Polyrhachis vernoni

This is one of only a few rainforest dwelling members of the subgenus Hagiomyrma, with most specimens known collected foraging on the ground and large boulders at the summit and slopes of Mt Tozer in Iron Range National Park.

Identification
A member of the ammon species-group in the Polyrhachis subgenus Hagiomyrma. Kohout (2013) - Polyrhachis vernoni is a very distinct species, easily separated from all other Hagiomyrma by the unique, distinctly raised, angular margins of pronotal humeri and the strongly transverse first gastral tergite with blunt lateral prominences.

Key to Polyrhachis Hagiomyrma group species

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Castes
Known only from the worker caste.

Nomenclature

 *  vernoni. Polyrhachis (Hagiomyrma) vernoni Kohout, 2013: 524, figs. 4G-H (w.) AUSTRALIA.

Worker
(holotype cited first): TL c. 11.04, 11.04-11.74; HL 2.56, 2.56-2.78; HW 1.84, 1.84-2.00; CI 72, 70-73; SL 3.17, 3.17-3.48; SI 172, 167-178; PW 1.68, 1.68- 1.84; MW 1.12, 1.12-1.22; PMI 150, 146-160; MTL 3.88, 3.88-4.28 (12 measured).

Anterior clypeal margin with shallow, obtusely denticulate, median flange, laterally flanked by blunt angles. Clypeus with median carina; sinuate in profile, posteriorly rounding into well impressed basal margin. Frontal triangle indistinct. Frontal carinae sinuate with distinctly raised margins; central area relatively wide with distinct median carina. Sides of head in front of eyes converging towards mandibular bases in straight line; behind eyes, sides Eyes convex, in full face view exceeding lateral cephalic outline. Ocelli lacking. Pronotal humeri produced into dilated, angular prominences with distinctly raised margins; lateral margins behind humeri weakly raised, subparallel towards well impressed promesonotal suture. Mesonotal lateral margins weakly raised for most of length; posteriorly converging towards indistinct metanotal groove. Propodeal margins terminating in rather strong, divergent spines, obliquely raised from bases in side view and sinuate towards weakly upturned tips. Petiole with dorsum shallowly concave medially, armed with divergent, horizontal spines. First gastral tergite distinctly transverse, in dorsal view with sides produced into somewhat bluntly elevated, shoulder-like prominences.

Mandibles finely, longitudinally striate with numerous piliferous pits. Head, mesosoma and petiole reticulate-puncate; spines sculptured at bases, smooth and polished towards tips. Gaster shagreened.

Mandibular masticatory borders with numerous, curved, golden hairs and short, appressed hairs towards bases. Anterior clypeal margin with a few longer, anteriorly projecting setae medially and numerous, short setae, fringing margin laterally. Clypeus with only a few, paired, rather short, semierect hairs; central area and vertex with numerous, medium length, anteriorly directed, golden hairs, but no hairs breaking lateral cephalic outline between eyes and mandibular bases in full face view. Leading edges of antennal scapes with a few, semierect, short, bristle-like hairs. Dorsum of mesosoma, gaster and anterior face of fore coxae, with numerous, erect or variously curved, golden hairs, some as long as greatest diameter of eyes; somewhat shorter hairs on dorsum of petiole, mid and hind coxae and venter of femora; hairs more diluted and anteriorly directed on venter of gaster. Relatively long, appressed, somewhat untidy, golden pubescence on dorsum of head, mesosoma and petiole; pubescence distinctly shorter and much diluted on clypeus and sides of head and mesosoma. Dorsum of gaster with abundant, golden pubescence and very distinct, dark, reddish-brown median patch, extending posteriorly along first and second tergite; pubescence more diluted and silvery on gastral venter.

Black; mandibular masticatory borders, appendages and venter of gaster medium to dark reddish-brown.

Type Material


Type deposition: Holotype and 2 paratypes in ; 2 paratypes each in, , ; 1 paratype in.

Etymology
Named in honour of the collector of the holotype, Donald P. Vernon, formerly of the Queensland Museum, Brisbane, who was the only Australian member of the 1948 Archbold Expedition to Cape York.