Dorylus (Anomma) gerstaeckeri Emery

Type locality Ghana (Emery, 1895j: 713, illustrated, workers) from Accra .

The original description was of a single worker, TL 8.0; but Emery (1901) received others from Cameroun which were longer, TL 10 mm. These were characterised by a square head about 1/3 of TL; vertex shiny and puncturation sparse; petiole slightly wider than long; overall body stocky (stockier than burmeisteri) and appendages shorter.

The much redder Dorylus (Anomma) quadratus (Santschi) has been separated here as a distinct species.

Emery's (1895j) description is at . Emery's (1901c) description is at .

Forel (1912g) described specimens of "Anomma nigricans Ill." collected at Entebbe, Uganda, in September 1911, by Heinrich Schultze. Forel gave an illustration of the specimens, which from the dimensions and general appearance are gerstaeckeri. Comparision of the sexuals can be made with the photographs of Dorylus burmeisteri from Raignier & van Boven.

Raignier & van Boven (1955) under emeryi note comparison with gerstaeckeri; emeryi being bigger TL 12.7 mm; head rectangular, slightly longer than wide, and slightly more than 1/3 of TL (in gerstaeckeri it is slightly less than 1/3).

The Ghana record was from Aburi (F. Silvestri, in Wheeler, 1922). One of the two species studied in Ghana during 1971 by Gotwald (1974). He found it only in the high forest areas, especially in and around cocoa at CRIG, where the almost exclusive prey was earthworms.

Also from Cameroun by Conradt (in Wheeler, 1922).

Polymorphism

The photomontages are of specimens from collected in Cameroun - south-western tropical coastal forest area between Edéa and Campo (McKey Wolbachia project) - Cameroon 37 from location Kribi, 05 April 2001 - in herbaceous vegetation about 20 cm tall (garden of the Catholic Mission). The various morphs are shown in detail on Dorylus (Anomma) gerstaeckeri morphs page.

Full new description Cameroon 37 -
TL 8.5 HW 2.5 HL 2.25 HD 1.75 CI 111 SL 1.2 SI 53 AL 2.75 PW 0.9 PetL 0.75 GL 2.75 MFL 2.25
Overall - shiny but not polished chestnut, darker apically (head & gaster).
Head - widest at midlength, narrowest posteriorly; sides convex; posterior margin a shallow scallop; sculpturation of fine spiculation, no hair pits; median line faint but visible, very slightly impressed on occiput; clypeus near straight, slight forward curve; hairs equisized medium only moderately long and stout; mandible with single blunt preapical tooth; basal tooth subtriangular with anterior angle near 80º; scape , faintly striated relatively slender, out curved; funiculus slender, segment 2 shortest, moderate pilosity; in profile dorsum evenly arched, ventrally near flat; no erect hairs, no pilosity.
Alitrunk - shallowly convex TS & LS near flat, even transition into propodeum; spiracle circular, slightly raised at front so pointing backwards; propodeum near flat, gentle curve into declivity, that subvertical and short; metapleural gland upper flange slender extending beyond lower; sculpturation same as head, all over fine spiculation; no erect hairs, no pilosity.
Petiole - all edges rounded, flat dorsum, anterior 45º, posterior subvertical, evenly widening front to back by about 25%; spiracle small, flat, near front end; subpetiolar process a shallow triangle with apex forward; sculpturation as head & alitrunk; erect hairs pair on dorsum, several below after subpetiolar process.
Gaster - sculpturation of basal segment as body, rest smoother; distinct but slight waisting 1-2; erect hairs 2 pairs on basal dorsum, rest as normal.
Legs - coxae moderately long; femora, relatively short, smooth; tibiae smooth, with sparse decumbent pilosity; tarsi slender, pilosity moderate.

Minima morph
Head finely spiculate, shiny, colour dark yellow brown; dorsum with abundant fine decumbent pilosity, and distinct hair pits; funiculus segments dark edged, with extremely fine, abundant, short pilosity.