Iridomyrmex brennani, Heterick & Shattuck, 2011

Heterick, Brian E. & Shattuck, Steve, 2011, Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae) 2845, Zootaxa 2845 (1), pp. 1-174 : 53-54

Iridomyrmex brennani sp. n.

( Figs 18 , 93 )

Types. Holotype worker from E. Kambalda, Western Australia, 7 February 1999, K. Brennan, on/by salt lake, JDM 992 ( ANIC, ANIC32-053427 ) . Paratypes: 5 workers, same data as holotype ( ANIC) ; 2 workers from L. Acraman (Gawler Ra), South Australia, October 1972, P. J. M. Greenslade, salina to SE of lake ( MCZC, ANIC32-042486 ) ; 1 worker from 9km NNE Buningonia Spring , Western Australia, 18-25 October 1978, T. F. Houston ( BMNH, ANIC32-042718 ) .

Worker Description. Head. Posterior margin of head weakly concave; erect setae on posterior margin absent; sides of head noticeably convex; erect genal setae 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 elongate, or asymmetrical, curvature of inner eye margin more pronounced than that of its outer margin. Frontal carinae straight; 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 lacking or very minute (one or two tiny setae may be present). Mesonotum sinuous. Erect mesonotal setae sparse to absent. Mesothoracic spiracles prominent or inconspicuous; propodeal dorsum straight and long (half as long again as length of 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 sparse to absent. Petiole. Dorsum of node planar; node thick, orientation more-or-less vertical. Gaster. Non-marginal erect setae of gaster absent on first gastral tergite; marginal erect setae of gaster absent on first tergite. General characters. Allometric differences between workers of same nest absent. Colour of genae and clypeal area brick-red, rest of body reddish-black. Colour of erect setae whitish.

Measurements. Worker (n = 2)—CI 84–85; EI 27–27; EL 0.34–0.35; EW 0.26–0.26; HFL 2.30–2.32; HL 1.52–1.55; HW 1.29–1.30; ML 2.02–2.11; MTL 1.72–1.77; PpH 0.26–0.26; PpL 0.77–0.79; SI 117–117; SL 1.51– 1.53.

Comments. Iridomyrmex brennani is a rather handsome, medium-sized Iridomyrmex that has been collected rarely in the Kambalda district of Western Australia, near Lake Acraman, in the Gawler Range, South Australia and in the Murray Sunset National Park of north-western Victoria. It is superficially similar to I. anceps , but its almost glabrous pro- and mesonotum and variegated black-and-dark-reddish-brown body are distinctive. Terrestrial foragers only have been collected and it is commonly associated with salt lakes (A. Andersen, pers. comm.).

Etymology. Named in honour of Dr. Karl Brennan, who collected specimens of the ant in the Kambalda district while studying for his PhD at Curtin University of Technology.

Figures

FIGURE 18. Iridomyrmex brennani (paratype, Lake Acraman, Gawler Ranges, SA, ANIC32-042486): A. Front of head; B. Side of body; C. Top of body; D. Distribution of material examined.

FIGURE 93. Head length versus head width for I. brennani and I. minor.