Polyrhachis gressitti

Known only from the holotype worker. Nothing is known about the biology of .

Identification
Kohout (2007) - Another remarkable species very similar to P. decora, but with a distinctly longer and exceptionally high propodeum with its outline forming an almost perfect semicircle in dorsal view.

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

Castes
Known only from the worker caste.

Nomenclature

 *  gressitti. Polyrhachis (Aulacomyrma) gressitti Kohout, 2007a: 223, figs. 66, 69, 72 (w.) NEW GUINEA.

Worker
Holotype: TL c. 4.23; HL 1.15; HW 0.90; CI 78; SL 1.25; SI 139; PW 0.78; MTL 1.25.

Anterior clypeal margin with minute notch medially; clypeus in profile virtually straight with weakly impressed basal margin. Frontal triangle indistinct. Frontal carinae sinuate, with rather short, laminate, anteriorly truncate lobes. Sides of head in front of eyes converging anteriorly; rounding behind eyes into convex preoccipital margin. Eyes strongly convex, protuberant, in full face view clearly breaking lateral cephalic outline. Mesosoma laterally and posteriorly immarginate, distinctly antero-posteriorly compressed, notably when viewed from side. Pronotal humeri armed with rather strong, horizontal, anteriorly directed spines; pronotal dorsum evenly curved in profile. Promesonotal suture strongly impressed; metanotal groove lacking. Mesonotal-propodeal dorsum distinctly wider than long; propodeal declivity exceptionally high. Petiole with dorsal margin acute, sinuate in dorsal view, lateral spines relatively short, curved backwards. Anterior face of first gastral segment convex.

Mandibles finely longitudinally striate. Sculpture of head and mesosoma consisting of regularly spaced, smooth and glossy striae; mostly longitudinal and somewhat anteriorly converging on head, transverse and anteriorly bowed on pronotum; striae on mesonotal-propodeal dorsum forming imperfect semicircular pattern with outmost striae continuing obliquely onto sides and posteriorly extending into propodeal declivity. Petiole with both faces transversely striate, striae less distinct dorsally, becoming wrinkles just below dorsal margin. First gastral segment distinctly longitudinally striate, dorsum with striae finer and distinctly converging towards base.

Mostly medium length, erect or curved, golden hairs on dorsum of head, mesosoma and gaster; distinctly shorter hairs along leading edge of antennal scapes, dorsal margin of petiole and legs. Appressed pubescence virtually absent from most body surfaces, except dorsum of first gastral segment, where it is rather diluted and reddish.

Black; mandibular masticatory border, antennal scapes, most of femora, basal segment of tarsi and apical segments of gaster reddish brown to dark rusty red. Funiculi, trochanters, proximal ends of femora and apical tarsal segments, light to very light reddish brown.

Type Material
HOLOTYPE: PAPUA NEW GUINEA: Adelbert Mts, Wanuma, 04º36’S, 145º06’E, 800-1000m, 25.x.1958, J. L. Gressitt (worker). Type deposition: unique holotype in.

Etymology
Named in honor of the collector, the late J. L. Gressit, Bernice P. Bishop Museum, Honolulu, Hawai’i.