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PHYLOGENY

INTRODUCTION

The Age of Dinosaurs terminated rather abruptly 65 million years ago marking the beginning of the Tertiary epoch. Ungulates stem from condylarth ancestors which gave rise to at least five lines: the Cete, Meridungulata, Tethytheria, Phenacodonta, and Eparctocyon (McKenna 1975). Some of these do not concern us here. The Cete gave rise to the whales and dolphins. The Meridungulata radiated in the isolation of South America and now are extinct (Webb 1976). This leaves the Tethytheria which gave rise to the modern elephants and sea cows, the Phenacodonta which led to the perrisodactyls, and the Eparctocyon which includes the artiodactyls (Eisenberg 1981). The main difference between this and older classifications (eg. Colbert 1970) is that the Hyracoidea is now considered more closely allied to the perissodactyls than the proboscideans.

PROBOSCIDEAE

The Tethytheria include the divergent proboscideans (elephants) and the Sirenia (sea cows). The earliest proboscidean arose in Palaeocene Africa and radiated into a multitude of some 300 species by the beginning of the Miocene. These species have been grouped into four super-families; the Deinotheridae, Gomphotheridae, Mastodontidae, and Elephantidae. [Visit David Atkin's site]

Deinotheridae (extinct)

Deinotherium appeared in the Eocene, an animal almost the size of modern elephants but with tusks curving downward from the lower jaw. They became extinct in Eurasia during the Pliocene but survived in Africa into the Pleistocene.

Gomphotheridae (extinct)

The gomphotheres flourished from about 38 million years BP until the Holocene. Paeleomastodon, one of the earliest members, had short tusks on both upper and lower jaws and the trunk was poorly developed. Stegomastodon, a more recent gomphothere, had tusks of unusual length measuring almost three-quarters as long as its body

Mastodontidae (extinct)

Mastodonts first appeared in Eurasia during the lower Miocene and spread to Africa and North America and subsequently South America. They survived in the New World until about 6000 BP. Despite their numerical abundance as evidenced in the large numbers of fossil remains in North America, they did not appear to be widely hunted by early Man, although evidence points to greater use in South America. The mastodonts differed from the mammoths and modern elephants in the structure of their molars. Mastodonts had rounded cusps or crests which are relatively few in number. In the Elephantidae, the transverse crests (lamellae) are closer together, more numerous and spaces between them are filled with cementum. Most mastodonts were covered with hair.

Elephantidae

The last group of proboscideans arose in the Miocene from Stegolophodon, an animal with affinites to the mastodonts. Much of the early evolution occurred in Africa. The basic elephantine stock, Primelaphus, gave rise to three genera, Mammuthus, Elephas, and Loxodonta (Fig. 2).

The mammoths (Mammuthus) are the best known of the extinct elephants. Discoveries have been made of complete carcasses almost perfectly preserved in ice and frozen soil. These animals were highly evolved, in some respects more advanced than modern forms. They had closer affinites to Elephas than Loxodonta. Most members were adapted to grazing and lived on steppes and prairies. One of the largest members of the genus was the imperial mammoth (M. columbi) with a shoulder height of almost 4 metres compared with 3.5 metres for large African elephants. This species lived on the prairies of the southern United States and Mexico. The smaller woolly mammoth (M. primigenius) was about the size of the Asian elephant but had a number of adaptations for cold tundra steppes. The skin was thick and covered with long hair. The ears were small and large fat reserves were concentrated on the head and shoulders as well as large subcutaneous depots. The large tusks probably were used to sweep away snow exposing underlying vegetation.

Elephas recki dominates fossils of the African Pleistocene. While this species dominated the savannas, Loxodonta probably exploited forested habitats. With the extinction of Elephas, Loxodonta apparently invaded drier regions forming two subspecies, the forest elephant (Loxodonta africana cyclotis), and the bush elephant (L. a. africana).

More on mammoths

 

PERRISODACTYLA

 

Odd-toed ungulates probably adopted a diet rich in cellulose during the Paleocene while they were still small since post-gastric fermentation (either colonid or caeicalid) is a better digestive strategy than pre-gastric fermentation in animals smaller than about 5 kg. The earliest and best-known perissodactyl fossil is Hyracotherium (Eohippus), a small fox-sized animal which appeared in the Eocene epoch. From this or similar ancestral form evolved the tapirs, rhinos and horses as well as extinct lines, the brontotheres and chalicotheres (Fig. 3). Of the 156 known genera, 15 are in the fossil record, giving them one of the highest extinction rates of all mammalian groups (Rowlands 1981).

