Polyrhachis cognata

Nothing is known about the biology of .

Identification
A member of the Polyrhachis vestita species group.

Kohout (2008) - P. cognata  is relatively similar to the other species of the vestita-group, notably to Polyrhachis ogatai with which it shares the characteristic rusty red and black pilosity and pubescence. It differs by its smaller size and by lacking the peculiar antennal process found in the unique holotype of P. ogatai holotype.

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

Nomenclature

 *  cognata. Polyrhachis cognata Kohout, 2008a: 276, figs. 5A-B (w.) INDONESIA (Sulawesi).

Worker
(holotype cited first): TL c. 14.01, 13.91; HL 3.53, 3.48; HW 2.62, 2.57; CI 74, 74; SL 4.64, 4.64; SI 177, 180; PW 2.07, 2.07; MTL 5.44, 5.39 (2 measured).

Anterior clypeal margin arcuate, very shallowly and widely emarginate medially. Clypeus with rather blunt median carina and shallow depressions just behind weakly raised median portion of anterior margin; median carina distinctly higher and more prominent posteriorly. Clypeus in profile straight for most of its length, posteriorly rounding into moderately impressed basal margin, laterally indicated by a flat, thin line. Frontal triangle distinct. Frontal carinae with sharp, high and steeply elevated laminate lobes; central area concave with poorly defined frontal furow. Sides of head in front of eyes converging towards mandibular bases in weakly convex line; behind eyes sides rounding into convex, medially narrowly upturned and weakly emarginate, occipital margin. Eyes convex, in full face view just reaching or marginally breaking lateral cephalic outline. Ocelli lacking. Pronotal dorsum weakly convex, with pair of long, slender, anterolaterally directed, horizontal spines; dorsolateral edges of spines continuous with parallel-sided pronotal margins. Mesonotal dorsum rather flat, strongly transverse, with laminate, anteriorly upturned lateral margins that are rounded in dorsal view. Propodeum with lateral margins forming anteriorly rounded and upturned laminae; posterior margins weakly converging into upturned posterior angles. Propodeal dorsum rounding into steep declivity in medially uninterrupted curve. Petiole biconvex in profile; dorsum armed medially with a pair of blunt, broad-based teeth; margin between teeth emarginate and somewhat jagged laterally, terminating in weakly upturned denticles. Anterior face of first gastral segment rather flat basally, with anterodorsal margin widely rounding onto dorsum of gaster.

Mandibles distinctly, longitudinaly striate. Head, mesosoma, petiole and gaster generally very finely reticulate-punctate with sculpturation on vertex of head and dorsum of mesosoma organised into fine, longitudinal striae.

Mandibles along outer margins and masticatory borders with numerous, relatively long, erect and semierect, golden hairs. Anterior clypeal margin fringed medially with medium length, anteriorly directed, golden setae, reducing in length laterally. Leading edge of antennal scapes with numerous short, erect, black hairs; a few hairs arising along inferior edge distally. Front and sides of head with medium length, erect, black hairs, those on vertex distinctly longer and more anteriorly directed. Mesosomal dorsum with numerous, long, anteriorly curved, black hairs, those on sides of mesosoma distinctly shorter. Coxae with several long, black and rusty-brown hairs. Legs with abundant, black and rusty-brown hairs, notably on tibiae, basal segments of tarsi and ventral surfaces of femora. Dorsal surfaces of fore femora hairless; middle and hind femora with only a few, short hairs along dorsal surfaces distally. Petiole with several short, black hairs fringing dorsal margin. Gaster with abundant, relatively long, somewhat posteriorly directed, black and brown hairs. Very short, dense, appressed, rusty-red pubescence over most body surfaces, notably over anterior portion of pronotal dorsum and meso-and metapleurae; somewhat longer, more erect, yellowish pubescence on pronotal collar.

Colour. Black, with legs dark reddish-brown.

Type Material
HOLOTYPE: SULAWESI TENGGARA, Wolasi, Pangalulu, 04°10’S, 122°30’E, 140m, 13.x.1999, K. Ogata & K. Masaoka (worker). PARATYPE: data as for holotype (worker). Holotype in (QMT144147), 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.