The Ants of Africa
Genus Pheidole
Pheidole impressifrons Wasmann - new status

crassinoda group. Major with cordiform (heart-shaped) head - Arnold (1920a) group H

Pheidole impressifrons Wasmann - new status

return to key {link to the Hymenoptera Name Server} Type location South Africa (Pheidole megacephala subsp. impressifrons n. subsp., Wasmann, 1905: 110; replacement name for impressiceps, Wasmann, 1904a: 72, footnote, major, minor & queen) - major see below
variety atrocior (Ph. punctulata var. atrocior unpublished name given by Santschi, Emery, 1915j: 243, illustrated, major & minor, description unavailable, no collector) seemingly from Sierra Leone. .

Transferred here from Pheidole megacephala.


{Pheidole impressifrons}Wasmann's (1904a) description is at (with name change of 1905 appended) {original description}. Emery's (1915j) illustrated consideration of impressifrons, with atrocior, is at {original description}. Arnold's (1926a) translation of impressifrons is at {original description}.

South African specimens - Major. TL 4.5-5 mm, HW (Emery) 1.5-1.9 mm; colour brown. Minor. TL 2.5 mm
West African (atrocior) - Major. HW 1.35 - "a pygymy of impressifrons"; colour more or less testaceous.

Wheeler (1922: 814) listed atrocior (the Emery paper) from Sierra Leone, and impressifrons from Nigeria (W.A. Lamborn; in Lamborn, 1914).

The geographical separation suggests that atrocior could be a separate species. The images shown below illustrate the general similarity but smaller size and slightly different sculpturation of Cameroun/West Africa specimens.


{Pheidole impressifrons major}The photomontage of the type major worker is collated from http://www.antweb.org/specimen.do?name=casent0914348.


Oxford University Museum specimens

Pheidole impressifrons
B Taylor det.


South Africa
Peter Hlavác

Natal, Ladysmith In personal collection of Peter Hlavác
1
{album}
Pheidole impressifrons
B Taylor det.
South Africa
Gauteng
ex Peter Hlavác
09.xi.1921
25°46' S
28°14' E
Waterkloof
Host of Hylotorus hottentotus
major worker
1
{album}
Pheidole impressifrons
B Taylor det.
Ivory Coast
Erena Dupont
ii.2014
Taï National Park
5˚45'00" N
7˚07'00" W
08
minor
2
{album}
Pheidole impressifrons
B Taylor det.
Benin
J-F Vayssieres
RVA 3082.2
4.iv.2013
Koro
09°22'21'' N
02°40'13'' E
Mangifera indica orchard
prey of Oecophylla longinoda
1000-1100 h
major & minor
2
{album}
Pheidole impressifrons
B Taylor det.
Benin
J-F Vayssieres
RVA 3087.3

4.iv.2013
Koro
09°22'21'' N
02°40'13'' E
Mangifera indica orchard
prey of Oecophylla longinoda
1600-1700 h
minor
1
{album}
Pheidole impressifrons
B Taylor det.

Cameroun
G Debout & A Dalecky
Cameroon 82

5.iv.2001
BOU
3°13.31' N
10°15.01' E
nest in a dead hollow branch (external diameter 6 cm, internal diameter 2 cm)
1

Pheidole impressifrons
B Taylor det.
Cameroun
G Debout & A Dalecky
Cameroon 46
5.iv.2001
Nkolobondé
3°14' N
10°15' E
on soil and surface in the village
1
{album}
Pheidole impressifrons
B Taylor det.
Cameroun
A Fotso Kuate
Sample 72
27.vii.2010
Djazeng
03°54'30" N
11°25'58" E

4
{album}
Pheidole impressifrons
B Taylor det.
Ghana
S Sky Stephens
v-viii-2006
major 06G0041, minor 06G0047, minor 06G0088
3
{album}

South African type form


{Pheidole impressifrons major}The photomontage is of a major worker from South Africa, Natal, Ladysmith; from Peter Hlavác. HW = 1.9


{Pheidole impressifrons major}The photomontage is of a major worker from South Africa, Gauteng, Waterkoof; from Peter Hlavác.


{Pheidole impressifrons minors}The workers in this field photograph, enlarged below, were taken in Pretoria, South Africa, by Joan Young; no IMG7700.


{Pheidole impressifrons enlarged}foraging on a flower, Joan Young.


West African atrocior form

Comparison of major headsMontage of different major heads


{Pheidole species F}Nigeria specimens (as species F in Taylor, 1980a: 21).
Major. TL 4.88 mm, HL 1.71, HW 1.80, SL 0.78, PW 0.81
Minor. TL 2.43 mm, HL 0.68, HW 0.62, SL 0.72, PW 0.39
Colour red-brown, gaster darker, appendages lighter. Alitrunk of both morphs almost all over spiculate, fainter on the dorsal and lateral pronotum.


