Polyrhachis (Aulacomyrma) minima, Kohout, R. J., 2007

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 : 202-203

Polyrhachis (Aulacomyrma) minima , new species

Figures 12, 15, 18

TYPE MATERIAL

HOLOTYPE: PAPUA NEW GUINEA, Morobe Prov., Huon Pen , lower Busu R. , 5. v. 1955, lowland rf., E. O. Wilson # 954 (worker). Type distribution: unique holotype in MCZC .

WORKER

Dimensions of holotype: TL c. 3.98; HL 1.06; HW 0.98; CI 92; SL 1.15; SI 117; PW 0.81; MTL 1.06.

Anterior clypeal margin arcuate, with very shallow notch medially; clypeus in profile virtually straight anteriorly, with basal margin shallowly impressed. Frontal carinae strongly sinuate with laminate lobes. Sides of head in front of eyes only weakly converging anteriorly. Eyes convex, in full face view clearly breaking lateral cephalic outline. Mesosoma marginate, margins of pronotal dorsum rather weak, but reaching promesonotal suture. Pronotal dorsum virtually parallel sided; humeri armed with acute, laterally directed, broad-based teeth. Promesonotal suture distinct; metanotal groove indicated by distinct incisions in lateral margins. Propodeum with lateral margins weakly widened posteriorly, terminating in rounded prominences and continued inwards, forming medially discontinued ridges that partly separate propodeal dorsum from relatively high and concave declivity. Petiole transverse, dorsal margin acute and weakly notched medially, strongly sinuate in dorsal view; lateral spines backwardly curved. Anterior face of first gastral segment concave; anterodorsal margin of concavity acute but only very weakly elevated above dorsal face of segment.

Mandibles finely striate. Head mostly longitudinally, somewhat irregularly, striate; striae on sides of head more regular and weakly curved inwards. Sculpture of mesosomal dorsum consisting of longitudinal striae, somewhat anteriorly converging on pronotal dorsum, posteriorly converging on mesonotal-propodeal dorsum; oblique on sides. Propodeal declivity finely shagreened; somewhat tranversely wrinkled medially, very smooth and glossy ventrally. Petiole and dorsum of gaster shagreened, sides of first gastral segment longitudinally striate.

Relatively short, yellowish or off-white, erect or curved hairs on head and mesosoma, most dense and longest on mandibles and clypeus, only a few short, variously curved hairs breaking the outline of vertex and mesosoma. Dorsum of first gastral segment with only a few short hairs, more abundant, longer and more golden towards apex. Somewhat untidy, relatively long, appressed or decumbent, greyish or silvery pubescence present in various density on all body surfaces, densest along preoccipital margin, pronotal humeri, propodeal dorsum, meso- and metapleura and coxae; fairly dense on gastral dorsum, ranging from silvery to golden.

Black. Mandibles, antennae and legs light to medium yellow, only basal portion of scapes, distal ends of femora and first tarsal segments a shade darker.

Sexuals and immature stages unknown.

ETYMOLOGY

Name derived from the Greek word minys, meaning little or small, referring to its small size.

REMARKS

P. minima is one of the smallest members of the subgenus. It is somewhat similar to P. wardi but, besides its smaller size (HL 1.09 in minima versus HL 1.15 - 1.34 in wardi), it differs in having a more convex mesosoma, posteriorly weakened pronotal margins, propodeal margins that are not produced into laterally directed teeth and a higher and more concave propodeal declivity.