Iridomyrmex mayri Forel, 1915

Heterick, Brian E. & Shattuck, Steve, 2011, Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae) 2845, Zootaxa 2845 (1), pp. 1-174 : 101-103

Iridomyrmex mayri Forel , stat. n.

( Fig. 50 )

Iridomyrmex gracilis mayri Forel, 1915: 80 .

Types. Syntypes from Blackall Range, Queensland ( ANIC, ANIC32-017919 , 1 worker, examined); Lamington (as Glen Lamington), Queensland (not located during this study) and Ravenshoe (as Cedar Creek ), Queensland (not located during this study) .

Worker Description. Head. Posterior margin of head planar to 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 fullface view. 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, or elongate. Frontal carinae convex; 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; prominence on anteromedial clypeal margin projecting as blunt but distinct protuberance; mandible regularly 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 sinuous. Erect mesonotal setae numerous (12 or more), short and bristly. Mesothoracic spiracles always 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), short and bristly. Petiole. Dorsum of node convex; 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 present. Colour uniformly blackish- to reddish-brown, with pale to very pale blue or purple iridescence. Colour of erect setae pale, whitish.

Measurements. Worker (n = 6) — CI 86–89; EI 24–27; EL 0.24–0.27; EW 0.18–0.21; HFL 1.50–1.88; HL 1.02–1.24; HW 0.88–1.10; ML 1.41–1.76; MTL 1.08–1.31; PpH 0.19–0.23; PpL 0.54–0.67; SI 117–126; SL 1.11– 1.31.

Comments. Iridomyrmex mayri is a common, medium-sized Iridomyrmex of eastern Australian forests. Like close relatives, this ant has bristly, erect setae on the antennal scape, the mesosoma and the hind tibiae. Large workers could be mistaken for a small meat ant, but lack the strong anteromedial clypeal spur and distinctive mesosomal characters of the meat ants. This species is most easily confused with the closely related I. obscurior , from which it can be best distinguished by its longer antennal scape (extending more than one third of its length beyond the posterior margin of the head versus ≤ 0.30 × its length in I. obscurior ). The range of this species extends from northern Queensland south into southern New South Wales and the ACT. However, the ant appears to be absent from Victoria, and definitely does not occur in Western Australia, the Northern Territory, South Australia and Tasmania. Populations are restricted to areas near the coast, and dry sclerophyll forest appears to be preferred. Label data reveal that I. mayri commonly nests under stones but will also use rotting logs as nest sites. Workers have been taken in pitfall traps and not uncommonly by sweeping low vegetation. They will also forage on tree-trunks, and, like many other Iridomyrmex , will tend larvae of the lycaenid butterfly Jalmenus evagoras .

Figures

FIGURE 50. Iridomyrmex mayri (The Knoll National Park, Qld, ANIC32-041674): A. Front of head; B. Side of body; C. Top of body; D. Distribution of material examined.