Polyrhachis hoelldobleri

Kohout (2006): Polyrhachis hoelldobleri has been collected on only a few occasions. Repeated visits to the type locality failed to produce any additional specimens (S.K. Robson, pers. comm.). The type series specimens were swept from low foliage and vegetation (R.J. Kohout) and hand collected from low foliage (B. Hölldobler) or from the logs and trunks of recently felled trees (R.W. Taylor).

Identification
Polyrhachis hoelldobleri is characterised by its strongly transverse pronotal dorsum with the shoulders distinctly angular or bilobed and is similar to Polyrhachis pacifica from the Solomons. However, they differ markedly in the outline of the mesosoma. In P. hoelldobleri the mesosomal dorsum is more-or-less evenly rounded, while P. pacifica features a very prominent, strongly convex pronotal dorsum, similar to that in Polyrhachis emeryana and Polyrhachis expressa. (Kohout 2006)

Distribution
Believed to be restricted to the eastern slopes of the Great Dividing Range within Queensland’s Wet Tropics.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Abundance
Known only from types.

Castes
Males of Polyrhachis hoelldobleri have not been collected.

Nomenclature

 *  hoelldobleri. Polyrhachis hoelldobleri Kohout, 2006b: 99, figs. 2C, H-I (w.q.) AUSTRALIA.

Worker
Dimensions (holotype cited first): TL c. 5.64, 5.24-6.60; HL 1.47, 1.47-1.68; HW 1.50, 1.43-1.65; CI 102, 96-102; SL 1.75, 1.68-2.00; SI 117, 117-121; PW 1.22, 1.18-1.40; MTL 2.03, 2.03-2.40 (9 measured).

Clypeus in profile straight anteriorly, weakly rounging posteriorly into moderately impressed basal margin. Frontal triangle indistinct. Frontal carinae sinuate with moderately raised margins; central area weakly convex with short, weakly indicated frontal furrow. Sides of head in front of eyes weakly convex; behind eyes sides rounding into convex occipital margin. Eyes moderately convex, in full face view just reaching cephalic outline. Ocelli lacking; relative positions indicated by shallow punctures in sculpture. Pronotum in dorsal view strongly transverse with humeri distinctly toothed or bilobed. Mesosoma in profile more-or-less evenly convex; promesonotal suture distinct, metanotal groove lacking dorsally, weakly indicated laterally; propodeum armed with pair of relatively long, upturned spines; declivity rather short, steep. Petiole relatively low, anterior face almost straight, posterior face moderately convex; dorsum armed with four spines; lateral pair more slender and slightly longer than dorsal pair. Subpetiolar process angular anteriorly, narrowly rounded posteriorly. Anterior face of first gastral segment relatively low, evenly rounding onto dorsum of segment.

Mandibles very finely, longitudinally rugose with shallow, minute punctures. Head, mesosoma and gaster finely shagreened; intensity of sculpturation moderately increasing across lateral portions of mesosoma with meso- and metapleurae and petiole rather weakly reticulate-rugose.

Several curved and semierect hairs arising from mandibular masticatory borders. Anterior clypeal margin medially with 1 or 2 anteriorly directed longer setae and several shorter setae lining margin laterally. Medium length, erect hairs, mostly in pairs, near anterior and basal clypeal margins, along frontal carinae, on vertex and summit of mesosoma. Only a few hairs lining apical gastral segments with more hairs on gastral venter.

Colour. Mostly black, with extreme tips of apical funicular segments, condylae and mandibular masticatory border narrowly reddish-brown. Antennae, including funiculi, very dark brown to black. Legs, including trochanters, light to medium reddish-brown with distal half of femora and proximal half of tibiae a shade darker; tarsi black.

Queen
Dimensions: TL c. 7.51; HL 1.81; HW 1.78; CI 98; SL 2.03; SI 114; PW 1.72; MTL 2.68 (1 measured). Single dealate queen, apart from sexual characters, very similar to worker mounted on same pin except: eyes more prominent, clearly breaking lateral cephalic outline in full face view. Pronotal humeri produced into blunt, angular prominences; mesoscutum marginally wider than long with lateral margins distinctly converging anteriorly, forming rounded anterior margin; median line weakly indicated, bifurcate posteriorly; parapsides flat, weakly raised posteriorly; mesoscutum in profile with widely rounded anterior margin and flat dorsum. Mesoscutellum in lateral view marginally raised above dorsal plane of mesosoma, weakly convex; metanotal groove distinct. Propodeum armed with pair of distinct, blunt, somewhat dorsoventrally flattened spines; propodeal declivity very steep. Petiole relatively low with lateral spines only moderately elongated; dorsal pair reduced to short, broad-based teeth. Sculpturation, pilosity and colour as in worker.

Type Material
HOLOTYPE: QUEENSLAND, Kirrama Ra., c. 9km W of Kennedy, 18°12’S, 145°52’E, 110m, 4.vi.1996, primary rf., R.J. Kohout et al. acc. 96.13 (worker). PARATYPES: data as for holotype (7 workers); Kuranda, 16°49’S, 145°39’E, 5.vii.1980, B. Hölldobler #109 (2 workers); The Boulders, c. 6km W of Babinda, 17°21’S, 145°52’E, 3.ii.1958, Darlingtons (1 worker); East Palmerston, 1.6km E, 17°35’S. 145°50’E, c. 200m, 6.xi.1966, rf., R.W. Taylor accs 66.283, 286 (2 workers, 1 queen). Holotype (QMT99337) and 2 paratypes in ; 2 paratype workers, 1 paratype queen in, 2 paratype workers in and ; 1 paratype worker in B. Hölldobler collection.