Polyrhachis lumi

Identification
P. lumi is close to Polyrhachis exarata, but has the head, in full face view, distinctly larger and the eyes only reaching and not exceeding the lateral cephalic outline; the mesosoma in lateral view strongly arched, terminating in rather distinct, posteriorly and dorsally directed, blunt teeth and the legs dark brown. In contrast, the eyes in exarata clearly break the lateral cephalic outline, the mesosomal dorsum is almost flat with the propodeum terminating in narrowly rounded processes that are weakly widened laterally before rounding inwards and forming a transverse posterior margin and the legs are mostly yellow.

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

Nomenclature

 *  lumi. Polyrhachis (Aulacomyrma) lumi Kohout, 2007a: 201, figs. 11, 14, 17 (w.) NEW GUINEA.

Description
Dimensions: TL c. 5.69-5.90 (5.69); HL 1.50-1.53 (1.53); HW 1.31-1.37(1.37); CI 89, 87-89 (89); SL 1.53-1.56 (1.56); SI 114-117 (114); PW 1.15-1.18 (1.18); MTL 1.43-1,47 (1.47) (3 measured). Clypeus arcuate, anterior margin medially truncate; median carina blunt, but distinct; in profile clypeus straight with base rather flat. Frontal triangle well defined. Frontal carinae sinuate with raised laminate lobes; central area relatively wide with weak, blunt, longitudinal carina. Sides of head in front of eyes weakly converging towards mandibular bases. Eyes moderately convex, in full face view just reaching lateral cephalic outline. Mesosoma with lateral margins converging posteriorly. Pronotal humeri armed with broad-based, acute teeth, their anterior and lateral margins sharp and distinctly raised. Mesonotum and propodeum with hairline break in dorsal sculpture and emarginations of lateral margins indicating position of metanotal groove. Propodeal dorsum with lateral margins emarginate, terminating posteriorly in blunt, tooth-like prominences that are distinctly raised, posterior margins continued for some distance, forming short, transverse, medially unconnected ridges. Dorsal margin of petiole sharp, with some irregularities along outline, lateral petiolar spines acute, posteriorly curved. Anterior face of first gastral segment medially concave with anterodorsal margin of concavity blunt. Sculpture of body consisting of more-or-less regular striae of various intensities, striae rather flat and anteriorly converging on clypeus and vertex, where they are strongly impressed, meeting along midline; striae mostly longitudinal on sides of head. Mesosomal dorsum with striae regularly spaced, those along pronotal margin somewhat converging anteriorly towards pronotal collar; striae converging posteriorly on propodeum and oblique on sides of mesosoma. Both faces of petiole finely shagreened. Sides of first gastral segment with regular longitudinal striae, less distinct on dorsum. Erect to semi-erect, medium length hairs on mandibular masticatory border, median portion of anterior clypeal margin, along frontal carinae, antennal scapes and vertex. In full face view, hairs completely absent from sides of head between eyes and mandibular bases. Dorsum of mesosoma and gaster with numerous erect hairs that are directed posteriorly on gastral dorsum and distinctly longer towards apex of gaster. Petiole with a few, short, erect hairs along dorsal margin. Mostly silvery, appressed pubescence scattered in various densities over body; most dense on pronotal humeri and propodeal dorsum, almost obscuring underlying sculpture. Pubescence off-white or yellowish on gaster, densest along gastral margins and curving towards midline. Black; distal funicular segments and legs medium to dark reddish-brown. Sexuals and immature stages unknown. Named after the type locality, Lumi village in the Torricelli Mountains, Papua New Guinea.
 * ETYMOLOGY