Iridomyrmex macrops, Heterick & Shattuck, 2011

Heterick, Brian E. & Shattuck, Steve, 2011, Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae) 2845, Zootaxa 2845 (1), pp. 1-174 : 99-100

Iridomyrmex macrops sp. n.

( Figs 48 , 91 )

Types. Holotype worker from 5km W Broken Hill , New South Wales, 15 September 1974, P. J. M. Greenslade ( ANIC, ANIC32-038004 ) . Paratypes: 4 workers from 55km S Balladonia , 32°50’S 123°31’E, Western Australia, 241m, 2 April 1992, S. Shattuck ( ANIC, 2 workers, MCZC, 1 worker, BMNH, 1 worker, ANIC32-038653 ) ; 1 worker from Gluepot Reserve , 6.2km E Gluepot Homestead, 33°45’44”S 140°11’19”E, South Australia, 26 November–6 December2000, pitfalls, clearing with mainly Acacia sp. and a few mallees ( ANIC, ANIC32- 031277 ) ; 1 worker from 10km E Mt. Ive Homestead , South Australia, 22 October 1980, P. J. M. Greenslade ( ANIC, ANIC32-038106 ) ; 1 worker from Koonamore , South Australia, 24–27 February 1973, P. J. M. Greenslade, pitfall traps) ( ANIC, ANIC32-038125 ) .

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 noticeably convex, or straight or weakly 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 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 straight; antennal scape surpassing posterior margin of head by 0.2–0.5 x its length. 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 absent. Mesosoma. Pronotum moderately and evenly curved over its length. 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 inconspicuous; propodeal dorsum smoothly and evenly convex, or straight and short (equal in length to propodeal declivity); 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 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 yellow, with or without brownish infuscation of the head and a yellowish-brown gaster. Colour of erect setae yellow, same colour as body.

Measurements. Worker (n = 5) — CI 78–82; EI 37–46; EL 0.22–0.36; EW 0.15–0.26; HFL 0.94–1.63; HL 0.73–1.00; HW 0.60–0.80; ML 0.99–1.52; MTL 0.66–1.13; PpH 0.11–0.19; PpL 0.39–0.59; SI 124–161; SL 0.74– 1.21.

Comments. The large-eyed I. macrops resembles a hairy I. dromus . Erect setae are present on the hind tibiae, the sides of the head and (in some specimens only) the antennal scape. The ant is much more occasional in its occurrence than I. dromus , but is likely to have a similar ecology. One worker from the Holland Track, east of Hyden, Western Australia, was hand collected at night, foraging in heathy sandplain, and specimens taken SSW of Coolgardie, Western Australia, were collected from mallee trunks. Currently, records of this species are restricted to Western Australia and South Australia.

Etymology. Greek: referring to the large eye.

Figures

FIGURE 48. Iridomyrmex macrops (holotype, Broken Hill, NSW, ANIC32-038004): 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.