The Ants of Africa

Subfamily FORMICINAE Wheeler, 1920: 53

Diagnostic Features - Pedicel of a single segment, usually with a narrow connection to the gaster so that the petiole has a distinct posterior face. Eyes usually present. Clypeus developed so that the antennal insertions are some distance behind the anterior margin of the head. Frontal carinae may cover antennal insertions. No sting and apex of gaster with a circular acidopore formed from the hypopigium, this structure often projecting as a nozzle and fringed with hairs. Occasionally the orifice of the acidopore is hidden by a projection of the pygidium, in which case the pronotum, petiole or both are armed with spines.

As a whole the Subfamily has been the subject of little in the way of modern revisionary studies. The sole modern generic studies are of Agraulomyrmex (Prins, 1983), a partial revision of Cataglyphis (Agosti, 1990) and of Polyrhachis (Bolton, 1973b). The genus Camponotus has a very large number of species, a vast number of "subspecies", "varieties" and simply code-referenced "forms" and has many members which appear to be abundant, successful and of economic importance. Yet it remains a baffling enigma untackled by contemporary taxonomists.

Revised after Bolton (2003: 267) - separating Anoplolepis as previously understood into two separate genera Anoplolepis (in Tribe Lasiini; with Zealleyella as a junior synonym) and Tapinolepis (in Tribe Plagiolepidini; with Mesanoplolepis as a junior synonym).

Bolton's prime separation points are :-
Anoplolepis - mandible with 6-9 teeth, when closed not concealed by clypeus; dorsum of head behind clypeus with erect stout setae; eye behind mid-length of head, and anterior arc of torus around eyes posterior to and not touching clypeal margin; ocelli absent (sometimes one median ocellus in largest workers); metatibia with a large distinct apicoventral spur, with a coarse seta on each side; anterior face of gaster without distinct concavity.
Tapinolepis - mandible with 5 teeth, when closed mostly concealed by clypeus; dorsum of head behind clypeus without erect stout setae; eyes set variably around midlength of head but anterior arc of torus around eyes touching and slightly indenting clypeal margin; three ocelli distinct; metatibia with a divergent pair of large coarse setae on each side, no median spur; anterior face of gaster with distinct cavity, into which the petiole fits when alitrunk and gaster in horizontal alignment.

In Bolton's separation (2003), however, there are some anomalies which, as he gave no species details or even indication of any review, are questionable. For example Anoplolepis (Anacantholepis) bothae is given as Tapinolepis bothae [queen & male only known]; Anoplolepis (Anoplolepis) macgregori is given as Tapinolepis macgregori; and Anoplolepis (Anoplolepis) pernix is gven as Tapinolepis pernix. Typically, as in others of his generic revisions, Bolton synonymises subgenera and then creates species-groups, in this instance, under Anoplolepis, he wrote of the gracilipes group (being monomorphic) and the custodiens group (polymorphic).

LaPolla et al. (2010, link) have examined the phylogeny and taxonomy of what they term "the Prenolepis genus-group".  In that they include the genera Euprenolepis, Nylanderia gen. rev., Paraparatrechina gen. rev and stat. nov., Paratrechina, Prenolepis and Pseudolasius. Euprenolepis appears to be restricted to Southeastern Asia and, so, is not covered by this website. Prenolepis they found to include a single species from sub-Saharan Africa (previously Paratrechina kohli). They have transferred the sub-Saharan Pseudolasius species (P. bufonus and P. weissi) to Paraparatrechina.  Until they present a full review of the sub-Saharan species, however, I choose not to recognise their species placement. This is because the species I recognise (albeit possibly wrongly) do not separate according to their key to genera. I also have reservations about the basic definition of the type species of Paratrechina Motschoulsky as being Paratrechina longicornis (as a senior synonym of P. currens)

