Polyrhachis schistacea (Gerstäcker)

Type location Mozambique (Hoplomyrmus schistaceus, Gerstäcker, 1859: 262, worker; Forel, 1907a: 38, queen but no description); junior synonyms atrociliata (Santschi, 1913c: 141, worker, & 1914b: 141) from Zaïre; divina (Forel, 1913b: 348, worker) from Tanzania; divinoides (Forel, 1913c: 348, worker; Arnold, 1924: 344) from Zaïre, collected at Sankisia, by J. Bequaert; fracta (Santschi, 1914b: 141, worker) from Kenya; gagatoides (Santschi, 1913c: 314, worker) from Congo; and rugulosus (Mayr, 1862: 685, illustrated, worker; with its junior synonyms cafrorum, Forel, 1879a: 120, all forms; and carinatus, F Smith, 1858b: 71, illustrated, worker) from South Africa; plus unavailable names benguelensis (as a strain of atrociliata, Santschi, 1913c: 141a) from Angola, mediopilosa (Santschi, 1923: 295, worker) from Zaïre, collected at Irumu by J. Bequaert; and subplana (Santschi, 1914b: 142, worker) from Kenya; all forms known (see Bolton, 1995) .

Gerstäcker's (1859) description is at . F Smith (1858b: 71) had given a description of "carinatus" from New Caledonia and from West Africa and Port Natal; this is at . Mayr's (1862) description of rugulosus is at (note Mayr 1893: 195, corrected the location from Brazil to Port Natal, South Africa) . Forel's (1879a) description of cafrorum is at . Forel (1913b) reported a re-examination of the type specimens by Stitz and gave notes on divina and divinoides - these are at . Santschi's (1913c) brief descriptions of atrociliata, benguelensis and gagatoides are at . Santschi's (1914b) described atrociliata, fracta and subplanata at . Santschi (1914b) also gave a key the then known varieties, this is at . A translation and expanded description by Arnold (1924), with divinoides and rugulosa (illustrated) is on and . Santschi's (1923e) description of mediopilosa is at Bolton's modern description (1973b) is at and .

WORKER - TL 9.3-13.7 mm; eyes virtually flat to strongly convex, sides of head in front of eyes gently convex, occipital margin distinctly convex. Very numerous erect hairs, usually on all surfaces, vary from white to black. Pubescence greyish and dense but never so dense as to mask the sculpturation. Colour uniform black (Bolton, 1973b: 318, not illustrated).

Photograph from http://www.museums.org.za/bio/ants/formicinae/polyrhachis/polyrhachis_schistacea.htm

A common, soil-nesting, savannah species with a very wide distribution in sub-Saharan Africa, although not in the rain forest (Bolton (1973b). From West Africa - Sierra Leone (no data); Ivory Coast, at Bouaké (G. Schmitz); Togo (at Agou, Y. Schach; also rugulosa and schluteri from Bismarckburg, by Conradt, in Wheeler, 1922); and from Guinea (atrociliata from Conakry, by F. Silvestri, in Wheeler, 1922) and Cameroun (rugulosa from Etombé by Adametz, in Wheeler, 1922, no details).

In Nigeria, specimens from Ogbomosho (B. Bolton) and Obudu (J.T. Medler) were seen by Bolton (1973b); and Eguagie (1971) reported finding it at Ilugun near Ibadan.

Earlier, Bernard (1952, not referenced by Bolton, 1973b) had reported it from Guinea, the Mt. Nimba surveys having found 26 workers, 6 alate queens and 4 males, mostly in the high regions and the denuded areas of the massif, at Pierré-Richard, crests of Nion (1300 m), and Mount Tô (1600 m); with a few examples from Nion, Kéoulenta; and Thio.

Lévieux (1983a) noted its presence in Ivory Coast savannah, at Ferkéssédougo, where its nests were in the same general area as those of Myrmicaria opaciventris (as nitidans).

Hall Cushman et al. (1998) described how ant-tended homopterans indirectly benefit figs (genus Ficus) across southern Africa (Madagascar, Malawi, South Africa, Zambia and Zimbabwe). Among the ants was P. schistacea found on 0.8% of sampled fig trees.

The photomontage is of a specimen from Gabon; Pongara National Park, Pointe Wingombe 0°19'336"N 9°19'102"E, 27.vi-23.vii.2006, from malaise trap at edge of savannah, alongside the lagoon, collector Yves Braet. Other images can be seen in the folders at - from Gabon ; and, from Central African Republic