Polyrhachis cubaensis

Bolton (1973) - Arnold (1924:753) records the species nesting “in hollow stem galls, the walls of the gall partly covered with a web.”

Identification
A member of the Polyrhachis viscosa species-group.

Distribution based on Regional Taxon Lists
Afrotropical Region: Kenya, Mozambique, South Africa, Sudan, United Republic of Tanzania.

Nomenclature

 *  cubaensis. Polyrhachis cubaensis Mayr, 1862: 687 (w.) SOUTH AFRICA (not Cuba; see Mayr, 1893: 195). Combination in P. (Myrma): Wheeler, W.M. 1922a: 994. Senior synonym of striolatorugosa: Bolton, 1973b: 325.

Worker
Bolton (1973) - TL 6.4-7.5, HL 1.77-1.85, HW 1.59-1.67, CI 89-91, SL 1.75-1.88, SI 110-113, PW 1.33-1.41, MTL 1.85-1.93. (4 measured.)

Anterior clypeal margin entire, somewhat truncated medially and with a pair of notch-like pits from which long hairs arise. In profile the slope of the clypeus is suddenly less steep towards the anterior margin and this area is rather more convex than the rest of the clypeus. Eyes convex. The head broadly convex behind, the sides of the head in front of the eyes gently convex and convergent. Alitrunk marginate throughout its length, the dorsal surfaces transversely convex; the propodeal dorsum usually strongly convex medially and with the margination somewhat projecting. Pronotum armed with a pair of broad spines. Promesonotal suture and metanotal groove represented by incised lines; the former better developed than the latter which may in places fail to break the sculpturation; Propodeum with a pair of upcurved spines of variable length and thickness. Between these spines and separating the propodeal dorsum from the declivity runs a transverse ridge, the centre of which is raised up into a median eminence, tubercle or tooth. The size of this eminence is variable and may be small in some individuals, but the ridge is always present and distinct. Petiole with four spines of approximately equal size, the dorsal pair directed upwards and recurved over the base of the gaster; the lateral pair directed outwards and somewhat upwards. Anterior face of the first gastral segment shallowly concave.

Erect hairs present on the clypeus and usually with a double row running between the frontal carinae and on to the vertex. Gaster with hairs usually on the second to last tergite, but absent from the first. A fine, sparse, greyish pubescence present, especially on the appendages, gaster and lateral alitrunk.

Clypeus finely reticulate. Head finely longitudinally rugose, the rugae on the vertex fanning out from the space between the frontal carinae. Sculpturation of the dorsal alitrunk usually of fine longitudinal rugae overlying a fine, dense reticulate-puncturation. The rugae are usually most distinctly longitudinal in the middle of each segment and tend to a fine rugoreticulum laterally; this is especially true of the pronotum. Gaster finely and densely reticulate. The intensity of sculpturation varies. In some the longitudinal rugae may be sharp and distinct, in others low and rounded. Colour black; the legs usually dark brown but may be lighter or almost black.

Queen
Rigato (2016) - Holotype. HL 1.45, HW 1.24, CI 86, SL 1.40, SI 113, FW 0.47, FI 38, ScW 1.15*, MnL 1.60*, ML 2.34*, HTL 1.47. (*These measurements are imprecise because the specimen was pinned through the mesosoma; the mesoscutum is slightly misplaced and is missing most of its right and posterior portions.)

Clypeus medially faintly carinate and with its anterior margin moderately and evenly arched. Head in full face view oval, wider behind than in front, posterior margin wide, moderately and evenly convex without posterior corners; sides in front of the eyes anteriorly converging and feebly convex. Eyes relatively large and convex. Ocelli small. Pronotum laterally weakly marginate. Pronotal teeth anteriorly diverging, stout and blunt, their tips weakly upturned. Propodeal dorsum feebly marginate laterally, strongly arched in profile and weakly convex transversely, about twice as wide as long. Propodeal teeth minute and upturned. Propodeal dorsum and declivity divided by a sudden change of slope, no ridge occurs between them. Petiole with two pairs of spines, the mid pair looks stouter and slightly shorter than the lateral one; the mid pair a little more distant from one another than mid and lateral spine of the same side. All petiolar spines weakly backward tilted. First gastral tergite anteriorly slightly concave.

Mandibles shagreened and with sparse piligerous pits. Body mostly subopaque with a slightly shining gaster. Body and appendages finely reticulate-punctate, with no trace of rugosity. Clypeus, pronotal dorsum, mesonotum, mesanepisternum, propodeal dorsum and declivity, posterior petiolar surface and gaster mostly appearing more superficially and tidily sculptured.

Standing hairs mostly wanting, occurring only at the gastral apex, on gastral sternites I-IV, at the anterior clypeal margin and mandibular apex. Pubescence very short, inconspicuous on most of the body and moderately dense on gaster and appendages, but never hiding the sculpturation; on the gaster the distance between two adjacent elements is about equal to their length.

Colour mainly black, legs mostly brown with proximally darker tibiae, tarsi and coxae. Antennae piceous, except their dark brown funicular apices; mandibles apically ferrugineous. Wings moderately infuscated.

Type Material
Rigato (2016) - Holotype gyne [not worker as reported in Bolton, 1973], originally labeled CUBA, 1843; then corrected into SOUTH AFRICA, Port Natal [currently Durban] (see Mayr, 1893: 195, footnote) [examined].