its diameter. Erect setae on scape present and abundant, or present and sparse, or absent, except at tip; prominence on anteromedial clypeal margin present as an indistinct swelling or undulation; mandible elongate triangular with oblique basal margin; long, curved setae on venter of head capsule present.

Mesosoma. Pronotum moderately and evenly curved over its length. Erect pronotal setae numerous (12 or more) and longest setae elongate, flexuous and/or curved. Mesonotum sinuous, or straight. Erect mesonotal setae numerous (12 or more) and elongate, flexuous and/or curved. Mesothoracic spiracles prominent or 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) and elongate, flexuous and/or curved. Petiole. Dorsum of node convex; node reduced to anterior lip only, the rest incorporated in the petiole. 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 foreparts and legs orange to brick red, gaster dark chocolate with blue iridescence. Colour of erect setae depigmented pale yellow.

Measurements. Worker (n = 15) — CI 91–98; EI 25–28; EL 0.31–0.37; EW 0.18–0.22; HL 1.20–1.44; HW 1.10–1.38; ML 0.55–0.70; PpH 0.16–0.22; PpL 0.69–0.82; SI 81–95; SL 0.96–1.18.

Comments. This species is distinctive in its colouration, being the only member of the I. rufoinclinus speciescomplex with a uniformly red or yellowish-red head and mesosoma and blue iridescence on the gaster. Iridomyrmex rufoinclinus occurs across the entire top end of Australia, from the Kimberley region to south central Queensland, and Shattuck (1993b) states that this species appears to favour woodland. Shattuck (1993b) also reports that workers from the colony from which the type series was taken were foraging throughout the day in a loosely formed column. Observations of other colonies revealed workers would move on to low vegetation. The nest housing ants belonging to the type series was a low, asymmetrical disc of loose soil, and had a single entrance hole.

Figures

FIGURE 68. Iridomyrmex rufoinclinus (holotype, Katherine Gorge National Park, NT, ANIC32-000062): A. Front of head; B. Side of body; C. Top of body; D. Distribution of material examined (A. Noble, www.antweb.org).