|The Ants of
SUBFAMILY PSEUDOMYRMECINAE - Genus Tetraponera
|Contents - Pseudomyrmecinae|
Genus Tetraponera F Smith (1852: 44) (includes previous Pachysima and Viticicola).
Diagnostic Features - Slender elongate ants with relatively short legs. Clypeus sometimes produced into a spine or armed with a row of teeth or with a crenulate anterior margin. Either petiole alone with a ventral process or both segments without ventral processes.
F Smith's (1852) genus definition is at . [Smith, F. 1852. Descriptions of some hymenopterous insects captured in India, with notes on their oeconomy, by Ezra T. Downes, Esq., who presented them to the Honourable the East India Company. Ann. Mag. Nat. Hist., (2) 9, 44-50]. Roger's (1863a) definition of Sima is at .
All are arboreal species and very active, with characteristic rapid, jerky movements, and abrupt changes of direction. The previous Pachysima and Viticicola, were characterised because of their habit of living inside plant stems, sometimes as commensals, Pachysima in plants of the genus Barteria and tending large coccids on the plants. Hölldobler & Wilson (1990, page 535) describe the protection provided by Tetraponera (as Viticicola) tessmanni, which live only in stems of the liana, Vitex staudtii Guerkel; and by Tetraponera (as Pachysima) aethiops for Barteria fistulosa in Zaïre; they also list the incidence of Tetraponera ledouxi as a temporary parasite of Tetraponera anthracina (page 438, and Terron, 1969); and how one species, Tetraponera unidens (as nasuta), uniquely has a major caste with unknown functions (Terron (1971).
Earlier, Bernard (1952) remarked how all genus members inhabit hollow stems or dead wood and some support specific plants. From Africa, he reckoned there were some 30 species, with many still to be found.
Ward (1990: 449, 470) covered Tetraponera and confirmed earlier suggestions of the synonymy of Pachysima Emery and Viticicola Wheeler, also the non-African Parasima and Sima. The synonymy within Tetraponera is recognised also by Bolton (1994, 1995) but now Ward & Downie (2005), using DNA analysis appear to find differences that might substantiate the early genera as having merit.
Ward & Downie (2004) made several analyses of the phylogenetic relations within the Pseudomyrmecinae, of which Fig. 2 is an example. Morphological features that they considered useful were (w = worker, q = queen) - the angulate surface of the mandible above the trulleum (w), reduction in mandibular teeth (w, q), and the narrow notchlike cleft on the distal margin of the labrum (w, q). Non-African species listed are rufonigra (India), pilosa (Borneo), grandidieri (Madagascar), allaborans (Sri Lanka), morondaviensis (Madagascar), nigra (India) and punctulata (Australia). The possible separation might be into Pachysima for the rufonigra group; Tetraponera for the T. nigra group (represented by the bottom couplet); and, Sima Roger "for some fraction of the remaining species". I note that Ward & Downie have separated caffra and natalensis, whereas Bolton (1995) has caffra as a junior synonym of natalensis.
Ward (2006) continued his publication of studies of the genus mambers. In this latest part, he has established five monophyletic species groups covering all the Afrotropical and Malagasy species. These groups, for which he gave a key (adapted below), are rufonigra-group, ambigua-group, allaborans-group, grandidieri-group (Malagasy only] and natalensis-group. He also offered a revision of the T. ambigua-group. The paper can be seen in full - WARD, P.S. 2006: The ant genus Tetraponera in the Afrotropical region: synopsis of species groups and revision of the T. ambigua-group (Hymenoptera: Formicidae). Myrmecologische Nachrichten, 8, 119-130 http://antbase.org/ants/publications/21121/21121.pdf.
NOTE - I am not convinced that Ward's
interpretation of the T. ambigua-group
is correct. My species
key, below, therefore, does not wholly support his revisions. The
availability of type images now (April 2015) appears to show I am
Ward designated one new species, Tetraponera parops Ward, from East Africa. He was hesitant to treat it as a new species but I think his designation is correct. However, I have specimens of Tetraponera unidens (Santschi) new status that have the lateral rough patches on the occiput used by Ward as a primary distinguishing character for parops. Ironically, Tetraponera parops actually seems close to the original description of ambigua. The further specimens from Tanzania support the separation of parops, which is distinctly smaller than the related species.
With fresh specimens from Gabon, I regard Tetraponera angolensis (Santschi) as a clearly distinct species.
Under the blanket species Tetraponera ambigua (Emery), Ward states "mesonotum weakly convex and not separated from anterior margin of propodeum by prominently raised metanotal spiracles". He appears unaware that the drawing of occidentalis by Stitz (1917) and the description of angolensis by Santschi (1930b) have these spiracles as prominent.
Tentatively, I have separated occidentalis (ambigua race erythraea var. occidentalis Stitz 1917: 336; Menozzi, 1934: 154, worker) from Algeria to subspecies of Tetraponera erythraea (Emery), as having a wider, oval postpetiole. Moreover, if occidentalis is a genuine subspecies of ambigua, the distribution in North Africa is strange; Menozzi (1934) wrote of the finding in southwest Algeria, plus his record of its collection in Libya (Cirenaica, by Professor L di Caporiacco) as being of the form typical of southern Africa. My co-author on Ants of Egypt, Mostafa Sharaf, collected a specimen that clearly shows the distinctiveness of the North African species.
Ward's drawing of ambigua shows roughened patches on the lateral occipitum and prominent erect hairs on the sides of the head. Santschi's description of angolensis has no roughened patches on the occipitum, no lateral erect hairs on the head, indeed very few erect hairs at all, a more rounded propodeum amd a lower petiole. It is distinctly smaller than the specimen in Ward's illustration, for which he gave no origin, and has the darkened posterior to the gaster mentioned by Santschi, plus the narrow frontal area shown by Santschi. There appear to be five distinct teeth on the mandible as opposed to four for Ward's ambigua (also in Arnold's note on rhodesiana). I feel justified in elevating angolensis to full species status - Tetraponera angolensis (Santschi).
As Ward states he examined syntype workers of angolensis and erythraea (but not occidentalis) I surmise that he followed the style of Bolton, in "lumping" the ancient "varieties, subspecies and stirps", mostly attributable to Forel and Santschi. The converse, however, is that, at least by Bolton, other species have been erected on quite small characteristics. My experience from reading all the source papers and with a wide range of fresh material is that Santschi was remarkably accurate in separating his "stirps" but was influenced by his mentor, Forel, and so was reluctant to designate new species.
I have mentioned Tetraponera unidens above, Ward (1990: 489) gave the "current nominal combination" T. ophthalmica Emery (1912: 98; from Cameroun), Tetraponera ophthalmica tenebrosa Santschi (1928: 61; from Zaïre) and Tetraponera ophthalmica unidens Santschi (1928: 60; from Zaïre); with the annnotation that he had examined specimens. I am confident from the original descriptions, my own drawings of a Nigerian specimen and fresh specimens from Cameroun and Congo, that it is correct to separate Tetraponera unidens and Tetraponera tenebrosa off from Tetraponera ophthalmica (Emery).
Fresh specimens from Tanzania, have revealed Tetraponera bifoveolata (Mayr) to be like unidens in having a major worker. In both species this form has a curiously elongated head.
Grouping defined by Ward, with additions by myself (BT)
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