The ant genus Tetramorium Mayr in the Afrotropical region (Hymenoptera, Formicidae, Myrmicinae): synonymisation of Decamorium Forel under Tetramorium, and taxonomic revision of the T. decem species group

In this study we synonymise the genus Decamorium Forel under Tetramorium Mayr, revise the new T. decem species group by providing a diagnosis of the group, an illustrated identification key to species level, and worker-based species descriptions for all five species, which include diagnoses, discussions, images, and distribution maps. The following species are revised in this study: T. decem Forel, comb. r., T. raptor sp. n., T. uelense Santschi, comb. r., T. ultor Forel, comb. r., stat. r. & stat. n., and T. venator sp. n. In addition, we also designate lectotypes for T. decem, T. uelense, and T. ultor.