The Order formed three main lines two of which have surviving members; the Ceratomorphs (rhino-like) and Hippomorphs (horse-like). Three families are represented in modern faunas.

Tapiridae

 

The tapirs are the most primitive of the living perissodactyls retaining four toes on the front limbs and three toes on the hind. The body is heavy and the back is curved. One ancient line apparently gave rise to the rhinos, a branch which occurred at a time when artiodactyls began their major radiation and according to Janis (1976) perhaps in response to this competition.

Today, the family is represented by 1 species Asia and 3 in South America. The Malay tapir (Tapirus indicus), a strikingly marked black and white animal, is found in forest habitat in Sumatra, the Malay Penninsula and the southern parts of Indo-China and Thailand. The mountain tapir (Tapirus pinchaque) inhabits the temperate zone forests and adjacent paramos of Colombia and Equador. This species and the central American tapir (Tapirus bairdi) are quite rare. The Brazilian tapir (Tapirus terrestris) is widely distributed east of the Andes in north Central America from Mexico to Equador.

Rhinocerotidae

From a tapiroid similar to Hyrachus The first recognizable rhinos (e.g Hyracodon) appeared in the Eocene as rather slender and graceful animals. Arising from these running rhinos were several lines which became numerous in most continental regions during the late Miocene. In general, members of this group are large perhaps to minimize competition with the artiodactyls (Janis 1976). The extreme in size (perhaps 30 tonnes) was attained by Indricotherium, the largest land mammal that ever lived. Rhinos became extinct in North America during the Pliocene but persist to the present day in the Old World. Northern Eurasia was once populated by an array of rhinos. The best known species of the Pleistocene were Merck's rhino (Dicerorhinus kirchbergensis), woolly rhino (Coelodonta) and an elephantine grazing rhino (Elasmotherium). The phylogeny of living species is reviewed by Groves (1983).

 

Living forms include 5 species belonging to 4 genera. Asian rhinos are most primitive, particularly the Sumatran rhino (Dicerorhinus), which is one of the oldest living mammalian genera dating to the Oligocene. Today it is found in scattered groups in hill forests of Burma, Thailand and Malaya as well as the islands of Borneo and Sumatra (Flynn and Abdullah 1984). The Javanese one-horned species (R. sonadaicus) perhaps is the rarest of all large land mammals with less than 00 surviving in the Udjong Kulon Penninsula on the western tip of Java. The largest, the Indian one-horned rhino (Rhinoceros unicornis), is confined to parks encompassing small areas of riverine grassland in Assam and Nepal.

In Africa, the black rhino (Diceros bicornis), a browser inhabiting wooded habitats, still has a wide but increasingly discontinuous distribution. Ceratotherium simum, a large grazing rhino, exists in two widely separated populations, one in South Africa (C. s. cottoni) and one in Sudan (C. s. simum). Heavy poaching in the past decade has reduced both species to precariously low numbers.

Equidae

The evolution of the horse has received more study than other species.

 

Hyracotherium. The fossil record of the horse is remarkably complete beginning with the once wide-spread Hyracotherium (Short 1975). Subsequent evolutionary development of the horse occurred mainly in North America. The progression of evolutionary change culminating in the modern horses included increased size, lengthening of legs, reduction of lateral toes, straightening and strengthening of the back, and progressive advancement of tooth structure.

 

Anchitheriinae. In the middle and upper Eocene, horses remained little changed from Hyracotherium. In the Oligocene (38 million B.P.), the subfamily Anchitheriinae evolved with a reduction in number of toes. With environmental change in the Miocene (4 million B.P.), horses responded in an evolutionary sense to the rapid spread of grasslands. Merychippus, a three-toed speceis, was the first grazing horse giving rise to modern lineages as well as a sidebranch of equid evolution, the Hipparioninae.

 

Dolichohippus. In the late Miocene, Merychippus was replaced by Pliohippus, the first one-toed horse, which in turn gave rise to Equus in the Pliocene. There is some debate regarding the approximate date and place that the subgenera Equus, Amerhippus, Asinus, Hippotrigris, and Dolichohippus formed separate lines. The zebras, particularly Dolichohippus, appear to be the most primitive group. The two subgenera arose in North America about 5 million years B.P., spreading to Eurasia and Africa several million years later.

