Systematics or PhylogeneticsRead full entry
Diversity of Living Bovidae
The family Bovidae (hollow-horned ruminants) is the largest and most diverse family in the mammal order Artiodactyla (even-toed ungulates). Bovids range in size from the 1.5 kg Royal Antelope (Neotragus pygmaeus) to the 1000 kg Common Eland (Taurotragus oryx) and Yak (Bos mutus). In most bovid species, females are hornless or have only small, fragile horns. Many of the more delicate-looking bovids are commonly known as "antelopes" (and some of the smaller antelopes are often known as "gazelles"). There are several bovids that are very familiar as domesticated animals, including cattle, buffaloes, sheep, and goats. Groves and Leslie (2011) provide an overview of the complex and tangled taxonomic history of Bovidae. With the availability of molecular phylogenetic data from DNA sequencing beginning in the 1990s, many aspects of bovid taxonomy and phylogeny have become clearer. A number of taxa formerly treated as single species are now recognized to include several distinct species. Groves and Leslie (2011) and Groves and Grubb (2011) recognize two subfamilies and 279 living bovid species:
Subfamily Bovinae. The subfamily Bovinae includes three tribes: Bovini, Boselaphini, and Tragelaphini. Members of this subfamily are medium to very large. Most are heavily built and adapted to living in heavy cover, often on soft (even swampy) terrain (only the American Bison [Bos bison] and Yak are found on open plains and in uplands).
Tribe Bovini (cattle and buffaloes). The 14 species in this tribe are placed in four genera: Bos, Bubalus, Syncerus, and Pseudoryx. A large wild species, the Aurochs (Bos primigenius) once ranged from Europe through southwestern Asia and North Africa. This species was domesticated (beginning, probably, in the Middle East or southwestern Europe), eventually yielding the domestic cattle we see today. As domestic cattle spread throughout the world, Aurochs were actively hunted by humans as competitors with domestic cattle and as dangerous game. The last known Aurochs was reportedly killed by a peasant in Poland in 1627. Efforts have been made to reconstruct cattle similar to the Aurochs through focused breeding efforts.
Humped cattle, often known as Zebu, are descended from a wild species closely related to the Aurochs, Bos namadicus, that lived in India but is now extinct. Zebu have a floppy hump on the shoulder and a long, narrow dewlap and are well adapted to hot, dry conditions found in South Asia and drier parts of Southeastern Asia. African cattle, known as Sanga or Zeboid cattle, have small conical humps placed farther forward than those in Zebu and are apparently derived from an ancient cross between Zebu and humpless cattle.
The wild cattle of South and Southeast Asia are the Gaur (Bos gaurus), Kouprey (B. sauveli), and Banteng (Bos javanicus). The Gaur is among the largest of the bovids. Gaur populations in the border region of India, Bangladesh, Bhutan, and Burma have been domesticated, producing a smaller, stockier, short-horned form known as the "Mithan". Bantengs have been domesticated in central Indonesia, yielding a small domestic form known as Bali Cattle. The Kouprey, which was discovered by scientists only in the 1930s and inhabited the dry forests of northern Cambodia and adjacent parts of Thailand, Laos, and Vietnam, is tall and relatively slender with very large horns (especially in males) and a long, hanging dewlap. No Koupreys have been seen in the last several decades and the species may be extinct. Some genetic evidence suggests that Koupreys and Bantengs interbred in the past.
