Tetraponera species: Slender ants

PSEUDOMYRMECINAE

The Genus Tetraponera (Slender ants)

‘Tetraponera’ literally means ‘four-layered’ and may refer to the structure of the petiole in this genus. There are 86 species distributed from Africa, through India and the East Indies to Australia, with the greatest concentration in Madagascar. These slender, elongate ants with relatively short legs are widespread in the wetter, more vegetated areas of our region, from the Western Cape fynbos up into Zimbabwe, Mozambique and further north. Many species have very large eyes, and in some the workers have ocelli or simple eyes on the tops of their heads. They seem to be either dark black with paler legs, or pale ochreous yellow to red in colour. All are armed with stings and the larger species can give humans a painful jab. Most species are monomorphic but a few species with distinct major and minor workers have been found. They tend to be relatively aggressive, moving with rapid, jerky movements. In fynbos as well as grasslands on the forest edge they are often found in the dry, hollow stems of the flowers of various Iridaceae; others inhabit the thorns of sundry savannah trees. The eleven species from our region are arranged in descending order of size.

For the technically-minded and those with access to good magnification equipment, the genus is also defined by the fact that the clypeus is sometimes produced into a spine, or armed with a row of teeth or with a crenulate anterior margin. In some the petiole alone has a ventral process, or both segments are without ventral processes. 


Tetraponera aethiops (F Smith, 1877): 
Giant slender ant

The workers are 9 to 10 mm long, shining jet black, living in twigs and under bark. The heads are squarer than in most species, with smaller eyes, but the workers have three ocelli in addition to the compound eyes. There are noticeable ventral processes on both the petiole and postpetiole. In some Central and West African countries the ants specifically inhabit certain trees that do not occur in our region. In South Africa they are uncommon, and are only found in Mpumalanga, but they are also found in Namibia, Mozambique and Zimbabwe, and through Africa to Nigeria.
The name ‘aethiops’ literally means ‘burnt face’ in old Greek, in this context ‘black’.
No pics available yet.


Tetraponera schulthessi (Santschi, 1915):
Robust slender ant

Workers are 9.0 mm long and more robust than T. natalensis [see below]; the head is wider; the alitrunk dorsum flatter; the whole alitrunk [thorax] is distinctly marginated. The overall colour is matt yellow-rust, and not shiny. 
Occasionally found in KZN; otherwise in Mozambique and Zimbabwe.
No info on the specific name for this fairly obscure ant, I’m afraid.
No pics available yet.


Tetraponera natalensis (F. Smith, 1858):
Natal slender ant

Workers are from 7 to 8 mm long. The overall colour is yellow/red with a darker apex to gaster; the head sometimes a darker reddish shade; the margins of the mandibles may be blackish. The whole body is covered with a very short pubescence, giving the ants a matt rather than shiny appearance. The large eyes are set on or slightly behind the midline of the head; there are usually two posterior ocelli present. The thorax or alitrunk is distinctly marginate; the first segment of the gaster is longer than wide. Commonest in grasslands where it lives mainly under tree bark and has taken to the invasive Australian Acacia mearnsii (Black wattle). The commonest subspecies is caffra, which some think should be re-instated as a separate species (Tetraponera caffra, Santschi 1914)
Smith (1876) reported observations by J.M. Hutchison, at Weenen in South Africa, of the species making “formicaria in the thorns of a species of acacia”.
Found in the Western and Eastern Cape, KZN, Mpumalanga and Limpopo as well as Namibia, Swaziland, Zimbabwe and northwards to Tanzania, Kenya and the DRC.
The name means ‘from Natal’, which under the circumstances is patent nonsense.
iSpot pics are at:
www.ispotnature.org/node/764178
www.ispotnature.org/node/763233
www.ispotnature.org/node/534763


Tetraponera angusta (Arnold, 1949): 
Narrow-headed slender ant

Workers are about 7.0 mm long. The head is narrower than usual, with the petiole also very narrow when seen from above. The ants are reddish ochreous in colour, with dull body and shiny gaster. As well as the usual compound eyes there are three ocelli on top of the head. The alitrunk or thorax has prominent margins. ‘Angusta’ means ‘narrow’.
Recorded from Zimbabwe only; we have no pics at present


Tetraponera capensis (F Smith, 1858 ):
Southern slender ant

Workers are about 7.0 mm long and dark reddish yellow in colour; Forel described the species as smooth and shiny, not matt like T. natalensis. The alitrunk or thorax has prominent margins. ‘Capensis’ literally means ‘from the Cape’, but is generally used to mean ‘from Southern Africa’. The ants are seldom seen and their precise distribution is not known.
South Africa only; no pics yet.


