Polyrhachis callima

Nests of P. callima, which are identical to those of Polyrhachis conciliata, are excavated in soil with entrances under pieces of wood, stone, or beneath tufts of grass. The holotype colony, which was almost completely excavated, contained 129 ants, including a dealate queen and a male.

Identification
A member of the ammon species-group in the Polyrhachis subgenus Hagiomyrma. At the type locality, Polyrhachis callima was sympatric with Polyrhachis conciliata. These species are superficially very similar and I originally considered them to represent a single species. However, closer examination revealed several characters clearly separating them. The most apparent difference is their pilosity which, in P. callima, is distributed almost evenly over the entire dorsum of the body, with the longest hairs reaching or exceeding the greatest diameter of the eyes in length. In contrast, the pilosity in P. conciliata is distinctly shorter and completely absent from the mesonotal and propodeal dorsa.

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Castes
Male and immature stages (larvae and pupae from holotype colony) present in the QM spirit collection.

Nomenclature

 *  callima. Polyrhachis (Hagiomyrma) callima Kohout, 2013: 513, figs. 2G-H (w.q.m.) AUSTRALIA.

Worker
(holotype cited first): TL c. 12.20, 10.89-12.20; HL 2.71, 2.56-2.71; HW 2.06, 1.93-2.06; CI 76, 74-79; SL 3.73, 3.43-3.73; SI 181, 171-183; PW 1.65, 1.53- 1.65; MW 1.31, 1.25-1.31; PMI 126, 124-130; MTL 4.89, 4.54-4.89 (21 measured).

Anterior clypeal margin with median, denticulate flange, flanked laterally by acute angles. Clypeus with median carina; in profile distinctly concave anteriorly, straight posteriorly towards virtually flat basal margin. Frontal triangle shallowly impressed. Frontal carinae with raised margins; central area relatively wide and flat with frontal furrow replaced with weakly raised ridge. Sides of head in front of eyes converging towards mandibular bases in virtually straight line; behind eyes, sides converging into weakly convex occipital margin. Eyes situated close to occipital corners, convex, in full face view clearly exceeding lateral cephalic outline. Ocelli lacking. Pronotal dorsum with humeri moderately dilated, rounded, with upturned margins; lateral margins behind humeri weakly notched, parallel towards promesonotal suture. Mesonotal dorsum with posteriorly converging margins; metanotal groove distinct. Propodeum with lateral margins terminating in moderately divergent acute spines, tips weakly turned outwards; propodeal dorsum widely rounding into distinctly convex propodeal declivity. Petiole with dorsum narrowly rounded, armed with divergent, acute spines. Anterior face of first gastral segment widely rounding onto dorsum.

Mandibles finely longitudinally striate with numerous piliferous pits. Head and mesosoma very finely and closely reticulate-punctate. Gaster finely shagreened.

Mandibles with numerous medium length, golden hairs, distinctly longer at masticatory borders, shorter towards mandibular bases. Numerous, anteriorly directed setae fringing anterior clypeal margin. Several, rather long hairs on clypeus, along frontal carinae and vertex, but no hairs breaking lateral outline of head in full face view. Numerous, pale golden or silver, erect and somewhat undulated hairs, longer than greatest diameter of eyes on dorsum of mesosoma, front coxae and petiole; somewhat shorter hairs on middle and hind coxae. Gaster with numerous, golden, posteriorly inclined hairs, longest on gastral venter and around apex where they exceed greatest diameter of eyes. Very sparse, closely appressed, mostly silvery pubescence on dorsum of mesosoma; pubescence more abundant on sides of mesosoma and petiole. Abundant, closely appressed, somewhat medially radiating pubescence over all gastral surfaces, obscuring underlying sculturation; pubescence silvery on venter, rich golden with distinct, dark reddish-brown, median patch on gastral dorsum.

Black with only mandibles very dark reddish brown; condylae medium reddish-brown.

Queen
TL c. 12.25-12.60; HL 2.37- 2.40; HW 1.81; CI 75-76; SL 3.12-3.28; SI 172-181; PW 2.96-3.18; MTL 4.08-4.38 (3 measured).

Apart from sexual characters, very similar to worker except: pronotal dorsum with humeri subacute, widely rounded posteriorly. Mesoscutum distinctly wider than long; anterior margin evenly rounded; median line distinct, bifurcate; parapsides rather flat; dorsum of mesoscutum flat in lateral view; mesoscutellum convex, distinctly raised above dorsum of mesoscutum. Propodeal and petiolar spines similar to those in worker, but distinctly shorter. Pale golden and silvery, erect hairs over most body surfaces, rather short on dorsum of mesoscutum, distinctly longer on mesoscutellum; appressed pubescence very similar to worker with identical patch on gastral dorsum.

Etymology
Derived from the Greek word kalos, meaning beautiful.

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