Polyrhachis exotica

Nothing is known about the biology of this species.

Identification
Kohout 1987: This species is a very distinct member of the Polyrhachis sexspinosa-group. It possesses all the combined characters of the group except that the gaster is smooth and shining, in contrast to those of other species, where it is characteristically pubescent. This character together with the exceptionally produced pronotal dorsum render exotica immediately identifiable, and readily separable from any other member of the sexspinosa-group.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Philippines.

Castes
Males are unknown.

Nomenclature

 *  exotica. Polyrhachis exotica Kohout, 1987: 170, figs. 9, 11, 15 (w.q.) PHILIPPINES.

Worker
Dimensions (holotype cited first): TL 14.46, 13.31-14.66; HL 3.43, 3.17-3.43; HW 2.22; 2.07- 2.22; CI 65, 64-66; SL 4.48, 4.28-4.59; SI 202, 201-207, PW 2.06, 1.96-2.17; MTL 6.05, 5.74-6.10 (13 measured).

Mandibles with 4 distinct teeth. Clypeus with a median longitudinal carina; convex in profile. Sides of head in front of eyes feebly convex, nearly straight; narrowed behind eyes with occipital margin narrow and without lateral angular prominences. Antennal carinae well elevated, sinuate; the furrow between them 2 x as wide in front than behind. Antennal scapes long, extending beyond the occipital margin by at least half their length. Eyes convex, but not as prominent as in some species of the group. Median ocellus present, though rather obscure in some specimens. Pronotum in profile very strongly convex, dome-like. Pronotal spines long, projecting laterally and strongly curved forward. Mesonotal dorsum in profile straight; propodeal dorsum shallowly concave, declivity abrupt. Mesopleural process produced to form an acute ventral angle. Propodeal spines very strong, long, elevated from their bases, divergent and recurved. Petiole with dorsum sloping anteriorly, spines scarcely elevated and curved to the base of gaster, which is short and broadly ovate; first tergite covering almost half of the gastral dorsum.

Mandibles relatively smooth and shining at the masticatory border; punctate-opaque laterally, with numerous piliferous pits at their bases. Sculpturation a fine reticulate punctation on clypeus, front and sides of head; increasing posteriorly to coarsely punctate on vertex and at the occipital border. Mesosoma and petiole fairly coarsely and closely punctate; sides of mesonotum and propodeum foveolate-punctate. Dorsum of gaster shining, with only very fine microscopic punctations.

All surfaces of the body and appendages, except the tips of spines and dorsum of the first gastral segment, with numerous yellow or off-white long erect undulate hairs. These are longest and most dense on the mesosomal dorsum and only slightly shorter on the head, petiole, gaster and legs. Appressed, somewhat radiating, bright golden pubescence abundant all over the body, except the mandibles, legs, apices of pronotal, propodeal and petiolar spines, and most of gaster (where it is much diluted, and virtually absent from dorsal aspect of the first tergite).

Head and body black or very dark reddish brown; mandibles at the masticatory border, apical portions of antennal segments, subpetiolar process and legs reddish brown, the femora always a shade lighter. Gaster black with deep red reflections.

Queen
Dimensions: TL 16.08-16.63; HL 3.73-3.88; HW 2.47-2.57; CI 65-67; SL 4.74-4.99; SI 190-196; PW 2.37-2.47; MTL 6.20-6.35 (3 measured).

Females differ from workers in the usual characters identifying full sexuality - three ocelli, complete mesosomal structure and wings. The sculpturation, pilosity and colour patterning is identical, but development of the spines is different. The pronotal spines are short and stout, projecting laterally and bent only weakly forward. The propodeal spines are directed posteriorly, projecting horizontally, with their tips curved slightly inwards. The petiolar spines are closely similar to those of the workers, but slightly shorter.

Type Material
Holotype and most paratypes (6 workers and 2 females) in BPBM; 3 paratypes (2 workers, 1 female) in RJK; 1 paratype worker each in ANIC, BMNH, USNM and QMBA (with kind consent of Bernice P. Bishop Museum).

References based on Global Ant Biodiversity Informatics

 * Kohout R. J. 1987. Three new Polyrhachis sexspinosa-group species from the Philippines (Hymenoptera: Formicidae). Mem. Qld. Mus. 25: 169-176