The living buffaloes of Africa are all species of Syncerus, whose earliest fossils have been found in Omo in Ethiopia where they lived some 2,5 million years ago. The early species may have lived in mountainous terrain but later moved onto the plains of East Africa before moving westward and southward. The climate of Africa showed huge monsoonal changes from 2,6 million to 11 700 years ago, which were driven by variations in the orbit of the Earth and caused consequent vegetational changes. These vegetation changes were the drivers of the expansion and contraction of the early buffalo populations, and have influenced their shape and size.

Detailed genetic and morphometric analyses of the living buffaloes over the entire Africa indicate a genetic split between a South-East and a West-Central evolutionary lineage, which happened some 449 000 to 145 000 years ago in the region of the current Democratic Republic of the Congo. The region around Uganda seems to have played a prominent role throughout the history of the South-East lineage consisting of the Cape buffalo Syncerus caffer, while Chad, Cameroon and the Democratic Republic of the Congo played a prominent role in the West-Central lineage consisting of the Lake Chad buffalo Syncerus brachyceros, the Virunga buffalo Syncerus mathewsi and the red, or forest buffalo, Syncerus nanus.
Morphologically, the buffaloes show a gradual, continuous change from the central African rainforest through West Africa and the Sudan to the eastern and southern African savannas. Based on their mitochondrial DNA D-loop sequences, the African buffaloes fall into two distinct groups (clades), with each group containing all the evolutionary descendants of a common ancestor.
The first group consists entirely of the buffaloes from Eastern and Southern Africa, and the second one mainly consists of the forest buffaloes from Cameroon, Gabon and Angola, and two species from Uganda. Because of the climate and vegetation changes over a long time, the Cape buffalo expanded as well as contracted its range, migrating rapidly from the north to the south and back again and genetically swamping the forest buffaloes north of the Lowland forest belt of Africa.
There are no genetic differences between the Cape buffaloes of Southern and Eastern Africa, including the western Rift Valley. Although the buffaloes from South Africa have a somewhat greater mean curved horn length and a smaller span, these differences are extremely small when measured over its entire distribution. All the individuals from Chad, Sudan and Northern Nigeria are genetically similar and represent Syncerus brachyceros. This species includes what is called the Nile buffalo, which was originally described scientifically as Syncerus aequinoctialis by Blyth in 1866, but is no longer a valid species or even subspecies.
Continual, variable environmental conditions have lead to morphological adaptations to create ecological buffalo variants that have no genetic base, such as the unique shape and size of the horns of the savanna buffaloes in East Africa and the physical appearance of the Nile buffalo.
In the so-called Nile buffalo, the shoulder height is around 1,2 m and a bull weighs around 600 kg. The coat colour is fawn to dark brown, usually slightly reddish but never quite black, and the ears are longer, hang below the base of the skull and are poorly fringed. The horns spread wide laterally but are much less curved than in the Cape buffalo, and the bases of the horns are greatly expanded and nearly meet in the midline of the forehead, but do not form a boss. It occurs in Ethiopia and Sudan westwards through the savanna belt to Senegal and in Central Africa north of the Shari River. In East Africa it is the common type of buffalo for most of Uganda along the Nile River to Lake Victoria, and along the eastern side of the Great Lakes at least as far as the Kazinga Channel in Uganda. ASM

Groves, C & P Grubb 2011. Ungulate taxonomy. Baltimore, Maryland: Johns Hopkins University Press, pages 119 – 124.
Smitz, N, C Berthouly, D Cornélis, R Heller, P van der Hooft, P Chardonnet, A Caron, H Prins, B Janse van Vuuren, H de Jongh & J Michaux 2013. Pan-African genetic structure in the African buffalo (Syncerus caffer): Investigating intraspecific divergence. PLoS One 8(2): e56235.