 

Equus. The horses and asses appear to have evolved from the hippotrigrine zebras reputedly in Eurasia. However, there was a migration of these more modern forms back into North America. A tundra race of the tarpan (Equus ferus alaskae) entered Alaska more recently in the Upper Pleistocene.

 

Asinus/Hemionus. The earliest wild ass (Equus stehlini) dates to 1.5 million years B.P. in Northern Italy. The onagers seem to have become separated from the African asses more than 1/ million years ago. Onagers and asses (e.g. Equus conversidens) also are known from deposits in the United States and Canada (Kurten and Anderson 1980).

 

Amerhippus. The subgenus Amerhippus never migrated to the Old World. Several species are known in North America apparently until quite recent times. It has been speculated that some may have survived to interbreed with the feral mustangs introduced by the Spaniards but this is unlikely (Groves 1974). South American species related to Equus andium had zebrine features.

 

Living Equids

 

The living equids are represented by less than 10 species all belonging to the genus Equus (Table .). Groves (1974) divided them into 5 subgenera but on the basis of analysis of additional materials Groves and Willoughby (1981) argue for the distinction of 6 subgenera.

 

Dolichohippus. The most primitive, Dolichohippus, is represented by one living species, the Grevy's zebra of northern Kenya and adjoining Ethiopia. The world population is about 1500 individuals. This species is rather similar to the wild asses in behaviour and conformation.

 

Hippotigris. The remaining zebras are assigned to the subgenus Hippotigris which includes the familiar plains zebra (Equus burchelli) and the mountain zebra (E. zebra) of South Africa. The plains zebra is most abundant and widespread (Grubb 1981). Kingdon (1979) interprets regional variations in color patterns as the product of four major subspecies with extensive areas of overlap. The northern group with clear broad stripes is E. b. boehmi. The most abundantly striped race is E.b. crawshayi of the Mozambique zone. Southward, shadow stripes are more common and bold stripes do not extend as far down the belly and legs. In the temperate grasslands of South Africa, there once was a distinctive population of E. b. burchelli with greatly reduced striping. Today a large heterogeneous population of intermediate color morphs is commonly identified as E.b. antiquorum or E.b. chapmani. The extinct quagga was an endemic species confined to the arid Karoo of South Africa with stripes confined mainly to the head, neck and shoulders and with a usually brown upper body.  (For more information on stripes...)

 

Asinus. There has been some question whether Asiatic and African wild asses should be placed in the same (Groves and Mazak 1967) or separate (Groves and Willoughby 1981) subgenera. The Asiatic onager or kulan (E. (Hemionus) hemionus) is found in the deserts of the Rann of Kutch and Baluchistan. The Tibetan wild ass (E. h. kiang) is appears to be a distinct species with three subspecies. It is found in the high open plateau of Ladak and Tibet.

 

True wild asses belong to the subgenus Asinus. The African wild ass (E. (Asinus) africana) is found in the Somalia arid zone where it is threatened by genetic swamping by feral asses.

 

Equus.  The caballine horses are assigned to the type subgenus Equus. The only remaining wild species is the Przewalski's horse (E. ferus przewalskii), although attempts have been made to genetically reconstruct the tarpan (E. ferus ferus) through selective breeding of domestic horses.

 

[For more on the evolution of horses ...]

 

ARTIODACTYLA

Despite their great diversity, the artiodactyla share the same diagnostic leg structure. There are generally or 4 digits with the axis of the foot passing between the third and fourth. The most primitive members had a full complement of teeth but during evolution there has been a strong trend toward reduction of the upper incisors which in most persisting species have been replaced with a horny pad. The lower canine often assumes the shape and position of lower incisors. The upper canines may be absent or, in some of the more primitive forms, long and dagger-like.

 

The first artiodactyls appear in the early Eocene from condylarth-like ancestors (Fig. 4). Interestingly, these early artiodactyls were much less advanced than perissodactyls of the same period. The even toed or cloven hoofed ungulates fall into four modernsuborders; Suina (pigs), Tylopoda (camels), Tragulina (chevrotains), and Pecora (ruminants).

