Polyrhachis inflata

The type series collected in a rainforest clearing on trunks of recently felled trees.

Identification
Polyrhachis inflata is probably related to Polyrhachis luctuosa with both distinguished from all other known New Guinean species of the subgenus by the very closely reticulate-punctate sculpturation of their body, giving them a distinct opaque appearance. However, Polyrhachis inflata is easily separated by its exceptionally high pronotal dorsum which bears a well-defined, median, longitudinal furrow along its summit. The pronotum in Polyrhachis luctuosa is not swollen and has no furrow. With its highly raised pronotum, Polyrhachis conspicua also resembles Polyrhachis inflata, but the body sculpturation in Polyrhachis conspicua is rather smooth and polished. (Kohout 2006)

Distribution
New Guinea

This taxon was described from New Guinea.

Worker
Dimensions (holotype cited first): TL c. 7.26, 6.50-7.26; HL 1.81, 1.68-1.84; HW 1.72, 1.62-1.81; CI 95, 94-98; SL 2.34, 2.09-2.34; SI 136, 128-136; PW 1.37, 1.28-1.40; MTL 2.78, 2.43-2.81 (5 measured).

Clypeus in profile almost straight, with weak median tubercle just before narrowly rounding into weakly medially impressed basal margin. Frontal triangle weakly impressed. Frontal carinae sinuate with weakly raised margins; central area almost flat with frontal furrow indicated along most of its length. Sides of head in front of eyes almost straight, strongly converging towards mandibular bases; behind eyes sides rounding into convex occipital margin. Ocelli lacking, shallow punctures indicating relative positions of lateral ocelli poorly visible under overlying sculpturation. Pronotum in dorsal view widely rounded; greatest width of pronotal dorsum at mid-length of segment. Mesosoma in profile with pronotum strongly convex, very high, anterior face very steep; summit narrow with short, median, longitudinal furrow; promesonotal suture distinct; mesonotal dorsum virtually straight except for depression indicating position of metanotal groove; propodeal dorsum descending in open, uninterrupted curve into oblique declivity. Petiole with anterior face straight, posterior face very weakly convex; dorsum armed with four subequal spines; dorsal pair closer to each other than to lateral spines, tips slightly bent backwards. Subpetiolar process acute anteriorly, rounded posteriorly. Anterior face of first gastral segment straight, rounding in even curve onto dorsum of segment.

Mandibles finely, longitudinally striate with numerous piliferous pits. Head, mesosoma and petiole very closely reticulate-punctate; sculpturation on sides of mesosoma more coarse, becoming reticulate-rugose on meso- and metapleurae. Petiole finely, mostly transversely reticulate, distinctly reticulate-rugose around base. Gaster rather strongly shagreened, sculpture generally less coarse than on head and mesosoma. All dorsal body surfaces with numerous piliferous pits and puctures.

Mandibles with numerous semierect hairs on masticatory borders. Anterior clypeal margin with a few anteriorly directed setae medially and several shorter setae laterally. Paired, relatively long, erect hairs near anterior and basal clypeal margins and along frontal carinae; single longer pair on vertex. One or 2 long, erect hairs on anterior and posterior faces of fore coxae. Numerous, medium length, erect hairs lining posterior margins of gastral segments; ventral surfaces with hairs distinctly more abundant, posteriorly directed and with rather dense cover of decumbent hairs. Abundant, very short, appressed hairs arising from numerous pits over all dorsal body surfaces.

Colour. Black, with only mandibular teeth, condylae, extreme tips of apical funicular segments and narrow band on trochanters, medium reddish-brown.

Queen
Dimensions: TL c. 8.11; HL 1.93; HW 1.72; CI 89; SL 2.34; SI 136; PW 1.84; MTL 3.17 (1 measured). Apart from sexual characters, very closely resembling worker except: pronotal humeri widely rounded; mesoscutum in profile widely rounded anteriorly, dorsum rather flat; mesoscutum in dorsal view only marginally wider than long, lateral margins converging anteriorly into narrowly rounded anterior margin; median line clearly indicated, bifurcate posteriorly; parapsides rather flat, weakly raised posteriorly. Mesoscutellum in profile convex, higher than mesoscutum; metanotal groove distinct. Propodeal dorsum descending into oblique declivity in narrow curve. Sporadic pilosity and sculpturation as in worker, except mesothoracic epimera and episterna very finely reticulate without punctures or piliferous pits.

Male
Unknown

Type Material
Holotype worker (QMT99345) and paratype queen in ; 1 paratype worker each in, , and.

Type Locality Information
HOLOTYPE: PAPUA NEW GUINEA, West Sepik Prov., Torricelli Mts, Lumi, 03°29’S, 142°02’E, x.1984, D. Waisi (worker). PARATYPES: data as for holotype (2 workers); ditto, 1-2km NE of Lumi, 400-500m, 11-13.viii.1984, rf, RJK acc. 84.283 (queen). Madang Prov., Adalbert Mts, Wanuma, 04°36’S, 145°06’E, viii.1968, N.L.H. Krauss (1 workers). Gulf Prov., Ivimka camp, Lakekamu Basin, 07.7°S, 146.8°E, 120m, 11-20.xi.1996, Malaise trap, R.R. Snelling (1 worker).