Nesomyrmex innocens

This species is only known from very few specimens, collected from the D.R. Congo and Kenya. Based on the limited data available, N. innocens nests in the stem of trees. (Hita Garcia et al. 2017)

Identification
Hita Garcia et al. (2017) - A member of the angulatus species-group. The following character combination distinguishes N. innocens from the other members of the group: eyes with 7–9 ommatidia in longest row; in profile mesosomal dorsum with conspicuously impressed metanotal groove; propodeal spines short and thick, elongate-triangular and only weakly longer than their basal width; in profile petiolar node nodiform, appearing approximately as long as high; in dorsal view petiolar node laterally denticulate; subpetiolar process without a long cuticular flange running back to the postpetiolar junction; dorsum of propodeum with standing hairs; first gastral tergite with standing hairs evenly distributed throughout.

Nesomyrmex denticulatus, Nesomyrmex innocens and Nesomyrmex stramineus are morphologically similar. Nesomyrmex innocens and N. stramineus differ from N. denticulatus by generally smaller body size, smaller eyes with less ommatidia, and a subpetiolar process without a long cuticular flange running back to the postpetiolar junction. The separation of N. innocens and N. stramineus is a bit more difficult, as already mentioned by Bolton (1982). Nesomyrmex innocens has shorter and thicker propodeal spines and a lower and thicker petiolar node compared to N. stramineus. Their status as separate species is questionable, as Bolton (1982) also noted, but the current scarcity of material does not allow for further evaluation at this time.

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

Nomenclature

 *  innocens. Tetramorium (Leptothorax?) innocens Forel, 1913b: 317 (w.) DEMOCRATIC REPUBLIC OF CONGO. Combination in Leptothorax: Forel, 1916: 425; in Nesomyrmex: Bolton, 2003: 272. See also: Bolton, 1982: 330.

Worker
Bolton (1982) - TL 2.3-2.5, HL 0.60-0.62, HW 0.49-0.50, CI 81-82, SL 0.34-0.35, SI 69-70, PW 0.35-0.36, AL 0.66-0.68 (2 measured).

Mandibles extremely finely and delicately superficially shagreened, almost smooth. Median portion of clypeus with anterior margin evenly arcuate-convex, with a narrow cuticular apron. Median clypeal carina vestigial to absent. Frontal carinae and antennal scrobes absent, the scapes short. Maximum diameter of eye 0.12-0.13, about 0.24-0.26 x HW and with 7-8 ommatidia in the longest row. With the head in full-face view the sides narrower in front of the eyes than behind and somewhat convergent anteriorly. Behind the eyes the sides very slightly convex and rounding into the occipital corners, the occipital margin itself very feebly impressed medially to almost straight. With the alitrunk in profile the promesonotum shallowly convex, the metanotal groove impressed and the propodeum convex, more strongly so than the promesonotum. Propodeal spines broadly triangular and stout, about as long as their basal width. Propodeal declivity concave between the spines and the rounded low metapleural lobes. In dorsal view the alitrunk with the pronotal shoulders obtusely and bluntly rounded, the promesonotum narrowing to the metanotal groove. Behind this the sides of the propodeum diverge to about the level of the spiracle, pass through an obtuse angle and then converge again to the bases of the spines. Petiole in dorsal view with a tubercle at either side of the node and the posterior margin of the node with a much smaller and inconspicuous pair of tubercles. Petiole in profile with a short anterior peduncle which has a small triangular process ventrally. Dorsal surfaces of head, alitrunk, petiole and postpetiole finely densely sharply reticulate-punctate, the promesonotum and head also with traces of fine rugular sculpture. First gastral tergite basally with very delicate superficial shagreening. All dorsal surfaces of head and body with numerous very short blunt hairs; legs and scapes without standing hairs. Colour uniform yellow.

References based on Global Ant Biodiversity Informatics

 * Forel A. 1913. Formicides du Congo Belge récoltés par MM. Bequaert, Luja, etc. Revue Zoologique Africaine (Brussels). 2: 306-351.
 * 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.