The two species commonly known as "bison" are not essentially distinct from other Bos (cattle) species, although they are sometimes segregated into a different genus, Bison. The American Bison has two forms. The first, the Plains Bison (Bos bison bison) is adapted to open, treeless plains and at one time millions of individuals roamed the North American plains. This number was reduced to around a thousand individuals by the 1880s as a result of large-scale slaughter. Populations have recovered somewhat thanks to concerted conservation efforts beginning early in the 20th century, although due to interbreeding with domestic cattle, many of the American Bison with us today are of mixed ancestry. A second form of American Bison, the Wood Bison (Bos bison athabascae) lived in the woodlands of northern Alberta and Mackenzie, Canada, until the early 20th century. In 1925, a large number of Plains Bison were released into the Wood Buffalo National Park, resulting in extensive interbreeding between the two forms, and it is now not clear just how distinct the Plains and Wood Bison were. The second bison species, the Wisent ("European Bison", Bos bonasus) was formerly found throughout the woodlands of central Europe, but was extinct in the wild by 1919. A third species, the Caucasian Bison (Bos caucasicus), persisted in a remnant population in the wild on the northwestern slopes of the Caucasus until 1927. As a consequence of concerted conservation efforts, the extinction of the European Bison was averted. However, of several hundred individuals in captivity today, around half are of pure lowland stock and half are the descendants of a single Caucasian bull crossed with lowland Wisents (European Bison reintroduced to the wild in Poland are all of pure lowland origin). The Yak of the Tibetan Plateau, which is adapted to living in open plains and uplands, is essentially a shaggy, long-horned bison.
The buffaloes belong to two genera, Bubalus (Asian buffaloes) and Syncerus (African buffaloes). The Asian Wild Buffalo (Bubalus arnee) lineage gave rise to the two forms of domestic water buffalo, the "swamp buffalo" of Southeast Asia and the "river buffalo" of South Asia (and widely introduced elsewhere). Several dwarf Bubalus species have evolved on islands. Although Syncerus was long treated as including just a single geographically variable species, new data have led to the recognition of several distinct Syncerus species.
Tribe Boselaphini (Nilgai and Chowsingha). The 2 species in this tribe are both found in India. Although they share many anatomical characters, the Nilgai (Boselaphus tragocamelus) is around ten times the size of the Chowsingha (Tetracerus quadricornis). The male Chowsingha is the only wild mammal with four horns (the females lack horns altogether and in some populations males have only two horns). The Nilgai, Chowsingha, and Saolo are the only Bovinae with facial glands (located in front of the eyes).
Tribe Tragelaphini (bushbucks, kudus, and elands). The 24 species in this tribe are placed in five genera: Nyala (the Nyala [N. angasii]), Tragelaphus (Bongo [T. eurycerus], Gedemsa [T. buxtoni], 8 bushbuck species, 5 sitatungas), Ammelaphus (2 lesser kudu species), Strepsiceros (4 greater kudu species), and Taurotragus (2 eland species, the Giant Eland and Common Eland; the Giant Eland is named for its enormous horns and actually has a smaller body than the Common Eland; both sexes of elands have horns). Genetic and chromosomal studies have clarified a number of questions re. species boundaries and relationships within this tribe, but also suggest a complex ancient history of genetic introgression among some lineages. The horns of Tragelaphini are keeled, with the keel starting above the eye and following the spiral of the horn nearly to its tip. The elands are the tallest of the African antelopes, followed by the greater kudus; male greater kudus have the longest and most widely spiraled horns of all African antelopes.
Subfamily Antilopinae. The Subfamily Antilopinae includes nine tribes: Neotragini, Aepycerotini, Antilopini, Reduncini, Hippotragini, Alcelaphini, Caprini, Cephalophini, and Oreotragini. This subfamily includes species ranging from the smallest bovid to medium- and large-sized forms. Many species have brownish upperparts and lighter (often strikingly white) underparts, frequently with a dark band along the flanks separating the two zones. The face often has longitudinal dark and light stripes from the eye to the nostril, sometimes reduced to a white eye ring. The horns are transversely ringed, sometimes strongly so. There are nearly always prominent glands on the face, in front of the eyes, and in the feet (at least the forefeet). With the exception of mountain-dwelling species, members of the Antilopinae tend to be more lightly built than bovines and most live in relatively open country (the tribes Cephalophini and Neotragini being exceptions). Antilopine social structure usually involves territorial males and separate herds of females.
