Polyrhachis curtospinosa

The distribution of P. curtospinosa is similar to that of Polyrhachis bispinosa and appears to be restricted to the northern parts of the Northern Territory and the Mt Isa basin in north-western Queensland.

Identification
A member of the Polyrhachis gravis species-group. Kohout (2013) - Polyrhachis curtospinosa is very similar to Polyrhachis gravis but differs in having distinctly shorter antennal scapes (SI 114-116 in curtospinosa versus 125-131 in gravis), very short, tooth-like dorsal petiolar spines and mesosomal dorsum that completely lacks the short, bristle-like pilosity seen in P. gravis.

Key to Polyrhachis gravis species-group workers

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Castes
Sexuals and immature stages unknown.

Nomenclature

 *  curtospinosa. Polyrhachis (Campomyrma) curtospinosa Kohout, 2013: 99, figs. 2C-D, G-H (w.) AUSTRALIA.

Worker
TL c. 9.22, 9.22-9.78; HL 2.31, 2.28-2.36; HW 2.12, 2.09-2.15; CI 92, 91-92; SL 2.43, 2.40-2.50; SI 115, 114-116; PW 1.84, 1.65-1.84; MTL 2.93,2.87-2.96 (1 +3 measured).

Mandibles with 6 teeth. Anterior clypeal margin widely truncate, with truncate portion irregularly denticulate. Clypeus smoothly curved without median carina; weakly sinuate in profile with flat base. Frontal triangle distinct. Frontal carinae sinuate with moderately raised margins; central area with rather indistinct frontal furrow. Sides of head in front of eyes weakly convex towards mandibular bases; behind eyes sides narrowly rounding into moderately convex occipital margin. Eyes convex, in full face view clearly breaking lateral cephalic outline. Ocelli lacking. Prenotal humeri bluntly angular with lateral margins behind emarginate, before converging posteriorly towards well impressed promesonotal suture. Mesonotal lateral margins converging posteriorly, virtually forming a continuous line with margins of propodeum; metanotal groove flat. Propodeal dorsum strongly narrowed posteriorly with lateral margins terminating in upturned, somewhat medially flattened teeth; dorsum somewhat medially and posteriorly concave before curving through narrow gap between closely approximated teeth into steeply descending declivity. Petiole scale-like in lateral view; dorsum armed with a pair of tooth-like spines, hardly longer that their basal width; outer margins of spines descending into slender, acute, lateral spines. Gaster in lateral view with anterior face flat; anterior margin of first gastral tergite with blunt transverse carina.

Mandibles finely, longitudinally striate with numerous piliferous pits. Clypeus reticulate-punctate; head distinctly, mostly longitudinally striate. Pronotal dorsum with distinctly finer striae that curve medially from humeral angles towards centre, before turning towards promesonotal suture and posterior corners of segment. Dorsa of mesonotum and propodeum mostly longitudinally striate, striae on propodeum strongly converging posteriorly towards narrow gap between propodeal teeth. Sides of mesosoma and petiole finely wrinkled. Gaster very finely and closely reticulate, somewhat semipolished.

Mandibles with numerous, curved, golden hairs at masticatory and outer borders; anterior clypeal margin with numerous, relatively long, golden setae medially and fringe of shorter setae laterally. Several semierect, rather short, golden hairs on clypeus; only a few, very short, bristle-like hairs along frontal carinae and on vertex, none breaking cephalic outline in full face view. Only a few, very short, anteriorly inclined hairs evident on pronotal dorsum of some specimens, no hairs on mesonotal and propodeal dorsa and petiole. Dorsum of gaster with only a few, very short, golden hairs along posterior margins of segments; hairs distinctly longer and posteriorly curved on vertex and gastral apex. Closely appressed, golden pubescence in various densities on most body surfaces, virtually absent from dorsum of mesosoma.

Head, mesosoma and petiole generally black. Mandibles, mandibular bases and anterior portion of clypeus distinctly orange or light reddish-brown, narrowly bordered brown or black. Antennae black or very dark brown with funicular segnlents progressively lighter reddish-brown towards apices. Legs, including coxae, light to medium reddish-brown with basal portion of tibiae and tarsi black; apical tarsal segments reddish-brown. Dorsum of gaster black with dorsoanterior margin, sides, venter and apex progressively lighter reddish-brown.

Type Material


Type deposition: Holotype in ; 1 paratype each in, and.

Etymology
Derived from the combination of the Latin curtus , meaning shorten and spina, meaning thorn or spine, in reference to the distinctly shortened dorsal petiolar spines.