Iridomyrmex cephaloinclinus

Collections of this taxon have been made at widely separated sites in Western Australia and Queensland, but the species appears to be morphologically fairly uniform across its range (see Shattuck, 1993b). Based on field observations by the first author, this large member of the I. rufoinclinus complex appears to be a solitary forager, unlike most dolichoderines.

Identification
As with other members of the I. rufoinclinus species-complex, I. cephaloinclinus is distinguished by colour pattern. In this case, the entire head capsule is reddish-brown to black, but the mesosoma is uniformly yellowish-red to reddish.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  cephaloinclinus. Iridomyrmex cephaloinclinus Shattuck, 1993b: 1315, figs. 32, 33, 37 (w.) AUSTRALIA. See also: Heterick & Shattuck, 2011: 59.

Description
Worker Description. Head. Posterior margin of head weakly concave, or strongly 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 full-face view. Number of ocelli one (a minute ocellus), position of obsolete ocelli indicated by small pits only or pits lacking; 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, or semi-circular. Frontal carinae concave; antennal scape surpassing posterior margin of head by 1–2 x its diameter. Erect setae on scape present and abundant; prominence on anteromedial clypeal margin projecting as blunt but distinct protuberance; 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. Erect mesonotal setae numerous (12 or more) and elongate, flexuous and/or curved. Mesothoracic spiracles always prominent as small, vertical protuberances; propodeal dorsum 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. Petiole. Dorsum of node convex; node thick, orientated anteriad. 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 (except lower genae) and gaster blackish-brown, coxae brown, legs (some workers) cloudy orange-brown, lower genae, mesosoma and legs (some workers) brick-red. Colour of erect setae yellowish-white.

Measurements. Worker (n = 7)—CI 92–98; EI 25–27; EL 0.26–0.33; EW 0.16–0.19; HL 1.11–1.35; HW 1.05–1.32; ML 0.42–0.64; PpH 0.15–0.23; PpL 0.66–0.83; SI 82–89; SL 0.91–1.13.

References based on Global Ant Biodiversity Informatics

 * Heterick B. E., and S. Shattuck. 2011. Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae). Zootaxa 2845: 1-174.
 * Shattuck S. O. 1993. Revision of the Iridomyrmex calvus species-group (Hymenoptera: Formicidae). Invertebrate Taxonomy 7: 1303-1325.