Anochetus ghilianii

Brown, WL Jr.,, 1978, Contributions toward a reclassification of the Formicidae. Part VI. Ponerinae, tribe Ponerini, subtribe Odontomachiti. Section B. Genus Anochetus and bibliography., Studia Entomologica 20, pp. 549-638 : 598-600

[26] A. ghilianii

, long known to collectors, is restricted to north and central Morocco and the Algeciras region of extreme southern Spain, but it belongs to a species complex that ranges widely in Africa, up until now mostly known under the names A. traegaordhi and A. gracilicornis (and A. angusticornis ). The available samples of this complex, mostly each consisting of one or a very few workers and a very few ergatoid and dealate queens, shown a bewildering range of variation in a number of traits, including body size, eye size, gracility of antennae, abundance and erectness of pilosity and pubescence, sculpture of vertex and pronotum, and size and shape of petiolar node. In fact, in the light of this variation, ghilianii itself appears to be just a local form of the complex with eyes (EL 0.16-0.22 mm) smaller than average (EL 0.20-0.35 in traegaordhi ) and antenna! funicular segments II-IV only about twice as long as broad (vs. 2.5 or more times as long as broad). Specimens approaching ghilianii in these respects are found in 3 nest series from Eritrea, especially in a sample from Agordat (G. Müller) that I had determined earlier as A. gracilicornis . For the time being, I am recognizing the slight differences between ghilianii and the trans-Saharan populations as still marking a species-level separation, but this separation is largely an arbitrary formality that future systematists may well not recognize.

Of the samples from south and east of the Sahara, some with pronotum transversely or concentrically rugulose or striate completely or in part, and with the petiolar node in side view slender and tapered to a rather narrow apex (fig. 47) agree best with the type of A. traegaardhi in NM-Vienna: Diani Beach, Kenya, N. L. H. Krauss; Balla Balla, S. Rhodesia, G. Arnold, 2 paratype workers of

A. angusticornis (BMNH-London); 11 miles S Maktau, 1000 m, Teita Prov., Kenya, E. S. Ross and R. E. Leech; Stanleyville, Zaire, F. Kohl, 1 worker determined as A. traegaardhi by Forel. Other African samples are more like syntypes of gracilicornis and its synonym sudanicus in MCZ: Isiolo, 1250 m, Kenya, 4 workers, E. S. Ross and R. E. Leech; Tafo, Ghana, 3 workers from rotten log,

B. Bolton. The Tafo specimens have rather narrow heads (Cl in one worker 84, MI 54, as compared with a ghilianii worker from Boulhaut, Morocco, R. and C. Koch, Cl 89, MI 54; a traegaardhi worker from Isiolo, Kenya, has Cl 88, MI 52) and rather small eyes (EL 0.20 mm in the Tafo worker measured, HL + ML = 2.24 mm), but are otherwise like the traegaordhi type. In these samples, the pronotum is at least partly smooth and shining, on the disc; petiole in side view thick, gently tapered to a blunt apex, with anterior slope convex. The thickening of the node reaches an extreme in 2 samples from NW Angola (fig. 49); these very large specimens are described below as A. angolensis n. sp. [27].

Because the traegaordhi and gracilicornis patterns grade into one another more and more completely as the pool of material grows, I consider them as a single species, and here place gracilicornis and sudanicus in the synonymy of traegaordhi . One series, from Agordat, Eritrea, has already been mentioned as gracilicornis approaching ghilianii , but an ergatoid (with 3 weak ocelli) pinned with workers in the lot, and presumably a nestmate, has the traegaordhi pronotal sculpture and nodal form.

Another set of 4 Ghanaian workers, 3 of them also from Tafo, apparently belong to the ghilianii group, but have divergent pronotal sculpture and nodal form (fig. 25) that seem to place them in the little-known species A. maynei [28].

Another set of scattered samples from: Salazar, Angola, Southern African Expedition, BMNH 1972, 1 worker; Kawanda, Uganda, N. A. Weber, 1 worker; Makokou, Gabon, W. H. Gotwald, 2 workers, is notable because of the development of rather large but bluntly rounded teeth or tubercles at the junction of the dorsum and declivity of the propodeum on each side. These individuals also tend to be rather smooth; the pronotum and pleura are shining, often with faint bluish reflections, and even the posterior propodeal dorsum has the transverse rugules somewhat reduced; the propodeal dorsum is also distinctly sulcate longitudinally. Only more material will tell,us whether such forms are part of the variation of A. traegaordhi , or whether they represent a related undescribed species.

Finally should be considered the status of A. rothschildi , a large (HL + ML = 2.60 mm) member of the ghilianii complex that is ferruginous tan in color and has the entire body smooth and shining, except for the short, fan-shaped area of striation between and just behind the frontal carinae. This species, from Ethiopia and Somalia, is much like traegaordhi , and could be an extreme variant of that species.