Tetraponera andrei (Mayr, 1895):
André’s slender ant

Workers are about 4.5 mm long, primarily black but dull, not shiny, with leg joints and flagellum yellowish brown. The head is rectangular and longer than wide, with coarsely grooved [striate] mandibles. Covered in a very fine but sparse pubescence with few erect hairs; legs short. The alitrunk or thorax has prominent margins. 
Ernest André (1838 – 1911) was a French entomologist who specialised in Hymenoptera and wrote books about ants, wasps and other insects.
Mozambique only; no pics at present.


Tetraponera ambigua (Emery 1895):
Small yellow slender ant
The workers are 4 – 5 mm long, and yellow to yellow-red all over, the apex of the gaster a little darker. They have large eyes, nearly half a head length, angled slightly inward at the anterior end, and set on or slightly behind the midline of the head. There is a sparse short pilosity on the head and upper alitrunk; the species has longer legs than most others. 
‘Ambigua’ means uncertain, doubtful, indecisive – or simply ambiguous. 
The ants are widespread in Southern Africa, in the Western Cape, KZN, Mpumalanga and Gauteng as well as Namibia, Mozambique and Zimbabwe
iSpot has pics at
www.ispotnature.org/node/746178


Tetraponera emeryi (Forel, 1911):
Emery’s yellow slender ant

Workers are 4 – 4.5 mm long. They are reddish-yellow all over and very shiny, giving them an almost translucent appearance. The eyes are about one-third of the head length and situated on the midline, with little or no inward angling. The alitrunk does not have margins; the petiole is very narrow. 

Carlo Emery (1848 – 1925) was an Italian entomologist who, from 1869 until he died, devoted himself almost entirely to the study of ants. He is well-known for ‘Emery’s Rule’, which suggests that social parasites among insects tend to be parasites of genera or species to which they are closely related. 
The ants occur in forested or bushy areas in the Western Cape, KZN and Swaziland, where they nest in hollow stems and twigs.
iSpot has pics at
www.ispotnature.org/node/607778


Tetraponera braunsi (Forel, 1913):
Brauns’ slender ant

Workers are 4 – 4.4 mm long. The ants are black with reddish or orange appendages; the eyes are not angled but in line with the head. The head shape is distinctive, ‘bulging’ slightly behind the eyes. 
The type variety braunsi is found in the Willowmore area and down to the South Coast.
The variety equidentata is also black but is smaller, workers at 3.5 – 4 mm, than braunsi and occurs mainly in the Western Cape.
The variety durbanensis has workers that are 3.8 – 4 mm long and are entirely dark ochreous yellow, with the head, alitrunk and gaster smooth and shining. As the name implies they occur mainly in the Durban area.
Dr Brauns was an entomologist and collector who lived in Willowmore for many years; his collection of Hymenoptera boasted over 10 600 species and was bought by the Ditsong Museums of South Africa for £1500.
www.ispotnature.org/node/779719

Tetraponera clypeata (Emery 1886):
Black slender ant

This graphic is to be redrawn

Workers are from 3.6 to 4.0 mm long. The colour is shiny black, with legs brownish black; mandibles tinted dark red; leg joints reddish brown; antennae reddish yellow, darker at the base. The head is widest between the eyes and about one third longer than wide. The eyes are on the midline and about 25% of the length of the head in size. The femora or upper legs are much swollen in the middle. The anterior margin of the clypeus has two pairs of sharp processes or teeth, from which the specific name. The species occurs widely in fynbos in the Western and Eastern Cape, where it favors the hollow flower-stems of various Iridaceae as nesting sites. How it survives regular veld fires is not known.
There are iSpot pics at:
www.ispotnature.org/node/523643
www.ispotnature.org/node/526508


Tetraponera liengmei (Forel, 1894)
Small black slender ant

These are the smallest of our Tetraponera, with workers from 3.4 – 3.7 mm. The colour is a very shiny brown-black, with brown-red mandibles and yellowish leg joints. The antennae and legs are short and thick. The head is rectangular and about 50% longer than wide; the eyes are relatively small. 
I have been unable to find out much about Dr Liengme, who appears to have collected ants, mainly in Mozambique, in the late 19th and early 20th centuries.
His ant occurs in Limpopo, Mozambique and Zimbabwe and is uncommon. 
No pics are available yet.





Survive invasive species:
Linepithema humile       : Argentine ants       : Possibly
Pheidole megacephala  : House ants            : unknown
Lepisiota sp.                  : Small Black ants    : unknown
Anoplolepis gracilipes   : Yellow Crazy ants  : unknown