Polyrhachis variegata

Known only from the holotype.

Identification
Kohout (2007) - A rather distinct species easily separated from most others by the posteriorly wide head and distinctly flat eyes, that are situtated well away from the lateral margins of the head. The rather flat and fine sculpture, untidy silvery pubescence and notably the obliquely descending propodeal declivity are also quite distinctive.

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

Castes
Known only from the worker caste.

Nomenclature

 *  variegata. Polyrhachis (Aulacomyrma) variegata Kohout, 2007a: 212, figs. 39, 42, 45 (w.) NEW GUINEA.

Worker
Holotype: TL c. 5.54; HL 1.43; HW 1.37; CI 96; SL 1.47; SI 107; PW 1.06; MTL 1.40.

Anterior clypeal margin distinctly medially emarginate; in profile clypeus very weakly convex, almost straight with rather flat but distinct basal margin. Frontal carinae sinuate, rather short, only moderately raised; frontal triangle indistinct. Sides of head convex, distinctly converging anteriorly towards mandibular bases. Eyes distinctly flat, not reaching cephalic outline in full face view. Mesosoma marginate with propodeal margins somewhat weakly defined. Pronotal humeri armed with laterally directed, broad-based teeth, margins raised and laterally continuous with pronotal margins. Promesonotal suture distinct; metanotal groove lacking. Propodeum terminating in small but distinct tuberculae. Propodeal dorsum descending into oblique declivity in uninterrupted curve. Petiole with acute, finely jagged dorsal margin and short, weakly backwards and upwards curved lateral spines; in dorsal view, dorsal petiolar margin weakly anteriorly bowed. Anterior face of first gastral segment very weakly concave with anterodorsal margin blunt, not raised above dorsum of segment.

Mandibles finely longitudinally striate at bases, becoming more reticulate with several shallow pits towards masticatory borders. Clypeus with very fine, weakly V-shaped striae at base, merging into irregular rugae anteriorly. Vertex and sides of head with fine, rather flat, mostly longitudinal striae. Pronotal dorsum with striae diverging, more-or-less parallel with lateral pronotal margins; striae posteriorly convering on mesonotal-propodeal dorsum, mostly oblique on sides of mesosoma, propodeal declivity only finely shagreened. Petiole with both faces finely shagreened. Gaster with sides longitudinally striate, striae distinctly finer dorsally, first gastral tergite finely reticulate anteromedially.

A few, rather short, erect hairs along outer mandibular edges, anterior clypeal margin, leading edge of antennal scapes, frontal carinae and outer surfaces of hind tibiae; a solitary hair arising from vertex. Hairs completely absent from dorsum of mesosoma, petiole and first gastral segment; only a few hairs, shorter than greatest diameter of eye, concentrated on apex and venter of gaster. Silvery, appressed and semierect, somewhat untidy pubescence in various densities on vertex, pronotal humeri, propodeal dorsum, metapleura, coxae and anterior face of petiole; pubescence virtually absent from front of head; gaster with pubescence more abundant dorsally but not obscuring underlying sculpture.

Black, mandibular masticatory border dark red. Funiculi apically and legs generally dark to medium reddish-brown, tibiae and apical tarsal segments a shade lighter.

Type Material
HOLOTYPE: INDONESIA, IRIAN JAYA, Guega, W of Swart Valley, 03º36’S, 138º25’E, 1200m, 15.xi.1958, J. L. Gressitt (worker). Type distribution: unique holotype in.

Etymology
Named for its somewhat different appearance from that of other members of the subgenus (Latin varius , variegatus = different, different sort).

References based on Global Ant Biodiversity Informatics

 * Janda M., G. D. Alpert, M. L. Borowiec, E. P. Economo, P. Klimes, E. Sarnat, and S. O. Shattuck. 2011. Cheklist of ants described and recorded from New Guinea and associated islands. Available on http://www.newguineants.org/. Accessed on 24th Feb. 2011.
 * Kohout R.J. 2007. Revision of the subgenus Aulacomyrma Emery of the genus Polyrhachis F. Smith, with descriptions of new species (pp. 186-253). In Snelling, R.R., Fisher, B.L. & Ward, P.S. (eds). Advances in ant systematics: homage to E.O. Wilson  50 years of contributions. Memoirs of the American Entomological Institute 80: 690 pp.