Polyrhachis strumosa

Nothing is known about the biology of Polyrhachis strumosa.

Identification
With its rather massive mesosoma, Polyrhachis strumosa is similar to Polyrhachis hybosa. However, they differ in a number of characters, including the outline of mesosoma which, in Polyrhachis strumosa, features a very short pronotal summit and rather high propodeal declivity. In Polyrhachis hybosa the summit of pronotal dorsum is longer and the propodeal declivity distinctly lower. Also, the pronotal dorsum in Polyrhachis strumosa is widest just behind the more-or-less angular humeri, while the pronotal humeri in Polyrhachis hybosa are widely rounded with the pronotal dorsum widest at its mid-length. The petiolar scale in Polyrhachis strumosa is distinctly transverse, while it is virtually quadrate in Polyrhachis hybosa. (Kohout 2006)

Distribution
Only known from the type locality (see below).

Distribution based on Regional Taxon Lists
Indo-Australian Region: New Guinea.

Abundance
Only known from the type series.

Castes
Known only from the worker caste.

Nomenclature

 *  strumosa. Polyrhachis strumosa Kohout, 2006b: 132, figs. 11E-F (w.) NEW GUINEA.

Worker
Dimensions (holotype cited first): TL c. 6.80, 6.30-7.26; HL 1.68, 1.53-1.72; HW 1.62, 1.53-1.65; CI 96, 94-96; SL 2.28, 2.11-2.34; SI 141, 137-143; PW 1.50, 1.29-1.54; MTL 2.71, 2.53-2.84 (8 measured).

Clypeus in profile weakly convex, posteriorly rounding into rather flat basal margin. Frontal triangle indistinct. Frontal carinae sinuate with raised margins; central area concave medially with rather distinct frontal furrow. Sides of head in front of eyes convex, converging towards mandibular bases; behind eyes sides rounding into convex occipital margin. Eyes convex, in full face view marginally exceeding lateral cephalic outline. Ocelli lacking. Pronotum in dorsal view with humeri distinctly subangular; greatest width of pronotal dorsum just behind shoulders. Mesosoma in profile with pronotum rising towards short summit in rather steep, almost straight line; promesonotal suture distinct; mesonotal dorsum very weakly convex, sloping down posteriorly to feebly indicated metanotal groove; propodeal dorsum weakly convex, rounding into relatively high, virtually vertical declivity. Petiole very broad, transverse, anterior face in profile almost straight, posterior face weakly convex; dorsum armed with four spines; lateral pair slightly longer. Subpetiolar process anteriorly acute, weakly concave posteriorly. Anterior face of first gastral segment straight, narrowly rounding onto dorsum of segment.

Mandibles longitudinally rugose with numerous piliferous pits. Head, mesosoma and gaster shagreened, sculptural intensity increasing laterally to become reticulate-rugose, notably on meso- and metapleurae. Petiole finely, mostly transversely wrinkled dorsally, sculpture coarser at base. Numerous shallow punctures and piliferous pits in various densities over all dorsal surfaces.

Mandibles with several short semierect hairs at masticatory borders. Anterior clypeal margin with a few anteriorly directed setae medially and very few shorter setae laterally. A few pairs of medium length, erect hairs near anterior and basal clypeal margins and along frontal carinae. Gaster with numerous, medium length, erect hairs lining posterior margins of apical segments, more abundant on ventral surfaces.

Colour. Black; mandibular teeth, condylae and distal ends of antennal scapes reddish-brown. Funiculi brown with distal segments progressively lighter towards apices; tip of apical segments light yellowish-brown. Legs medium to dark reddish-brown with fore and middle tibiae a shade lighter; tarsi very dark brown or black.

Type Material
HOLOTYPE: PAPUA NEW GUINEA, East Sepik Prov., Maprik, 03°36’S, 143°03’E, 150m, 29.xii.-17.i.1960, T.C. Maa (worker). PARATYPES: data as for holotype (7 workers). Holotype and 1 paratype in ; 2 paratypes in ; 1 paratype each in, , and.

References based on Global Ant Biodiversity Informatics

 * Janda M., G. D. Alpert, M. L. Borowiec, E. P. Economo, P. Klimes, E. Sarnat, and S. O. Shattuck. 2011. Cheklist of ants described and recorded from New Guinea and associated islands. Available on http://www.newguineants.org/. Accessed on 24th Feb. 2011.
 * 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.