Polyrhachis masaokai

Nothing is known about the biology of .

Identification
A member of the Polyrhachis vestita species group.

Kohout (2008) - Like other members of the vestita-group, P. masaokai has a scale-like petiole with its dorsal margin arcuate, more-or-less entire or only weakly and obtusely dentate or jagged. Polyrhachis masaokai differs from all the other known species of the group in having the dense body pubescence silvery white, while in Polyrhachis cognata and Polyrhachis ogatai the pubescence is distinctly rusty red and in Polyrhachis vestita rich golden or yellow. It also differs from P. ogatai in lacking the peculiar process near apex of the antennal scapes found in that species. Polyrhachis masaokai differs from P. vestita by the shape of dorsal petiolar margin that, in P. vestita is virtually entire, while it is dentate with distinct lateral teeth in P. masaokai.

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

Castes
Known only from the worker caste.

Nomenclature

 *  masaokai. Polyrhachis masaokai Kohout, 2008a: 279, figs. 5C-D (w.) INDONESIA (Sulawesi).

Worker
(holotype cited first): TL c. 12.50, 12.80; HL 3.12, 3.12; HW 2.34, 2.32; CI 75, 74; SL 4.23, 4.23; SI 181, 182; PW 2.02, 2.07; MTL 4.74, 4.63 (2 measured).

Anterior clypeal margin arcuate, very shallowly and obtusely truncate medially. Clypeus with distinctly raised median carina; clypeus in profile straight for most of its length, narrowly rounding into weakly impressed basal margin, indicated laterally by a very thin line breaking culpturation. Frontal triangle weakly impressed. Frontal carinae with sharp, highly and steeply elevated laminate lobes; central area deeply concave with weakly impressed frontal furrow. Sides of head in front of eyes converging towards mandibular bases in very weakly convex line; behind eyes sides rounding into convex, medially strongly narrowed and posteriorly weakly emarginate, occipital margin. Eyes convex, in full face view marginally exceeding lateral cephalic outline. Ocelli lacking, relative positions poorly indicated by shallow punctures. Pronotal dorsum weakly convex in profile, with pair of long, slender, anterolaterally directed, horizontal spines; their dorsolateral edges continuous with weakly laminate lateral margins of pronotum. Mesonotal dorsum strongly transverse, with laminate, weakly upturned, posteriorly converging lateral margins. Propodeum with lateral margins weakly laminate, narowly rounded and upturned anteriorly, posteriorly produced into distinct, strongly upturned teeth; propodeal dorsum descending into oblique declivity in medially uninterrupted line. Petiole in profile with anterior and posterior faces convex at base, strongly converging dorsally; dorsum margin medially with a pair of blunt, broad-based teeth and additional blunt denticles laterally before terminating in rather distinct, strongly upturned, dorso-laterally directed teeth. First gastral segment flat at base with anterior face widely rounding onto dorsum.

Mandibles distinctly and regularly, longitudinally striate. Head, mesosoma, petiole and gaster mostly shagreened, with sculpturation on vertex and sides of head distinctly more intense, somewhat reticulate; sides of mesosoma and base of petiole reticulate, finely wrinkled dorsally.

Mandibles with several, curved hairs near masticatory bordes and along outer margins; several appressed hairs arising from pits towards bases. Anterior clypeal margin with several relatively long, anteriorly directed, golden setae and a few shorter setae fringing margin laterally. Clypeus, front and sides of head and mesosoma with numerous, short to medium length, erect, hairs. Vertex of head and dorsum of mesosoma with abundant, distinctly longer, erect and somewhat curved, mostly anteriorly directed hairs. A few, very short, erect hairs on leading edge of antennal scapes; one or two hairs arising from inferior edge distally. Fore coxae and legs, excluding dorsal surfaces of femora, with medium length, erect, mostly golden hairs. Petiole with several shorter hairs near dorsal margin. Gaster with patch of posteriorly curved, rather long hairs at anterodorsal margin and shorter, erect hairs lining posterior margins of dorsal and ventral surfaces of apical segments. A very few, short erect hairs arising from dorsum of first gastral segment. Short, silvery white or greyish, closely appressed, rather dense pubescence on most body surfaces.

Colour. Black throughout, with only mandibular masticatory borders diffusely dark reddish-brown.

Type Material
HOLOTYPE: SULAWESI SELATAN, Sampulage nr Mangktana, 02°16’S, 120°47’E, 1000m, 19.x.1999, K. Ogata & K. Masaoka (worker). PARATYPE: data as for holotype (worker). Holotype in (QMT144149), paratype in.

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.