Polyrhachis kyawthani

The specimens of the type series were collected from a silk nest attached to the underside of a leaf on a low tree in rainforest.

Identification
Polyrhachis kyawthani is very similar to Polyrhachis aporema. They share a similar mesosomal profile with a widely rounded propodeum and very steep declivity. However, Polyrhachis aporema differs in the distinctly convex eyes that clearly break the lateral cephalic outline in full face view. The eyes in Polyrhachis kyawthani are rather flat and situated well inside the cephalic outline. Although similar, the propodeal declivity in Polyrhachis aporema is distinctly lower and weakly concave at the base, while in Polyrhachis kyawthani the declivity is higher and virtually vertical. The petiole in Polyrhachis aporema features a straight anterior face and convex posterior face, while the petiole in Polyrhachis kyawthani is lower and distinctly biconvex. (Kohout 2006)

Distribution
Known only from New Ireland, PAPUA NEW GUINEA.

This taxon was described from New Guinea.

Abundance
Known only from type material.

Castes
Immature stages (eggs, larvae and pupae) present in spirit collection. (Kohout 2006)

Worker
Dimensions (holotype cited first): TL c. 7.06, 6.35-7.56; HL 1.65, 1.56-1.75; HW 1.56, 1.43-1.62; CI 94, 92-96; SL 2.15, 2.03-2.25; SI 138, 135-144; PW 1.25, 1.15-1.31; MTL 2.59, 1.59-2.71 (12 measured).

Clypeus in profile very weakly convex, narrowly rounding into weakly impressed basal margin. Frontal triangle weakly indicated. Frontal carinae sinuate with weakly raised margins; central area rather flat with frontal furrow clearly indicated for most of its length. Sides of head in front of eyes very weakly convex, converging towards mandibular bases; behind eyes sides rounding into broadly convex occipital margin. Eyes weakly convex, in full face view not reaching lateral cephalic outline. Ocelli lacking, relative positions indicated by shallow punctures in sculpture. Pronotum in dorsal view widely rounded, humeri in some specimens subangular; greatest pronotal width at mid-length of segment. Mesosoma in lateral view with pronotum weakly convex, almost flat, narrowly rounding into weakly impressed promesonotal suture; mesonotal dorsum convex; metanotal groove indicated by shallow depression in outline and faint line in some specimens; propodeum unarmed, dorsum widely rounding into virtually vertical declivity. Petiole in profile biconvex; dorsum armed with rather small, acute, subequal teeth; tips of dorsal pair distinctly bent backwards. Subpetiolar process acute anteriorly, widely rounded posteriorly. First gastral segment with anterior face lower than apices of petiolar spines, widely rounding onto dorsum of segment.

Mandibles very finely rugose with piliferous pits, density reducing towards bases. Head, mesosoma and gaster finely shagreened dorsally; intensity of sculpturation increasing laterally with meso- and metapleaurae reticulate-rugose. Petiole very finely, mostly transversely reticulate, distinctly reticulate-rugose around base. Rather shallow piliferous pits scattered over most body surfaces, but almost completely absent from rather polished dorsum of mesosoma.

Mandibles with numerous, medium length, curved hairs along masticatory borders. Anterior clypeal margin usually with 2 long, anteriorly directed setae medially and several rather short setae laterally. Mostly paired, medium length, erect hairs near anterior and basal clypeal margins and along frontal carinae; pair of long, somewhat forward-curved hairs on vertex. Pair of long, erect hairs on anterior faces of fore coxae, several shorter, somewhat isolated, erect hairs ventrally on trochanters and femora. Numerous, medium length, erect hairs along posterior margins of gastral segments, more abundant on ventral surfaces.

Colour. Black; mandibular teeth, condylae, tips of apical funicular segments and legs medium reddish-brown. Coxae and tarsi black. Apex of gaster diffusely reddish-brown.

Queen
Queen. Dimensions: TL c. 9.32; HL 2.09; HW 1.87; CI 89; SL 2.43; SI 130; PW 1.93; MTL 3.21 (1 measured). Apart from sexual characters, similar to worker except: pronotal humeri evenly and widely rounded; mesoscutum marginally wider than long, lateral margins distinctly converging anteriorly, forming distinctly narrowly rounded anterior margin; median line short, weakly indicated; parapsides rather flat, slightly raised posteriorly; mesoscutum in profile with widely rounded anterior face and very weakly convex dorsum. Mesoscutellum weakly convex, marginally elevated above dorsal plane of mesosoma; metanotal groove distinct. Propodeal dorsum weakly convex, rounding abruptly into virtually vertical declivity. Very fine body sculpturation, rather sporadic pilosity and polished appearance as in worker.

Male
Unknown

Type Material
Type deposition: Holotype, most paratype workers and paratype queen in ; 2 paratype workers each in, , , , , and.

Type Locality Information
HOLOTYPE: PAPUA NEW GUINEA, New Ireland Prov., East Coast, 3km S of Konos, 03°09’S, 151°43’E, <50m, 22.vii.1984, R.J. Kohout acc. 84.105 (worker). PARATYPES: data (and nest) as for holotype (58 workers, dealate queen).