Key to Genera known or likely to found in Africa

1 Antennae with 9 segments 2
-- Antennae with 10 or more segments 4
2 {Petalomyrmex phylax}Palp formula 3,3; head heart-shaped in full-face view; TL 1.78-2.46 mm (single species) Cameroun - Petalomyrmex
-- Head near rectangular in full-face view 3
3 {Aphomomyrmex afer} Eyes set well away from the sides of the head; palp formula 5,3; TL 3.0-3.3 mm (single species) western Congo Basin - Aphomomyrmex
-- {Brachymyrmex species}Eyes not well away from sides of head and alitrunk profile even, TL ca 1.2 mm (single species) Gabon - Brachymyrmex
4 {Agraulomyrmex meridionalis}Antennae with 10 segments; TL < 2.2 mm - (two species) southern Africa - Agraulomyrmex
-- Antennae with 11 or 12 segments 5
5 Antennae with 11 segments 6
-- Antennae with 12 segments 10
6 {Lepisiota gerardi}Propodeum armed with a pair of spines, teeth or tubercles; petiole usually similarly armed; numerous species all small, most TL ca 2.5-3.0 mm Pan-African - Lepisiota
-- Propodeum with rounded variably angular transition from dorsum to declivity 7
7 {Acropyga arnoldi}Palp formula 1,3 or 2,3; eyes reduced to no more than a few facets; three species, all TL < 3.5 mm Pan-African - Acropyga
-- Palp formula 6,4; all with quite large eyes 8
8 {Plagiolepis (Plagiolepis)}{Plagiolepis polita}Metanotum a clearly separate segment of the alitrunk; numerous species all TL < 2.5 mm Pan-African - Plagiolepis
-- Metanotum fused with the mesonotum 9
9 {Anoplolepis tenella}Mandible with 6-9 teeth, when closed not concealed by clypeus; dorsum of head behind clypeus with erect stout setae; eye behind mid-length of head; ocelli absent (sometimes one median ocellus in largest workers); anterior face of gaster without distinct concavity; two groups/subgenera - Zelalleyella moderate size, TL up to 7.0 mm; Anoplolepis all small TL < 4.5 mm Pan-African - Anoplolepis
-- {Tapinolepis trimenii}Mandible with 5 teeth, when closed mostly concealed by clypeus; dorsum of head behind clypeus without erect stout setae; eyes set variably around midlength; three ocelli distinct; anterior face of gaster with a distinct cavity, into which the petiole fits when alitrunk and gaster in horizontal alignment; nine species all small TL < 3.5 mm eastern & southern Africa - Tapinolepis
10 {Santschiella kohli}Eyes enormous; single species TL 3.6 mm Congo Basin - Santschiella
-- Eyes variable but not dominating the head 11
11 {Cataglyphis viaticus}Metapleuron with a distinct wide orifice for the metapleural gland; antennal sockets close to the posterior margin of the clypeus 12
-- {Camponotus minisculus}Without a distinct metapleural gland orifice; antennal sockets set well back from posterior margin of the clypeus 17
12 {Cataglyphis abyssinicus} Propodeal spiracle elliptic to slit-like; ocelli present; ca 25 species, most dimorphic or polymorphic TL up to 13 mm in the largest north of the Equator (savannah) - Cataglyphis
-- Propodeal spiracle small and circular; no visible ocelli 13
13 Palp formula 6.4; monomorphic or slightly polymorphic 14
-- {Pseudolasius weissi}Palp formula 3,4; 3,3 or 3,2; polymorphic; eyes small or absent; 5 species, all no more than TL 3.0 mm - LaPolla et al (2010) place these in Paraparatrechina Congo Basin east to Uganda and S. Sudan - Pseudolasius
14 Mandibles always with 5 teeth; mesothorax not constricted immediately behind pronotum, scapes always lacking erect hairs  15
-- Mandibles typically with 6-7 teeth 16
15 {Paratrechina (?) longicornis}Propodeum without erect hairs; erect hairs on head scattered across surface; dorsal face of propodeum broad and gently rounded; femora and tibiae with large erect hairs Pan-African - Paratrechina (?) longicornis-group
-- Paraparatrechina albipesOne pair of erect hairs on propodeum; erect hairs on the head form a pattern of 4 on the posterior margin and 6-7 rows from the posterior margin to the clypeal margin; dorsal face of propodeum typically short and angular; femora and tibiae without erect hairs; eyes set forwards of mid-line of head Pan-African - Paraparatrechina
16 {Paratrechina grisoni}Mesothorax not constricted immediately behind the pronotum; eyes set with about half their length each side of the mid-point of the head; mandibles without striations across anterior surface
[LaPolla et al have these as Nylanderia]
Pan-African - Paratrechina
-- {Prenolepis kohli}Mesothorax constricted behind pronotum; eyes largely above midlength of head; mandibles with distinct striations across anterior surface Congo Basin - Prenolepis
17 {Oecophylla longinoda}Palp formula 5,4; mandible relatively elongated with 10 teeth; petiole reduced to a low node; 4 or 5 species, all dimorphic, max TL up to 8-9 mm West Africa, Congo Basin and East Africa - Oecophylla
-- Palp forumla 6,4; mandibles no more than triangular; petiole a domed to narrow scale 18
18 {Camponotus seriiceus}Petiole and propodeum always unarmed (latter may be angular); dimorphic to polymorphic .
. {Camponotus maculatus major}Numerous species, most if not all di- or trimorphic; medium or large sized; TL range ca 6 mm to > 20 mm Pan-African - Camponotus
-- At least petiole armed with teeth of spines; monomorphic 19
19 {Phasmomyrmex aberrans}Acidopore open and fringed with hairs; anterior margin of clypeus broadly concave; 3-4 species, two with TL 6-7.5 mm, one with TL 12 mm Congo Basin & Angola - Phasmomyrmex
-- {Polyrhachis weissi}Acidopore concealed when not in use; anterior margin of clypeus not concave; numerous medium to large species, TL range most 5-6 mm, a few up to ca 14 mm Pan-African - Polyrhachis
2008, 2009, 2010, 2013 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.