Probolomyrmex aliundus

This rarely encountered species is known from a limited number of collections made in rainforest on Cape York Peninsula, Queensland.

Identification
Petiolar node relatively long and narrow (best viewed dorsally), the dorsal face (in side view) uniformly convex and without a separation of the anterior and dorsal faces; posterior projection of the subpetiolar process forming a 90° angle.

Probolomyrmex aliundus is similar to Probolomyrmex maryatiae (from Sabah, Malaysia) and will key to that species in Eguchi et al. (2006), and to Probolomyrmex simplex (from Papua New Guinea). The first two species differ in that the posterodorsal margin of the petiole in dorsal view is straight to weakly convex in P. aliundus (it is concave in P. maryatiae) and the posterior face of the node in lateral view is much less convex when compared to P. maryatiae (and more so than in P. vieti, another similar species from Indonesia and Thailand). Probolomyrmex aliundus differs from P. simplex in having less well developed and prominent foveae and in having the posteroventral tooth of the subpetiolar process angular rather than tooth-like. Probolomyrmex aliundus also averages larger than both P. maryatiae and P. simplex (HL > 0.59mm vs. < 0.59mm, HW > 0.38mm vs. < 0.38mm).

Key to Australian and Melanesian Probolomyrmex species

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  aliundus. Probolomyrmex aliundus Shattuck, Gunawardene & Heterick, 2012: 42, figs. 1, 7 (w.q.) AUSTRALIA.

Description
Worker description. Body ferruginous brown. Head in full-face view with weakly convex sides and weakly concave posterior margin. Eyes absent. Antennae relatively long. Dorsal outline of mesosoma essentially straight, the pronotum curving downwards slightly; posterior margin of propodeal dorsum in dorsal view straight; posterior face of propodeum margined laterally with a well-developed, thin, translucent lamella. Petiole including subpetiolar process longer than high, its dorsal surface in profile forming a relatively gentle and uniform curve; subpetiolar process with conspicuous anteroventral and posteroventral projections; the anteroventral projection forming a blunt tooth, the posteroventral projection forming a 90° angle. Abdominal segment III (gastral segment I) in profile narrowed anteriorly, broadest near its posterior margin.

Measurements. Worker (n=9)—CI 60–64; DPetW 0.18–0.20; HL 0.59–0.65; HTL 0.30–0.47; HW 0.38–0.40; LPetI 99–111; ML 0.77–0.88; PetH 0.27–0.29; PetNL 0.27–0.33; PronW 0.29–0.31; SI 96–112; SL 0.36–0.44