The Ants of Africa
Variability of the species "Oecophylla longinoda" (Latreille)
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Oecophylla longinoda sensu strictu (Latreille) - list as in Bolton (1995: 298)

{link to the Hymenoptera Name Server} Type location Senegal (Formica longinoda, Latreille, 1802c: 184, illustrated, worker; Emery 1892d: 564, queen; Forel, 1913b: 339, queen [not male as given in Bolton, 1995: 298]; status as species Dalla Torre, 1893: 176); minor described as Oecophylla brevinodis nov sp, André, 1890: 313 (synonymy by Wheeler, 1922a: 945; correctly this should be attributed to Emery, 1892d: 564, although he seems to have regarded brevinodis as simply very small examples of longinoda) from Sierra Leone
"current subspecies"
annectens (Oecophylla longinoda variety annectens new variety, Wheeler, 1922a: 230, all forms) from Zaïre
claridens (Oecophylla longinoda var. claridens, Santschi, 1928f: 211, worker & queen) from Ivory Coast
fusca (Oecophylla fusca n. sp., Emery, 1899e: 496, worker & queen) from Cameroun
rubriceps (Oecophylla longinoda variety rubriceps (Forel), Wheeler, 1922a: 229; first available use of Oecophylla smaragdina F. r. fusca Ern. v. rubriceps n. var., Forel, 1913h: 354, worker) from Zaïre
rufescens (Oecophylla longinoda var. rufescens, Santschi, 1928f: 211, worker & queen) from Congo
taeniata (Oecophylla longinoda var. taeniata, Santschi, 1928f: 212, queen) from Zaïre;
textor (Oecophylla longinoda var. textor, Wheeler, 1922a: 229, worker & queen; first available use of Oecophylla smaragdina st. longinoda var. textor, Santschi, 1914b: 128, worker & queen ) from Zanzibar (wrongly given in Bolton as Zaïre)
.

Note: Now (October 2014) type images are available of most of the above, the exceptions being the type major of longinoda and the type of rufescens

In my original Guide, I followed the information in Bolton (1973a) which simply described the "single West African species" as dimorphic and gave no indication of any variability. In Nigeria, all the numerous collections and innumerable observations we made on the species never once indicated anything other than simple dimorphism and no more than minor variations in overall body colour. Specimens sent to me in 2001 from Cameroun by Professor Doyle McKey's team showed how that simple view was a delusion.

Turning to Wheeler (1922) revealed how much the single species actually does vary. Despite that, Wheeler had the observation -

"fusca was originally described by Emery [1899e] as an independent species, but Forel reduced it to subspecific rank on finding the variety rubriceps, which shows some colour variation in the direction of the typical longinoda. The discovery of another variety, annectens described below, connecting rubriceps and longinoda, is additional evidence that fusca, cannot be maintained as a species. In my opinion it is merely an extreme melanic variety) for I am unable to detect in it any morphological characters of even subspecific value. All of the varieties of longinoda, are equally polymorphic in the worker caste and the smallest individuals all agree with the description of Andre's brevinodis, except in colour".

Wheeler's full commentary (1922: 224-231), with notes on the sexuals, can be seen at {original description}.

The specimens from Cameroun (Cameroon) sent to me by Professor Doyle McKey's Wolbachia research team, coupled with the ease and convenience of digital photography now (2005) have led me to what really is a reversion to the early opinion of Emery (1899). Thus, I come to a clear separation into two species-groups and possible further separation into distinct species. Despite the review by Wheeler (1922), to which he refers, in his contribution to Wytsman's "Genera Insectorum", Emery (1925b: 52) still had a single extant species - Oecophylla smaragdina, with subspecies Oecophylla longinoda and African varieties thereof - viz. annectens, fusca, rubriceps and textor. Contrary to what Wheeler wrote, Forel (1913h) had not reduced fusca to "subspecific rank" but regarded longinoda, fusca and rubriceps equally as races of smaragdina.

I have appended a section on Oecophylla smaragdina for comparison, especially with textor which perhaps is closer to smaragdina than to longinoda.

