Polyrhachis dougcooki

Nothing is known about the biology of .

Identification
A member of the ammon species-group in the Polyrhachis subgenus Hagiomyrma. Kohout (2013) - Polyrhachis dougcooki closely resembles Polyrhachis ammon but differs by its distinctly longer antennal scapes (SI 168-173 in P. dougcooki versus 145-155 in P. ammon) and relatively small, virtually quadrate pronotal dorsum. The pilosity in P. dougcooki is distinctly longer and the somewhat brassy golden pubescence is denser and covers the whole body, including the head. In contrast the pilosity in P. ammon is distinctly shorter and the more appressed golden pubescence is virtually absent from the head.

Key to Polyrhachis Hagiomyrma group species

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Castes
Male and immature stages unknown.

Nomenclature

 *  dougcooki. Polyrhachis (Hagiomyrma) dougcooki Kohout, 2013: 518, figs. 3E-F (w.q.) AUSTRALIA.

Worker
(holotype cited first): TL c. 10.03, 9.37-10.23; HL 2.31, 2.21- 2.40; HW 1.81, 1.72-1.86; CI 78, 76-78; SL 3.07, 2.95-3.12; SI 170, 168-173; PW 1.53, 1.47-1.59; MW 1.03, 1.03-1.15; PMI 148, 135-150; MTL 3.73, 3.53-3.78 (8 measured).

Anterior clypeal margin with denticulate median flange, laterally flanked by acute teeth. Clypeus with median carina, sinuate in profile, posteriorly rounding into moderately impressed basal margin. Frontal triangle distinct. Frontal carinae sinuate with moderately raised margins. Sides of head in front of eyes converging towards mandibular bases in straight line; behind eyes, sides widely rounding into occipital margin. Eyes moderately convex, in full face view marginally exceding lateral cephalic outline. Ocelli lacking. Pronotal dorsum quadrate; pronotal humeri rounded, lateral margins weakly emarginate behind humeri and subparallel towards well impressed promesonotal suture. Mesonotal dorsum with lateral margins converging posteriorly; metanotal groove indistinct. Propodeal margins terminating in rather strong, subparallel spines, with bases weakly elevated and sinuate towards tips in side view. Petiole armed with pair of horizontal, weakly divergent spines. Anterior face of first gastral tergite higher than full height of petiole, widely rounding onto dorsum.

Mandibles finely and densely striate-rugose with numerous piliferous pits. Head and mesosoma reticulate-punctate, sculpturation almost completely hidden by overlying pubescence. Spines rugose with tips rather smooth and polished. Gaster finely shagreened.

Mandibular masticatory borders with numerous, medium length golden hairs. Anterior clypeal margin medially with several longer setae and fringe of shorter setae laterally. Numerous medium length hairs on clypeus, along frontal carinae and vertex, but no hairs breaking lateral cephalic outline. Somewhat longer, more abundant, variously curved hairs on dorsum of mesosoma, petiole and spines, excluding extreme tips. Gaster with abundant, erect or posteriorly inclined, golden hairs, longest hairs reaching greatest diameter of eyes in length. Relatively long, closely appressed, golden pubescence with somewhat reddish hue, over most dorsal body surfaces; pubescence more abundant and distinctly medially radiating on mesosomal dorsum, silvery on sides. Gastral pubescence somewhat longer and more abundant dorsally where it completely hides underlying sculpturation; pubescence silvery on gastral venter and sides, rich golden with distinct reddish hue on dorsum.

Black throughout.

Queen
Dimensions: TL c. 10.68; HL 2.23; HW 1.78; CI 76; SL 2.93; SI 165; PW 2.34; MTL 3.68 (1 measured).

Apart from sexual characters, very similar to worker except: mesoscutum only marginally wider than long with anterior margins widely rounded; medial line bifurcate dorsally; dorsum relatively low and virtually flat in lateral view with parapsides only weakly raised posteriorly. Mesoscutellum not elevated above dorsal plane of mesosoma. Spines similar to those in worker, but marginally shorter. Sculpturation, pilosity, pubescence and colour virtually identical to worker, except mandibles in single available queen dark reddish-brown.

Etymology
Named in honour of the collector, Doug Cook, a long time associate of the Queensland Museum, who collected many species of Polyrhachis and other insects on numerous collecting trips to remote localities in Queensland.

Determination Clarifications
Polyrhachis dougcooki was listed earlier by Kohout (2000: 200) as ‘Hagio 20’.