Nesomyrmex grisoni

Very little information about the natural history of this species is available. It seems to live on vegetation in rain forest habitats. (Hita Garcia et al. 2017)

Identification
A member of the angulatus species-group.

Hita Garcia et al. (2017) - The following character combination distinguishes N. grisoni from the other species of the group: in profile mesosomal dorsum forming a single, uninterrupted flat surface without any trace of metanotal groove; petiolar peduncle short; body colour dark brown to black.

Nesomyrmex grisoni and Nesomyrmex angulatus are straightforwardly distinguishable from the remainder of the group. At the same time they are morphologically very close to each other and only separable on the basis of body colour. For a more in-depth discussion we refer to the species account of N. angulatus.

Distribution
Hita Garcia et al. (2017) - Nesomyrmex grisoni is only known from the Central African Republic, the D.R. Congo and Ghana.

Distribution based on Regional Taxon Lists
Afrotropical Region: Central African Republic, 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.

References based on Global Ant Biodiversity Informatics

 * Bolton B. 1982. Afrotropical species of the myrmicine ant genera Cardiocondyla, Leptothorax, Melissotarsus, Messor and Cataulacus (Formicidae). Bulletin of the British Museum (Natural History). Entomology 45: 307-370.
 * Hita Garcia F., Mbanyana N., Audisio T. L., and G. D. Alpert. 2017. Taxonomy of the ant genus Nesomyrmex Wheeler (Formicidae, Myrmicinae) in the Afrotropical region, with a review of current species groups and description of a new species of the N. angulatus group from Mozambique. European Journal of Taxonomy 258: 1–31.