SUBFAMILY AENICTINAE - Genus Aenictus Shuckard
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The Ants of Africa SUBFAMILY AENICTINAE - Genus Aenictus Shuckard |
Bolton (1990b, 1994) raised this as a new monogeneric subfamily, within the doryline section.
Diagnostic Features - Antenna 10-segmented; eyes absent; clypeus reduced bringing antennal sockets very close to anterior margin of head; pedicel of two segments; pygidium not impressed nor armed with spines or teeth. Posterior margin of clypeus and lobes of frontal carinae raised to form a ridge around the antennal insertions. Genae lateral of each antennal insertion with a carina of variable length. Dorsum of alitrunk without sutures, metanotal groove usually impressed. Monomorphic.
Shuckard's (1840b) genus description is on
The names given below are those listed by Bolton (1995). This presents something of a conundrum, as there is no published revision of the Afrotropical members of the genus and, like Dorylus many "species" are known from males only or workers only, suggesting some duplication of species. Gotwald & Barr (1987) made quantitative studies on many members of the whole genus, which is solely found in the Old World. They described how ten African species appeared to fall into a distinct group, within the subgenus Aenictus. Interestingly, although they would appear to have recognised that there might be three valid subgenera, Bolton (1995) denoted the subgenera as all synonymous under Aenictus. Moreover Gotwald & Barr (1987) named only one of the ten African species which they listed, Aenictus asantei, and noted that Gotwald was "currently revising" the African species. To date, however, it seems that this has not been published.
Bernard (1952) wrote how these eyeless, subterranean ants are numerous in Africa, with 37 species, with new forms being continually detected. He thought that it was the sole ant genus which does not reach its maximum diversity in "Congo-Rhodesia", but far from there in the north and east, from Senegal across to Sudan and Somalia; that region having some 19 species (Congo 13 and southern Africa 7); two other forms were Saharan. Relatively few forms appeared to be other than from lowland areas.
Often display 'army ant' habits, with narrow marching columns in leaf litter (Gotwald & Barr, 1987). Described as feeding primarily on other ants by Hölldobler & Wilson (1990, pages 560, 581 and 595).
Radoszkowsky (1881) listed Aenictus unicolor F Smith, from Angola, collected by Welwitsch. Bolton (1995: 61) has this as a nomen nudum.
Species known only from males -
* Santschi (1920d) gave illustrated descriptions of several of these
male-only species; this is at
.
Key to workers known from Africa
| 1 |  Large,
TL > 4.5 mm, stocky, heavily sculptured; head longer than wide,
widest at anterior margin; propodeum with distinct teeth; abundant long
pilosity, dark brown except gaster which is golden yellow |
West Africa & Congo Basin - weissi |
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| -- | Smaller | 2 |
| 2 |  TL
3.0-3.2 mm; petiole with no more than a convex ventral profile, no
distinct process; postpetiole with a low profile; head & alitrunk
red; rest yellow |
Guinea - villiersi |
| -- |  Petiole
with a distinct ventral process |
3 |
| 3 | Head more or less rectangular, longer than wide | 4 |
| -- | Head near circular in full-face view other than less curved posterior border; petiole with smaller triangular, rearward or downward directed ventral process | 9 |
| 4 | Very small, TL < 2 mm; head rectangular; mandibles narrow with 3 teeth; propodeum dorsum convex, declivity triangular, margined by a distinct ridge; pedicel nodes longer than wide; petiole with very short anterior ventral tooth; dirty yellow with brownish tinge, head and alitrunk rust-yellow | South Africa - rixator |
| Larger, TL > 2.0 mm; petiole with large anterior directed ventral process | 5 | |
| 5 | Petiole with triangular antero-ventral process | 6 |
| Petiole with blunt, rounded to square antero-ventral process | 8 | |
| 6 |  TL
2-3 mm; scape not reaching beyond mid-point of head; mandible with acute
apical tooth and 4 small teeth on inner margin; alitrunk relatively
short and broad; major reddish-ochre |
South Africa - mariae |
| -- | With propodeum about 1.5 X as long as wide | 7 |
| 7 |  TL
1.7-2.5 mm; mandibles short, stout, with acute apical tooth and three
denticles; propodeum rounded in profile; from above petiole 1.6 X
broader than long and rectangular; pale ferruginous |
Sudan - mentu |
| -- |  TL
2.3-3.8 mm; mandible with large apical tooth and 8-9 small teeth; scape
reaching posterior four-fifths of head; anterior clypeal margin with
denticles; propodeal declivity margined but only slightly concave;
sub-petiole process triangular; whole body red ochre |
South Africa - rotundatus |
| 8 |  TL
2.4-3.4 mm; scape reaching posterior sixth of head; propodeum with small
but distinct denticles; dark red-brown, gaster browner |
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Congo Basin - congolensis |
| -- |  TL
2.6 mm; scape reaching just past mid-point of head; propodeum with
smoothly rounded profile; orange yellow; only sculpturation is faint
spiculation on posterior alitrunk |
. |
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West Africa - guineensis |
| 9 | Mandible without a large basal tooth, relatively narrow | 10 |
| -- |  Mandibles
thick, with large basal tooth; TL ca 3.3 mm; head more elongate, though
still convex; mandibles thick, with large basal tooth; anterior border
of clypeus with median process; petiole with no more than a low ventral
process; rusty-red; sides of alitrunk longitudinally rugose |
West Africa (? East Africa) - decolor |
| 10 | Mandibles narrow; with sharp apical tooth but others reduced to denticles | 11 |
| -- |  TL
2.5-3.9 mm; mandibles thick but with pronounced longer apical tooth;
anterior border of clypeus with denticles; shiny, polished appearance,
except for posterior alitrunk, finely reticulopunctate |
West Africa - asantei |
| 11 |  TL
3.7-4.0 mm; head widest at anterior; scape long reaching posterior
border of head; anterior clypeal margin with a pair of small denticles;
propodeal declivity markedly concave; head & alitrunk bright
castaneous red, gaster lighter |
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East & South Africa - eugenii |
| -- | TL 2.8-3.2 mm; apparently very similar to eugenii but smaller and lacking teeth on the clypeus | Congo - brazzai |
| -- | Head widest in the middle | 12 |
| 12 |  TL
2.4-3.7 mm; head widest medianly; mandibles with large apical tooth and
6-7 small teeth; clypeus very short apical margin with numerous small
teeth; reddish-ochreous, gaster lighter |
Zimbabwe - furibundus |
| -- | Sides of propodeum amd metasternum with plentiful backwardly direct pubescence (rotundatum with little or no pubescence); propodeum like rotundatum but declivity deeper and margined only laterally | South Africa - steindachneri |
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© 2007, 2008 - Brian Taylor CBiol
FIBiol FRES 11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K. |
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