Dorylus (Anomma) kohli Wasmann

Type location Zaïre (Wasmann, 1904b: 669, workers; Santschi, 1921c: 114, soldier); subspecies minor (santschi, 1911g: 206, worker) from Angola, collected at Benguela, by J Cruchet; chapini (Wheeler, 1922: 45) from Zaïre; and frenisyi (Forel, 1916: 402, worker) from Zaïre (Raignier & van Boven, 1955); workers and queen known .

Wasmann's description (1904b), of worker TL 3-8 mm, is at . Santschi (1921c) gave a description of the major - . Santschi's (1911g) description of minor is at .

Raignier & van Boven summarized the descriptions as - head practically rectangular, wider and a little more scalloped posteriorly; petiole slightly longer than wide (Santschi). The worker media (Wasmann) head narrowing towards the rear; almost matt dorsally; petiole as wide as long and equally wide at both ends. Worker minima (3 mm) with 11-segmented funiculus, petiole as long as wide at its base but narrowing towards the front. Majors red-brown, red-yellow paling with smaller morphs. Forel (1909b) noted that Dorylus kohli was more robust, shinier and with shorter appendages than emeryi.Wheeler (1922) gave a description of chapini (given below).

Raignier & van Boven (1955) examined the types of frenisyi and considered them probably no more than the minor morphs of kohli s.s. From Forel's (1916) very brief description, with a TL 4-8.5 mm, etc., I agree.

In their own field work, Raignier & van Boven made one collection of kohli s.s, with 5 workers, TL 11-3 mm; major - CI 91, petiole as wide as long, scape width/length = 22 (relatively slender); practically glabrous and red to red-brown; anterior of head matt and blackish, rest shining, mandibles curved, semi-matt and with a basal tooth which lodged into the space below the antennal socket; the occiput was shiny with very sparse puncturation. They felt a key separation from congolensis is the mandible in kohli being longer relative to the head length, index > 160 ; ca 150 in congolensis.

Nigeria specimens (Taylor, 1978b: 11). WORKERS. TL 9.75-4.18. At least four morphs; largest HL 2.28, HW 2.34, SL 1.20, PW 1.20, petiole length 0.68
Colour very dark red-brown, lateral alitrunk and legs lighter, anterior of head and almost all of gaster darkest areas. Minor morphs more uniformly coloured, the smaller the morph the lighter the colour, with the smallest more yellow-brown. All over sculpturation of very fine reticulation; on major head extremely faint but enough to make appearance glossy rather than polished. Erect hairs on the posterior margins of gastral segments and subpetiole. Head widest just before anterior margin, and with posterodorsal lateral triangular tubercles. Antennal scapes thickening to a broad apex. Mandible higly polished with a long acute apical tooth and large triangular basal tooth, smooth margin in between, and sparse long seate on inner margin . Clypeal margin near straight but slightly produced centrally and laterally; with a long medial seta, other hairs short. Promesonotum only slightly convex dorsally. Subpetiolar process broad based and triangular, with a slight rearward curve.
I found it nesting in the ground and foraging widely on the surface at the Cocoa Research Institute of Nigeria, Idi Ayunre. Also known from Old Calabar (H W Bates, in Forel, 1911, and Wheeler, 1922).

Also known from Congo (Brazzaville, by A. Weiss), Zaire (Akenge, Niangara and Avakubi by Lang & Chapin; also St. Gabriel by Kohl) and Angola (in Wheeler, 1922). Note the variety congolensis Santschi, listed by Wheeler (1922) was later raised to full species status by Boven & Lévieux (1970), Dorylus (Anomma) congolensis, but has its type location as Congo, see above.

The original discoverer, Father Kohl, described the activities of kohli, noting that it seemed to be primarily hypogaeic, foraging below the soil surface, unlike the more common epigaeic habit of (Anomma) driver ants. The Zaïre findings also were from underneath surface cover. Raignier & van Boven (1955) confirmed the species migrated in a primarily subterranean way but found the nests opened with craters and the foragers dispersed on the surface, using narrow semi-covered trails.

