Iridomyrmex neocaledonica

The handful of specimens available for this species have been collected at a considerable elevation on New Calendonia (to 1200 m).

Identification
Apart from its biogeography, this handsome medium-sized, brown Iridomyrmex is distinguished from very similar species like Iridomyrmex splendens, Iridomyrmex meridianus and Iridomyrmex mjobergi (southern, mesic populations) by a combination of its longer antennal scape (extending beyond the posterior margin of the head by 3 × its greatest width) and lack of a row of setae on the posterior margin of the head.

Distribution based on Regional Taxon Lists
Australasian Region: New Caledonia.

Nomenclature

 *  neocaledonica. Iridomyrmex neocaledonica Heterick & Shattuck, 2011: 111, figs. 55, 96 (w.) NEW CALEDONIA.

Description
Worker Description. Head. Posterior margin of head planar to weakly concave; erect setae on posterior margin in full-face view, present singly or as a couple of setae on either side of posterior margin of head; 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 asymmetrical, curvature of inner eye margin more pronounced than that of its outer margin. Frontal carinae convex; 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 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 sparse (6 or fewer) and bristly. Mesonotum sinuous, or evenly curved. Erect mesonotal setae sparse (6 or fewer) and bristly. Mesothoracic spiracles always inconspicuous; propodeal dorsum smoothly and evenly convex; placement of propodeal spiracle posteriad and near 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 lacking or very minute (one or two tiny setae present). Petiole. Dorsum of node convex; node thin, scale-like, orientation more-or-less vertical. Gaster. Non-marginal erect setae of gaster present or 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 uniformly pale to dark brown. Colour of erect setae depigmented, pale.

Measurements. Worker (n = 3)—CI 85–86; EI 26–27; EL 0.21–0.22; EW 0.16–0.17; HFL 1.16–1.25; HL 0.95–0.98; HW 0.82–0.84; ML 1.23–1.27; MTL 0.82–0.86; PpH 0.16–0.17; PpL 0.51–0.52; SI 115–116; SL 0.94– 0.96.

Etymology
Latin: with reference to the distribution of the species (New Caledonia).

References based on Global Ant Biodiversity Informatics

 * Baroni Urbani C. 1977. Katalog der Typen von Formicidae (Hymenoptera) der Sammlung des Naturhistorischen Museums Basel (2. Teil). Mitt. Entomol. Ges. Basel (n.s.) 27: 61-102.
 * Berman M., A. N. Andersen, C. Hé ly, and C. Gaucherel. 2013. Overview of the distribution, habitat association and impact of exotic ants on native ant communities in New Caledonia. PLoS ONE 8(6): e67245. doi:10.1371/journal.pone.0067245
 * CSIRO Collection
 * Emery, C. 1914. Les fourmis de la Nouvelle-Calédonie et des îles Loyalty. Nova Caledonia. A. Zoologie 1:393-437.
 * Heterick B. E., and S. Shattuck. 2011. Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae). Zootaxa 2845: 1-174.
 * Heterick, B., and S. O. Shattuck. "Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae)." Zootaxa 2845 (2011): 1-174.
 * Jennings J. T., L. Krogmann, and C. Burwell. 2013. Review of the hymenopteran fauna of New Caledonia with a checklist of species. Zootaxa 3736(1): 1-53.
 * Wheeler W.M. 1935. Check list of the ants of Oceania. Occasional Papers of the Bernice Pauahi Bishop Museum 11(11):1-56.
 * Wheeler, W. M. 1927. The ants of Lord Howe Island and Norfolk Island. Proc. Am. Acad. Arts Sci. 62: 121-153