Polyrhachis nourlangie

The distribution of Polyrhachis nourlangie is centred on the northern parts of the Northern Territory, including the islands adjacent to Arnhem Land. It is locally common in open eucalypt forest, extending into savannah woodland in Nitmiluk National Park at the southern limit of its distribution.

Identification
A member of the trapezoidea species-group in the Polyrhachis subgenus Hagiomyrma. Kohout (2013) - Polyrhachis nourlangie is somewhat similar to Polyrhachis darlingtoni with the main distinguishing characters given in the remarks section of the latter.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Nomenclature

 *  nourlangie. Polyrhachis (Hagiomyrma) nourlangie Kohout, 2013: 566, figs. 13C-D (w.) AUSTRALIA.

Worker
(holotype cited first): TL c. 7.61, 6.6-8.3; HL 1.84, 1.62-2.09; HW 1.53, 1.36-1.75; CI 83, 81-86; SL 2.46, 2.25-2.71; SI 161, 152-165; PW 1.18, 1.06-1.40; MW 0.86, 0.84-1.00; PMI 137, 125-137; MTL 2.78, 2.43- 3.03 (17 measured).

Anterior clypeal margin shallowly emarginate and obtusely denticulate medially, without clearly defined median flange. Clypeus with median carina; sinuate in profile, posteriorly rounding into moderately impressed basal margin. Frontal triangle indistinct. Frontal carinae sinuate with moderately raised margins; central area relatively wide, flat with distinct frontal furrow. Sides of head in front of eyes converging towards mandibular bases in weakly convex line; behind eyes, sides rounding into convex occipital margin. Eyes moderately convex, in full face view, only marginally exceeding lateral cephalic outline. Ocelli lacking. Pronotal dorsum with humeri rounded; lateral margins emarginate at midlength; promesonotal suture distinctly impressed. Mesosomal dorsum with posteriorly converging lateral margins; metanotal groove indistinct. Propodeal margins subparallel; spines moderately long with inner margins parallel, outer margins sinuate, with extreme tips weakly curved outwards. Petiole markedly low and broad at base in lateral view, anterior face inclined forwards before rounding onto virtually flat, laterally marginate dorsum, margins terminating in bases of short, curved spines. Anterior face of first gastral segment widely rounding onto dorsum.

Mandibles finely, longitudinally striate with piliferous pits. Head, mesosoma and petiole closely reticulate-punctate. Spines sculptured at bases, rather smooth and polished towards tips. Gaster finely shagreened.

Mandibles at masticatory and along outer borders with numerous, curved, golden hairs. Anterior clypeal margin with several anteriorly projecting setae medially. Clypeus, central area and vertex with several short to medium length, erect hairs; outline of head in full face view with numerous, erect, relatively short hairs. Leading edge of antennal scapes with several, very short, erect hairs. Dorsum of mesosoma with numerous, somewhat posteriorly inclined hairs, those on propodeum and petiole marginally longer. Several, medium length hairs on coxae and venter of femora. Gaster with relatively abundant, distinctly longer, posteriorly inclined, golden hairs. Closely appressed, rich golden, pubescence, rather diluted on vertex of head and sides of mesosoma; pubescence somewhat medially radiating and dense on mesosomal dorsum and petiole, completely hiding underlying sculpturation. Gaster with dense, somewhat longer, golden pubescence on dorsum; pubescence less dense, pale golden on sides and silvery on venter.

Black; mandibular teeth reddish-brown.

Etymology
After the type locality, Nourlangie Rock in Kakadu National Park, Northern Territory.

References based on Global Ant Biodiversity Informatics

 * Kohout R.J. 2013. Revision of Polyrhachis (Hagiomyrma) Wheeler, 1911 (Insecta: Hymenoptera: Formicidae: Formicinae). Memoirs of the Queensland Museum  Nature 56: 487577