Polyrhachis starri

Identification
Although Polyrhachis starri closely resembles Polyrhachis murina, close examination and comparison of the available specimens has revealed a number of distinguishing characters. Polyrhachis starri is generally more slender (PW <1.15 versus >1.15 in murina), with the mesosoma longer and only moderately convex in outline, the profile of the clypeus shallowly impressed medially and the petiole with its dorsal margin raised and bluntly angular medially and armed with distinctly shorter dorsolateral spines. In contrast, in P. murina the mesosoma is wider and shorter, with the dorsum distinctly more convex in outline, the profile of the clypeus is virtually straight and the petiole has its dorsal margin only weakly raised and armed with a distinct intercalary tooth and longer dorsolateral spines. In addition, the head of P. murina has numerous short, erect hairs between the eyes and occipital corners that are totally absent in P. starri. As mentioned above, when describing P murina, Emery (1893) considered specimens from Sarawak and Philippines (Jolo) to be conspecific. However, following their comparison I believe they represent separate species, P. starri from the Philippines and P. murina from Borneo and Sumatra.

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

Nomenclature

 *  starri. Polyrhachis (Myrma) starri Kohout, 2013: 161, figs. 42-43, 46-47 (w.) PHILIPPINES.

Worker
Dimensions (holotype cited first): TL c. 6.75, 6.25-6.80; HL 1.81, 1.72-1.81; HW 1.37, 1.25-1.37; CI 76, 73-76; SL 2.15, 2.09-2.15; SI 157, 155-167; PW 1.09, 1.03-1.15; MTL 2.21, 2.06-2.21 (1+4 measured).

Anterior clypeal margin arcuate, medially very narrowly truncate. Clypeus with posteriorly raised median carina; in profile with shallow depression medially, posteriorly rounding into virtually flat basal margin. Frontal triangle distinct. Frontal carinae sinuate with moderately raised margins; central area with distinct frontal furrow. Sides of head in front of eyes almost straight, before rounding into mandibular bases; behind eyes sides rounding into relatively narrow occipital margin. Eyes moderately convex; in full face view clearly breaking lateral cephalic outline; eyes. Ocelli lacking. Pronotal dorsum with rather short spines, as long as their basal width or marginally longer; lateral edges of spines continuous with subparallel pronotal margins. Promesonotal suture distinctly impressed laterally, rather flat medially; mesonotal dorsum transverse, about 2x as wide as long, lateral margins converging posteriorly before rounding into metanotal groove that is poorly indicated medially. Propodeal dorsum with lateral margins converging posteriorly and terminating in weakly raised, blunt teeth, with dorsum between them descending into oblique declivity in medially uninterrupted line; short, rather blunt carinae extend from lateral propodeal margins towards distinct propodeal spiracles, dividing declivity from sides of propodeum. Petiole biconvex in lateral view, with dorsal margin raised and bluntly angular medially; dorsolateral spines relatively short, about as long as secondary spine situated laterally below base of each spine (Fig. 43). Anterior face of first gastral segment concave to accommodate posterior face of petiole.

Mandibles distinctly, longitudinally striate, with piliferous pits. Clypeus reticulatepunctate with rest of head rather finely longitudinally striate. Dorsum of mesosoma and petiole finely reticulate-punctate; sides of mesosoma wrinkled. Gaster closely reticulate-punctate.

Mandibular masticatory borders and outer margins with numerous curved, golden hairs. Anterior clypeal margin with a few anteriorly directed setae medially and fringe of shorter setae lining margin laterally. A few paired, erect, golden hairs on clypeus and along frontal carinae; several longer hairs on fore coxae. Gaster with numerous posteriorly inclined, golden hairs on venter and around apex. No hairs on vertex of head, dorsum of mesosoma, petiole, antennal scapes and legs. Closely appressed, silvery pubescence rather diluted on clypeus, more abundant on rest of head and notably on dorsum of mesosoma and petiole, where it completely hides underlying sculpturation. Pubescence distinctly longer and golden on gastral dorsum, silvery on gastral venter.

Colour. Black; legs black or very dark reddish brown.

Queen
Dimensions: TL c. 8.47; HL 2.06; HW 1.59; CI 77; SL 2.28; SI 143; PW 1.87; MTL 2.50 (1 measured).

Queen distinctly larger than worker with usual characters identifying full sexuality, including three ocelli, complete thoracic structure and wings. Pronotal spines distinctly shorter, tooth-like, with posterior lateral margins widely rounded. Mesoscutum marginally wider than long; lateral margins converging anteriorly into broadly rounded anterior margin; median line distinct, bifurcate anteriorly; parapsides flat, only weakly raised posteriorly; mesoscutum in profile with anterior face widely rounding onto posteriorly flat dorsum. Mesoscutellum only weakly convex, not elevated above dorsal plane of mesosoma. Propodeum convex in outline with rather blunt lateral margins terminating posteriorly in indistinct, medially directed, short ridges; propodeal dorsum between ridges descending into propodeal declivity in medially uninterrupted line. Petiole with dorsal margin bluntly angular medially and dorsal spines reduced to obtuse teeth; dorsolaterally situated secondary spines relatively long and acute. Sculpturation, pilosity and colour scheme very similar to worker, except pubescence on dorsum of mesosoma with somewhat golden tint.

Etymology
Named after the collector of the type series, Dr Chris K. Starr of the University of the West Indies, Trinidad & Tobago, for his generous donations of many Polyrhachis ants collected during his tenure as an Associate Professor at De La Salle University in the Phillippines.