Suina

The first suids appeared in the Oliogocene; pigs evolved in the Old World and peccaries in North America. Evolution of the group involved increased size, lengthening of the skull, and development of large outwardly curving tusks. The peccaries emphasized development of more cursorial body conformation rather than size as in Old World pigs. Hippos, the remaining member of the Suina, arose from advanced anthracotheres relatively recently in the late Pliocene. Most pig-like artiodactyls are omnivores. The two notable exceptions are the babirussa which has developed some measure of pre-gastric fermentation and the hippopotami which assumed a much larger size with their adoption of a basically herbivorous diet. The Suina include three families; Suidae (true pigs), Tayassuidae and Hippopotamidae. Most members are found in the Old World.

Suidae

Domestic pigs arose from selective breeding of Sus scrofa, the European wild boar, and Sus cristatus, a closely related species in Asia. Other wild Asian forms are the pygmy hog and the babirusa, an unusual form with advanced pregastric fermentation. Modern African suids include 3 species. The bushpig (Potamochoerus porcinus) is the most generalized species found throughout the equatorial forest and moister eastern and souther savannas. They require relatively dense vegetation and moist and hence soft soils. The giant forest hog (Hylochoerus meinertzhageni), the largest living suid, is distributed in dense equatorial and montane forests. The warthog (Phacochoerus aethiopicus) is more familiar because of its diurnal habits and preference for wooded and open savannas.

Tayassuidae

The peccaries (Sowls 1984) are restricted to the New World. Until recently, it was believed that only two species remained, the collared peccary (Tayassu tajacu) and the white-lipped peccary (Tayassu albirostris). However, a new species (Catagonus wagneri) has been recently discovered in Paraguay.

Hippopotamidae

Hippopotami are now endemic to the Ethiopian region. The familiar Hippopotamus amphibius is widely distributed in lakes and rivers where it spends much of its daylight hours partially or completely submerged. Most feeding is done at night on coarse grasses which are often onsiderable distances from loafing pools. The less social dwarf hippo (Choeropsis) is found in forested areas of Western Africa.

Tylopoda

The tylopods (camels and llamas) originated in North America. They are not considered ruminants in spite of their ruminant-like digestive function. They are distinguished by a less compartmentalized digestive tract (3 instead of 4 compartments) and the presence of incisors in the upper jaw which modern ruminants lack. The first camels appeared in the late Eocene. The llamas represent camels in a Miocene stage of evolution while the large Old World camels represent the culmination of the central camelid line. In North America, forms like Camelops, somewhat intermediate between llamas and true camels, persisted throughout the Pleistocene. The present distribution in South America and in the Old World represent emigrations during the Pleistocene.

Camelidae

The suborder is comprised of only one family, Camelidae. Representatives are Camelus (dromedary and bactrian camels) of the Old World and Llama and Vicugna of South America. The Neotropical camelids, the guanacos and vicugnas are now confined to the Pantagonian subregion. The llama and the alpaca, are domestic forms of the guanaco selected primarily for work or wool, respectively.

Tragulina

Ruminants stemmed from primitive traguloids such as Archaeomeryx. Modern-day chevrotains (mouse deer) give a glimpse of what these ancestral forms were like except that the chevrotains have reduced the tail, suppressed upper incisors, and enlarged canines into tusks used in fighting. Some of the hyertragulids were quite advanced in size and conformation but selective extinctions have left the more primitive forest-dwelling forms.

Tragulidae

Today three species live in Asia (Tragulus napu, T. javanicus and T. meminna) and one in Africa (Hyemoschus aquaticus).

Ruminantia

True ruminants are the most diverse group, represented by 61 genera and approximately 163 species. There are four families in modern faunas, Giraffidae (giraffes), Cervidae (deer), Antilocapridae (pronghorn antelope), and Bovidae (sheep, cattle, antelopes)

Giraffidae

Primitive forms were similar to the okapi (Okapia johnstoni), which is now restricted to the dense forests of northeastern Zaire. Advanced moose-like giraffes with enormous palmated ossicones (Sivatherium) occupied savannah habitats into post-Pleistocene times since they are known in cave art in North Africa and figurines in mesoptamia. They were replaced by the familiar savanna giraffe (Giraffa camelopardalis) which is relatively widespread in Africa.

