P. nigeriensis group:

Very small species (minor worker HW: 0.41–0.56 mm, n=60), with short scapes and legs (SI: 90–114, FI: 95–122). Minor workers: posterior head margin straight to weakly concave and eyes small with a maximum of six ommatidia in the longest row. Promesonotal dome well-rounded to slightly angulate in profile view, propodeum, spines and postpetiole relatively short. Postpetiole not higher than petiolar node and without ventral process. Major worker: head longer than wide, very large compared to the rest of the body, anteriorly weakly longitudinally rugulose. Upper half of head mostly smooth (similar to megacephala group), inner hypstomal teeth well-developed to relatively large. Mesosoma, petiole and postpetiole similar to minor workers. The group contains Pheidole nigeriensis Santschi and several morphospecies collected from different localities.