{Pheidole species F}The photomontage is of a major worker collected in Cameroun - south-western tropical coastal forest area between Edéa and Campo (McKey Wolbachia project) - Cameroon 46 from Nkolobondé (3°13.31' N 10°15.01'; flat land, between the Chapel and the river), 05 April 2001, on soil and surface in the village; Cameroon 82 from location BOU, nest in a dead hollow branch (external diameter 6 cm, internal diameter 2 cm). 

Major - differs from Ph. megacephala in several details, as well as being somewhat larger. The head has more rounded occipital lobes; the clypeus is emarginate, and the median carina is short. There are more pronounced anterior fine rugae and moderate pilosity on the dorsum and mandibles. Pronotum with pronounced dorsolateral tubercles. Propodeal spines moderately long, stout and blunt. Postpetiole with fairly acute dorsolateral prominences.
From the Cameroun specimens - mandibles heavy, with two blunt apical teeth and strongly sclerotised dark margin, striate. Clypeus with slightly concave centre to anterior margin, striate, with median carina ending before posterior apex. Small frontal triangle; frontal area and genae with weak longitudinal striations (rugae), ending about mid-face, at same level as length of scapes, but no scrobe; occiput smooth shiny with distinct but sparse hair pits, each with a short, fine, yellow decumbent hair. Scapes quite slender, slightly sinuous with moderately swollen apex, faintly striate with moderately long semi-decumbent hairs, and a few longer erect hairs; funiculus segments 1-8 bead-like, apical three segments progressively longer and all with convex sides, widest about the mid-point; abundant short-semi-decumbent hairs giving a bristly appearance. Sides and posterior border of occiput with fairly long, fine, erect hairs. Pronotum domed in profile, dorsally dark with transverse rugae; antero-ventral border of pronotum strongly sclerotised and flared outwards. Gaster with flattened dorsum and swollen ventrally; dorsum shiny over faint dense spiculation. Numerous long erect hairs on alitrunk, pedicel and gaster, quite stout and dark on pronotum.

In Nigeria positive identifications were rare but it may be as common as Ph. megacephala, because it is impossible to distinguish the two species in the field. The nesting and other habits, such as tending Homoptera, also probably are similar.

Bernard (1952) writing on the Guinea findings from Mt. Nimba, urged caution when it came to defining new species. He reported megacephala senus stricto from Gouéla, T 91, grassland at 1600 m (Lamotte), moderately common. Far more abundant was the race melancholica, with a larger and more indented head than the other races (somewhat similar to Pheidole picata but that has a more slender thorax); It was found in the savanna at Yalanzou, Nion, Ziéla and Kéoulenta; and from the forest at diverse altitudes, specially on the crests at 1300-1600 m (where the greatest numbers of soldiers and 2 alated queens were found). He noted the subspecies as known from Guinea, Ivory Coast, Ghana and Nigeria, with varieties from Zaïre and eastern Africa; and described the queen (hitherto undescribed).

Also reported from the Mamfe-Mampong cocoa farm and once elsewhere in Ghana by Room (1971), but he collected it only on herbs and on the ground. Found on cocoa at Kade by Majer (1975).


{Pheidole impressifrons major}The photomontage is of a major worker from Cameroun; Djazeng; 27.vii.2010; aphid survey (fk unmounted sp 72); coll. A Fotso Kuate.


{Pheidole impressifrons major Ghana}The photomontage is of a major worker from Ghana, collected by S Sky Stephens, 2006. Previously thought by me to be Pheidole aurivillii this now appears to be similar to the Sierra Leone form shown by Emery (1915j).


Minor workers

{Pheidole sp F minor}Minor appears close to the minor of Ph. megacephala.
From the Cameroun Nkolobounde specimens - head with distinct posterior sclerotised border but not produced only as a very narrow nuchal collar; in full face view the highly polished head is a near perfect oval, slightly flattened at both anterior and posterior. Scapes only slightly surpassing the occiptal border. Postpetiole in dorsal view as crassinoda (above), smoothly elongate convex, widest posteriorly.


{Pheidole impressifrons minor}The photomontage is of a minor worker from Cameroun; Djazeng; 27.vii.2010; aphid survey (fk unmounted sp 72); coll. A Fotso Kuate.


{Pheidole impressifrons minor}The photomontage is of a minor worker from Ivory Coast; Tai NP; Erena Dupont, ii.2014.


{Pheidole impressifrons minor}The photomontage is of a minor worker from Ghana, collected by S Sky Stephens, 2006.


Pheidole impressifrons majorThe photomontage of a major worker is collated from http://www.antweb.org/specimen.do?name=casent0173311.

On the Antweb site this and the minor below, both from Cameroun and accessed October 2012, are listed as Pheidole punctulata. That they clearly are not but they match exactly the Cameroun specimens above and my Nigeria drawing.


{Pheidole impressifrons minor}The photomontage of a syntype minor worker is collated from http://www.antweb.org/specimen.do?name=casent0173310.


© 2007, 2008, 2009, 2010, 2011, 2013, 2014 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

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