The Ants of Africa
Genus Dorylus - Subgenus Anomma
Dorylus (Anomma) quadratus Santschi - new status

GERSTAECKERI group - characterised by relatively short thick scapes and short legs

Dorylus (Anomma) quadratus Santschi - new status

return to key {link to the Hymenoptera Name Server} Type locality Tanzania (Dorylus (Anomma) Gerstaeckeri Em. stirps quadratus n.st., Santschi, 1914a: 230, major; Raignier & van Boven, 1955, major) collected at Manou, by Viehmeyer - see worker morphs page (note there are two workers, a media 3 and a minima, labelled from Manow) .


Santschi's (1914a) description is at {original description}.

In his note, Santschi (1914a) described quadratus as known from a single major worker (using the sign for that), TL 10 mm, from Tanzania (German East Africa, at Manow) as dark red, differing from the type (Dorylus (Anomma) gribodoi as gerstaeckeri) by the denser and stronger puncturation of the petiole; the head straighter to the front; pilosity of petiole and gaster more abundant than on burmeisteri. As noted above, however, the surviving worker specimens, as imaged by the Antweb team, are what I judge to be a media 3 and a minima.


{Dorylus burmeisteri (Arnold paper)}Arnold (1952) commented on a queen and workers taken together at Kinganop, Kenya, by Mrs V Fey. I have adapted his illustration (right) (see also {original description}. Arnold titled his paper as a note on "a Female Dorylus (Anomma) Nigricans Ill. taken with workers" and labelled the illustration "Anomma nigricans var. molesta" (now molestus), arguing that, according to the key produced by Santschi (1912), because the posterior angles of the petiole are prolonged backwards, they must be molestus. My interpretation (2007) is that they are quadratus. The head shape of the major in Arnold's picture and the female match the illustrations I use here; the latter being that of Raignier & van Boven. Essentially, I feel the same way about the specimens described by van Boven (1972) as molestum (molestus) [see pdf], which to me are not molestus but are quadratus.


Note Schoning et al. (2008: 49) recognized quadratus as clearly distinct from D. gribodoi but place it as a junior synonym of Dorylus (Anomma) kohli, having sighted the types of both. They gave no other information. If my diagnosis of the latter from Guinea is correct then there are clear but subtle differences between the two species.


Oxford University Museum specimens

Dorylus (Anomma) quadratus
B Taylor det.

Tanzania
S Uehara
03-03-02

3.iii.2002
Mahale
6015' S
29 55' E
In forest
4
{album}
Dorylus (Anomma) quadratus
B Taylor det.
Tanzania
S Uehara
III-57

3.iii.2002
Mahale
6015' S
29 55' E
forest 2

Dorylus (Anomma) quadratus
B Taylor det.

Tanzania
S Uehara
III-58

3.iii.2002
Mahale
6015' S
29 55' E
jforest

2
{album}
Dorylus (Anomma) quadratus
B Taylor det.
Ethiopia
Nuru Adgaba

2011
Bonga
0723'N
3614'E
Hand collected, surface foraging
1650 m

13
{album}

{Dorylus quadratus polymorphism} Polymorphism

The photomontages are of specimens from Tanzania, collected by the Chimpanzee study project led by the late Professor Shigeo Uehara. The various morphs are shown in detail on Dorylus (Anomma) quadratus morphs page.  A full range of morphs from Ethiopia can be seen on the Dorylus (Anomma) quadratus Ethiopia morphs page (the minima morph at least differs slightly).


{Dorylus quadratus major} Full new description Uehara 03/03/02

Major. TL 10.05 HW 2.75 HL 2.75 HD 1.85 CI 100 SL 1.5 SI 55 AL 3.0 PW 0.9 PetL 0.8 GL 3.5 MFL 2.5
Overall appearance - shiny but matt rather than polished generally orange chestnut, darker on anterior of head and apical gaster.
Head - widest at about 1/8 from anterior, posterior perhaps 1/5 narrower; sides smoothly convex, curve steepening in hind 1/3; posterior margin shallow scallop, with flat central area, angles quite sharp; fine spiculation visible evenly all over face, sparse minute hair pits; median line almost invisible; clypeus sinuous, with strong down turned median hair and other long fringing hairs; mandible moderately long and stout, quite large subapical tooth and denticles, basal tooth a large oblique triangle; scape out curved, stout, broadening from base to apex, matte; funiculus with basal two segments fairly slender, rest stout not much longer than wide very bristly; segment 10 only 1.5 X 9; head with very bulbous dorsum, venter shallowly convex; slight extension of posterior corners; very minute sparse pilosity on occiput.
Alitrunk - profile shallowly domed, with shallow step down to distinct but not pronounced "saddle"; spiracle vertically ovoid and strongly raised anterior so facing rearward; deep groove subtending lower margin; propodeum rising noticeably from saddle, then steepening curve to sub-vertical declivity; metapleural gland upper longer than lower and slightly upturned; sculpturation all over fine spiculation, coarsening rearward and downwards; hairs minute sparse fine on shoulders.
Petiole - in profile moderately long, with all edges rounded; distinct posteroventral protrusion; in dorsal view straight sided but doubling in width from front to back; strong posteroventral processes; spiracle small and strongly raised; subpetiolar process quite large narrow triangle rising from flange full length of venter; sculpturation as alitrunk; hairs - none dorsally, several quite coarse hairs ventrally.
Gaster - sculpturation of basal segment as petiole, rest near smooth and shiny; moderately waisted; coarse hairs on dorsum of 1, fringes of others and ventrally.
Legs - coxae short and broad based; femora moderately wide, matte with micropilosity; tibiae relatively short, with fine and quite sparse bristles; tarsi relatively short, moderate claws.


{Dorylus gerstaeckeri minima} Minima morph
Head shiny, colour dark chestnut; dorsum with very fine decumbent pilosity; funiculus slender with fine pilosity.

Contents
2007, 2008, 2011, 2012 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

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