The Ants of Africa
SUBFAMILY MYRMICINAE - Genus Pheidole
provisional key to major workers of all African species - Section 1
Genus Pheidole Introduction

{Structural features}I have attempted to compile a key to those species for which I have sufficiently detailed descriptions and/or have illustrations. Two very old keys exist - Mayer (1896) for a few species; and Arnold (1920a) for Southern Africa. The latter provided the drawing (right) of key anatomical features. Now the term propodeum is used rather than epinotum; and I use the term "welt" rather than scutellum.

In addition to the key given below, I drawn up a comparative table for the species of which I have been able to photograph the underside of the major head and, so, illustrate the arrangement of hypostomal teeth. This is at Pheidole majors hypostomal teeth.


The sizes given in the key are a close approximation, assuming that the Antweb scales are accurate. The indices, CI and SI, are reliable being derived on measurement of images.




Hypostomal Teeth
(non-type)
Status dubious Guinea - guineensis
Queen and male only known (photographs on species page)
Zare - neokohli
Minor only, description dubious Senegal - pallidelutea
. Adequately defined species --
1 {Pheidole megacephala pedicel}{Pheidole sp F995 pedicel}Major postpetiole wider than long; trapezoidal but variably dentate at widest point - extremes shown right Section 2
-- {Pheidole rugaticeps pedicel}Major postpetiole not or hardly wider than long, only rounded or slightly angled at sides; minors also with small spherical postpetioles
2
. rugaticeps-group - concinna, rugaticeps, tenuinodis & victoris --
2 Major occiput with transverse striation; minors with long scapes, SI ca 160 or more
3
-- Major occiput near smooth and shining; minors with shorter scapes, SI max. 140
4
3 {Pheidole concinna major}
TL ca 5.6 mm, HL 1.97, HW 1.87, SL 1.1, PW 0.84; CI 93, SI 58; postpetiole about twice as long as wide and with a moderate, rounded, lateral angle; head with very fine puncturation/shagreening (much finer than rugaticeps), background of underlying longitudinal striation which becomes oblique posterior to the eyes angling outwards to occipital corners; erect pilosity yellowish, long and quite abundant all over, longer and denser on the head than in rugaticeps; colour alitrunk dark red; head, funiculus & mandible lighter; border of mandibles, anterior of clypeus, scapes, summit of pedicel nodes and gaster blackish; femora brown, tibiae and tarsi yellowish brown
.
. Pheidole concinna
TL 3.5-4.3 mm, HL 1.09, HW 0.91, SL , PW 0.62; CI 82, SI 157; head narrower than long, frontal area wide and very distinctly impressed, occiput rounded and narrowed; clypeus often weakly carinate; mandibles with two apical teeth and 5-6 denticles; mandibles very finely striate; scape surpasses occiput by more than a quarter of its length; alitrunk impressed between the pronotum and mesonotum, with transverse welt; metanotal groove deep, spines slightly longer than one-third the propodeal dorsum; legs long; petiole narrow and elongate, postpetiole about one-third longer than wide; rest of head smooth and shiny other than irregular longitudinal rugae on the sides; alitrunk and pedicel densely punctate but less so on the pronotum dorsum and pedicel which are shiny; lateral propodeum striate; erect pilosity abundant and long, yellowish; longer and denser on the head than on rugaticeps; gaster and legs smooth; dull red with head the same colour as the alitrunk
Congo - concinna
-- {Pheidole rugaticeps major}
TL 5-6.5 mm, HL 2.2, HW 2.0, SL 1.10, PW 0.8; CI 91, SI 55; postpetiole scarcely wider than long, with a moderate, rounded, lateral angle; sides of head striate to occiput in a straight longitudinal manner; ferruginous, gaster fuscous
. rugaticeps teeth
. {Pheidole rugaticeps minor}
TL 3-3.5 mm, HL 0.84, HW 0.65, SL 1.67, PW 0.46; CI, SI ; CI 76, SI 177-180; head elongated, clypeus without a carina; propodeal spines short, oblique & divergent; postpetiole wider than petiole, subconical; head smooth other than lateral rugae; alitrunk finely coriaceous; all over with numerous erect hairs; ferruginous-testaceous, gaster darker
Sahel zone - rugaticeps
-- {Pheidole andrieui}
TL 5.3-5.5 mm, HL 1.86, HW 1.66, SL 1.00, PW 0.80; CI 88, SI 60; head matt with occipitum shiny, regular striation, longitudinal in anterior two-thirds, becoming finer and converging towards occiput where they are transverse; overall quite heavily sculptured, pedicael and gaster with dense fine spiculation; overall dark brown, gaster blackish
Hypostoma of major with no teeth or solely a minute pair of submedian teeth; from underneath mandibles distinctively margined with the area between impressed
. andrieui

