Pheidole impressifrons (Wasmann) new status

Soldier - Minor - Type location South Africa (Pheidole megacephala ssp impressifrons,Wasmann, 1905: 110; replacement name for impressiceps, Wasmann, 1904a: 72, footnote, soldier, worker & queen); variety atrocior (unavailable name, Emery, 1915j: 243, illustrated, soldier & worker, name attributed to Santschi, description unavailable, no collector) from Sierra Leone. .

Transferred here from Pheidole megacephala.

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

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

Wheeler (1922) listed impressifrons from Nigeria (W.A. Lamborn).

Nigeria specimens - as Species F
Soldier 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.

The photomontage is of specimens collected in Cameroun - south-western tropical coastal forest area between Edéa and Campo (McKey Wolbachia project) - Cameroon 46 from location Nkoloboundé, 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). Other images can be seen in the folder at -

Soldier - 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.

Minor appears almost identical to the minor of Ph. megacephala.
From the Cameroun 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.

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).

The photomontage is of a specimen from Ghana, collected by S Sky Stephens, 2006. Other images can be seen in the folder at -