I do not believe there is an African antelope with a name that begins with "top." You might be thinking of Topkapi, an ancient palace in Turkey. Also, there is a movie title "Topkapi."
Addax is an antelope species in Africa. It begins with the letter a.
the pronghorn antelope
Eland is an antelope species in Africa. It begins with the letter E.
Maxwell's Duiker is an antelope in Africa. It begins with the letter m.
Addax is an antelope species in Africa.
Impala
Topi is an antelope species in Africa.
Topi or Tsessebe Tibetan antelope
Waterbuck is an antelope species in Africa.
Topi
Gemsbok
oribi