{Pheidole andrieui minor}
TL 3.5 mm, HL 0.75, HW 0.50, SL 1.00, PW 0.40; CI 80, SI 180; eyes unusually large; head oval less than twice as long as wide when the eyes are ignored; occipital border with nuchal collar (?); clypeus smooth weakly convex with a short median carina; frontal carinae about one fifth longer than they are apart; frontal notch weak and short; alitrunk fairly elongate, mesonotum profile convex, propodeal spines upright, fairly divergent and about as long as three-quarters their basal interval; petiole with a long pedicel, summit entire; postpetiole about one quarter longer than posterior width, laterally obtusely angled; most of head smooth and shiny, sides reticulo-punctate; alitrunk & pedicel regularly reticulo-punctate, reduced on pronotum dorsum; gaster smooth other than a few basal reticulations; dark brown, alitrunk sometimes dorsally lighter, appendages brown, articulations and tarsi yellow brown
Sahel zone - andrieui
. Head smooth and shiny --
4 Pheidole tenuinodis major
TL 4.5 mm, HL 1.18, HW 1.18, SL 0.72, PW 0.50; CI 100, SI 61; anterior three-fifths of head, strongly and longitudinally striate; colour of head and alitrunk dark yellowish-red, propodeal spines and lateral propodeum dark brown, gaster brown but basally paler; postpetiole subglobose, feebly convexly angled laterally, narrowed behind, 75% wider than petiole and about as long as wide
. Pheidole tenuinodis major underhead
. Pheidole tenuinodis minor
TL 2.8-3.2 mm, HL 0.86, HW 0.61, SL 0.88, PW 0.85; CI 83, SI 126-140; head wider behind than in front, anterior margin of clypeus shallowly emarginate, median area with a raised line; funiculus with first segment as long as next two together; propodeum dorsum weakly marginate; pilosity long and abundant; colour similar to punctulata but head and alitrunk darker and more reddish-brown - seems variable but may include more than one species
Pan African  savannah - tenuinodis
-- Pheidole sipapomae major
TL ca 5.6 mm, HL 1.75, HW 1.75, SL 0.86, PW 0.7, CI 100, SI 50.
Larger with shallower impression to occiput
.
. Pheidole sipapomae minor
TL ca 3.10 mm, HL 0.78, HW 0.68, SL 0.86, PW 0.48, CI 87, SI 127.
Head more elongated
Zimbabwe - sipapomae
-- Pheidole rva minor
Minor only known; TL ca  3.5 mm, HL 0.58, HW 0.47, SL 0.57, PW 0.33; CI 86, SI 115; postpetiole small and globular; bicoloured with head and gaster contrasting with the orange-brown alitrunk
Benin - RVA 2900
-- Pheidole victoris major
TL 4.2 mm, HL 1.44, HW 1.44, SL 0.87, PW 0.48; CI 100, SI 60; postpetiole almost twice as wide as petiole, about 25% wider than long, sides obtusely angled at the widest mid-point; head dull except posterior quarter which is microscopically rugulose and slightly shining; colour very similar to tenuinodis
.
. Pheidole victoris minor
TL (2.3) 3.5 mm (fresh minor, shown), HL 0.75, HW 0.64, SL 0.82, PW 0.35; CI 88, SI 132; head more rounded widest in the middle, eyes very convex placed at mid-point; propodeal spines quite small; propodeum declivity oblique shorter than dorsum; head sides finely reticulate-punctate and with longitudinal striae which do not extend back beyond the eyes; reddish-yellow, head darker behind, gaster brown, paler at base
Namibia & Zimbabwe - victoris

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Genus Pheidole Introduction

Contents MYRMICINAE Introduction
2007, 2008, 2009, 2010, 2011, 2013, 2014, 2016, 2017 - Brian Taylor CBiol FRSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

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