Polyrhachis bosi

The type material was collected from a fogging sample.

Identification
A member of the Polyrhachis relucens species group in the subgenus Myrma

Kohout (2008) - P. bosi is somewhat similar to Polyrhachis festina, but differs in having the base of antennal scapes distinctly widened and strongly bent, and the frontal carinae very close together, leaving the central area extremely narrow (see image in caste section below).

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

Nomenclature

 *  bosi. Polyrhachis bosi Kohout, 2008a: 265, figs. 2A-B, 6A (w.) INDONESIA (Sulawesi).

Worker
Dimensions (holotype cited first): TL c. 7.96, 8.32; HL 1.93, 2.09; HW 1.50, 1.65; CI 78, 79; SL 2.15, 2.34; SI 143, 142; PW 1.18, 1.25; MTL 2.28, 2.50 (2 measured).

Anterior clypeal margin arcuate, very narrowly truncate medially. Clypeus with blunt, median carina; in profile almost straight, only weakly raised anteriorly; posteriorly rounding into shallowly impressed basal margin. Frontal triangle indistinct. Frontal carinae sinuate with sharply raised, almost vertically laminate margins; central area extremely narrow, with clearly indicated median frontal furrow. Antennal scapes relatively short, bases distinctly broadened with excavated inner margins; in dorsal view scapes somewhat twisted and strongly bent. Sides of head in front of eyes only weakly converging anteriorly; behind eyes sides rounding into broad occipital margin. Eyes moderately convex, situated well forward from occipital corners; in full face view eyes only marginally breaking lateral cephalic outline. Lateral ocelli poorly developed; position of median ocellus indicated by distinct pit in cephalic sculpturation. Pronotal dorsum virtually flat between pair of rather long, anterolaterally directed, somewhat dorsomedially flattened, acute spines; their outer edges acute and basally continuous with lateral margins of pronotum. Mesonotal dorsum wider than pronotal dorsum at base, strongly transverse, with medially emarginate lateral margins. Propodeal dorsum slightly wider than long, virtually parallel-sided, with weakly sinuate lateral margins terminating in rounded, upturned, transverse ridges that meet medially and form an inwardly bowed carina dividing propodeal dorsum from shallowly concave declivity. Petiole biconvex in profile, armed with a pair of dorsolaterally and posteriorly directed, acute spines that are situated on dorsolateral angles (apex of left petiolar spine in holotype bent weakly, but distinctly inwards); dorsal petiolar margin between spines transverse, with indication of a median intercalary tooth; lateral margins of petiole with secondary, short, acute tooth below bases of spines. Anterior face of first gastral segment concave, with anterodorsal margin reaching height of dorsal petiolar margin.

Mandibles finely, mostly longitudinaly striate. Head, petiole and gaster shagreened; dorsum of mesosoma with weakly indicated longitudinal striae; sides of mesosoma more distinctly sculptured, reticulate-punctate, with reticulae somewhat oblique. Tips of pronotal and petiolar spines rather smooth, polished.

Mandibular masticatory borders and outer margins apically with several semierect, golden hairs. Anterior clypeal margin with a few long, anteriorly directed setae medially and fringe of shorter setae laterally. Several pairs of medium length, erect, golden hairs near anterior and basal margins of clypeus and along frontal carinae; single pair on vertex arising from pits next to lateral ocelli. Antennal scapes with a few, short, erect hairs fringing apex. Pair of downwardly directed, longer hairs on anterior face of fore coxa. Gaster with several medium length hairs on apical segments, their length distinctly increasing towards gastral apex and on ventral gastral surfaces. Most of body with rather dense, closely appressed, mostly silvery pubescense obscuring underlying sculpturation. Pubescence on dorsum of mesosoma follows longitudinal pattern of striation, distinctly longer and irregular pubescence on sides of mesosoma.

Colour. Black throughout.

Type Material
HOLOTYPE, SULAWESI TENGAH: Lore Lindu NP, Toro, Gn. Kalabui, 950m, 6.v.2005, nat. forest, fog., M. M. Bos (worker). PARATYPE: Lore Lindu NP, Toro, Gn. Kamonua, 1080m, nat. forest, fog., M. M. Bos (worker). Holotype in (QMT144145), paratype in GUGG (M. Bos private collection).

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.