Tribe Neotragini (dwarf antelopes). Although other small antelopes used to be included in this tribe, it is now clear that only the 5 species in the genus Neotragus actually belong in th Neotragini. Neotragus includes the tiny Royal Antelope of West Africa, the Dwarf Antelope (N. batesi) of Central Africa, and the three suni species of East Africa. The horns of these antelopes (which are present only in males) are short and grow backward approximately in the plane of the forehead. Neotragus antelopes are the only African bovids other than Cephalophini (duikers), Forest Buffalo (Syncerus nanus), and Bongo that are associated with closed forest.
Tribe Aepycerotini. This tribe includes only the 2 species of impalas, the Black-faced Impala (Aepyceros petersi) and Common Impala (A. melampus). The very slender horns have strong transverse ridges and a single wide twist, with tips that turn upward. Impalas have inguinal glands but no facial glands, carpal glands, or foot glands. Impalas are found in eastern and southern Africa.
Tribe Antilopini (gazelles, dik-diks, and relatives). The 64 species in this tribe are placed in 13 genera: Raphicerus, Antidorcas, Ammodorcas, Litocranius, Saiga, Antilope, Nanger, Gazella, Eudorcas, Dorcatragus, Madoqua, Ourebia, and Procapra. Members of this tribe are all found in open grassland or dry woodlands. All Antilopini have a slender build and most have disruptive coloration, typically sandy toned or reddish or gray above and white below, with the upper and lower zones often separated by a dark band along the lower flanks. The buttocks are white, with this area demarcated by another dark stripe on either side. A white eye ring on the face often continues downward to the nostrils as a white stripe, flanked above by a dark stripe. Large preorbital glands are present. In most species in this tribe, only males have horns (however, in most of the species commonly known as gazelles, the females have small, slender horns). The horns in larger species have transverse ridges, at least on the front surface; in smaller species, the horns are more or less smooth. Five major clades are recognized within this tribe:
1) 4 spp. The genus Raphicerus includes the Steenbok (R. campestris) and 3 species of grysboks from southern and eastern Africa. These small antelopes, which have straight, slender, vertically oriented horns are found in brushland, high-grass country, and woodland.
2) 40 spp. This clade includes small and medium-sized antelopes of arid and semi-arid country: the springboks (Antidorcas, 3 species), gerenuks (Litocranius, 2 spp.), and the Dibatag (Ammodorcus clarkei) of Africa; the Blackbuck (Antilope cervicapra) of the South Asian plains, in which males are black and females are tawny; and the gazelles. All of these have facial glands, foot glands, and carpal glands, and most have inguinal glands. At one time, the Blackbuck was found throughout the open plains of India and Pakistan, but the population of at least a million in the 19th century has dropped to a few tens of thousands. The three genera known as gazelles (which are not actually a phylogenetically coherent group) are placed in the genera Gazella (21 species of small gazelles of desert country from the Sahara to the Gobi); Eudorcas (larger gazelles, including 3 species of red-fronted gazelles and 2 species of Thompson's gazelles from the Sahel and East African savanna); and Nanger (5 spp., including the large Grant's Gazelle [N. granti], Soemmerring's Gazelle [N. soemmerringii], and Dama Gazelle [N. dama]). The unusual-looking Saiga (Western Saiga [S. tatarica] and Mongolian Saiga [S. mongolica]) of the Central Asian steppes also fall within this clade.
3) 13 spp. This clade includes the dik-diks (Madoqua, 12 spp.), which live in arid thornbush country in the same areas as the gerenuks and the Beira (Dorcatragus megalotis). The horns (present only in males) are tiny. Dik-diks have facial glands, but the Beira does not. Dik-dik's are well adapted for hot, dry environments. Guenther's Dik-diks (M. guentheri), for example, pant rather than sweat and their blood is cooled by an enormous nasal cavity, the flexible proboscis acting like a bellows to increase airflow. These dik-diks licks droplets that condense on the outside of the nose and their kidneys are reportedly second only to those of jerboas and kangaroo rats (desert-adapted rodents) in their ability to concentrate urine.
