Polyrhachis penelope

Polyrhachis penelope is an uncommon species with its distribution centred on Mackay and extending along the Queensland coast from about Rockhampton as far north as Cairns. It is an inhabitant of open eucalypt forests and woodlands that mostly nests in the ground although one nest was located in a rotten tree stump.

Identification
A member of the penelope species-group in the Polyrhachis subgenus Hagiomyrma.

Key to Polyrhachis Hagiomyrma group species

Distribution based on Regional Taxon Lists
Australasian Region: Australia. Indo-Australian Region: New Guinea.

Castes
Male unknown. Immature stages present in the QM collection.

Nomenclature

 *  penelope. Polyrhachis penelope Forel, 1895a: 46 (w.) AUSTRALIA. Forel, 1901b: 31 (q.m.). Combination in P. (Hagiomyrma): Forel, 1915b: 108.

Worker
Kohout (2013) - (syntypes cited first): TL c. 6.65-7.61, 6.50-7.61; HL 1.68-1.75, 1.65-1.78; HW 1.40-1.46, 1.34-1.59; CI 80-81, 80- 85; SL 2.03-2.09, 2.03-2.15; SI 145-149, 135-151; PW 1.28-1.40, 1.28-1.47; MW 0.90-1.03, 0.84-1.03; PMI 139-142, 139-154; MTL 2.06-2.18, 2.06-2.34 (5+10 measured).

Anterior clypeal margin with denticulate median flange, laterally flanked by acute angles. Clypeus with distinct median carina; sinuate in profile, posteriorly rounding into moderately impressed basal margin. Frontal triangle weakly indicated. Frontal carinae sinuate with only weakly raised margins; central area flat. Sides of head in front of eyes converging towards mandibular bases in weakly convex line; behind eyes, sides rounding into convex occipital margin. Eyes moderately convex, in full face view marginally exceeding lateral cephalic outline. Ocelli lacking. Pronotal humeri widely rounded with anterior margins weakly raised; pronotal margins weakly emarginate medially before terminating at well impressed promesonotal suture. Mesonotal dorsum with lateral margins converging towards indistinct with moderately long, weakly divergent spines with tips weakly curved outwards. Petiole with posterior face descending towards base in weakly convex line; dorsum weakly concave medially, laterally armed with pair of broad-based, horizontal, divergent spines. Anterior face of first gastral tergite distinctly higher than full height of petiole, widely rounding onto dorsum.

Mandibles longitudinally striate with numerous piliferous pits. Head, mesosoma and petiole distinctly, more-or-less regularly reticulate-punctate, with punctures very smooth, polished. Spines sculptured at bases, smooth and polished towards tips. Gaster finely shagreened.

Mandibular masticatory borders with numerous, curved, golden hairs. Anterior clypeal margin with a few, anteriorly projecting setae medially and several very short setae fringing margin laterally. Dorsa of head, mesosoma and petiole with numerous, rather short, erect, bristle-like hairs; a few hairs fringing anterior face of fore coxae and venter of mid and hind coxae and femora. Gaster with more abundant, golden hairs on dorsum; distinctly longer, posteriorly directed hairs around apex and on venter. Rather diluted, closely appressed, silvery pubescence on dorsa of head and mesosoma; pubescence more abundant on sides of mesosoma, declivity and petiole, except its smooth and polished anterior face. Gaster with abundant golden pubescence on dorsum, hiding underlying sculpturation; pubescence much diluted and silvery on venter of gaster.

Black; mandibular teeth reddish-brown.

Queen
Kohout (2013) - TL c. 8.52; HL 1.81; HW 1.53; CI 84; SL 2.03; SI 133; PW 1.72; MTL 2.18 (1 measured).

Apart from sexual characters, very similar to worker except: mesoscutum as wide as long; relatively low in lateral view, anteriorly rounding onto very weakly convex dorsum; median line bifurcate anteriorly; parapsides weakly raised. Mesoscutellum only marginally raised above dorsal plane of mesosoma. Propodeal and petiolar spines similar to worker, but shorter. Sculpturation, pilosity, pubescence and colour identical to worker, except pilosity on dorsum of mesoscutum completely lacking.