Polyrhachis monista

Bolton (1973) - P. monista nests and forages arboreally. The nests are a mixture of silk and vegetable particles, often enclosed between a pair of leaves. Forel (1916:452) reported a carton nest built inside a rolled-up leaf.

Identification
A member of the Polyrhachis monista species-group. Bolton (1973) - The species is separated from its closest relative, Polyrhachis spitteleri, by the absence of a deep promesonotal groove and the presence of a prominence between the propodeal spines in the latter species.

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

Nomenclature

 *  monista. Polyrhachis monista Santschi, 1910c: 398, fig. 20 (q.) CONGO. Santschi, 1914d: 384 (w.). Combination in P. (Myrma): Santschi, 1914d: 384. See also: Bolton, 1973b: 343.

Worker
Bolton (1973) - TL 5.5-6.4, HL 1.27-1.52, HW 1.22-1.41, CI 88-94, SL 1.40-1.59, SI 113-120, PW 0.96-1.04, MTL 1.40-1.74. (9 measured.)

Anterior clypeal margin arcuate and entire. Sides of head in front of the strongly convex eyes converging anteriorly, almost straight. Alitrunk not marginate, the dorsal surfaces of the pronotum and propodeum rounding evenly into the sides. Pronotum and propodeum each armed with a pair of thick spines, those of the pronotum directed outwards and upwards, those of the propodeum somewhat shorter and upcurved. Pronotum separated from mesonotum by a very deep broad groove. Mesonotum and propodeum similarly separated, the direction of the groove slanting forwards in profile so that its base meets the base of the promesonotal groove above the anterodorsalmost point of the mesopleuron. A welt bearing the mesothoracic spiracle projects from the base of the groove posteriorly. Petiole with four spines, the lateral pair slightly longer than the dorsal pair; all the spines curved backwards towards the base of the gaster. Median portion of anterodorsal border of the first gastral segment with a sharp, transverse margin separating the concave anterior face from the convex dorsal face.

Coarse, erect hairs present on all dorsal surfaces, varying in colour from white through straw-yellow to pale brown. Hairs strongly curved posteriad on the dorsum of the anterior half of the first gastral segment. Pubescence everywhere sparse or absent, densest on the pleurae.

Basic sculpturation of the head and alitrunk of fine, dense striation, longitudinal on the dorsum of the head, more or less longitudinal on the pronotal dorsum but tending to diverge posteriorly and following the curve of the sclerite, so that they are oblique on the sides of the pronotum. Striation transverse on the mesonotum, broadly V-shaped on the propodeum. Gaster with a fine, superficial reticulation, smooth and highly polished. Colour black, the colour of the extremities variable. In the majority of specimens the antennal funiculi become lighter apically, almost yellow in some smaller individuals but usually brown. Femora usually brown-black but may be paler, in one very small specimen from Nigeria the tibial apices are a deep red-brown.

Queen
Bolton (1973) - In general very much like the worker but the adaptations of the alitrunk seen in, and so diagnostic of the worker are much reduced in the present caste. The promesonotal suture is well developed, but does not form a broad, deep groove as in the worker, whilst the developed metanotum more or less fills the posterior groove, but still leaves enough space for a deep, narrow trench between itself and the propodeum.

Type Material
Bolton (1973) - Holotype queen. CONGO (Brazzaville) (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.
 * IZIKO South Africa Museum Collection
 * Medler J. T. 1980: Insects of Nigeria - Check list and bibliography. Mem. Amer. Ent. Inst. 30: i-vii, 1-919.
 * Robson Simon Database Polyrhachis -05 Sept 2014
 * Santschi F. 1910. Formicides nouveaux ou peu connus du Congo français. Annales de la Société Entomologique de France 78: 349-400.
 * Tadu Z., C. Djieto-Lordon, R. Babin, Yede, E. B. Messop-Youbi, and A. Fomena. 2013. Influence of insecticide treatment on ant diversity in tropical agroforestry system: some aspect of the recolonization process. International Journal of Biodiversity and Conservation 5(12): 832-844.
 * Taylor B. 1978. Ants of the Nigerian Forest Zone (Hymenoptera: Formicidae). II. Formicinae, Dolichoderinae. Cocoa Research Institute of Nigeria Research Bulletin 5: 1-57.
 * Wheeler W. M. 1922. Ants of the American Museum Congo expedition. A contribution to the myrmecology of Africa. VIII. A synonymic list of the ants of the Ethiopian region. Bulletin of the American Museum of Natural History 45: 711-1004