 

Kingdon (1979) recognizes 4 major populations of the savanna giraffe. The subsaharan is designated G.c. peralta. The Somali arid region supports G.c. reticulata/camelopardalis. The northern woodland population is designated G.c. congoensis while the southern savannah population is comprised of G.c. tippelskirchi of East Africa and G.c. giraffa/angolensis of southern Africa. The Rothschild giraffe is considered to be basically part of the G. c. congoensis population with admixture of eastern races. All subspecies hybridize freely where ranges integrade producing individuals which are difficult to assign to any particular taxon.

Moschidae

Although musk deer have been considered as members of the subfamily Moschinae, recent taxonomic revisions assign them to a distinctive family (Corbet and Hill 1980, Leinders and Heintz 1980, Janis & Scott 1987). Moschus shows a mixture of bovid and cervid characteristics (it is the only cervid with a gall bladder) and may represent the branching point of these two families (Thenius 1969). They give us a good idea of what early Miocene cervids were like.

 

The family is represented by three living species (Groves 1976): Moschus moschiferous, M. chrysogaster and M. sifanicus. They are rare in many parts of their range because of the demand for musk contained in an abdominal pouch.

Antilocapridae

The antilocaprids or prongbucks have been limited largely but not

entirely to North America where only one species, the pronghorn antelope (Antilocapra americana), survives. Recent morphological and biochemical evidence suggests that the pronghorn (Antilocapridae) should be included as a subfamily of the Bovidae (O'Gara and Matson 1975, Curtain and Fudenberg 1973). Pronghorns have a gall bladder while cervids do not. Although the horn sheath is shed annually, exfoliation of horn covers does occur in bovids. But other evidence such as the configuration of lacrimal orifices suggests that the pronghorns may be an offshoot of the primitive cervoids at an early stage of evolution (presumably before gall bladders were lost, Leinders 1979, Leinders and Heintz 1980). Bovid characteristics may represent convergent evolution.

Cervidae

Cervids arose from palaeomerycid ancestory during the Oligocene. These primitive deer were small, antlerless with upper canines enlarged as long sabers. Modern deer are distinguished from other ruminants by the presence, in most recent species, of bony deciduous antlers which are generally borne only by males. However, some of the more primitive members such as the water deer of Asia do not carry antlers but have long curved upper canines. The muntjac or barking deer which has canine tusks and bears small antlers on long pedicles is also of primitive type resembling the Tertiary cervid ancestors. In reindeer and caribou, antlers are also carried by a large proportion of females.

 

Modern deer arose from two distinct lines recognized on the basis of the structure of the metacarpals. The plesiometacarpalia (Cervinae) are characterized by the retention of both distal and proximal parts of the metacarpals (of digits II and V). The main center of evolution of this group was Eurasia but one member, the wapiti, entered North America in the late Pleistocene, probably during the Sagamonan Interglacial. Pleistocene representatives of the Old World were the relatively advanced forms, the Irish elk (Megaloceros) and the brush-antlered elk (Eucladoceros).

 

In the telenmetacarpalia, the metacarpals are greatly reduced; only the distal parts remain (Fig. .5). This group comprises all the endemic deer of the Americas (Odocoileinae) as well as the roe deer, moose and reindeer/caribou. The earliest deer in America was Odocoileus brachydontus which appeared in the early Blancan. White-tailed deer are recognized in the late Blancan (3 my B.P.). Mule deer made their first appearance in the Irvingtonian, probably arising from the same basic stock as did the South American genera (e.g. Blastocerus, Hippocamelus).

 

Today, the Cervidae (Table .3) are a numerically dominant group outside Africa with about 37 species belonging to 15 genera and 6 subfamilies (Whitehead 197, Corbet and Hill 1980, Baker 1984).

Hydropotinae

Chinese water deer (Hydropotes inermis)is the sole representative of this primitive subfamily. It superficially resembles the musk deer.

Muntiacinae

The muntjacs are tusked deer with small antlers. There are two species, Muntiacus muntjac (muntjac) and Elaphodus cephalophus (tufted deer or Tibetan muntjac).

Cervinae

The Old World deer probably arose in northern India from muntjac-like ancestors but today they have a northern circumglobal distribution but most species are found in Eurasia and the Orient. The genus Dama contains the fallow deer (1 species), a medium-sized animal with characteristically palmated antlers. It is distributed in the wild throughout Europe and in zoos and parks throughout the world. A number of related palmate-antlered forms appear in the fossil record and the Irish elk (Megaloceros) is believed to have been an advanced form which may have persisted into classical times (perhaps 500 BC).

