Polyrhachis alatisquamis

Identification
Closely similar to Polyrhachis pubescens but differing by its generally smaller size, more slender body, distinctly less convex eyes and more strongly transverse dorsum of the petiole (Kohout, 2013).

Distribution based on Regional Taxon Lists
Oriental Region: India, Myanmar, Thailand.

Castes
Sexuals and immature stages unknown.

Nomenclature

 *  alatisquamis. Polyrhachis pubescens var. alatisquamis Forel, 1893c: 17 (diagnosis in key) (w.) MYANMAR. Combination in P. (Myrma): Emery, 1925b: 205. Raised to species: Kohout, 2013: 152.

Worker
Kohout (2013): Redescription. Dimensions (holotype cited first): TL c. 5.85, 5.49-6.00; HL 1.43, 1.43-1.50; HW 1.12, 1.06-1.18; CI 78, 74-79; SL 1.84, 1.72-1.96; SI 164, 162-166; PW 1.00, 0.97-1.06; MTL 1.78, 1.72-1.84 (1+2 measured).

Mandible with 5 teeth slightly reducing in length towards mandibular base. Anterior clypeal margin arcuate, narrowly medially truncate. Clypeus with distinct median carina; virtually straight in profile with moderately impressed basal margin. Frontal triangle poorly indicated. Frontal carinae sinuate with margins moderately raised; central area with distinct frontal furrow. Sides of head in front of eyes weakly convex towards mandibular bases; behind eyes sides rounding into relatively narrow occipital margin. Eyes convex, distinctly protracted posteriorly; clearly exceeding lateral cephalic outline in full face view. Ocelli lacking. Dorsum of mesosoma evenly convex in profile; pronotal dorsum armed with very slender and acute spines, about 3x as long as their basal width; spines anterolaterally directed and curving slightly downwards; lateral edges of spines acute and continuous with subparallel margins of pronotum. Promesonotal suture distinctly impressed laterally, virtually flat medially; mesonotal dorsum strongly transverse, about 2.5x as wide as long with lateral margins narrowly rounded and raised anteriorly, widely rounded posteriorly into medially indistinct metanotal groove. Propodeal dorsum with lateral margins converging posteriorly and terminating in distinct, dorsally raised ridges; inner borders of ridges continued medially and merging into transverse carina dividing dorsum from weakly concave declivity; secondary carinae extending from propodeal margins towards propodeal spiracles, dividing declivity from sides of propodeum. Petiole biconvex in profile; dorsum strongly transverse with weakly convex dorsal margin armed with pair of dorsolaterally and posteriorly directed spines situated on dorsolateral angles of petiole; shorter, rather flat, secondary spine situated laterally at base of each spine. Anterior face of first gastral segment concave to accommodate posterior face of petiole; anterior margin rather narrowly rounding onto dorsum.

Mandibles distinctly, longitudinally striate, semipolished. Clypeus reticulate-punctate with rest of head and dorsum of mesosoma distinctly, rather regularly, longitudinally striate, opaque. Sides of mesosoma wrinkled; petiole finely reticulate. Tips of pronotal and petiolar spines smooth, highly polished. Gaster rather distinctly reticulatepunctate, opaque.

Mandibular masticatory borders and outer margins with numerous, suberect, golden hairs. Anterior clypeal margin medially with a few anteriorly directed, golden setae and fringe of very short setae laterally. Numerous relatively long, erect or suberect, pale golden hairs on clypeus, along frontal carinae, vertex and sides of head; moderately long, suberect hairs lining superior edge of antennal scapes. Somewhat less abundant and shorter hairs on dorsum of mesosoma and petiole; hairs distinctly more abundant on gaster, with notably longer hairs towards gastral apex and on venter. Closely appressed, relatively long, white or greyish pubescence abundant over most body surfaces and almost completely hiding underlying sculpturation; pubescence less abundant on antennal scapes and legs and completely absent from mandibles and tips of spines.

Colour. Black; antennae, legs and gastral venter and apex dark to very dark reddish brown; mandibular masticatory borders and teeth a shade lighter.

Additional References

 * Kohout, R.J. 2013. A review of the Polyrhachis aculeata species-group of the subgenus Myrma Billberg (Hymenoptera: Formicidae: Formicinae), with keys and descriptions of new species. Australian Entomologist, 40, 137-171.