4) 4 spp. The Oribi (Ourebia, 4 spp.) are small to medium-sized antelopes living in grassland and bush country throughout sub-Saharan Africa. Oribi have facial glands and large glandular carpal tufts and a bare patch of skin beneath each ear (as in reedbucks, to which they are not especially closely related). Oribi have long legs, a fairly long neck, and large ears. The horns, which are thin spikes, are present only in males.
5) 3 spp. Procapra includes the Mongolian Gazelle (P. gutturosa), Przewalski's Gazelle (P. przewalskii), and Tibetan Gazelle (P. picticaudata). Members of this group have noticeably short tails lack carpal glands, have only small facial glands, if any, and lack the striking facial patterns of "true" gazelles. Females lack horns.
Tribe Reduncini. The 22 species in this tribe include the reedbucks, waterbucks, and relatives. Most are water-dependent medium to large antelopes. Horns, which are transversely ridged, are present only in males. The three genera in this tribe are Redunca (9 spp.), Kobus (8 spp.), and Pelea. Redunca (reedbuck) are found in open habitats of sub-Saharan Africa, mainly in moist environments. Kobus includes three species-groups (sometimes treated as distinct genera). The first of these, the waterbucks, are found throughout the plains of sub-Saharan Africa, always near water. The rather small kobs have large inguinal and preorbital glands and somewhat S-shaped horns and live in well-watered plains from West Africa to the Sudan and Uganda. The Puku (K. vardoni) lives much farther south, from Botswana to Mozambique. The lechwe, which are intermediate in size between waterbucks and kobs, lack preorbital glands and have long, sweeping S-shaped horns and reddish or blackish shaggy coats. Lechwe are among the most strongly water-associated antelopes, second only to most of the sitatunga, and are found in the floodplains of Zambia and neighboring countries and in Sudan. The Rhebok (Pelea capreolus), found in the highveld of South Africa, is the smallest member of this tribe. Rheboks have glands in the feet (but no other skin glands), soft wooly gray fur, and short, straight, upright horns.
Tribe Hippotragini. The 10 species in this tribe are placed in 3 genera: Hippotragus, Oryx, and Addax. Members of this tribe are medium-sized to large antelopes with long horns in both sexes. The horns are parallel or only slightly divergent. They curve back or are nearly straight or spiraled and are clearly ringed all along their length. Hippotragus includes 3 species found in well-watered high-grass habitats: Southern Sable Antelope (H. niger) and Roosevelt's Sable Antelope (H. roosevelti), found in southern and eastern Africa, and the Roan Antelope (H. equinus), which occurs throughout the grasslands of sub-Saharan Africa, An additional species, the Blaubok (H. leucophaeus) lived in the Cape provinces of South Africa but was wiped out by Boer expansion. When first discovered, it was known only from a small area of the southwestern Cape. That population was extinct by 1800, but another population may have persisted in the Free State province until the 1850s. Oryx includes desert and semi-desert species in both Africa and Arabia. Most species have very long, almost straight, backward-pointing horns. The Beisa Oryx of East Africa provides an example, not uncommon among bovids, of a group long treated as a variable single species turning out to represent several distinct species, in this case Beisa Oryx (Oryx beisa), Galla Oryx (O. gallarum), and Fringe-eared Oryx (O. callotis). Addax includes just a single species, the Addax (A. nasomaculatus) of the Sahara. The Addax resembles an Oryx but with spiral horns, large spreading hooves, and a bushy tuft of hair on the forehead.
