The Ants of Africa
Genus Dorylus - Subgenus Anomma
Dorylus (Anomma) nigricans Illiger

NIGRICANS group - characterised by the head being widest mid-length, with smoothly convex sides and rounded posterior angles.

Dorylus (Anomma) nigricans Illiger

return to key Male return to key {link to the Hymenoptera Name Server} Type location Sierra Leone (Dorylus nigricans, Illiger, 1802: 188, male) from a single male specimen, in Hellwig's collection - type male images not on Antweb (July 2014) .

Illiger's (1802) description is at {original description}.

Santschi (1930a: 55) described what he regarded as the soldier & worker of "nigricans" from Mali (Bamakou, by Andrieu); this is at {original description}. As with other authors, he did not see either a queen or male and noted only small differences from burmeisteri soldiers and workers. He pointed out that nigricans s.s. was known only from the male. The availability of type specimens on Antweb (July 2014), however, show the Santschi specimens to exactly match the Westwood types of Dorylus (Anomma) arcens.

What I regard as the probable workers are shown on the Dorylus (Anomma) nigricans workers page.

{Dorylus nigricans male}{Dorylus nigricans male petiole}Haldeman (1849a) gave illustrations of the male head and F Smith (1859) included the petiole profile in a plate comparing Dorylus males.

Raignier & van Boven (1955) cite Illiger's description as - "Schwärzliche Aemsenwespe [blackish wasp], nigricans, brunneo-holo-sericeus, abdominis petiolo acetabuliformi. Lange : Einen Zoll [ca TL 25 mm] bis einen Zoll und drei Linien [TL 28.4 mm]". The specimen was a little bigger than the already known species Dorylus (Dorylus) helvolus and without hairs; the wings of nigricans were smoky black with black veins.

{Dorylus nigricans male}

Thus, the Illiger, Shuckard, Haldeman, F Smith male has -
Dark smoky black wings;
The alitrunk dorsum has a shiny brown pubescence;
A steeply domed head, with relatively small eyes and a straight margin across between the anterior of the compound eyes;
The petiole profile has a shallow curve from the anterior to the dorsum, the ventral process has a straight anterior at about 45° and the posterior is convex.

Oxford University Museum specimens

{Dorylus nigricans male}The photomontage is of a male from the Central African Republic, Bayanga; collector Philippe Annoyer (CAR DK02). .

The colouration and the velvety appearance matches the Shuckard (Illiger) description exactly. The head shape matches the Haldeman drawing. It has a relatively flat occiput, strong median sulcus, shorter scapes; shorter mandibles; scape length to basal 7.1 segments of funiculus; SL = distance between inner margin of eye and centre of median ocellus (in full face view scape reaches median sulcus); eye shorter but just as wide, EW/EL = 79; ocelli set closer together; from above front of head is concave; posterior margin of petiole is near flat, with a distinct fringe of hairs; gaster apex, evenly convex, with prominent stipes extruding.

See a larger photomontage and a second male from the Central African Republic on the linked page - Dorylus nigricans males.

The identification by Caspar Schöning of workers (see the linked page) as D. nigricans appears to be a good match to Santschi's description but I presume that, as Santschi noted, this is as a "most likely candidate" from comparison with other specimens, e.g. of Dorylus burmeisteri and Dorylus arcens. There is, however, on a set of images of a male accompanied by two sets of worker specimens. I note, however, that the male shown on Antweb was collected at a different location in the Tai National Park, at light and not from a nest.  I feel that male is Dorylus burmeisteri. Those shown as Dorylus (Anomma) burmeisteri match Emery (1910) - no frontal sulcus, occiput domed; from above front of head is convex; scape length to basal 6.3 segments of funiculus; SL = distance between inner margin of eye and outer edge of median ocellus (in full face view scape does not reach the faint median line); EW/EL = 71/66; posterior margin of petiole is shallowly concave; without any fringing hairs (Antweb specimen from different angle to my two; apex of gaster shallowly concave, with the stipes barely visible.

© 2007, 2009, 2010, 2013, 2015 - Brian Taylor CBiol FSB FRES
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