Polyrhachis brisbanensis

Polyrhachis brisbanensis is a relatively common species in open eucalypt forests and woodlands of the greater Brisbane region. Its distribution extends north to Fraser Island and the Cooloola coast and south to the Queensland-New South Wales border and almost reaches the Great Dividing Range in the west. It is a ground-nesting species with nest entrances usually hidden under pieces of wood or rock. Colonies are relatively small with examined nests containing about 50-60 workers and one dealate queen.

Identification
Polyrhachis brisbanensis is similar to several species, notably Polyrhachis ammon and Polyrhachis brutella. It differs from the former by its almost quadrate pronotal dorsum, closely spaced, parallel petiolar spines and the narrow patch of dark reddish pubescence on the gastral dorsum. In contrast, in P. ammon the pronotal dorsum is rectangular and wider than long, the petiolar spines are distinctly divergent and rich golden pubescence is distributed over most of the gastral dorsum. Besides its generally smaller size (HL 2.15-2.37 in P. brisbanensis versus 2.28-2.56 in P. brutella), P. brisbanensis differs from P. brutella in several other characters, including the straight profile of the clypeus, the weakly sinuate propodeal and parallel petiolar spines and the abundant, brassy golden pubescence of the body. In contrast, the clypeus in P. brutella is shallowly, but distinctly concave in profile, the tips of the propodeal and petiolar spines are curved outwards and the rather sporadic body pubescence is mostly pale silvery. Differences between the queens of the species are even more pronounced. The queen of P. brutella features an exceptionally massive mesosoma, which lacks any pilosity or pubescence.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  brisbanensis. Polyrhachis (Hagiomyrma) brisbanensis Kohout, 2013: 508, figs. 2A-B (w.q.m.) AUSTRALIA.

Type Material


Type deposition: Holotype, most paratypes and paratype queen in, 3 paratype workers and paratype queen in ; 2 paratype workers each in , , , , , and.