of the Oriental region. Madagascar ami other islands 

 of the Mascarene group are sometimes considered a 

 region distinct from continental Africa because they 

 have a number of peculiar forms (Rand 1936). 



At the levels of order and family, there are some 

 similarities between the forest and savanna faunas 

 of the F.thiopian and Oriental regions : at genus and 

 species levels, however. difTerences are conspicuous. 

 The similarities at higher levels are explained by geo- 

 logical history. During the Miocene and Pliocene. 

 .Africa, Arabia, and India shared a rather uniform, 

 moist climate. Continuous land bridges supporting a 

 rich uniform vegetation connected the three areas, 

 and animals moved freely between them. .An ocean 

 barrier then developed between .Africa and Arabia 

 on the west and India on the east, and drying of the 

 climate in northern .Africa and .Arabia interposed arid 

 grassland and desert between the forests of central 

 .Africa and India. Separation of the forest fauna into 

 two isolated populations has permitted evolution of 

 distinct species and genera in those families and or- 

 ders that the two regions share in common (Moreau 

 1952 V 



The Ethiopian region is remarkable in having 

 neither deer nor bears. Except for the guinea-fowl, 

 there are few gallinaceous species, so common in the 

 Oriental region. It has several endemic bird families, 

 however, including the Musophagidae and Coliidae : 

 -Africa also has the ostrich. Hornbills occur both in 

 .Africa and the Oriental region. Peculiar to Africa, 

 but extending north into Palestine and Syria, are the 

 mammalian hyracoid coneys. Africa is noted espe- 

 cially for giraffes, antelopes, zebras, elephants, and 

 other ungulates that wander around in large herds. 

 The presence of the large hippopotamus and rhinoc- 

 eros should be mentioned and also the number of cats 

 (lion, leopard) and dogs (jackals, foxes, hunting 

 dogs, and others). The tiger of the Orient is absent. 

 Edentates include the aardvark and scaly anteaters. 

 .Among the primates are found lemurs, baboons and 

 macaques, the chimpanzee, and the gorilla. Rodents 

 and insectivores are well represented. It appears that 

 most of the mammals, except for the elephants, 

 coneys, and aardvarks, had a Holarctic origin and 

 entered the Ethiopian region from the North. Rep- 

 tiles are well represented in Africa : the chameleons 

 are highly varied in Madagascar. Salamanders and 

 the tree frogs are absent from the amphibian fauna. 



The fish fauna in the Ethiopian region contains a 

 great proliferation at the species level. Several relict 

 species, such as the lungfish Protoptcrus. occur : 

 and several families of primitive teleosts are endemic. 

 Otherwise there is considerable relationship between 

 the fish fauna of the Ethiopian and Oriental regions. 



The Madagascar or Malagasy sub-region has 

 been isolated from Africa certainly since the Eocene 

 and possibly since early Mesozoic. Most modern 



families of mammals have evolved since early Ter- 

 tiary and would have had to enter Madagascar by 

 the sweepstakes route, it is no wonder then that such 

 groups as ungulates, rodents, carnivores, and mon- 

 keys are so ]50orly re()rcsented, at best, in this sub- 

 region. On the other hand, peculiar insectivores 

 (Centetidae), carnivores, rodents, and primates 

 (especially lemurs) occur here, the derivatives of 

 |)rimitive stock which is ])oorly represented if not 

 extinct on tiie continent. A similar situation obtains 

 among groups other than mammals. The avifauna in- 

 clude several families, genera, and species peculiar 

 to the sub-region. Bird groups show affinities both 

 with continental .Africa and the Oriental region ; and 

 it is possible that some forms may have been driven 

 hither by heavy winds. In general, the avifauna dif- 

 fers more from the Ethiopian region than the latter 

 does from the Oriental region (Rand 1936). Mada- 

 gascar has no poisonous snakes, but there is a good 

 representation of other reptiles. It is of special inter- 

 est that Madagascar, the Comoro Islands, Bourbon, 

 Mauritius, Rodriguez, Aldabra, Admiralty Islands, 

 and Seychelles in the Indian Ocean all support pecul- 

 iar species or subspecies of large land tortoises. The 

 only other place in the world where large tortoises 

 occur is on the Galapagos Islands off the west coast 

 of South America, but these are not related, being 

 independently derived from small forms. There are 

 no strictly limited fresh-water fish on Madagascar, 

 although fresh-water forms also tolerant of salt-water 

 occur. Parastacid crayfishes are found in Madagas- 

 car, South America, and in the Australian region, but 

 nowhere else. 



Oriental region 



The Oriental region includes tropical Asia, con- 

 spicuously demarked from the Palaearctic to the 

 Xorth by the Himalayas. To the West it gradually 

 gives off into the Ethiopian region. An inexact 

 boundary line (for our purposes, we may adopt 

 Weber's line here) separates it from the Australo- 

 Papuan region to the Southeast. Java, Sumatra, 

 Borneo, and the Philippines belong to the Oriental 

 region and, according to Gressitt (1956) so properly 

 do many of the outlying Pacific islands. The Indian 

 peninsula is an old land mass separated from conti- 

 nental Asia during the Eocene by the Tethys Sea, 

 which intruded eastward from the Mediterranean 

 through much of southern Asia before the uplift of 

 the Himalayas. India may have been connected with 

 Africa at various times in the past, most recently 

 during the Miocene and Pliocene as discussed earlier. 

 Tree-shrews ; the gibbon, orangutan, and tarsier ; 

 fresh- water tortoises (Platysternidae) ; and the slen- 

 der-nosed fish-eating gavials are exclusive to the 



Distributional units 271 



