Polyrhachis bruehli

Polyrhachis bruehli is known only from the single holotype specimen. It was collected in a fogging sample.

Identification
Polyrhachis bruehli resembles Polyrhachis achterbergi and Polyrhachis widodoi but differs from both by the presence of short, but distinct propodeal spines and by the configuration of the petiolar spines. It also differs in the shape of anterior clypeal margin that is shallowly and widely emarginate with the emargination flanked by distinct, anterolaterally projecting, acute teeth (Kohout 2006).

Distribution
Known only from the type locality (see below).

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

Abundance
Known only from the holotype.

Castes
Known only from a single worker.

Nomenclature

 *  bruehli. Polyrhachis bruehli Kohout, 2006b: 111, figs. 6C-D (w.) BORNEO.

Worker
Dimensions of holotype: TL c. 6.55; HL 1.78; HW 1.81; CI 102; SL 1.78; SI 98; PW 1.40; MTL 2.34.

Anterior clypeal margin broadly and shallowly emarginate medially; emargination flanked by distinct, anterolaterally projecting, acute teeth. Clypeus in profile straight with basal margin flat; shallow median depression on clypeus near basal margin, may be due to partly collapsed cuticula as holotype is probably not fully sclerotised. Frontal triangle shallowly impressed; frontal carinae sinuate, relatively short with only weakly raised, posteriorly converging margins; central area wide with distinct longitudinal furrow terminating in shallow depression on vertex that indicates position of median ocellus. Head broad, wider than long. Sides of head in front of eyes almost straight, converging towards mandibular bases; behind eyes sides rounding into broad, medially weakly concave occipital margin. Eyes weakly convex, situated well forward and inward from occipital corners; in full face view eyes not reaching lateral cephalic outline. Ocelli lacking. Pronotal humeri armed with short, acute spines; lateral margins below spines narrowly emarginate. Mesosoma in profile convex; promesonotal suture distinct; metanotal groove lacking; propodeum armed with pair of short, acute, triangular, upturned spines. Petiole narrow in profile; dorsum armed with long, posteriorly curved, lateral spines; dorsal spines lacking. Anterior face of first gastral segment shallowly concave at base.

Mandibles very finely, mostly longitudinally rugose with numerous piliferous pits. Clypeus with smooth, weakly indicated, median line, running from anterior clypeal process towards base, reaching shallowly impressed frontal triangle. Body sculpturation consisting of regular reticulate-puncturation, uniformly distributed on head, mesosoma and petiole. Gaster very finely shagreened.

A few, short, curved and semierect hairs on mandibular masticatory borders. Anterior clypeal margin medially with 1 long and 2 shorter, anteriorly directed setae; fringe of shorter setae lining margin laterally. Medium length, erect hairs, mostly in pairs, near anterior and basal clypeal margins and along frontal carinae. Gaster with several medium length hairs lining posterior margins of apical segments, hairs more abundant on venter. Hairs completely absent from vertex, mesosoma and petiole. Extremely short, closely appressed pubescence distributed sparingly over all dorsal body surfaces.

Body generally reddish-brown with dorsum of head, mesosoma and petiole with distinct blue sheen. Mandibles, antennae, including condylae, coxae and legs very light yellow; mandibular teeth and apical segments of tarsi a shade darker.

Type Material
HOLOTYPE: EAST MALAYSIA, SABAH, Danum Valley, i-iv.1999, fogging, col. C. Brühl (worker). Unique Holotype (QMT99342) in.

References based on Global Ant Biodiversity Informatics

 * Kohout R.J. 2006. Review of Polyrhachis (Cyrtomyrma) Forel of Australia, Borneo, New Guinea and the Solomon Islands with descriptions of new species. Memoirs of the Queensland Museum 52: 87-146.
 * Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58