Nesomyrmex angulatus (Mayr)

Type location Egypt (Leptothorax angulatus, Mayr, 1862: 739, worker; from Sinai Peninsula, by R v Frauenfeld); subspecies lybica (Menozzi, 1934: 155, worker) from Libya; junior synonyms concolor (Santschi, 1914b: 107, illustrated, worker; Emery, 1915g: 16, queen & male) from Kenya, and ilgii (Forel, 1894b: 82, worker; Santschi, 1912c: 148, queen) from Ethiopia; see Bolton (1982: 324, illustrated; Bolton, 1995); genus name change by Bolton (2003: 249) .

For reasons set out below, I prefer to revert to the original status determined by Mayr and revert Nesomyrmex latinodis to full species status.

Mayr's (1862) description is at . Arnold (1916: 258) gave an illustrated translation; this is at . Forel's (1894b) description of ilgii is at . Mayr's (1895) description of latinodis is at Santschi's (1914b) description of concolor is at . Menozzi's (1934) description of lybica is at . Bolton's modern description (1982) is at

In his 1982 paper and his other revisionary works, Bolton adopted a curious approach to his analyses. There are instances where, when dealing with what he decided to describe as new species, relatively small characteristics were deemed significant. When dealing with the work of the early authors, notably Forel and Santschi, he commonly adopted the obverse tactic and wrote of variations in colour, size and morphology as not justifying separation of forms (subspecies, varieties, strips, etc) and made sometimes substantial synonymization of such forms.

In the instance of N. angulatus he took all specimens he examined from sub-Saharan Africa as meeting the characters of the type form from Egypt (noting that he had examined a lectotype worker from the original collection, Mayr, 1862). It seems curious that Bolton, who had not been able to sight latinodis should have ignored the simple fact that it was Mayr, an obviously very accurate and cautious worker, who described both species.

With fresh specimens from Egypt (Bolton does not report sighting any specimens other than the lectotype) and the Antweb specimen of a cotype from Tunisia, I show below how the type form contrasts markedly with sub-Saharan specimens, as drawn by me from life in Nigeria and the photomontage of specimens from Tanzania.

1. In full face view, the North African specimens have heads which narrow from occiput to anterior and very much so anterior to the eyes (however, not to the extent shown in Bolton's drawing). The sub-Saharan specimens have heads which are near parallel throughout their length.
2. The sculpturation of the head and ailtrunk is much less prominent in the North African specimens.
3. The petiole of the North African specimens is noticeably shorter and more rounded in both lateral and dorsal views; and, does not have very distinct sharp anterior and dorsal margins.
4.The postpetiole of the North African specimens is only slightly wider than the petiole and has no more than weak sculpturation; whereas the postpetiole of the Tanzanian specimens can be seen to be some 50% wider than the petiole, more angular and to have strong sculpturation.
5. The erect pilosity on the North African specimens is quite fine; whereas it is much coarser on the sub-Saharan specimens.

My conclusion is that, if viewing the specimens without prior knowledge, it seems a strong likelihood that the North African and sub-Saharan populations compose at least two distinct species. Despite the wide distribution of "Nesomyrmex angulatus" specimens are not common and a firmer decision is unwise at present.

North African - type location populations

The photomontage is collated from http://www.antweb.org/specimen.do?name=casent0101794 - a cotype from Tunisia.

The photomontage is of a specimen from Egypt, Talkha (El-Mansoura), 13.vii.2003, collected by Mostafa Sharaf. Other images can be seen in the folder at -

Collingwood (1985) reporting it from Saudi Arabia (with a relatively poor sketch), noted it as extending northward to the Middle East; it was found mostly in old dead wood of Acacia.

East African populations

Here there does seem to be an overlap in forms as Santschi's concolor (1914b) from Kenya seems more like the North African forms. However, the N. latinodis specimens shown from Tanzania are similar to those I drew in Nigeria. Santschi noted that Forel's ilgii (1894b) was consistently darker than the type form.