Bothroponera, Mayr

Wheeler, W. M., 1922, The ants collected by the American Museum Congo Expedition., Bulletin of the American Museum of Natural History 45, pp. 39-269 : 69-73

Bothroponera Mayr

Worker.-Small, medium-sized or large, opaque or subopaque, usually strongly sculptured black or dark brown ants. Workers monomorphic. Head subrectangular, with the eyes usually well developed, rarely vestigial, placed at or in front of the posterior third of the head. Mandibles subtriangular, with coarsely dentate apical margin. Cheeks without a carina. Clypeus with rounded, obtusely angular or feebly and sinuately marginate anterior border, prolonged backward as a narrow point between the frontal carinae, which are broadly and lobularly expanded, incrassated and covering the insertions of the antennas. Frontal groove distinct. Antennae stout, 12-jointed. Thorax with distinct premesonotal suture, but with the mesoepinotal suture and that between the mesosternum and mesepisternum absent or obsolescent. Pronotum not marginate on the sides; epinotum usually unarmed. Petiole with a thick, more or less transverse node, in a few species somewhat compressed and dentate above or behind. Gaster subcylindrical, with pronounced constriction between the postpetiole and succeeding segment, the postpetiole truncated in front; sting rather short and blunt. Middle and hind tibiae each with a large pectinated and a simple lateral spur; claws simple.

Female only slightly larger than the worker; winged; in other respects very similar to the worker; ocelli small; pronotum broad and exposed; mesonotum small, flattened, broader than long. Wings rather broad; with a discoidal cell, two cubital cells and a closed radial cell.

Male nearly the same size as the worker. Head short, rounded behind; eyes and ocelli very large; mandibles small, flat, edentate. Palpi long, the labial pair 3-jointed, the maxillary pair 5-jointed. Frontal carinae short. Antennae very long, filiform, 13-jointed; the scape short, scarcely twice as long as broad; the first funicular joint not longer than broad, the remaining joints long and cylindrical. Pronotim transverse, truncated in front; mesonotum without Mayrian furrows; scutellum very convex. Abdomen strongly constricted behind the postpetiole; pygidium terminating in a downwardly directed spine. In some species the penultimate stcrnite of the gaster is notched and prolonged on each side as a prominent lobe. Genitalia retracted.

Mayr described Bothroponera as a genus; but Emery, Forel, and Santschi have been treating it as a subgenus of Pachycondyla . I return to Mayr's conception for the following reasons: First, the larvae of Bothroponera (Fig. 9a -d) arc quite different from those of Pachycondyla , as I have shown in a former paper.1 Second, Bothroponera , being a strictly paleotropical group may be advantageously separated as a distinct genus from the purely neotropical Pachycondyla . Ectomomyrmex may be regarded either as a subgenus of Bothroponera or as an independent genus. I prefer to adopt the latter course. I also separate out a small group of species of Bothroponera ( gabonensis Ern. Andre and sveni Forel ) as a distinct genus Phrynoponera (vide infra). Third, there are certain peculiarities in the habits of Bothroponera which indicate that the species are generically distinct. Like Pachycondyla , they form small colonies under stones in rather moist, clayey soil, but are more sluggish and do not sting readily when captured and instead emit from the posterior end of the body a peculiar mass of frothy substance. I have observed this in some of the Australian species, and Bingham and Taylor have seen similar behavior in the Indian B. rufipes (Jerdon) , according to Wroughton.1 Bingham says that this ant "blows a whitish, acrid smelling, rather gelatinous froth when seized" and according to Taylor it exudes when seized "a milky substance of a frothy nature which hardens on exposure to the air and resembles fine cotton; it is called' domona chunti' or 'gendu,' the 'domonas' being the weaver caste in Orissa." B. tridentata(F. Smith) of Borneo seems to have the same habit, according to Beccari.2

The genus Bothroponera is widely distributed over the Ethiopian, Indomalayan, Papuan, and Australian Regions (Map 10). Africa is very rich in species but Australia possesses almost as many.

The following table may be of some assistance in identifying the workers and females of the Ethiopian species of Bothroponera .

1. Head, thorax, petiole and postpetiole coarsely punctate, punctate-rugulose or striated..........................................................2.

These regions finely and densely punctate, sometimes with superimposed, larger but shallow punctures............................................9.

2. Mandibles striate.......................................................3.

Mandibles smooth, sparsely punctate...................................7.

3. Petiolar node broadly excised posteriorly..................... cariosa Emery .

Petiolar node sharply truncated posteriorly..............................4.

4. Length 8 mm.; testaceous yellow........................ cribrata (Santschi) .

Length not less than 9 mm.; black or brownish black.....................5.

5. Antennal scapes reaching to occiput................... cavernosa (Roger) .

Antennal scapes not reaching to occiput; eyes small.....................6.

6. Length 9 mm.; golden pubescence on body, especially on head, abundant;

sculpture less pronounced............................ talpa Ern. Andre .

Length 12 to 15 mm.; golden pubescence less pronounced; sculpture coarser. pachyderma (Emery) .

7. Petiolar node broadly excised posteriorly; body covered with golden pubescence. granosa (Roger) .

Petiolar node truncated behind; body without golden pubescence..........8.

8. Gaster opaque, finely striated........................... strigulosa Emery .

Gaster more or less shining......................... pumicosa (Roger) .

9. Eyes well developed in the workers....................................10.

Eyes vestigial in the workers..........................................15.

10. Length 5.5 mm............................................................11.

Length at least 7 mm.................................................12.

11. Mandibles 7-toothed; petiole as long as broad................ picardi (Forel) .

Mandibles 6-toothed; petiole nearly twice as broad as long.. silvestrii (Santschi) .

12. Mandibles shining, sparsely punctate...................... soror (Emery) .

Mandibles finely striate.............................................13.

13. Opaque; head ovoid................................... krugeri (Forel) .

Subopaque or shining; head subrectangular............................14.

14. Very shining; length 12 mm.; clypeus angularly produced in middle; eyes small........................................... laevissima (Arnold) .

Subopaque; length 7 to 7.5 mm.; clypeus feebly sinuate in middle; eyes larger. crassa Emery .

15. Length only 4.5 to 5.5 mm.; mandibles smooth, sparsely punctate; eyes very small, with less than a dozen facets.................. sjostedti (Mayr) .

Length 6.5 to 7 mm.; mandibles striate at the tip; eyes larger, with about 45 facets............................................... fugax (Forel) .