Aenictus, (Mayr, 1879)

Gómez, Kiko, 2022, A revision of the Afrotropical species of the Dorylinae ant genus Aenictus (Hymenoptera: Formicidae) based on the worker caste, Belgian Journal of Entomology 124, pp. 1-86 : 19

decolor species group

DIAGNOSIS. The mandibles in this group are massive and conspicuously different from the rest of the species in the genus worldwide with its basal half modified with a blunt, large proximal tooth clearly separated from the rest of the mandible by a constriction rendering the mandible mitten-shaped.

Other characteristics are mandibles closing against the clypeus armed with a big sharp apical tooth followed by a smaller preapical tooth. In some workers mandibles are highly eroded and the apical, the preapical or both teeth are not clearly distinguishable, blunt and sometimes damaged or broken. Head quadrate (CI~95-100) with relatively long scapes (SIL~75–100). Ventrolateral carinae developed, extending ventrally to its medial line.

Clypeus reduced a rectangular lamella with two small blunt triangular denticles between the antennal sockets, protruding from the middle of the anterior border between the frontal ridges. Sometimes teeth eroded. Frontal ridges present and not fused, laterobasally rounded into a low vertical triangle; parafrontal ridges present but weak, with a small apical tooth pointing upwards. Pronotum convex and propodeum flat in lateral view; transverse mesopleural groove and mesometapleural suture present but not deeply impressed. Propodeal declivity slightly convex, encircled by a well-developed ridge. Femora and tibiae with its apical half swollen. Head, pronotum, legs, scapes and gaster glassy smooth, remainder of mesosoma, petiole and postpetiole smooth to reticulated, always smoother dorsally; mesopleurae and lateropropodeum horizontally rugulose.

OVERVIEW. This group consists of three very similar species, with subquadrate heads (CI 95- 105) and identifiable via SIL index and subpetiolar process. A. villiersi has the longest scapes for the Afrotropical region (SIL~100) and a poorly developed subpetiolar process. A. bidentatus and A. decolor can be differentiated based on smaller size and relatively smaller scapes for A. bidentatus (HW: 0.62-0.70; SIL: 63-75) than for A. decolor (HW: 0.67-0.76, SIL: 85-89). This group seems to be closely related to the popeyei group, as they share similar habitus and dentition, but the basal half of the mandibles is highly specific.