Polyrhachis tubifera

Polyrhachis tubifera is evidently a ground-nesting species, with a few, rather shallowly excavated, leaf-mould covered nests found at the bases of trees.

Identification
A member of the tubifera species-group in the Polyrhachis subgenus Hagiomyrma. Kohout (2013): With its short and broad mesosoma, P. tubifera resembles Polyrhachis diversa, with most distinguishing characters listed in remarks of the latter species.

Key to Polyrhachis Hagiomyrma group species

Distribution
Kohout (2013): Polyrhachis tubifera is relatively common, ranging from Cape York Peninsula south to Brisbane, southeast Queensland.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Habitat
It occurs mostly in open eucalypt forests and woodlands, however, it is also occasionally encountered along the edges of lowland rainforests.

Castes
Males in MHNG. Immature stages (larvae and pupae) in QM spirit collection.

Nomenclature

 *  tubifera. Polyrhachis tubifera Forel, 1902h: 517 (w.m.) AUSTRALIA. Combination in P. (Hagiomyrma): Emery, 1925b: 185.

Worker
Kohout (2013) - (syntypes cited first): TL c. 6.0-7.25, 5.49-7.25; HL 1.6, 1.40-1.6; HW 1.37-1.4, 1.15-1.4; CI 86-87, 82-89; SL 1.8, 1.56-1.81; SI 128-131, 125-141; PW 1.45, 1.15-1.45; MW 1.12, 0.90-1.12; PMI 129, 120-139; MTL 1.9, 1.64-1.93 (2+16 measured).

Anterior clypeal margin truncate medially, truncation obtusely denticulate. Clypeus with rather flat carina; weakly sinuate in profile, basal margin shallowly impressed. Frontal triangle distinct. Frontal carinae sinuate, with moderately raised margins. Sides of head in front of eyes converging towards mandibular bases in almost straight line; behind eyes, sides rounding into rather low, weakly convex occipital margin. Eyes weakly convex, in full face view not or only marginally reaching lateral cephalic outline. Ocelli lacking. Dorsum of mesosoma markedly broad and short, strongly convex in lateral view. Pronotal dorsum with humeri rounded; lateral margins converging towards deeply laterally impressed promesonotal suture. Metanotal groove indistinct; mesonotal and propodeal dorsa in lateral view forming interrupted line before rounding into vertical declivity. Propodeal spiracles prominent, situated on laterally projecting tubercles. Lateral margins of propodeum divergent, terminating in broad-based, short, subparallel, acute, spines. Petiole very narrow in lateral view with anterior face straight, posterior face very weakly convex; dorsum transversely wide, armed with very short, divergent, weakly upturned spines. Anterior face of first gastral tergite widely rounding onto dorsum.

Mandibles very finely, longitudinally striate with numerous piliferous pits. Head, mesosoma and petiole very finely and closely reticulate-punctate with characteristic opaque appearance. Gaster very finely shagreened.

Mandibles at masticatory borders with numerous, curved, golden hairs. Anterior clypeal margin medially with a few, medium length, golden setae. Several short to medium length, mostly suberect hairs on clypeus, along frontal carinae, vertex, anterior face of front coxae and venter of mid and hind coxae and femora; only a few, very short, erect hairs on dorsum of pronotum and mesonotum. Dorsum of gaster with several short hairs, more abundant posteriorly; apical segments and venter of gaster with numerous, medium length, posteriorly directed, golden hairs. Closely appressed, silvery pubescence, very short and diluted on dorsum of mesosoma, more abundant and somewhat longer on head, propodeal declivity, metapleurae and dorsum of petiole. Abundant, mostly pale golden, closely appressed pubescence on dorsum of gaster, completely hiding underlying sculpturation; sides and venter of gaster with rather diluted, silvery pubescence.

Black; mandibles and appendages medium to dark, reddish-brown. Antennae with funicular segments progressively lighter towards apices.

Queen
Kohout (2013) - TL c. 7.31-7.36; HL 1.65- 1.68; HW 1.34; CI 80-81; SL 1.70-1.73; SI 127-129; PW 1.68-1.78; MTL 1.87-1.96 (2 measured).

Apart from sexual characters, very similar to worker except: clypeus in lateral view distinctly sinuate. Eyes more convex, exceeding lateral cephalic outline. Pronotal humeri with widely rounded, weakly raised margins. Mesoscutum distinctly wider than long, with widely rounded anterior margin in dorsal view; dorsum relatively low, weakly convex in lateral view; median line short, bifurcate; parapsides flat. Dorsum of mesoscutellum very weakly convex, not raised above dorsal plane of mesosoma. Propodeal and petiolar spines shorter than in worker. Sculpturation, pilosity, pubescence and colour virtually identical to those in worker.