Polyrhachis (Aulacomyrma) mamba, 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 : 229-230

Polyrhachis (Aulacomyrma) mamba . new species

Figures 82, 85, 88

TYPE MATERIAL

HOLOTYPE: PAPUA NEW GUINEA, Northern Prov., Owen Stanley Ra. , Mamba Plantation , c. 7 km WNW of Kokoda , 08 º 51 ’ S, 147 º 41 ’ E, 500 m, 31. viii- 1. ix. 1984, R. J. Kohout acc. 403) (worker). PARATYPES: data as for holotype (60 workers, 1 dealate [[ queen ]]). Type distribution: holotype, most paratype workers and paratype [[ queen ]] in ANIC; 2 paratype workers in each BMNH, CASC, MCZC, LACM and QMBA .

WORKER

Dimensions: TL c. 6.00, 5.04 - 5.54; HL 1.47, 1.31 - 1.40; HW 1.28, 1.12 - 1.18; CI 87, 84 - 85; SL 1.47, 1.37 - 1.40; SI 115, 119 - 122; PW 1.06, 0.90 - 0.94; MTL 1.50, 1.34 - 1.40 (4 measured).

Anterior clypeal margin arcuate, entire to narrowly truncate or very shallowly emarginate medially. Longitudinal median carina weakly raised, terminating posteriorly in a shallow basal margin. Frontal carinae strongly sinuate with rather short, laminate, anteriorly sharply truncate lobes. Side of the head in front of eyes very weakly convex, rounded behind into preoccipital margin. Eyes flat, situated well forward on sides of head, virtually identical to those in P. impressa and P. roomi , not breaking lateral cephalic outline in full face view. Mesosoma immarginate laterally and posteriorly. Pronotal humeri armed with rather broad-based, laterally and anteriorly directed, more-or-less blunt spines. Promesonotal suture shallow; metanotal groove lacking. Petiole in profile with dorsum rounded, lateral teeth minute, upturned. Anterior face of first gastral segment convex.

Mandibles finely and densely, longitudinally striate. Dorsum of head with mostly regular striae, similar to those in P. roomi in orientation; longitudinal and anteriorly converging on clypeus; obliquely curving from sides of head towards basal clypeal margin; transverse and anteriorly bowed on vertex, outermost striae converging forwards between frontal carinae. Mesosoma with striation resembling that of P. kokoda , notably on mesonotum and propodeum. Pronotal striation in mamba somewhat different, due to shape of dorsum between pronotal spines; curved inwards in kokoda, straight in mamba. Anterior and posterior faces of petiole with tranverse, slightly dorsally bowed striae, that are connected along sides. First gastral segment with sides finely longitudinally striate; dorsally striae becoming less distinct, dorsum finely shagreened.

Short to medium length, erect, curved or sinuate, off-white to silvery hairs present on dorsum of head, mesosoma, petiole and first gastral segment; somewhat longer, yellowish to golden and more erect hairs on legs and gaster. Appressed, mostly greyish pubescence in various densities on most of body, notably on pronotal dorsum, including spines, meso- and metapleuron, lateral borders of propodeal declivity and coxae; somewhat longer on dorsum of gaster and almost obscuring underlying sculpture.

Black; mandibular masticatory border, antennal scapes, joints of femora and tibiae, basal tarsal segments and apical segments of gaster dark reddish-brown. Funiculi, except base of first segment, and most of legs light to very light reddish-yellow.

QUEEN

Dimensions: TL c. 6.35; HL 1.53; HW 1.37; CI 89; SL 1.56; SI 114; PW 1.34; MTL 1.59 (1 measured).

Similar to worker with usual differences indicating caste. Sculpture of head and body similar to worker, direction of striae following structural characteristics of fully developed mesosoma. Colour as in worker except funiculi distinctly darker and femora and tibiae with more extensive dark patches around joints.

ADDITIONAL MATERIAL EXAMINED

PAPUA NEW GUINEA: Northern Prov., Kokoda, 25. v. 1972 (P. M. Room # 360) (w); ditto, 1. vi. 1972 (P. M. Room # 360) (w); Oivi Ridge, Kokoda Rd, 1200 ft, rf., 18. i. 1971, B. B. Lowery (dealate [[ queen ]]). Morobe Prov., Bulolo, 2500 - 3500 ft, rf., 2. i. 1968, B. B. Lowery (w).

ETYMOLOGY

Species named after the type locality, Mamba Plantation nr Kokoda, Papua New Guinea.

REMARKS

P. mamba is similar to P. kokoda , with distinguishing characters given in the remarks section of the latter species. Among these, the most important are the flat eyes in mamba that do not reach the lateral cephalic outline in full face view. Also, the striae on the vertex in mamba are tranversely bowed, while they are longitudinal in kokoda. One dealate queen was collected foraging with workers on the trunks and branches of freshly felled trees on the edge of a recent rainforest clearing. The second queen was collected with a kokoda worker at Oivi Ridge nr Kokoda.