Polyrhachis schistacea (Gerstäcker)

Type location Mozambique (Hoplomyrmus schistaceus n. sp., Gerstäcker, 1859: 262, worker; Forel, 1907a: 38, queen but no description) - see below
junior synonyms
atrociliata (Polyrhachis (Myrma) schistacea Gerst. stirps atrociliata n. st., Santschi, 1913c: 141, worker, & 1914b: 141) from Zaïre, Ubangi, R P Augustin - see http://www.antweb.org/specimenImages.do?code=casent0912134
divina (Polyrhachis schistacea Gerst. v. divina n. var., Forel, 1913b: 348, worker) from Tanzania, Pemba - see http://www.antweb.org/specimen.do?code=casent0910911
divinoides (Polyrhachis schistacea Gerst. v. divinoides n. var., Forel, 1913c: 348, worker; Arnold, 1924: 344) from Zaïre, Sankisia, J. Bequaert- see http://www.antweb.org/specimenImages.do?code=casent0910912
fracta (Polyrhachis (Myrma) schistacea st. fracta nov., Santschi, 1914b: 141, worker) from Kenya, Fort Hall, 1330 m, i.1912, Alluaud & Jeannel
gagatoides (Polyrhachis (Myrma) schistacea Gerst. var. gagatoides n. var., Santschi, Santschi, 1913c: 314, worker) from Congo - http://www.antweb.org/specimenImages.do?code=casent0912138
rugulosus (Polyrhachis rugulosus n. sp., Mayr, 1862: 685, illustrated, worker; synonymy, Bolton, 1973b: 319) from South Africa - no images on Antweb (December 2014)
with its junior synonyms
cafrorum (Polyrhachis militaris r. P. Cafrorum n. stirps = P. carinata Smith (cat.) nec. Fabr., Forel, 1879a: 120, all forms) from South Africa - no images on Antweb (December 2014)
carinatus (Polyrhachis carinatus, F Smith, 1858b: 71, illustrated, worker) from South Africa - see http://www.antweb.org/specimenImages.do?name=casent0903450
unavailable names
benguelensis (Polyrhachis (Myrma) schistacea Gerst. var. benguelensis, Santschi, 1913c: 141a) from Angola - http://www.antweb.org/specimenImages.do?code=casent0912135
mediopilosa (Polyrhachis (Myrma) schistacea Mayr st. atrociliata Sants. v. mediopilosa n. var., Santschi, 1923: 295, worker) from Zaïre, Irumu, J. Bequaert - see http://www.antweb.org/specimenImages.do?code=casent0912137
subplana (Polyrhachis (Myrma) schistacea st. fracta var. subplanata nov., Santschi, 1914b: 142, worker) from Kenya, Gazi, coast, xi.1911, Alluaud & Jeannel - see http://www.antweb.org/specimenImages.do?code=casent0912136
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) with several synonymies is at and .

The photomontage of the type worker is collated from http://www.antweb.org/specimen.do?name=focol2576.

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.

Oxford University Museum specimens

Polyrhachis schistacea B Taylor det.	Central African Republic P Annoyer Ngoto-Obanga	14.iii.2005 Dzanga-Sangha	on plant ACA Note this has black erect hairs not the more common white hairs	2
Polyrhachis schistacea B Taylor det.	Central African Republic P Annoyer QS	7.xii.2010 Dzanga-Sangha 4°00'11.7"N 18°02'12.9"E	matin, site termitières au retour vers Bangui Note this has black erect hairs not the more common white hairs	1
Polyrhachis schistacea B Taylor det.	Congo E Zassi 12-t-2	6-7.ii.2008 Lésio-Louna 03°20'12.0" S 015°28'43.6" E	Village Mah; 24h pitfall tra	1
Polyrhachis schistacea B Taylor det.	Gabon Y Braet Gabon 59	27.vi-25.vii.2006 Pongara 00°34' N 09°19' E	Pointe Wingombe; forest edge and mini-savannah edging lagoon; malaise trap	1
Polyrhachis schistacea B Taylor det.	Gabon Y Braet Gabon 204	17.v-09.vi.2006 Pongara 00°34' N 09°19' E	Savannah, malaise trap	2
Polyrhachis schistacea B Taylor det.	Gabon Y Braet	8.viii.2006 Pongara 00°34' N 09°19' E	Yellow tray trap; savannah at edge of lagoon	1
Polyrhachis schistacea atrociliata B Taylor det.	Uganda C A Wiggins	10.x.1909 Entebbe 0°02'40"N 32°27'57"E	ca 3800' asl woodland by lake shore Note this has black erect hairs not the more common white hairs	8
Polyrhachis schistacea B Taylor det.	Tanzania G McGavin tree 5-64	13.i.1997 Mkomazi 3°54.75' S 37°48.58' E	pkd collection from Acacia nilotica	1
Polyrhachis schistacea B Taylor det.	Tanzania G McGavin tree 5-28	6.i.1997 Mkomazi 3°54.75' S 37°48.58' E	pkd collection from Acacia zanzibarica;  37M 0374778 UTM 9553640	2
Polyrhachis schistacea B Taylor det.	Botswana King 116	1.xi.2010 Xakanaxa Camp 19.11.01 S 23.24.30 E	961 m Forest Foraging on the ground.  Nest in soil	1

The photomontage is of a worker from Gabon; Pongara National Park, Pointe Wingombe; collector Yves Braet (Gabon 59).

The photomontage is of a worker from Congo, Réserve de Lésio-Louna; collector Eric Zassi.

The photomontage is of a worker from Tanzania, Mkomazi NP; collector G McGavin (Tree 5-64).

Arboreal. The specimens in these field photographs were taken in Pretoria, South Africa, by Joan Young; Pretoria; two sets 101-2329 to 2336; and, 100_4152 to 4198, 100_5261.

Terrestrial activity, Joan Young.