Family Bovidae

The Bovidae (9 suborders; 45 generals; 143 species) are the most diverse group of Ruminantia and began its evolution in Africa around 19 million years ago, then rapidly diversified with 78 genera known from the Miocene. The greatest diversities of bovids occur in Africa. And the maximum concentration of species is in the savannas of eastern Africa. Other bovid species also occur in Europe, Asia, and North America.

The bovids show great variation in size (~ 2-1200 kg) and pelage colouration (ranging from a pale white to black). They have 3 feeding classes (browsers, intermediate feeders, and grazers) and include numerous domesticated animals, namely sheep, goats, water buffalo, yak, zebu, gayal and Bali cattle, which provide human leather, meat, and wool.

One of the defining characteristics of this family is the presence of unbranched horns. Horns are present in males of all bovid species and in females of some genera (most frequently in large species where adult females weigh over 40 kg). When horns are present in both sexes, those of males are always thicker at the base and more complex. The horns are permanently attached to the frontal bones of the skull, and are composed of a bone core covered with a keratin sheath (which is never shed). An air space separates these two layers, with the result that bovids are often called "hollow-horned ungulates". Tetracerus is unique among wild bovids in that males regularly bear four horns (two pairs); all other genera (with the exception of some domestic sheep) have only one pair. The upper canines are always absent. A single lacrimal canal is usually present in the orbits of the skull.

Using fossil calibrations, we estimated the emergence of Bovidae at ~21 Mya. Our results support Moschidae is the sister group of Bovidae.

References  

1. Hackmann T J, Spain J N. Invited review: ruminant ecology and evolution: perspectives useful to ruminant livestock research and production.[J]. Journal of Dairy Science, 2010, 93(4):1320-1334.
2. Hernández F M, Vrba E S. A complete estimate of the phylogenetic relationships in Ruminantia: a dated species-level supertree of the extant ruminants[M]. 2005.
3. Hofmann R R. Evolutionary steps of ecophysiological adaptation and diversification of ruminants: a comparative view of their digestive system[J]. Oecologia, 1989, 78(4):443-457.
4. Davis E B, Brakora K A, Lee A H. Evolution of ruminant headgear: a review[J]. Proceedings Biological Sciences, 2011, 278(1720):2857-2865.
5. http://www.ultimateungulate.com/ungulates.html
6. https://en.wikipedia.org/wiki/Bovidae

The Bovidae Family Tree