Euconnus (Tetramelus) melkei sp. n. is described, based on a male specimen collected in the Eastern Cape province of the Republic of South Africa. This species is characterized by the most elaborate and extensive male sexual dimorphic features known in Euconnus, comprising glandular projections and impressions that cover most of the head dorsum, strongly modified scapes, long projections on protrochanters, and thickened profemora with glandular porous and setal patches. The most similar species, Euconnus nasicornis Franz and E. paranasicornis Franz, previously treated as incertae sedis within Euconnus, are placed in Tetramelus. The E. nasicornis species group of Tetramelus that includes the abovementioned species is defined by an extremely elongate adult body, multiple dimorphic features in males, and a pair of lateral longitudinal sulci on the pronotum. The current state of knowledge of South African Euconnus is discussed, and a checklist of the currently known 159 nominal species that inhabit RSA is given.