Polyrhachis braxa

The type material, 3 workers, were collected from a Cocoa tree in Ghana.

Identification
A member of the Polyrhachis revolii species-group. Bolton (1973) - The species appears to be related directly to Polyrhachis revoili as it possesses an arcuate clypeal margin without a rectangular and truncated lobe, and a pair of tubercles upon the propodeum as opposed to a pair of ridges. It is however separated from revoili and from all other species of the group by the presence of the facial groove outside the antennal insertion, the reduced pronotal armament, and the lack of raised or incised sculpturation on any part of the head capsule, alitrunk or gaster. Superficially braxa resembles some members of the Polyrhachis rastellata species-group of the Indo-Australia regions.

Distribution based on Regional Taxon Lists
Afrotropical Region: Ghana.

Nomenclature

 *  braxa. Polyrhachis braxa Bolton, 1973b: 333, figs. 50, 56 (w.) GHANA.

Worker
Holotype. TL 5.7, HL 1.29, HW 1.18, CI 91, SL 1.52, SI 129, PW 1.11, MTL 1.52.

Mandibles with five teeth; anterior clypeal margin arcuate and entire. Eyes weakly convex, situated close to the posterior corners of the head in full-face view. Sides of the head in front of the eyes shallowly convex; behind the eyes rounding almost immediately into the convex occipital margin. Head on each side with a short but distinct longitudinal groove terminating in a pit-like depression posteriorly; best seen in full-face view with the light incident upon the side of the head. This structure is situated close to the external margin of the antennal insertion, its total length about equal to the diameter of the antennal socket. Alitrunk not marginate, the dorsum transversely convex and everywhere rounding into the sides. Pronotum armed with a pair of very small, blunt teeth. Promesonotal suture and metanotal groove present but represented only by very weakly incised lines, the latter less well developed than the former. Propodeum with a pair of minute tubercles, considerably smaller than the prominences bearing the spiracles; declivity of propodeum between these tubercles and the spiracular openings concave. Petiole thick and strongly biconvex in lateral view; in front view equipped with a pair of widely separated, straight spines dorsally, which are subtended by a pair of lateral teeth. The dorsum of the petiole between the spines straight and more or less flat. Anterior surface of first gastral segment shallowly concave medially to receive the posterior face of the petiole.

Head, alitrunk, gaster and appendages with numerous erect, pale, off-white hairs. Pubescence sparse and greyish, most dense on the sides of the alitrunk and on the petiole. On the pronotum the pubescence is densest dorsally in a transverse band running across the segment just in front of the promesonotal suture.

Entirety of head, alitrunk, gaster devoid of sculpturation except for a very fine superficial reticulation and the pits from which the hairs arise. The whole body shining. Petiole more dull and reticulate-punctate, but weakly so, the sculpturation partially hidden by the pubescence.

Colour black, shining; the legs dark brown and the apical segments of the funiculus yellow-brown.

Two paratype workers, similar to the holotype but in one the pronotal teeth are better developed and more acute than in the holotype, the gaster is dark brown in colour and the legs are lighter brown. Dimensions: TL 5.7-5.9, HL 1.29-1.34, HW 1.18-1.22, CI 91, SL 1.52-1.56, SI 128-129, PW 1.11-1.13, MTL 1.52-1.56.

Type Material
Holotype worker, GHANA: Eastern Region, CRIG, New Tafo, on cocoa tree, 4.iii.1970 (C. A. Collingwood).

Paratypes. Two workers, same data as holotype (BMNH).