Polyrhachis nigrita

Bolton (1973) - Probably a ground nesting species which forages on low vegetation as the specimens from Uganda studied during the course of this survey were obtained by sweeping in a marsh. Wheeler (1922a:267) states that a single worker from Akenge, Congo (Kinshasa) was taken from the stomach of a toad.

Identification
A member of the Polyrhachis viscosa species-group. Bolton (1973) - The general body form allies this species to Polyrhachis viscosa and Polyrhachis cubaensis as was pointed out by Mayr in the original description. The species is distinguished by the marked reduction of the dorsal pair of petiolar spines and the lack of a transverse ridge separating the propodeal dorsum from the declivity.

Distribution based on Regional Taxon Lists
Afrotropical Region: Democratic Republic of Congo, Ghana, Uganda.

Nomenclature

 *  nigrita. Polyrhachis nigrita Mayr, 1895: 153 (w.) GHANA. Combination in P. (Myrma): Wheeler, W.M. 1922a: 267. Senior synonym of schoutedeni: Bolton, 1973b: 328.
 * schoutedeni. Polyrhachis (Myrma) schoutedeni Santschi, 1919c: 249 (w.) DEMOCRATIC REPUBLIC OF CONGO. Junior synonym of nigrita: Bolton, 1973b: 328.

Worker
Bolton (1973) - TL 7.0-8.9, HL 1.70-2.04, HW 1.48-1.70, CI 83-87, SL 1.89-2.22, SI 130-134, PW 1.15-1.34, MTL 1.92-2.37. (6 measured.)

Clypeus usually with the anterior margin slightly raised, may be weakly emarginate. Eyes convex; occipital margin strongly convex. Antennal scapes broadening apically, about two or three times broader at the apex than at the base but not distinctly and abruptly thickened apically as in viscosa. Alitrunk marginate throughout its length, the marginations only poorly developed. Pronotal and propodeal spines well developed, the latter without a transverse ridge running between them, the dorsum rounding evenly into the declivity. Promesonotal suture distinct, metanotal groove represented by a weakly incised line which in places fails to break the sculpturation. Petiole with the lateral pair of spines long and strong, produced outwards and upwards and curved backwards around the base of the gaster. Between these spines are a pair of short teeth, which may be reduced to blunt tubercles. Anterior face of the first gastral segment concave.

Development of erect hairs variable. In smaller specimens a few hairs are present on the anterior clypeal margin and the gastral apex only, but in larger individuals a few may also be present on the dorsum of the head and the alitrunk. Pubescence greyish white, sparse, densest on gaster and sides of alitrunk.

Clypeus with extremely fine longitudinal striae, contrasting to the rest of the head which has a fine reticulate-rugulation, the spaces enclosed by the reticulae finely punctate. A similar sculpturation is found on the dorsum of the alitrunk but laterally the rugae are effaced, leaving the surface finely reticulate-punctate. Gaster minutely and densely reticulate-punctate.

Type Material
Bolton (1973) - Holotype worker, GHANA : Chama (Brauns) (probably in ).

References based on Global Ant Biodiversity Informatics

 * Bolton B. 1973. The ant genus Polyrhachis F. Smith in the Ethiopian region (Hymenoptera: Formicidae). Bulletin of the British Museum (Natural History). Entomology 28: 283-369.
 * Mikissa J. B., J. H. C. Delabie, J. L. Mercier, and D. Fresnau. 2008. Preliminary Assessment on the Interactions of Wasmannia auropunctata in Native Ant Communities (Hymenoptera: Formicidae) of a Mosaic Gallery Forest/Savannah in Lope National Park, Gabon. Sociobiology 51(1): 207-218.