Nesomyrmex angulatus (Mayr)
Type location Egypt (Leptothorax
angulatus n. sp., Mayr, 1862: 739, worker) from Sinai
Peninsula, by R v
Frauenfeld - see below
subspecies lybica (Leptothorax
var. lybica n. var., Menozzi,
1934: 155, worker)
from Libya, Cufra - no images on Antweb (December 2018).
junior synonym ilgii (Leptothorax
angulatus Mayr, r. Ilgii,
n. stirps, Forel, 1894b: 82,
worker; Santschi, 1912c: 148, queen) from Ethiopia,
Sudabessinien, Ilg; see Bolton
(1982: 324, illustrated; Bolton, 1995) - see below
genus name change by Bolton
(2003: 249) .
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
On the ilgi queen, Santschi
(1912c0, wrote: Leptothorax angulatus
Mayr stirps ilgi
For., queen undescribed, TL 3.8 mm, alitrunk much darker than that of
the worker; scutellum sculptured as the rest of the alitrunk, the
propodeal spines and rest as the worker.
For the following reasons, I prefer to revert to the
original status determined by Mayr and revert Nesomyrmex
latinodis to full species status, with probable junior synonym concolor
(Santschi, 1914b: 107, illustrated, worker; Emery, 1915g: 16, queen
& male) from Kenya.
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 the Antweb images of a cotype from Tunisia and the
type of ilgii, together with
the fresh specimens from Egypt (Bolton does not report
sighting any specimens other than the lectotype), Sudan and Senegal,
the Mike Lush
photomontage (below) of a coastal scrub specimens from Gambia,
I show below the
type form. These can be contrasted with most sub-Saharan specimens, as
by me from life in Nigeria and the photomontage of specimens from
Tanzania - on Nesomyrmex
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
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.
Santschi noted that Forel's ilgii (1894b) was
consistently darker than the type form; ilgii seems from
Forel's (1894b) description to have the same shape of head, etc., as
the type angulatus.
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.