Several lines stayed in the tropics. The genus Axis of India has two members, the brightly spotted axis or chital (Axis axis) and the smaller hog deer (Axis porcinus) from which it may have arisen. Three species belong to the subgenus Rusa (the sambars). The final subgenus (Rucervus) contains the barasingha (C. (Rucervus) duvauceli) and Eld's deer (C. (Rucervus) eldi). One of the most unusual species is Pere David's deer (Elaphurus davidianus) which is known only in captivity (Beck and Wemmer 1983).

Most members belong to the type genus Cervus. This complex group is often divided into several subgenera. The type subgenus (Cervus) designates the red deer, maral, Asiatic wapiti and North American wapiti. These forms are now considered to be members of a single species (Cervus elaphus). The closely-related sika deer is assigned to the subgenus Sika and the rare Thorold's deer to Przewalskium.

Odocoileinae

Odocoileinae (American deer) are represented by 6 genera. Pygmy deer (Pudu) inhabit temperate forests of Colombia, Equador and Chile. The spike-antlered brockets (Mazama) are primitive deer. Branch-antlered deer include the guemals (Hippocamelus), marsh deer (Blastoceros), white-tailed and black-tailed deer (Odocoileus) and pampas deer (Ozotoceros). The guemals, marsh deer and pampas deer are threatened species.

Alcinae

Alcinae (moose-like deer) are represented by three genera, Libralces, Cervalces and Alces which appeared during the Pleistocene in Eurasia. Libralces is the most primitive with long-beamed, weakly-palmated antlers and an unspecialized skull. Cervalces is intermediate between Libralces and Alces. Cervalces and Alces are known from sites in Alaska dated about 34 000 B.P. The terminal date for Cervalces is 15 0000 000 B.P. Modern moose (Alces alces) apparently arose from a larger form, Alces latifrons.

Rangiferinae

Rangiferinae (reindeer and caribou) probably originated in Beringia and the mountains of northeastern Asia. The earliest European record is a mid-Pleistocene deposit in Germany. In North America, the earliest fossils are from the Irvingtonian.

Bovidae

The family Bovidae includes all of the true hollow horned ruminants. The bovids include many of the most advanced ungulates. Like other artiodactyls, they first appeared at a time of climatic change during the Miocene which coincided with the appearance of grasslands and the radiation of graminoid plants (Fig. .8). They apparently originated in northern areas from ancestors similar to the neotragines. Other groups invaded Asia and Africa where they reached their maximum adaptive radiation and environmental specialization. They are still found in tremendous variety including approximately 13 species. Their distribution is world wide except for Australia and the Neotropics.

The taxonomic arrangement of the bovids is a subject of some debate. Some authorities subdivide the group into 10 subfamilies each with several tribes. Others treat tribes as subfamilies (Simpson 1945, Dorst and Dandelot 197). The entire family is presently undergoing taxonomic revision (Ansell 1968) so that the classification offered in Table .4 should be considered tentative.

The present-day African fauna still comprises representatives of many of these forms, while postglacial extinctions impoverished the once equally diverse assemblages of Asia. The reduncines (kobs, waterbuck and reed buck) and the alcelaphines (wildebeest and hartebeest) are now extinct in Asia while representatives of Antelopinae and Hippotraginae persist in both continents. Most antelope remained in tropical areas but several of the gazelles and the saiga spread widely. The saiga even invaded the Alaskan refugium (Guthrie 1968).

The phylogeny of the bovids includes 4 major lineages representing neotragine, boselaphine, antilopine and caprine radiations.

Neotragine Radiation

Modern Neotraginae have changed least from the basic Eotragine stock. This subfamily contains the dwarf antelope such as the dik dik (Madoqua),.klipspringer (Oreotragus), steenbok (Rhaphicerus), oribi (Ourebia), and the suni (Neotragus). Kingdon (198) thinks this line gave rise in the late Miocene to the Cephalophinae which became specialized to tropical forest habitats and Reduncinae which exploited valley grasslands.