Key to speciues

¤ Queen only; TL 14 mm; reddish-yellow; mandibles, basal 2/3 of scape, posterior of scutellum, middle of mesonotum, sides of propodeum and petiole, also anterior and posterior borders of gaster segments dark brown, to blackish brown; Congo Basin - taeniata
1 Ferruginous or testaceous throughout 2
-- Brown or black 4
2 Colour ferruginous (rust-coloured); pubescence sparse and overall appearance quite shiny
 (Panafrican ?) West Africa - longinoda type form
-- Colour paler, more testaceous - generally blotchy, overall more slender, with petiole shorter, head relatively slightly broader, apical tooth of mandibles sharper East Africa - textor
3 Colour red-brown, brown-rust to darker, mandibles brown, scape concolourous Congo Basin - rufescens
-- Ferruginous red slightly darker than type, gaster more brown; mandibles yellow-rust and much clearer than rest of head, as are the appendages Ivory Coast - claridens
4 At least the alitrunk and mandibles black 5
-- Body rather uniformly brown; with duller appearance due to microreticulation of entire surface; dense covering of fine pubescence, most notably on the gaster, giving a silky appearance
 Congo Basin - annectens
5 Head dull red, gaster often brownish; appendages unicolourous except for apex of funiculus Congo Basin - rubriceps
-- Head and gaster black or dark brown; tibiae, tarsi and most of funiculus yellow Congo Basin & West Africa - fusca
Feature longinoda-group fusca-group textor
General Note: Apparently purely dimorphic
Pronotum with humped profile, mesonotum raised behind promesonotal suture
Evidentially more than one species - annectens, claridens, longinoda & rufescens		 Apparently trimorphic or polymorphic (with a range of media worker sizes)
Pronotum with humped profile, mesonotum raised behind promesonotal suture
lateral edge of pronotum with a distinctive out-turned or flanged edge - absent in the other groups
Two species - fusca & rubriceps		 Major only seen; smaller than others
Pronotum with smoother more convex profile, mesonotum not raised behind promesonotal suture
One species - textor
Colouration: Variably ferruginous but generally uniform Darker orange-brown Dusky yellow but with blotchy pattern
Major
Clypeus and frontal notch:
 {short description of image}
frontal "triangle" polygonal with narrower apex than base; clypeus with paler flanged anterior margin, margin with fringe of short hairs		 {short description of image}
frontal "triangle" triangular with little or no truncation of the apex; clypeus without paler flanged anterior margin but with median group of yellow longish hairs, clypeus also with distinctive pale median area		 {short description of image}
frontal "triangle" polygonal with narrower apex than base; clypeus with homocolorous flanged anterior margin, margin with fringe of short hairs, medially longest
Mandible:
 {short description of image}
appearance matt without striations, apical tooth relatively narrow, subordinate teeth broad based; with a line of longish hairs along masticatory border		 {short description of image}
appearance coarse with distinct striation, apical tooth broader, subordinate teeth sharper with a much greater differential between large and small teeth; with a line of longish hairs along masticatory border		 {short description of image}
note this is a mirror image for comparison - in both specimens seen the left mandible crosses above the right mandible (see details below); almost smooth; apical tooth long & narrow; subordinate teeth quite large but broad based; without longish hairs along masticatory border
Lateral profile of head:
 {short description of image}
posterior lateral angle shallowly rounded; underside only very shallowly convex, head depth/head length = 0.70
eye length 0.293 of HW		 {short description of image}
posterior lateral angle produced and much more distinctly angled; underside pronouncedly convex, head depth/head length = 0.78
eye length 0.223 of HW		 {short description of image}
posterior lateral angle produced and much more distinctly angled; underside almost flat, head depth/head length = 0.73
eye length 0.329 of HW
Ventral view of head:
 {short description of image}
finely sculptured, mandibles with a stout basal portion		 {short description of image}
coarsely sculptured, mandibles with relatively slender bases		 {short description of image}
unsculptured, mandibles with a short stout basal portion
Antennae:
 {short description of image}
scape slender, with shallow curve in basal half and relatively small degree of apical thickening, funiculus unicolorous with proportionately longer first segment, second segment shorter than third 		{short description of image}
scape stouter, with distinct curve in basal half and pronounced apical thickening, funiculus lighter than scape at least in apical half and with proportionately shorter first segment, second and third segments equisized		 {short description of image}
scape stouter, with weak curve in basal half and pronounced apical thickening, funiculus colour similar to scape and with proportionately shorter first segment, second and third segments equisized; scape with coarser decumbent pubescence
Surface texture of head {short description of image}
The claridens head surface has distinct but scattered shallow pits, whereas the type form (assumed) has no sculpturation other than the fine micro-reticulation
 {short description of image} {short description of image}
Petiole:
 {short description of image}
in dorsal view with anterior width about half maximum width, spiracles distinctly raised, median groove reduced anteriorly; in profile with more pronounced convexity		 {short description of image}
in dorsal view with anterior width more than half maximum width, spiracles barely raised, median grooved distinct for whole length; in profile with more pronounced convexity		 {short description of image}
in dorsal view with anterior width half maximum width, spiracles distinctly raised, median grooved distinct for whole length, posteriorly alomost bilobed; in profile with most pronounced convexity
Minima
Full face view:
 {short description of image}
finely sculptured, without obvious median longitudinal line on clypeus, occiput shallowly concave		 {short description of image}
coarsely sculptured, with distinct median longitudinal line, occiput with raised median area		 not seen
Lateral profile of head:
 {short description of image}
posterior lateral angle shallowly rounded; underside near flat, head depth/head length = 0.60		 {short description of image}
posterior lateral angle produced and much more distinctly angled; underside more obviously convex, head depth/head length = 0.70
Petiole:
 {short description of image}
in profile rounded with relatively shallow ventral convexity, with no significant median longitudinal groove		 {short description of image}
in profile with angular transition from anterior to posterior faces, the latter near flat, highly convex ventrally, node divided into distinct lobes
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© 2007, 2008, 2010, 2012, 2014 - Brian Taylor CBiol FSB FRES
11, Grazingfield, Wilford, Nottingham, NG11 7FN, U.K.

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