Polyrhachis pulleni

Identification
A member of the Polyrhachis continua species group in the subgenus Myrma

Kohout (2013) - With its larger size (HL >2.90) and distinctly upturned pronotal and mesonotal lateral margins, P. pulleni somewhat resembles Polyrhachis robusta. Both feature distinct propodeal teeth and a transverse carina dividing the propodeal dorsum from the declivity, similar to Polyrhachis neuguinensis. However, in the latter species the propodeal teeth are acute and distinctly upturned and the carina completely divides the dorsum from declivity. In both the other species the carina is incomplete, with the propodeal dorsum descending into the declivity in weakly curved, medially uninterrupted line. The pronotal spines in P. pulleni are relatively shorter, broad-based and only about 2x as long as their basal width, while in P. robusta they are distinctly longer, about 3x as long as their basal width. Also, the antennal scapes in the former are generally shorter (SI 179-188 in P. pulleni versus 185-199 in P. robusta).

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

Castes
Sexuals and immature stages unknown.

Nomenclature

 *  pulleni. Polyrhachis pulleni Kohout, 2013:, figs. (w.) INDONESIA.

Worker
Dimensions (holotype cited first): TL c. 12.40, 12.10-12.85; HL 3.06, 2.93-3.09; HW 2.21, 2.12-2.28; CI 72, 71-75; SL 4.08, 3.98-4.13; SI 185, 179-188; PW 2.12, 2.03-2.15; MTL 4.48, 4.33-4.54 (7 measured).

Anterior clypeal margin arcuate, shallowly truncate. Clypeus with poorly distinct median carina, sinuate in profile, with shallow basal margin. Frontal triangle indistinct. Frontal carinae sinuate with strongly raised margins; central area relatively narrow with weakly impressed frontal furrow. Sides of head in front of eyes almost straight before rounding into mandibular bases; behind eyes, sides produced into blunt carina extending towards occipital corners. Eyes convex; in full face view clearly exceeding lateral cephalic outline. Ocelli lacking. Pronotal dorsum with relatively long, broad-based, anterolaterally directed, acute spines; lateral edges of spines acute, terminating posteriorly in more-or-less distinct notches before merging with distinctly upturned, subparallel pronotal margins. Promesonotal suture distinctly impressed laterally, rather flat medially; mesonotal dorsum transverse with rather highly and widely raised lateral margins, weakly converging into medially flat metanotal groove. Propodeum with lateral margins raised anteriorly, flat posteriorly and terminating in blunt tuberculae; propodeal dorsum descending into declivity in weakly curved, medially uninterrupted line.

Petiole scale-like with anterior and posterior faces almost flat, strongly converging dorsally; dorsal margin armed with two slender, posteriorly curved, acute spines with inner margins forming ‘U’-shaped petiolar dorsum; lateral margin of petiole below base of each spine with short, distinct, acute tooth. Anterior face of first gastral segment flat at base, narrowly rounding onto dorsum.

Mandibles finely, longitudinally striate with numerous piliferous pits towards masticatory borders. Clypeus reticulate-punctate; sculpturation obliquely striate on sides and mostly longitudinally striate on vertex and between frontal carinae and eyes. Pronotal dorsum and bases of spines finely reticulate-punctate with sculpture somewhat organised into indistinct striae towards promesonotal suture. Mesonotal and propodeal dorsa rather regularly longitudinally striate, with propodeal declivity finely reticulate-punctate. Petiole reticulate-punctate, with spines towards tips almost smooth. Gaster shagreened.

Mandibles along outer margin and towards masticatory borders with numerous suberect, relatively long, golden hairs. Anterior clypeal margin with a few, rather long setae medially and several shorter setae fringing margin laterally. Numerous, semierect or erect, medium length or relatively long hairs on clypeus and front ofhead; numerous hairs fringing outline of head in full face view; antennal scapes with numerous, relatively long hairs along leading edge and somewhat fewer hairs along inferior edge. Mesosoma and legs with numerous, medium length hairs; petiole with numerous hairs around base and along lateral margins and inner margins of spines. Gaster with numerous, posteriorly directed, relatively long hairs with longer than half greatest diameter of eyes. Closely appressed, rather diluted, silvery pubescence over most body surfaces, more dense and distinctly reddish on gastral dorsum.

Colour. Black; wide band along masticatory borders and apical funicular segments reddish brown. Legs medium to dark reddish brown with trochanters and apical tarsal segments a shade lighter. Gaster very dark brown dorsally, with base, venter and apex reddish brown.

Etymology
Named after the collector, R.J. Pullen, who collected many species of ants during his field work throughout Papua New Guinea.

References based on Global Ant Biodiversity Informatics

 * Kohout R. J. 2013. A review of the Polyrhachis continua species-group of the subgenus Myrma Billberg (Hymenoptera: Formicidae: Formicinae) with keys and descriptions of new species. Australian Entomologist 40(1): 13-46.