Polyrhachis (Aulacomyrma) sculpta Emery, 1887

Kohout, R. J., 2007, Revision of the subgenus Aulacomyrma Emery of the genus Polyrhachis F. Smith, with descriptions of new species., Advances in ant systematics (Hymenoptera: Formicidae): Homage to E. O. Wilson - 50 years of contributions. (Memoirs of the American Entomological Institute 80), pp. 186-253 : 207-208

Polyrhachis (Aulacomyrma) sculpta Emery, 1887

Figures 29, 32, 35

Polyrhachis sculpta Emery, 1887: 226 . Holotype worker. Type locality: NEW GUINEA, Sorong (L. M. D ’ Albertis), MCSN (examined) .

Polyrhachis (Campomyrma) sculpta Emery ; Emery, 1925: 180. Combination in P. (Campomyrma) .

WORKER

Dimensions of holotype: TL c. 5.24; HL 1.40; HW 1.18; CI 84; SL 1.47; SI 124; PW 1.09; MTL 1.34.

Clypeus arcuate, medially shallowly emarginate with distinct longitudinal median carina; in profile clypeus virtually straight with basal margin weakly impressed medially. Frontal triangle indistinct. Frontal carinae strongly sinuate with raised laminate lobes. Eyes relatively large, convex, in full face view clearly breaking lateral cephalic outline. Sides of head only weakly converging anteriorly, convex and converging behind eyes. Pronotal and mesonotal dorsa marginate, lateral margins of propodeal dorsum ill-defined. Pronotal humeri armed with triangular teeth, lateral margins shallowly emarginate at bases. Promesonotal suture distinct; metanotal groove lacking, position indicated by interruption of lateral mesosomal margin. Propodeal dorsum descending into virtually vertical declivity in rather abrupt, medially unbroken curve; lateral propodeal margins terminating in small, blunt, tubercles. Petiole with sharp dorsal margin, shallowly emarginated medially; lateral teeth short, very weakly curved backwards. First gastral segment concave anteriorly, anterodorsal margin of concavity elevated above dorsal surface of segment.

Mandibles finely, longitudinally striate. Sides and front of head regularly, longitudinally striate, striae on clypeus converging anteriorly and meeting along midline; striae on vertex distinctly transversely bowed, almost semicircular. Mesosoma with striae converging anteriorly on pronotal dorsum, somewhat V-shaped on mesonotal and propodeal dorsa and oblique on sides. Petiole and dorsum of gastral segments shagreened.

Silvery or off-white hairs present on all body surfaces and appendages. Numerous, semi-erect to erect, very short to medium length hairs on front and sides of head in front of eyes; hairs very short and strongly anteriorly inclined on vertex. Antennal scapes with numerous hairs along leading edges and at distal ends. Hairs on pronotal dorsum very uneven in length and direction, ranging from short to medium, erect to semi-erect or undulated; hairs mostly posteriorly directed on mesonotal and propodeal dorsa. Petiole with a few hairs along dorsal margin. Gaster with mostly short, posteriorly directed hairs on dorsum of first gastral segment, increasing in length and density towards gastral apex where they are relatively long and more golden. Silvery appressed pubescence scattered over body; most dense on dorsum and sides of propodeum, where it almost completely hides underlying sculpture, and along posterior margins of gastral segments.

Black, with antennal scapes, basal segments of funiculi and femora very dark reddish brown. Apical segments of funiculi, tibiae and tarsi light to very light yellowish brown.

Sexuals and immature stages unknown.

REMARKS

P. sculpta is characterized by the posteriorly less distinct lateral margins of the mesosoma, leaving the propodeum only weakly margined laterally and completely immarginate posteriorly. The sculpture of the vertex is transversely bowed in contrast to the longitudinal striation of the rest of the head. With its rather untidy silvery pubescence sculpta superficially resembles P. variegata , but they differ in many aspects, especially the eyes, that are convex in sculpta , and distinctly flat in variegata . The propodeal declivity is virtually vertical in sculpta , while it is distinctly oblique in variegata . The anterodorsal margin of first gastral segment is elevated above the dorsal surface of the segment in sculpta , while it is only weakly concave in variegata , with the dorso-medial margin blunt.