Polyrhachis curta

The two specimens before me, a worker and a queen, were both collected by pyrethrum knock-down from the forested regions of Ghana. The previous captures of the species show that it ranges throughout the rain forest areas of the continent but is very uncommon. Previous authors make no mention of the nesting site of the species, and nothing is known of its biology save that it is arboreal. (Bolton 1973)

Identification
A member of the Polyrhachis alexisi species group. Bolton (1973) - The form of the head, alitrunk, and especially the petiole render specimens very easily identifiable, in fact, the petiolar structure is unique.

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

Biology
Bolton (1973) - A recently dealate female was recorded in Ghana in April. This very distinctive but rare species seems to have been found on only six or seven occasions, in each case a single worker or female being captured.

Nomenclature

 *  curta. Polyrhachis curta André, 1890: 312 (w.) SIERRA LEONE. Bolton, 1973b: 347 (q.). Combination in P. (Pseudocyrtomyrma): Emery, 1925b: 206; in P. (Myrma): Wheeler, W.M. 1922a: 995; Bolton, 1973b: 346. Senior synonym of lyrifera, maynei: Bolton, 1973b: 346.
 * maynei. Polyrhachis maynei Forel, 1911f: 282 (w.) DEMOCRATIC REPUBLIC OF CONGO. Combination in P. (Myrma): Wheeler, W.M. 1922a: 997. Junior synonym of curta: Bolton, 1973b: 346.
 * lyrifera. Polyrhachis (Pseudocyrtomyrma) lyrifera Stitz, 1933: 73, fig. 5 (w.) CAMEROUN. Junior synonym of curta: Bolton, 1973b: 346.

Worker
Bolton (1973) - TL 7.4-7.6, HL 1.70-1.77, HW 1.52-1.78, CI 89-100, SL 2.07-2.11, SI 118-136, PW 1.48-1.74, MTL 2.00-2.04. (2 measured.)

Anterior clypeal margin arcuate, with a pair of minute denticulae which form the borders of an extremely shallow median lobe. Sides of head convex posteriorly, tending to be more straight and somewhat convergent in front of the eyes. Eyes situated well up on the sides of the head, not breaking the outline of the sides in full-face view. Pronotum armed with a pair of spines, marginate between the base of each spine and the distinct promesonotal suture. Mesonotum marginate from the promesonotal suture almost to the junction with the propodeum. Metanotal groove absent, replaced by an angle which separates the mesonotum from the very oblique dorsal surface of the propodeum. Propodeum not marginate, unarmed, the dorsum very oblique and sloping into the vertical and weakly concave declivity. In front view the sides of the petiole diverge from the base, pass through a rounded angle and then converge dorsally to the bases of a pair of curved spines. The spines rise almost vertically from the dorsum of the petiole and then curve outwards and somewhat backwards, giving the petiole a lyre-like appearance. There are no lateral teeth or spines. Anterior face of the first gastral segment very deep and concave.

Erect hairs absent from all dorsal surfaces except the clypeus, gastral apex, and one or two pairs on the vertex. Pubescence everywhere short and yellowish grey in colour.

Sculpturation everywhere of a fine, dense reticulation.

Queen
Bolton (1973) - Answering to the above description, but with the expected modifications of the alitrunk. The propodeum is more orthodoxly shaped than in the worker, having a definite, convex dorsal surface, which rounds into the declivity. Pubescence is rather more dense than in the worker, and the dorsal sclerites of the mesothorax have a few erect hairs, particularly on the mesoscutellum.

Type Material
Bolton (1973) - Holotype worker, SIERRA LEONE (probably in ).

References based on Global Ant Biodiversity Informatics

 * André E. 1890. Matériaux pour servir à la faune myrmécologique de Sierra-Leone (Afrique occidentale). Rev. Entomol. (Caen) 9: 311-327.
 * 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.
 * 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