Tribe Alcelaphini. Members of this tribe are large antelopes with horns in both sexes. There are 23 species in this tribe, placed in four genera: Beatragus (1 species), Alcelaphus (hartebeest, 9 spp.), Damaliscus (11 spp.), and Connochaetes (wildebeest, 5 spp.). Hartebeest have strikingly long faces and horns that are raised on a high shelf-like pedicle. They are found in grasslands across sub-Saharan Africa and at one time their range extended into North Africa and even Israel, but this northernmost representative, the Bubal Hartebeest (A. buselaphus) ,went extinct in the 1920s. Hartebeest horns are always much thicker and sturdier in males than in females. Male hartebeest fight by dropping to their knees and battering each other and the positioning of their horns on raised pedicles displaces the impact of the blows away from the braincase. Damaliscus species have elongated faces, like hartebeests, but do not have elongated horn pedicles. The Bontebok (D. pygargus) was driven nearly to extinction by the early Dutch settlers of South Africa, but today is no longer in danger of extinction. Most of the other Damaliscus species are fairly numerous, but the Uasin Gishu Topi (D. selousi), of western Kenya, has not been recorded in recent years and is likely extinct. The Critically Endangered Herola (Beatragus hunteri) is known in historical times only from the region between the Tana River in Kenya and the Juba River in Somalia. The best known members of this tribe are the wildebeests. Wildebeest are found only in southern and eastern Africa, not reaching Sudan or West Africa.
Tribe Caprini. The 61 species in this tribe include the sheep, goats, and relatives. Most species live in hilly or mountainous regions and tend to have short, sturdy metapodials (shin bones). In nearly all species, both sexes have horns.
1. The Chiru (Pantholops hodgsonii) is found on the Tibetan Plateau. It has very long upright horns (present in males only) and has inguinal glands but no glands on the face or feet. Although its numbers are much reduced from the past, it still occurs in herds of thousands. Its wool is extemely fine and much sought after.
2. Oreamnos includes just a single species, the Rocky Mountain Goat (O. americanus) of the higher mountains of western North America. It is a stocky, shaggy, white goat-like animal with short, simple back-curved horns
3. Budorcas includes 4 species known as takins and found on the high mountain slopes of western and central China and the eastern Himalayas. They apparently have no glands on the face or in the feet or groin.
4. Rupicapra includes 6 species known as chamois. These occur in the high mountains of Europe from Spain east to the Caucasus. Chamois have gazelle-like facial stripes, a lighter underside, and slender horns that rise vertically and hook backward at the tips. They have small foot glands and no glands on the face, but have a pair of glands behind the horns.
5. Nemorhaedus, Capricornis, and Ovibos form a clade together. Nemorhaedus is composed of six species of gorals, small, compactly built "goat-antelopes" with short back-curved horns. Gorals live in high, steep areas from northern Thailand west through the Himalayas to Kashmir and north to the Russian Far East. The 7 species of serows (Capricornis) look superficially like very large gorals, with the same short, back-curved horns, but unlike Gorals, they have facial glands and a very short tail. Serows live at relatively low elevations, but also in steep country as far south as Sumatra and north to central China and in the Himalayas. Ovibos includes a single species, the Muskox (Ovibos moschatus), which is a heavily built animal of the North American Arctic with very long shaggy hair and white fibrous horns that curve outward, down, then up. Like the related serows, Muskoxen have very short tails, but they have only small facial glands.
