Aenictus guineensis

Identification
Its sparse, erect, long setae, the presence of a developed subpetiolar process and the lack of a developed propodeal ridge separates this species from the rest of the species present in the rotundatus complex, except for Aenictus ugaduwensis and Aenictus rotundatus, and separation is feasible only via index analysis. It is more slender and presents more rectangular heads than Aenictus ugaduwensis (details under that species).

Aenictus guineensis is the western counterpart of the Southern and Eastern African A. rotundatus, and separating individuals can be difficult, especially with small, isolated individuals.

There are some characteristics that may separate series of workers, but it’s a matter of comparison and very variable among individuals. Some of these for A. guineensis are a more developed propodeal ridge (but as a thin line at most in larger individuals), smoother mandibles (which can become shagreened in the most sculpted A. rotundatus), more rectangular rounded subpetiolar process (against more shark-finned), slightly longer scapes and relatively more elongated petiole.

Distribution based on Regional Taxon Lists
Afrotropical Region: Guinea, Guinea-Bissau, Ivory Coast, Kenya, Nigeria, Senegal.

Castes
Known only from the worker caste.

Nomenclature

 * . Aenictus rotundatus st. guineensis Santschi, 1924b: 204, fig. 7b, 7b’ (w.) GUINEA.
 * Type-material: 2 syntype workers.
 * Type-locality: Guinea (“Guinée française”): Kakulima (F. Silvestri).
 * Type-depository: NHMB.
 * Subspecies of rotundatus: Bolton, 1995b: 59; Hita Garcia, et al. 2013: 201.
 * Status as species: Taylor et al., 2018: 10; Gomez, 2022: 61.
 * Distribution: Guinea.

Type Material

 * Syntype, GUINEA: Kakulima (Silvestri) (1w) [CASENT0911438] NHMB [Examined by Gomez, 2022]; Syntype, same data (1w, beheaded) NHMB [Examined by Gomez, 2022]. The type material [CASENT0911438] presents two labels, as A. rotundatus v. guineensis and as A. guineensis.

Taxonomic Notes
Taylor et al. (2018): Type worker CASENT0911438, as Aenictus rotundatus Mayr stirps guineensis n.st., Santschi, 1924; type location Guinea. Additional prior record from Nigeria (Taylor, 1980, as Aenictus sp. 1). This species is some 75-80% of the size of the Eastern Africa species Aenictus rotundatus and has a notably more rectangular head and a flatter profile to the petiole among other differences. New record from Benin: J.-F. VAYSSIÈRES, Korobourou, RVA 3015, 9.xi.2012, M. indica orchard, Quadrat 1, série 1, variété Gouverneur, ground nesting, n = 2.