The Cephalophinae (duikers) are a primitive subfamily adapted to lowland and mountain forests except for several members which extend into savanna areas. They are small browsing animals with forelegs shorter than the hind giving them a peculiar wedge-shaped conformation. The horns are small and pointed backwards. Their social organization is simple; sedentary, solitary and territorial. The largest genus (Cephalophus) has fifteen species ranging in weight from 10-75 kg. Although these traits are primitive, they may represent secondary adaptations to reinvasion of densely forested habitats.

The subfamily Reduncinae includes the reedbucks, waterbucks and their allies. These species are primarily grazers inhabiting open grasslands and wet meadows. The reedbucks are placed in the genus Redunca while the waterbucks, kobs and lechwes are placed in the genus Kobus. The waterbuck (K. ellipsiprymnus and K. defassa) is the largest and most widely distributed member. The puku (K. vardoni) has a restricted distribution in the southern savanna. It prefers open grassland adjacent to water. The ecologically similar Uganda Kob (Adenota kob) replaces the puku in the northern savanna. The lechwe (K. leche and K. megaceros) are found on shallowly inundated flood plains and probably represent the most advanced members of this group.

Boselaphine Radiation

The modern tragelaphines and bovines probably can be traced to an ancient boselaphine origin. Much of the early evolution of this group occured in Eurasia but one boselaphine line penetrated Africa giving rise to the modern tragelaphines. Modern members of the subfamily Boselaphinae include two species found in Asia. The four-horned antelope (Tetracerus quadricornis) lives in undulating country sheltered in tall grass and open jungle. The nilgai (Boselaphus tragocamelus) is a large animal found only in the Indian penninsula from the base of the Himalayas to Mysore. They avoid dense forests, preferring hills sparsely dotted with trees.

The closely related African Tragelaphinae generally inhabit wooded savannah. Sexual dimorphism is marked with the typical twisted horns carried only by males in all species except the bongo and eland. The smallest and most widespread is the bush buck (Tragelaphus scriptus). The nyala (T. angasi) is somewhat similar but larger and limited in distribution as is the sitatunga (T. spekei), a marsh-dwelling member with unusually long hoofs. The spekei), a marsh-dwelling member with unusually long hoofs. The bongo (Boocerus) is an aberrant large member confined to rather heavy forests.

The kudus, the greater (T. strepiceros) and the lesser (T. imberbis), are widely distributed in dry bush country. They carry the most spectacular spiral horns of the Ethiopian bovids. The largest bodied tragelaphine (750 kg) is the eland which is represented by two species, Taurotragus oryx and T. derbianus. Eland prefer more open landscapes than other members of the subfamily.

The subfamily Bovinae (wild oxen) evolved from large antelopes similar to the nilgais. Several attempts have been made to unravel their relationships (Gentry 1978, Groves 1981). The bovini emerged over 4 million years ago from a form similar to Parabos. By 3 million years (BP), three presumptive lines had formed. Proamphibos gave rise to the Asian buffalos (Anoa, Bubalus). The African buffalo (Syncerus) arose from Ugandax. The widest speciation occurred in the Bos group which radiated into Bibos (gaur, banteng), Prophagus (yak) and Bison. Of the bovines, only the bison gained access to North America where it was remarkably successful, radiating into a number of different forms (Guthrie 1970, McDonald 1981). The yak entered Alaska but did not spread widely. Today, wild oxen are found in most faunal regions. The African buffalo (Syncerus caffer) is the sole species in the Ethiopian Region. The best known form is the large dark savanna buffalo. It intergrades with a smaller red forest form found in central and western Africa. These animals are grazers and locally are often abundant. Wild cattle form an amazingly diverse assemblage in Asia. The largest is the gaur or Indian bison (Bos gaurus) followed in size by the kouprey (Bos sauveli) and banteng (B. banteng). The yak (P. mutus) of the Tibetan plateau and the wild buffalo (Bubalus bubalus) of the grass jungles of the Nepal Terai and the plains of Assam are two further notable members. Several small species, the anoas, are found in south east Asia.