6. The goats and relatives have been the focus of much taxonomic debate. Molecular data have now confirmed that blue sheep, the Aoudad (Ammotragus lervia), and the tahrs are more closely related to goats than to sheep. The Greater Blue Sheep (Pseudois nayaur) and Lesser Blue Sheep (P. schaeferi) are superficially sheep-like, but have no facial glands and the foot glands are at most rudimentary. The Greater Blue Sheep is abundant in the higher alpine zone of the Himalayas and the eastern margins of the Tibetan Plateau and the Dwarf Blue Sheep occurs in the arid upper reaches of the Yangtze Gorge, separated from the alpine zone by a 1000 m wide forest belt. The Aoudad, also known as the "Barbary Sheep", is found in the semi-arid massifs of the Sahara. It is one of only three species in the tribe Caprini occurring in Africa (the other two being Nubian Ibex [Capra nubiana] and Walia Ibex [C. walie]). Like blue sheep, Aoudads have no glands in the face or feet. The Himalayan Tahr (Hemitragus jemlahicus) is found on the southern slopes of the Himalayas in very steep, rocky areas. Recent work has indicated that what has been treated as a three closely related Hemitragus species is actually several species: H. jemlahicus, related to goats (Capra),b ut even more closely related to Pseudois; Nilgiri Tahr (Nilgiritragus hylocrius), closely related to sheep (Ovis); and Arabian Tahr (Arabitragus), the sister group to Ammotragus. The Arabian Tahr lives in the mountains of northeastern Oman and the far north of the United Arab Emirates. The genus Capra includes the goats. All Capra have beards and fairly short, triangular tails, bare underneath and with strong-smelling glands at the base. There are no facial glands and if foot glands are present they are only found on the front feet. Capra includes the ibexes, most of which live in high mountains from the Altai in Siberia west to Spain and south to Ethiopia, although the Nubian Ibex lives in lower but steep hills in Israel and along both sides of the Red Sea. The Wild Goat (Capra aegagrus), or "Bezoar", is the only wild representative of the "true goats". It lives in steep hilly areas from Turkey east to Pakistan and is probably the sole ancestor of domestic goats, although some authorities have suggested that a few breeds of goats may be partly derived from the Markhor (Capra falconeri), which lives in hilly areas of Pakistan, Indian Kashmir, Afganistamn, Tajikstan, and Uzbekistan. In Pakistan, Markhors and Wild Goats have interbred to produce a hybrid with loosely spiraled horns known as the "Chiltan Goat". Molecular phylogenetic studies suggest a complex history of ancient hybridization between lineages within the Capra clade.
7. The genera Ovis (sheep) and Nilgitragus form a clade. Sheep have both facial and foot glands (whether the Nilgiri Tahr has facial glands is not yet known). The Nilgiri Tahr lives in the alpine zones of the Western Ghats of India. Wild sheep (Ovis) are found from Turkey through West and Central Asia into northeastern Siberia, Alaska and the Rocky Mountains and desert hills of western North America. The American species inhabit steep terrain, almost like goats. Domestic sheep are derived from members of the Ovis gmelini group. Most lines of domestic shhep have been bred to increase the production of winter underwool at the expense of the normal contour hairs. Domestic breeds not selected for their wool often look very much like their wild ancestors (e.g., the feral "Mouflons" from the Mediterranean islands of Corsica, Sardinia, and Cyprus).
Tribe Cephalophini. This tribe includes the many small forest-dwelling antelopes known as duikers. There are 41 species, placed in three genera: Philantomba, are very small and are found throughout the forest zones of Africa, from the main rainforest belt of West and Central Africa through the highland and coastal forests of eastern and southern Africa. One species (Verheyen's Duiker [P. walteri], from West Africa) was described only in 2010. Duikers seem to be very abundant in rainforests. They are often a mainstay of the bushmeat trade yet appear nevertheless to remain common. Sylvicapra males have a long, narrow tuft of hair between the horns. Two Sylvicapra species occur in western Africa and a third species is found throughout non-forested regions in sub-Saharan Africa. Cephalophus includes more heavily built duikers. Two West African species (Banded Duiker [C. zebra] and Jentink's Duiker [C. jentinki]) and one East African species (Ader's Duiker [C. adersi]) are Critically Endangered.
Tribe Oreotragini. Oreotragus (the klipspringers) includes 11 species of small, stocky antelopes with short, thick hooves. They are found on isolated rocky outcrops so their distribution is patchy.
(Groves and Grubb 2011 and references therein; Groves and Leslie 2011 and references therein)