Messor capensis

Identification
The taxa capensis, Messor decipiens and Messor piceus, treated here as separate species, may in fact represent only a single variable species. The differences invoked to distinguish the three are minor (see key) and may eventually prove to be gradient. Among the species in which the first gastral tergite is uniformly hairy the three taxa mentioned above are characterized together by their relatively small eyes, lack of strong gastral sculpture, relatively straight-sided head and short propodeum, and lack of a median prominence on the posterior half of the clypeus. (Bolton 1982)

Distribution based on Regional Taxon Lists
Afrotropical Region: Botswana, Namibia, South Africa, Zimbabwe.

Biology
As is common in this genus, workers forage for seeds that are retrieved to the nest. In the Cederberg (Western Cape, South Africa), M. capensis gathers seeds of many species, including rooibos. The latter seeds are apparently not eaten and remain viable after years underground.

Rooibos seeds are tiny and housed in small pods. When each pod is ripe, it will burst open, scattering the seeds on the ground around the plant (which is usually sandy). Moreover the rooibos pods on a particular bush reach maturity at different rates, so it is difficult for local farmers to obtain large quantities of seeds by sifting. So they copy what the indigenous Khoisan people have done for hundreds (perhaps thousands) of years: Farmers dig up the ants' granaries every few years! (written by Christian Peeters based on Green 1949, internet records, and interviews with a local farmer)



Nomenclature

 *  capensis. Atta capensis Mayr, 1862: 743 (w.) SOUTH AFRICA. Mayr, 1866b: 896 (q.m.). Combination in Aphaenogaster: Roger, 1863b: 30; in Stenamma (Messor): Emery, 1895h: 35; in Messor: Forel, 1910e: 444. Subspecies of barbarus: Emery, 1891b: 12; Forel, 1910e: 444; Arnold, 1920a: 405; Emery, 1922c: 98; Stitz, 1923: 150; Prins, 1963: 100. Status as species: Santschi, 1917e: 94; Wheeler, W.M. 1922a: 804; Bolton, 1982: 345. Senior synonym of braunsi, donisthorpei, pseudoaegyptiaca, schencki: Bolton, 1982: 345.
 * pseudoaegyptiaca. Aphaenogaster pseudoaegyptiaca Emery, 1884a: 384 (w.) SOUTH AFRICA. Arnold, 1920a: 409 (q.m.). Combination in Stenamma (Messor): Emery, 1895h: 35; in Messor: Santschi, 1917e: 94. Subspecies of capensis: Santschi, 1917e: 94. Junior synonym of capensis: Bolton, 1982: 345.
 * braunsi. Messor braunsi Forel, 1913a: 138 (w.) SOUTH AFRICA. Stitz, 1923: 149 (q.). Junior synonym of capensis: Bolton, 1982: 345.
 * schencki. Messor capensis var. schencki Wheeler, W.M. 1922a: 805 (w.) NAMIBIA. [First available use of Messor barbarus subsp. capensis var. schencki Forel, 1910f: 15; unavailable name.] Junior synonym of capensis: Bolton, 1982: 345.
 * donisthorpei. Messor donisthorpei Santschi, 1937a: 51 (w.q.) NAMIBIA. Junior synonym of capensis: Bolton, 1982: 345.

Worker
Bolton (1982) - Medium to large, HW 2.35 -> 3.40.

Anterior clypeal margin varying from shallowly convex to transverse, only very rarely with the faintest vestige of a median indentation. With the head in full face view the sides more or less straight and approximately parallel, never evenly convex nor obviously diverging anteriorly. Occipital margin broadly and shallowly concave to indented medially. In HW range 2.35-3.44 the maximum diameter of the eye is 0.40-0.58, about 0.15-0.19 x HW, and the CI range is 103-119. Propodeum in profile with the dorsum rounding narrowly into the declivity in most cases; in some more broadly rounded and in a few right-angled, but only rarely with dentiform prominences and here usually only in the largest workers. Usual sculpture of entire dorsum of head of fine, densely packed parallel longitudinal rugulae, most commonly with fine punctulation between them. Variation in the sculpture consists of a reduction, in density or intensity, or one or both of these components. Sometimes the rugulae are more widely spaced and fainter than is usual, in which case the punctulate ground-sculpture is much more obvious and may appear as the dominant component in places. On the other hand the punctulate sculpture may fade out, leaving the rugulae sharply defined; the rugulae may then also become less intense and leave the head only feebly sculptured. Dorsal alitrunk usually rugose or rugulose everywhere but, as on the head, this sculpture may be reduced until it is very faint or even absent. When distinctly present the direction of sculpture on the pronotum shows variation. Commonly it is longitudinal but forms with the sculpture diagonal, transverse, irregular or varying on different parts of the surface are fairly frequent. First gastral tergite unsculptured or at most with a very faint superficial patterning. All dorsal surfaces of head and body with numerous conspicuous standing hairs. Colour black to dark reddish brown, the head and alitrunk always the same colour, the gaster sometimes darker.