The Ants of Africa
Genus Pheidole
Pheidole costauriensis Santschi - new status

crassinoda group; major with cordiform (heart-shaped) head - Arnold (1920a) group H

following may all = Pheidole neutralis

Pheidole costauriensis Santschi - new status

return to key {link to the Hymenoptera Name Server} Type location Ghana (Pheidole rotundata For. stirps costauriensis n. st., Santschi, 1914a: 433, major; Santschi, 1915c: 250, minor), from Winnebah, collector unknown - see below .

{Pheidole melancholica}Santschi's (1914a) description of costauriensis is at {original description}. Emery's (1915j) illustrated revision of Pheidole melancholica, with notes on costauriensis is at {original description}.

Major (Santschi, 1914a) - comparisons all with Pheidole rotundata - TL 5.3 mm; head oval, very convex, slightly longer than wide in posterior third; with a complete median notch; eyes in anterior third of head; clypeus feebly carinate with slightly scalloped anterior margin; mandibles with elongated punctures changing to striations on outer edges; scape reaches middle of head; segment three of funiculus as wide as long, others longer and longer; pronotum strongly conical laterally over all matt due to fine reticulo-puncturation, upper head and gaster submatt; pronotum with transverse rugae; yellowish pilosity sparse, except on gaster and legs; reddish-brown, alitrunk more red with angles of pronotum and propodeal spines dark brown, legs yellow brown
Minor - TL 3 mm; head longer and more rounded posteriorly; dorsum of alitrunk more strongly sculptured; propodeum longer with stronger spines; black or very dark brown, appendages and mandibles brownish.
Minor (Santschi, 1915c: 250) - TL 2.5 mm; head more rounded than rotundata; dorsum of alitrunk and sides of head lightly reticulo-punctate, but shiny (smooth in the type rotundata) dark brown

Holotype major collected at Winnebah, from Viehmeyer; minor from Guinea, Kindia, collector Silvestri, 1 minor Wheeler (1922) listed melancholica from Ghana (Aburi, F. Silvestri).

The specimens from Benin, Nigeria and Ghana (below) appear to match the overall description and colouration but are larger than those described by Santschi; although Santschi's size is larger than that of impressifrons.

{Pheidole costauriensisa}The photomontage of the type worker is collated from

{Pheidole costauriensis major}

Nigeria specimens (Pheidole crassinoda in Taylor, 1980a: 13)

Colour of both morphs, head and alitrunk brown/dark red-brown, gaster darker to black, appendages lighter with tarsi and antennal clubs brown.

MAJOR. TL 8.11 mm, HL 2.91, HW 2.86, SL 1.37, PW 1.21; with the head principally smooth apart from anterior longitudinal rugae, dorsum shiny. Pronotum rugulose; mesonotum, propodeum and pedicel spiculate; postpetiole with lateral sharp apices and light transverse rugae. Propodeal spines relatively short, narrow and out-turned triangular. Gaster finely punctate. Erect hairs few on the head but moderately abundant elsewhere.

{Pheidole costauriensis minor} MINOR. TL 4.36 mm, HL 1.01, HW 0.86, SL 1.24, PW 0.58; with head, pronotum and gaster; mesonotum, propodeum and pedicel spiculate. Erect hairs sparse and relatively short. Head with clypeus medially carinate, shallowly emarginate anteriorly; longitudinal rugae on the genae. Petiole produced laterally and the anterior of the peduncle.

An all over lighter variety was also found and this was denoted as species Tą.

Collected at the Cocoa research Institute of Nigeria, Idi Ayunre, from a nest in a cocoa crevice, the opening of which was closed with debris. Will tend aphids on cocoa flowers.

Ewuim, Badejo & Ajayi (1997) used pitfall traps to monitor the activity of ants in a forest floor and a one-year fallow plot in Ile-Ife, Nigeria, at monthly intervals from November 1980 to October 1981, with similar studies in October 1987 and June 1988. They also made manual collections of ants from the ground surface of the plots. Ten species of ants were collected, the most common of which was P. crassinoda. This species accounted for 52% and 88% of the ants collected manually from forest and fallow respectively. It was also significantly higher in the pitfall traps.

Oxford University Museum specimens - note the minors below may be Pheidole neutralis

Pheidole costauriensis
B Taylor det.

J-F Vayssieres
RVA 3099.14
09°14'07'' N
02°11'52'' E
running on the ground

{Pheidole costauriensis}The photomontage is of a major from Ghana, collector Sky Stephens, 2006. Specimens in the personal collection of Dr Stephens. Other images can be seen in the folder at - {album}

{Pheidole costauriensis minor}The photomontage is of a minor from Ghana, collector Sky Stephens, 2006. Other images can be seen in the folder at - {album}

{Pheidole costauriensis minor}The photomontage is of a minor from Benin, Kika-Beterou; collector J-F Vayssieres (RVA 3099).

© 2007, 2008, 2010, 2011, 2013, 2017 - Brian Taylor CBiol FRSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.