Polyrhachis hilaris

Specimens have been collected from fogging samples.

Identification
A member of the Polyrhachis flavicornis species group.

Kohout (2008) - Polyrhachis hilaris is relatively close to Polyrhachis fruhstorferi from Sulawesi and Polyrhachis flavicornis from South East Asia. It differs from both in the form of the petiole which has more slender and widely diverging lateral petiolar spines and a pair of short, acute dorsal, intercalary teeth that are absent in the other species.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Indonesia, Sulawesi.

Nomenclature

 *  hilaris. Polyrhachis hilaris Kohout, 2008a: 284, figs. 7C-D (w.) INDONESIA (Sulawesi).

Worker
(holotype cited first): TL c. 5.00, 4.38-5.19; HL 1.31, 1.15-1.37; HW 1.06, 0.90-1.06; CI 81, 78-84; SL 1.56, 1.40-1.65; SI 147, 144-159; PW 0.87, 0.65-0.87 MTL 1.37, 1.28-1.47 (17 measured).

Anterior clypeal margin medially with shallow, truncate flange, laterally flanked by blunt denticles. Clypeus with poorly defined, blunt median carina; in profile clypeus weakly convex with shallowly impressed basal margin. Frontal triangle distinct. Frontal carinae sinuate with weakly raised margins; central area weakly concave; frontal furrow indistinct. Sides of head in front of eyes straight, rather strongly converging towards mandibular bases; behind eyes sides rounding into evenly convex occipital margin. Eyes convex, in full face view clearly breaking lateral cephalic outline. Ocelli lacking. Pronotal humeri angular, shallowly emarginate behind agles and widely rounded posteriorly; greatest width of pronotal dorsum at mid-length of segment. Mesonotum with lateral margins very weakly raised, converging posteriorly. Propodeal dorsum transverse, with lateral margins terminating posteriorly in dorsally rounded ridges, appearing in profile as acute teeth; ridges continued medially for a short distance with propodeal dorsum between them descending into declivity in medially uninterrupted curve. Petiole armed with pair of relatively long, widely diverging, acute spines; dorsal margin between spines with pair of distinct, acute, intercalary teeth. Anterior face of first gastral segment flat at base, widely rounding onto dorsum.

Mandibles very finely longitudinally striate near bases, rather smooth at masticatory borders with numerous piliferous pits. Head, mesosoma and petiole rather coarsely reticulate-punctate with reticulae on pronotum somewhat irregularly, mostly longitudinally, directed. Antennae finely, legs and gaster more distinctly and closely reticulate-punctate.

Mandibles with several curved, short hairs at outer margins near masticatory borders. Anterior clypeal margin with one long, seta medially and several short setae fringing margin laterally. A few paired, short and medium length, erect, yellow hairs near anterior and basal clypeal margins, along frontal carinae and a single pair of anteriorly curved hairs on vertex. Anterior face of fore coxae with pair of long, erect hairs. Gaster with rather short, golden hairs lining posterior margins of dorsal apical segments; ventral gastral surface with several erect, distinctly longer hairs and numerous, posteriorly curved, shorter hairs. Appressed, white, rather diluted pubescence on dorsum of gaster, virtually absent from other body surfaces.

Colour. Black. Mandibles very dark reddish-brown at their bases, distinctly lighter apically with teeth dark brown. Antennal scapes and basal funicular segments dark reddish-brown, with subsequent segments gradually lightening; condylae, base of antennal scapes and apical funicular segments distinctly light, yellow. Legs distinctly bi-coloured with coxae and femora black, tibiae and tarsi yellow; first tarsal segment shade darker. Gaster dorsally very dark, reddish-brown; sides a shade lighter with somewhat reddish tint.

Type Material
HOLOTYPE: SULAWESI UTARA: Dumoga-Bone NP, nr Danau Mooat, 1100m, 1.viii.1985, coffee fog., N.E. Stork et al. (worker). PARATYPES: data as for holotype (8 workers); ditto, 230m, 5.ii.1985, fog., N.E. Stork et al. (worker); ditto, 230m, 11.vii.1985, fog., N.E. Stork et al. (3 workers); ditto, 230m, 2.xii.1985, fog., N.E. Stork et al. (2 workers). Holotype and (5) paratypes in ; 2 paratypes each in, , and.

References based on Global Ant Biodiversity Informatics

 * Kohout, R. J. 2008. A review of the Polyrhachis ants of Sulawesi with keys and descriptions of new species (Hymenoptera: Formicidae: Formicinae). Memoirs of the Queensland Museum 52:255-317.