The horned ungulates (Bovidae) are represented by the oxen (Bovini) and the spiral-horned bovines (Tragelaphini). The spiral-horned bovines are medium- to large-sized animals with a deep body and a narrow head, as described in The Kingdon Field Guide to African Mammals (1997).
EVOLUTIONARY HISTORY
I find the development of the spiral-horned bovines from earlier, more ancient forms most intriguing. Today, geologists and palaeontologists are using modern science to unravel the earth’s history in a way similar to forensic scientists investigating a crime scene. For example, in a recent study on the molecular evolution of the spiral-horned antelopes, Sandi Willows-Munro (MSc thesis, 2003, University of Stellenbosch) shows that the evolutionary history of the African tribe Tragelaphini is in fact more complicated than initial studies indicated. In her study, nuclear DNA sequence data shows that the evolutionary path of the early members of Tragelaphini separated from the other bovids during the mid-Miocene approximately 15,7 million years ago.
Fossil research has shown that the common nyala and lesser kudu represent the most basal (original) species that separated from the other tragelaphids approximately 7,1 million years ago. This was followed by the separation of two groups of species: The first group adapted to a more tropical environment (now Central Africa) and included the mountain nyala, bongo, sitatunga and bush-buck. The second group adapted to a more arid environment (Southern Africa) and consisted
