Nesomyrmex evelynae

Prefers rain forests where it lives in the canopy stratum. Based on canopy fogging samples from Kenya available to the first author, it appears that this species is found commonly on trees, even though in small individual numbers, suggesting smaller colony sizes. (Hita Garcia et al. 2017)

Identification
A member of the angulatus species-group.

Hita Garcia et al. (2017) - The following character combination distinguishes N. evelynae from the other species of the group: in profile mesosomal dorsum with conspicuously impressed metanotal groove; petiolar peduncle long; dorsum of propodeum without standing hairs; first gastral tergite lacking standing hairs except for single transverse row on posterior end of tergite.

The recognition of this species within the Nesomyrmex angulatus group is fairly straightforward, it is the only species that lacks standing hairs on most of the first gastral tergite while all other group species have standing hairs evenly distributed throughout this tergite. It also lacks standing hairs on the propodeum, a character shared only with Nesomyrmex inhaca, whereas the other five species have short, standing pilosity on the propodeum.

Bolton (1982) - The characteristic distribution of the body hairs renders evelynae quickly recognizable among the African Leptothorax species. The lack of hairs on the propodeum and first gastral tergite is paralleled only in Nesomyrmex simoni and Nesomyrmex braunsi, but these are both much larger (HW > 0.85), darker coloured species with much more massively developed petiole nodes and shorter antennal scapes (SI < 85).

Distribution
Hita Garcia et al. (2017) - Nesomyrmex evelynae is found in Equatorial Africa ranging from Burkina Faso and Ghana in the west through the Central African Republic and the D.R. Congo to Uganda and Kenya in the east. The known distribution is disjunctive since N. evelynae is not known from the countries between Ghana and the Central African Republic and the D.R. Congo. We consider this more of a sampling artefact though, and expect the species to be collected from the countries in between in future sampling projects.

Distribution based on Regional Taxon Lists
Afrotropical Region: Burkina Faso, Central African Republic, Democratic Republic of Congo, Ghana, Kenya, Uganda.

Nomenclature

 *  evelynae. Leptothorax (Goniothorax) evelynae Forel, 1916: 423 (w.q.) DEMOCRATIC REPUBLIC OF CONGO. Combination in Nesomyrmex: Bolton, 2003: 272. See also: Bolton, 1982: 328.

Worker
Bolton (1982) - TL 2.5-2.9, HL 0.58--0.70, HW 0.47-0.54, CI 77-81, SL 0.44-0.52, SI 92-98, PW 0.35-0.44, AL 0.65--0.82 (7 measured).

Mandibles finely shagreened. Median clypeal lobe evenly arched-convex. Median clypeal carina present but fine, incomplete in a few specimens. Frontal carinae and antennal scrobes absent. Antennal scapes relatively long, SI > 90. Maximum diameter of eye 0.12-0.16, about 0.26-0.29 x HW and with 7-8 ommatidia in the longest row. With the alitrunk in profile the metanotal groove shallowly but conspicuously impressed, the promesonotum evenly shallowly convex and the propodeal dorsum almost flat to shallowly convex. Propodeal spines straight, distinctly longer than their basal width. Metapleural lobes low and rounded. In dorsal view the alitrunk with the pronotal corners angulate and the sides of the promesonotum bluntly marginate. The dorsal surface gradually narrows from front to back but the sides of the mesonotum are slightly convex and the sides of the propodeum diverge from the metanotal groove to the level of the spiracle and then converge to the bases of the spines. Petiole in profile with a high narrow node which is not equipped with denticles. Ventral process of peduncle a simple small tooth, anteriorly situated. In dorsal view the petiole node broader than long. Dorsum of head with fine superficial reticulate-punctate ground-sculpture which is overlaid by a very fine narrow reticulate-rugulose net everywhere except in the area immediately behind the frontal lobes. Dorsal alitrunk with superficial punctulate ground-sculpture overlaid by fine rugulae. In specimens from Zaire this rugular sculpture is faint and weakly developed, forming a reticulum only on the anterior pronotum, but in material from Ghana the rugulae are more strongly developed everywhere and reticular meshes are frequent. Petiole and postpetiole finely punctulate or granular dorsally, sometimes with one or two fine rugulae. Base of first gastral tergite very lightly shagreened or with a superficial reticular pattern. Dorsum of head with scattered short stout blunt hairs. Similar hairs are present on the pronotum (several pairs), mesonotum (1-3 pairs), petiole and postpetiole (1-2 pairs each) but are absent from the propodeum and absent from the first gastral tergite except for a transverse row at the extreme apex. Gastral segments behind the first also with a transverse apical row each. Colour yellow.

References based on Global Ant Biodiversity Informatics

 * 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.