Iridomyrmex phillipensis

This species is endemic to Phillip Island, situated about 10 km south of Norfolk Island, where all known specimens were collected by J. Feehan in March/April 1984, and I. Naumann & T. Weir in Nov. 1984. The dates suggest the ants were collected in pitfall traps, but further information is lacking.

Identification
Iridomyrmex phillipensis is reminiscent of an extremely hirsute Iridomyrmex suchieri, but the iridescent gaster and the nature of the protuberant propodeum suggest that its true affinities are more likely to lie with Iridomyrmex rufoniger and relatives. The nature of the propodeum separates this species from I. suchieri, the species with which it is most likely to be confused (some very hairy populations of I. ‘obscurus’), and also I. rufoniger.

Distribution
This is the only Iridomyrmex confined to territory outside of the Australian mainland, apart from the three species found on New Caledonia.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  phillipensis. Iridomyrmex phillipensis Heterick & Shattuck, 2011: 122, fig. 62 (w.) AUSTRALIA (Phillip I.).

Description
Worker Description. Head. Posterior margin of head 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, or 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. Frontal carinae convex; 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 present as an indistinct swelling or undulation; mandible regular 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) and longest setae elongate, flexuous and/or curved. Mesonotum evenly curved. 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 posteriad and near propodeal declivity, or mesad, more than its diameter away from propodeal declivity; propodeal angle present as a bluntly defined right angle, the dorsal and declivitous propodeal faces never separated by a carina. 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 coppery brown to blackish- brown, with yellowish-green to faintly bluish iridescence on gaster. Colour of erect setae light brownish-yellow.

Measurements. Worker (n = 6)—CI 87–94; EI 23–26; EL 0.21–0.23; EW 0.16–0.18; HFL 1.07–1.26; HL 0.92–1.08; HW 0.82–1.00; ML 1.17–1.43; MTL 0.76–0.90; PpH 0.22–0.25; PpL 0.50–0.60; SI 94–100; SL 0.82– 0.95.

Etymology
The species is named after the island on which it was collected.

References based on Global Ant Biodiversity Informatics

 * CSIRO Collection
 * Heterick B. E., and S. Shattuck. 2011. Revision of the ant genus Iridomyrmex (Hymenoptera: Formicidae). Zootaxa 2845: 1-174.