The Ants of Africa
Genus Polyrhachis
Polyrhachis schistacea (Gerstäcker)

Polyrhachis schistacea (Gerstäcker)

return to key {link to the Hymenoptera Name Server} Type location Mozambique (Hoplomyrmus schistaceus n. sp., Gerstäcker, 1859: 262, worker; Forel, 1907a: 38, queen but no description) - no images on Antweb (December 2014)
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) .


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


{short description of image}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
{album}
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
{album}
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
{album}
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
{album}
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
{album}
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
{album}
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
{album}
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
{album}

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


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


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


{Polyrhachis schistacea}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.


{Polyrhachis schistacea}Terrestrial activity, Joan Young.

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© 2007, 2008, 2009, 2012, 2014 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

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