Polyrhachis palmerae

Polyrhachis palmerae is known only from the Kimberley region in Western Australia where it appears to be endemic.

Identification
A member of the Polyrhachis gravis species-group. Kohout (2013) - The black body with light orange appendages and rather polished appearance makes P. palmerae easily recognisable. The petiole is also very characteristic, with its highly and steeply raised dorsum which virtually forms a single base for two, slender, divergent spines.

Key to Polyrhachis gravis species-group workers

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  palmerae. Polyrhachis (Campomyrma) palmerae Kohout, 2013: 104, figs. 4C-D, G-H (w.) AUSTRALIA.

Worker
(holotype cited first): TL c. 9.07, 8.52-9.27; HL 2.28, 2.18-2.31; HW 2.00, 1.81-2.03; CI 88, 87-89; SL 2.25, 2.12-2.34; SI 112, 109-117; PW 1.72, 1.62-1.84; MTL 2.81, 2.71-3.12 (1 +4 measured).

Mandibles with 6 teeth. Anterior clypeal margin widely truncate, truncate portion irregularly denticulate. Clypeus with short, poorly defined, median carina towards base; vey weakly sinuate in profile. Frontal triangle distinct. Frontal carinae sinuate with weakly raised margins; central area with indistinct frontal furrow. Sides of head in front of eyes convex towards mandibular bases; behind eyes sides rounding into distinct occipital corners. Eyes convex, in full face view clearly breaking lateral cephalic outline. Ocelli lacking. Pronotal humeri bluntly angular somewhat laminate, with rather distinct anterior margins converging towards pronotal collar. Lateral prenotal margins converging towards moderately impressed promesonotal suture. Mesonotal lateral margins converging posteriorly into rather flat, metanotal groove. Propodeal lateral margins strongly converging posteriorly and terminating in relatively short, upturned teeth; dorsum descending into steep, weakly concave declivity in medially uninterrupted line. Dorsum of petiole strongly raising medially and dorsally, terminating in two, closely approximate, divergent spines; outer margins of spines steeply descending into slender, acute, lateral spines. Gaster in lateral view with anterior face flat; anterior margin of first gastral tergite with distinct transverse carina.

Mandibles very finely, longitudinally striate with numerous piliferous pits. Clypeus reticulate-punctate anteriorly, striate towards base; head distinctly, longitudinally reticulate-striate. Pronotal dorsum mostly longitudinally striate, striae distinctly curving towards posterior angles of segment; mesonotal dorsum longitudinally striate; propodeal dorsum with striae distinctly directed posteriorly and medially. Sides of mesosoma below lateral margins of segment very smooth and polished, sculpture becoming wrinkled ventrally. Petiole finely wrinkled. Dorsum of gaster very finely, longitudinally striate, somewhat polished.

Mandibles with several, curved, golden hairs at masticatory borders and along outer margins; truncate median portion of anterior clypeal margin with a few, relatively long, golden setae and shorter setae fringing margin laterally. Clypeus with several, medium length hairs, hairs on rest of head distinctly shorter bristle-like. Dorsum of mesosoma with numerous, rather short, variously inclined hairs; numerous hairs lining lateral margins of petiole. Antennae and legs with numerous, bristle-like hairs on all surfaces. Gaster with semierect, mostly posteriorly inclined, medium length hairs, distinctly longer on gastral venter and apex. Closely appressed, rather sparse, golden pubescence variously distributed on most body surfaces, virtually absent from dorsa of head, mesosoma and petiole.

Mandibles, including bases, distinctly light reddish-brown, teeth very dark, almost black. Clypeus medium reddish-brown anteriorly, anterior border lined black. Body, including fore coxae, black, distinctly polished. Antennal scapes medium reddish-brown with apices a shade lighter; funiculi rather light reddish-brown at bases, segments progressively lighter, yellow, towards apices. Legs, including middle and hind coxae, very distinctly light orange; tarsi a shade darker.

Type Material


Type deposition: Holotype in ; 1 paratype worker each in, , ,.

Etymology
Named after the collector, Ms Carol Palmer, a researcher with the Biodiversity Conservation Division of the NT Department of Natural Resources, Environment, Arts and Sport, who collected many ants, including several new species of Polyrhachis, during a broader fire project in the Kimberley region of WA.