The Ants of Africa SUBFAMILY MYRMICINAE - Genus Tetramorium
Contents - Myrmicinae - MYRMICINAE Introduction

Genus Tetramorium Mayr (1855: 423), includes previous Macromischoides, Triglyphothrix and Xiphomyrmex

In Tribe TETRAMORIINI. Synonymy of former genera by (Bolton, 1976, 1980, 1985).

Diagnostic Features - Antennae 11- or 12-segmented, with a 3-segmented club. Antennal scrobes absent to feebly present; frontal carinae often extended as a pair of diverging longitudinal rugae. Mandibles with three or four large teeth apically, followed by a variable number of denticulae. Posterior lateral margins of clypeus raised into a ridge bordering the antennal insertions (see image, right, adapted from Arnold, 1917: 272, and my own photography). Pronotum characteristically square-shouldered in dorsal view due to the sharp anterolateral angles. Promesonotal suture absent; metanotal groove usually impressed. Propodeum with a pair of spines or teeth; metapleural lobes present, acute, and may project as a lower pair of spines. Sting with an apicodorsal lamelliform appendage. Femora usually distinctly swollen.

Mayr's (1855) genus definition is at . Mayr (1861: 61) reiterated his earlier genus description, this is at .

Erect hairs simple in most species, but divided in many former Triglyphothrix, and bizarre in a few species. The former Macromischoides (or at least African members) do not have the posterior lateral margins of the clypeus raised into a ridge bordering the antennal insertions; are less noticeably square-shouldered; and have a more rounded shape to the head in full face view, plus antennal scapes which surpass the occipital margin.

Of Tetramorium sensu stricto, Bolton (1980) recognised 176 species from sub-Saharan Africa. In his review of the former genus Triglyphothrix, Bolton (1976) described 55 species, 33 being from the Afrotropical region. Initially in 1998, accepting the synonymy of Triglyphothrix with Tetramorium (Bolton, 1985), I selected those with occurrences in one or more West African countries (including more recent findings) and, because of the large number of species, plus the high quality of Bolton's keys (Bolton, 1976, 1980), I drew up a Key to facilitate identification of the species known from West Africa. The list included species known primarily or solely from savannah, as such species sometimes occur in open, drier spaces in the forested areas.

In addition to the species in the key, I listed the three so-far unnamed species found by Belshaw & Bolton (1994b); and seven species known from Gabon or Zaïre - which might be found in West Africa, see, for instance the recent discovery of the previously Angolan species Tetramorium youngi by Belshaw & Bolton (1994b). Unfortunately, Bolton (1976, 1980) gave no indication of what the well-used coding encountered in reports by CRIG and CRIN collectors meant in terms of the fresh revision of the genus. At the end of this page, I have listed such coding and indicate which species seem to be involved. Finally, the names used are those given in Bolton (1995), where species names with an adjective as their root were corrected where necessary to agree in gender with the masculine genus, and where some otherwise published but recent synonymies and revivals were listed.

In 2001, I decided to add species known from the Congo Basin. Although a little clumsy, I modified the key by adding couplets numbered xxA, xxB and so-on, rather than renumbering the entire key and adjusting the many links. This was in two parts.

New style interactive key

With the expansion to cover all the ants of sub-Saharan Africa, I have developed a fresh style of interactive key. This is a departure from the traditional dichotomous key but I am trying it as a way of making the key more visual and comparative. It is compiled largely from the groupings used by Bolton (1976 & 1980) and the synonymisation of Triglyphothrix by Bolton (1985); the names are as in Bolton (1995).

This starts on Tetramorium species-groups 1, which is the first of six pages. The species information is provided on twelve further linked pages (see below for a linked alphabetic list of the species).
The format in summary is -

Note ¤
Some groups are further divided into species-complexes.
In some instances, the diagnostic characters used by Bolton (1980) lead to a particular species-group at more than one point.
The final column gives the determination point for individual species when Bolton's dichotomous keys to species are followed. This shows that a few species appear in what seem to be odd places relative to other members of a species-group or species complex, as defined in Bolton's papers. Bolton explains this by noting - that some species-groups are convenience assemblages, apparently solely to avoid having too many species-groups with only one member; and - that his key to species-groups was provisional.
Includes revived species and new species status names as in Bolton (1995: 403).

MYRMICINAE Introduction

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

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