Antilopine Radiation

The presumptive antilopine line split with the isolation of Africa and Eurasia in the early Miocene. The solid-horned lineage gave rise to the Antilopinae, the African gazelles. The hollow-horned lineage probably radiated initially in Eurasia subsequently invading Africa. The subfamily Antilopinae contains rather small antelope of wide variety. They are predominantly selective grazers of open plains although several specialized members are browsers. The impala (Aepyceros melampus) is a common and widespread species which some authorities prefer to assign to a distinctive subfamily (Aepycerotinae) because of its affinities with Alcelaphinae. Two other aberrant forms are the gerenuk (Litocranius walleri) and the dibitag (Ammodorcas clarkeri) which have greatly elongated necks for browsing in their arid scrub savanna habitat. The genus Gazella, considered more typical of the subfamily, is represented by 8 species in sub-Saharan Africa. The gazelles are found in treeless savannas throughout the region. The Thomson's gazelle (G. thomsonii) is the most widespread small species. The Grant's gazelle (G. granti) is larger, less dependent upon water, and selects some browse as well as short grasses. The springbok (Antidorcas marsupialis) is a small gazelle similar to Thomson's gazelle which evolved in isolation in the South West Arid region.

Asian antelopes and gazelles belong to three tribes. The Pantholopini contains the Tibetan antelope or chiru (Pantholops hodgsoni). The tribe Antilopini contains the blackbuck and the gazelles. The chinkara or Indian gazelle (Gazella gazella) inhabits the plains and low hills of north-western and central India. The usual habitat is scattered bush but they do extend into the sand hills of the desert zone. The blackbuck (Antilope cervicapra) is strikingly colored and males carry beautiful spiralled horns. The species once occurred in most plains areas of India.

Kingdon (198) considers the Aepycerotinae (impala) to be the direct ancestors of the Alcelaphines, an advanced group adapted to relatively rich savannas. The Alcelaphinae are medium to large antelope grouped into three genera. Damaliscus includes the bontebok and blesbok (D. dorcas) of southern Africa, the topi and tsessebe (D. lunatus) and the geographically outlying Hunter's hartebeest (D. hunteri) of eastern Kenya. Alcelaphus includes the true hartebeests. The genus Connochaetes is represented by the black wildebeest (C. gnou) of southern Africa and the blue wildebeest or brindled gnu (C. taurinus) of southern and eastern Africa. All genera are grazers. The damaliscines are smallest and most selective grazers followed by the alcelaphines and finally the wildebeests.

Caprine Radiation

This group originated in Eurasia giving rise in the late Miocene to two major lines; one leading to the Hippotraginae and the other to a complex array of sheep, goats, and goat antelopes. The chamois, ibex, tahr, goral, and serow remained in the Palearctic and Oriental faunal regions. The bighorn sheep (Ovis) and the mountain goat (Oreamnos) invaded North America. Muskoxen originated in the Old World but had entered North America by the mid-Pleistocene giving rise to a number of distinctive forms such as Symbos, the woodland muskox.

The Hippotraginae are large bodied, long-horned antelope. The sable (Hippotragus niger) and the roan (H. equinus) are found in open woodlands. Two genera, Oryx and Addax, are adapted to desert areas. The beisa and fringed-eared oryx (O. beisa), gemsbok (O. gazella), and the scimitar-horned oryx (O. dammah) represent the first genus while the second is represented by a single species, Addax nasomaculatus, found in the Sahara.

The Rupicaprinae (goat antelopes) of Asia include the serow (Capricornis sumatraensis), goral (Nemorhaedus goral) and takin (Budorcas taxicolor). These species exist in a great mountain chain (Pamirs, Hindu Kush and Himalayas) which borders the northern part of the Oriental region (Schaller 1977). In Europe, the subfamily is represented by the chamois and in North America by the mountain goat (Oreamnos americana).

The sheep and goats belong to the subfamily Caprinae. The wild sheep include the urial or shapu (Ovis orientalis), Marco Polo's sheep (O. ammon) and blue sheep (Pseudois nayaur). Wild goats include the Ibex (Capra ibex), wild goat (C. hircus), markhor (C. falconeri), and tahr (Hemitragus jemlahicus).

Ovobovinae

Budorcatinae

Saiginae

SUMMARY

There are over 200 species of ungulates and subungulates belonging to three orders; Proboscidea, Perissodactyla, and Artiodactyla. The Probosidea contain extant species of elephants. Perissodactyla contains the tapirs, rhinos and horses. Artiodactyla contains a large number of taxa falling into three major groups; the Suiformes (pigs), Tylopods (camels), and Ruminantia (ruminants).

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