Polyrhachis arborea

Nothing is known about the biology of .

Identification
A member of the Polyrhachis mucronata  species group.

Kohout (2008) - The body sculpturation of P. arborea is rather variable. In most specimens of type series it consists of small punctures that are superimposed over larger, very shallow depressions. However, in the specimens from Lore Lindu the sculpturation is simply reticulate-punctate. Polyrhachis arborea resembles Polyrhachis moesta and Polyrhachis orpheus. It differs from both in having considerably longer and more slender antennal scapes. The propodeal spines are also longer and virtually horizontal in P. arborea, while they are oblique in profile in the other two species.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia, Sulawesi.

Nomenclature

 *  arborea. Polyrhachis arborea Kohout, 2008a: 303, figs. 10C-D (w.) INDONESIA (Sulawesi).

Worker
(holotype cited first): TL c. 6.25, 5.90-6.70; HL 1.59, 1.47-1.68; HW 1.22, 1.12-1.25; CI 77, 73-77; SL 2.09, 1.96-2.18; SI 171, 171-182; PW 0.87, 0.84-0.97; MTL 2.25, 2.09-2.34 (17 measured).

Anterior clypeal margin with median truncation, flanked by distinct, blunt denticles. Clypeus with blunt median carina that is weakly elevated posteriorly; clypeus in profile straight, rounding posteriorly into moderately impressed basal margin, laterally basal margin consisting of a thin, sculpture-breaking line. Frontal triangle distinct. Frontal carinae sinuate with distinctly raised margins; central area concave with rather short frontal furrow. Sides of head in front of eyes converging towards mandibular bases in weakly convex line; behind eyes sides rounding into relatively narrow, convex occipital margin. Eyes convex, in full face view clearly breaking lateral cephalic outline. Ocelli lacking. Pronotal humeri produced into blunt angles, rather indistinctly in some specimens. Mesosoma in profile with pronotal dorsum weakly convex; promesosonal suture distinct; mesonotal dorsum flat. Metanotal groove a distinct, posteriorly bowed line. Propodeal dorsum very short, with lateral margins terminating in broad-based, horizontal, weakly laterally and posteriorly directed spines; inner margins of spines curving onto propodeal dorsum, forming weakly open ‘U’ in dorsal view; declivity relatively high, oblique in profile. Petiole with pair of widely diverging, relatively short spines; petiolar dorsum rounded in profile, spines arising from below summit. Anterior face of first gastral segment widely rounding onto dorsum.

Mandibles finely, longitudinally striate, with numerous piliferous pits. Head shallowly reticulate-punctate, more distinctly on vertex. Mesosoma sculpturation ranging from very dense punctatation overlying larger, rather shallow depressions in some specimens to simply reticulate-punctate in others; general appearance ranging from opaque to moderately smooth and polished. Gaster finely shagreened.

Mandibular masticatory borders with several curved, golden hairs and numerous short, closely appressed hairs towards bases. Anterior clypeal margin with a few longer setae medially and a pair of rather short hairs arising laterally behing margin. Anterior face of fore coxae with one or two longer, erect hairs. Gaster with several medium length, erect hairs along dorsoapical margins segments; hairs more numerous and distinctly longer on gastral venter. Closely appressed, very short, golden pubescence arising from numerous pits over all body surfaces.

Colour. Head, mesosoma, petiole and mid and hind coxae black. Mandibles, clypeus and front of head blotched with diffuse reddish-brown. Antennae, legs and gaster medium reddish-brown with tarsi distinctly darker. Narrow band across bases of mandibular teeth, condylae, funicular segments towards apex and apical segment of tarsi, light yellowish-brown.

Type Material
HOLOTYPE: SULAWESI TENGAH: nr Morowali, Ranu R. area, 27.i.-20.iv.1980, M.J.D. Brendell, B.M. 1980-280 (worker). PARATYPES: data as for holotype (14 workers). SULAWESI UTARA: Dumoga-Bone NP, 9.-16.v. 1985 (N.E. Stork et al.) (worker); ditto, 230m, 2.xii.1985, fog., N.E. Stork et al. (worker). Holotype and (8) paratypes in ; 2 paratypes each in, and.