A 2001 phylogenetic study divided Cephalophus into three distinct lineages: the giant duikers, east African red duikers and west African red duikers. However, the status of two species, the zebra duiker and the Aders' duiker, remained dubious. In 2012, Anne R. Johnston (of the University of Orleans) and colleagues constructed a cladogram of the subfamily Cephalophinae (duiker) based on mitochondrial analysis. They showed that within the "giant duiker" group, the bay duiker formed a clade with Jentink's duiker, and the zebra duiker is sister to this clade. Similarly, Abbott's duiker and yellow-backed duiker form a clade sister to Sylvicapra. The bay duiker and Jentink's duiker probably evolved during the Pleistocene, less than 2.5 million years ago.
