« AnteriorContinuar »
and Somaliland, 0. beatrix from Arabia, and 0. leucoryx extending from Senegal to Nubia), and a distinct species of Kudu (Strepsiceros imberbis), which inhabits the Subregion from Somaliland as far south as the Tana. This Sub-region is also the headquarters of the Gazelles (Gazella), at least twelve species out of a total of twentyfive being found there.
Three genera of antelopes are endemic; these are the Dibatag (Ammodorcas), and the Gerénuk (Lithocranius), both found in Somaliland, and remarkable for their very long necks, by means of which they are enabled to reach down branches of trees from a considerable height. The third is the Addax (Addax), which is found throughout the Sahara, and extends into Arabia.
The Rodents are well represented in this Sub-region, but there are only three peculiar genera—Lophiomys, Heterocephalus, and Pectinator.
Lophiomys, a curious crested Rodent, forms a distinct family. The remarkable little animal Heterocephalus is almost entirely hairless, and apparently lives underneath the ground, burrowing in the soft sandy soil of the desert. It was originally obtained by the celebrated traveller Rüppell in Abyssinia, and has since been brought from the interior of Somaliland by Mr. Lort Phillips.
The third endemic genus, Pectinutor, is also from the coast of Somaliland and Abyssinia. It was first obtained by Captain Speke, and named by Blyth (P. spekei) after its discoverer.
The Saharan representatives of the Carnivora, Insectivora, and Bats are almost all widespread forms, and present no features of special interest. Among the Monkeys, however, we find one peculiar genus-this is
Theropithecus, containing two species of terrestrial baboons, which inhabit Abyssinia and the Galla country.
The other genera of African monkeys are fairly represented here, though by no means so abundantly as in the West African Sub-region.
The Saharan Sub-region, therefore, is characterized by the exclusive possession of the following genera :
(1) Ammodorcus, Lithocranius, and Addax among the antelopes.
(2) Lophiomys (forming a distinct family), Heterocephalus, and Pectinator among the rodents.
(3) Theropithecus among the Monkeys.
The following families, found in other parts of Africa, are absent from this Sub-region: Tragulidæ (chevrotains), Protelidæ (aard-wolf), Potamogalidæ (river-shrews), Chrysochloridæ (golden moles), and Simiidæ (the anthropoid apes).
The following is the summary of the mammals inhabiting the Saharan Sub-region :
SECTION VIII.—THE PAST HISTORY OF THE ETHIOPIAN
Up to the present time palæontology has afforded us little assistance in tracing out the past history of the African Mammal-fauna. With the exception of a few still surviving species found in a semi-fossil condition in caves, the only fossil mammal hitherto obtained from the Ethiopian Region is a form named by Owen Tritylodon, the remains of which were discovered in the Karoo beds of Basutoland, in South Africa. This formation is of Mesozoic age, and seems to correspond to the Trias of Europe. Near Stuttgart, also, in beds of the Trias age, another specimen closely resembling that of South Africa has been obtained. Tritylodon belongs to a group which was apparently allied to the modern Marsupials, and many somewhat similar forms have been found in other Mesozoic beds in Europe and North America.
The only conclusion to be drawn from this is, that before the commencement of the Tertiary epoch the whole world was, so far as is at present known, inhabited by small insignificant mammals distantly allied to the Marsupials, which are at present restricted to Australia and South America, Besides Tritylodon, the only fossil mammals hitherto known, from the Ethiopian Region, are those which have been described by Grandidier (3) and Forsyth-Major (4) from Madagascar, as mentioned above.
The resemblances between the Faunas of the Oriental and Ethiopian Regions have been noted and commented on by many writers; Mr. Allen is even disposed to join the two Regions into one realm. The number of prevailing genera, however, common to these two Regions, and not found in the Palæarctic Region, is very small, the total being, as was pointed out in the first article of this series, only eight, and of these one (Mellivora) has since then been recorded by Büchner (2) as occurring in the TransCaspian district, and is therefore also Palæarctic. Of the other seven, four have been found, in a fossil state, in various parts of the Palæarctic Region. These are—a) Manis (the Scaly Ant-eater), from the Pliocene of Samos; (6) Rhinoceros, which existed in various parts of Europe from the Miocene up to the Pleistocene times; (c) Elephas, which first appears in Pliocene times, and extends to late Pleistocene in Europe; and (d) Viverra, which commences earlier than the others, and also survived until Pliocene times in Europe. The three remaining genera common to India and Africa, but not hitherto found in fossil state in the Palæarctic Region, are Golunda (a Rat), Atherura (a Porcupine), and Nycteris (a small insectivorous Bat).
It is quite possible that these animals may eventually be discovered in the European Tertiaries. Besides this, the remains of a considerable number of the now endemic African genera have been found fossil in Europe. The list of these is instructive, and points almost unquestionably to the conclusion that Africa has been gradually peopled by successive inroads of animals from the North.
In the Eocene beds of Europe the still existing genera are few in number; but the Lemurs, and many of the more primitive forms of the Carnivora, such as form the present fauna of Madagascar, abound. It is, therefore, probable that the separation of Madagascar from the mainland of Africa took place at about the close of the Eocene period. During the Miocene and lower Pliocene times in Europe, a large number of new genera appear for the first time, the bulk of which still survive in Africa and India, though extinct or almost driven out of the Palearctic Region.
Examples of such genera are — Orycteropus, the Aardvark; Manis, the Scaly Ant-eater; Rhinoceros; Hyomoschus, the Water-Chevrotain (probably identical with Dorcotherium, a fossil form); Giraffa; several genera of Antelopes; the Porcupine; the Squirrel; Felis; Hyena; Viverra ; Herpestes, and even the higher Monkeys.
It must have been during this period that broad landconnections existed between Europe and Africa, by means of which the African continent became peopled by its present fauna,
In the succeeding Pliocene times in Europe, although a number of the more distinctly African forms still survive, there begin to appear certain genera, such as those of the Deer-family (Cervide), Ursus (the Bear), and others which have never reached Africa at all. This seems to show that Africa was, at the commencement of this period, cut off from the Palæarctic Region by an intermediate sea.
LIST OF THE PRINCIPAL AUTHORITIES REFERRED TO IN CHAPTER IV.
(1) BALFOUR, I. B.—“Botany of Socotra” (Mammals, p. xxx.) Trans. Roy. Soc. Edin., xxxi., 1888.
(2) BÜCHNER, E.-—“Ueber das Vorkommen der Mellivora indica, Kerr, im Transcaspi-Gebiet." Notes Leyd. Mus., XV., p. 99.
(3) GRANDIDIER, A.-" Histoire Physique, Naturel et Politique de Madagascar," vol. X., Mammiféres, by Milne Edwards and Grandidier, 1890.
(4) MAJOR, C. I, FORSYTH —“On Megaladapis madagascariensis, an extinct gigantic lemuroid.” Proc. Roy. Soc., 1893, p. 176.
(5) NEUMANN, B.-“Bericht über seine Reisen in Ost und Central Afrika." Verhandl. Gesellsch. Erdkunde Berlin, 1895 (p. 24 in separate copy).
(6) THOMAS, 0.-"On Some Specimens of Mammals from Oman, South-East Arabia.” P. 2. S., 1894, p. 448.