Nesomyrmex grisoni

Identification
The yellow angulatus is known from most of the continent from Ethiopia and Sudan to South Africa and Botswana, but the dark grisoni has only been found in Ghana and Zaire. angulatus also occurs in Ghana in the same areas where grisoni has been discovered, but even here the two maintain their distinctive colours, no intermediates being known. (Bolton 1982)

Distribution based on Regional Taxon Lists
Afrotropical Region: Democratic Republic of Congo, Ghana.

Nomenclature

 *  grisoni. Leptothorax (Goniothorax) grisoni Forel, 1916: 425 (w.q.) DEMOCRATIC REPUBLIC OF CONGO. Combination in Nesomyrmex: Bolton, 2003: 272. See also: Bolton, 1982: 329.

Worker
Bolton (1982) - TL 2.9-3.4, HL 0.76-0.86, HW 0.60-0.66, CI 77-81, SL 0.56-0.63, SI 94-98, PW 0.46-0.53, AL 0.85-1.02 (9 measured).

Answering to the description of Nesomyrmex angulatus, differing only in colour and intensity of sculpture. In grisoni the full adult colour is uniform blackish brown to black, as opposed to the uniform yellow found in angulatus. The dorsum of the head and alitrunk in grisoni is blanketed by a dense reticulate-punctate ground-sculpture which is overlaid by conspicuous fine rugulae which form a distinct reticulum on the alitrunk and on much of the head. Basically this sculpture is the same as that seen in angulatus, but here it is more intensely and sharply developed.