Polymorphism

The photomontages are of specimens collected at Bossou, south eastern Guinea, by Tatyana Humle (24.viii.2001, Humle 11), also examined were specimens from another collection at Bossou (02.ix.2001, Humle 2).

The various morphs are shown in detail on the Dorylus (Anomma) kohli morphs page.

Full new description of major -
Cameroon 104 - TL 10.05 HW 3.1 HL 2.75 CI 112 SL 1.25 SI 45 HD 2.0 AL 3.25 PW 0.9 PetL 0.8 GL 3.25 MFL 2.25
Humle 11 - TL 10.1 HW 3.0 HL 2.6 CI 115 SL 1.6 SI 61 HD 2.0 AL 3.25 PW 1.0 PetL 0.75 GL 3.5 MFL 2.5
kohli CRIN - TL 9.75 HW 2.34 HL 2.28 CI 102 SL 1.2 SI 53 HD 1.5 AL 2.6 PW 1.2 PetL 0.68 GL 3.3 MFL na
Overall appearance shiny sub-polished dark chestnut, most of gaster and anterior third of head near black
Head - widest at anterior margin, narrowest posteriorly; sides near flat for first 2/3 then steeper angle inwards; posterior margin impressed but as shallow triangle; sculpturation of very fine spiculation, no hair pits; median line visible for whole length of face, not impressed; clypeal margin very slightly sinuous, with median fine long hair plus 2/3 subtended pairs; mandible smooth, minute hair pits, shiny, no preapical teeth, basal tooth sharp equilateral triangle, internal fine hairs; scape relatively stout, near straight; funiculus moderately thick evenly increasing from 1-10, bristly; in profile occiput domed, narrower frontal area weakly concave; ventrally convex; erect hairs none, no pilosity.
Alitrunk - markedly domed TS & LS; not as domed in CRIN; mesonotum-metanotal groove area near flat well below level of rear of pronotum; spiracle circular but not obviously raised; propodeum a smooth shallow curve from front to back steeper but not angled to declivity; metapleural gland upper only a little longer than lower; sculpturation same as head; minute and very sparse pilosity on pronotum.
Petiole - shorter, all edges rounded, flat dorsum, anterior and posterior subvertical; dorsum evenly widening front to back, ca 25%; spiracle protruding seen from above; subpetiolar process peculiar narrow flange-like blade sticking downwards; with deformed or bifurcate apex; CRIN simple; sculpturation as head & alitrunk; erect hairs short pair on dorsum, lower moderately long.
Gaster - basal as body rest shiny, small hairs pits; noticeably waisted; erect hairs single pair on dorsum, others much fewer .
Legs - coxae short and wide; femora relatively stout; tibiae relatively wide, pilosity quite coarse from distinct hair pits; tarsi slender, pilosity moderate, quite large, slender claws.

Minima morph
Head shiny, colour dark chestnut; dorsum with very fine pilosity; funiculus with coarse semi-erect pilosity.

Wheeler (1922) had the following description of chapini.

Dorylus (Anomma) kohli variety chapini, new variety.
This is a very distinct form, represented by a series of two dozen workers from Kisangani, Zaïre (Stanleyville; Lang and Chapin), without further data.
TL measure 1.5 to 6 mm. The largest specimens are probably not the maxima forms as they have a preapical mandibular tooth. The body is only slightly shining and very similar in sculpture to the preceding variety except that the punctures are coarser, sharper and piligerous. They are evenly distributed over the dorsal surface of the head and pronotum, similar but smaller and shallower on the propodeum and gaster, and very indistinct or absent on the petiole. Mandibles and legs smooth and shining. The head, pro- and mesonotum, gaster, scapes, and legs are covered with short, subappressed, yellow hairs arising from the punctures and forming a conspicuous, rather abundant, coarse pubescence. The body is brownish ferruginous, the head slightly darker, and appendages paler, the mandibles blackish. The head is scarcely longer than broad in front, the sides very feebly convex and converging to the posterior border, which is only slightly excised and about four-fifths as long as the anterior border. The petiole is as broad as long. The smaller workers closely resemble the larger, except that the head is a little longer and the colour paler.