Recent genetic and morphological studies strongly suggest that the Bushbuck is actually two separate species: the larger southern and eastern taxon has been called Imbabala (Tragelaphus sylvaticus) whilst the smaller striped mainly western taxon has been called Kéwel (Tragelaphus scriptus).
Apparently they are sympatric in parts of Southern Sudan, Ethioipia, Northern Angola and part of the DRC where they do not interbreed.

Strangely genetic research reveals that Kéwel is actually most closely related to Nyala whilst Imbabala have a closer affinity to Bongo and Sitatunga than to each other!