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uniformity of climate, would naturally lead to less development of such a group as this, than in the vastly more extensive and varied and almost equally luxuriant Palaearctic region of Eocene and Miocene times; while on the other hand the greater number of the smaller Carnivora in the tropics during the Pliocene and Post-Pliocene epochs, would be a constant check upon the increase of these defenceless animals, and no doubt exterminate a number of them. . . . .
The Rodents thus offer a striking contrast to the Ungulates; and these two great orders afford an admirable illustration of the different way in which physical and organic changes may affect large and small herbivorous Mammalia; often leading to the extinction of the former, while favouring the comparative development of the latter.
The Sloths are a remarkable group of arboreal mammals, strictly confined to the great forests of the Neotropical region, from Guatemala to Brazil and Eastern Bolivia. None are found west of the Andes, nor do they appear to extend into Paraguay, or beyond the Tropic of Capricorn on the east coast. The genera as defined by Dr. Gray in 1871 are –Cholapus (2 sp.), “Sloths with two toes on fore limbs, sexes alike,” Costa Rica to Brazil; Bradypus (2 sp.), “Sloths with three toes on fore limbs, sexes alike,” Central Brazil, Amazon to Rio de Janeiro; Arctopithecus (8 sp.), “Sloths with three toes on fore limbs, males with a coloured patch on the back,” Costa Rica to Brazil and Eastern Bolivia (Plate XIV., vol. ii. p. 24).
Eacinct Bradypodidae.—In the caves of Brazil are found three extinct genera of Sloths—Caelodon, Sphenodon, and Ochotherium. More distantly allied, and probably forming distinct families, are Scelidotherium and Megatherium, from the caves of Brazil and the Pliocene deposits of La Plata and Patagonia.
The Manididae, or scaly ant-eaters, are the only Edentate Mammalia found out of America. They are spread over the Ethiopian and Oriental regions; in the former from Sennaar to West Africa and the Cape; in the latter from the Himalayas to Ceylon, and Eastward to Borneo and Java, as well as to South China, as far as Amoy, Hainan, and Formosa. They have been sub-divided, according to differences in the scaly covering, into five groups, Manis, Phatagin, Smutsia, Pholidotus and Pangolin, the three former being confined to Africa, the last common to Africa and the East, while Pholidotus seems confined to Java. It is doubtful if these divisions are more than sub-genera, and as such they are treated here.
No extinct species referable to this family are yet known.
The Dasypodidae, or armadillos, are a highly characteristic Neotropical family, ranging from the northern extremity of the region
in south Texas, to 50° South latitude on the plains of Patagonia. The distribution of the genera is as follows:–Tatusia (5 sp.), has the range of the whole family from the lower Rio Grande of Texas to Patagonia; Prionodontes (1 sp.), the giant armadillo, Surinam to Paraguay; Dasypus (4 sp.), Brazil to Bolivia, Chili, and La Plata; Xenurus (3 sp.), Guiana to Paraguay; Tolypeutes (2 sp.), the three-banded armadillos, Bolivia and La Plata; Chlamydophorus (2 sp.), near Mendoza in La Plata, and Santa Cruz de la Sierra in Bolivia.
Eactinct Armadillos.—Many species of Dasypus and Xenurus have been found in the caves of Brazil, together with many extinct genera—Hoplophorus, Euryodon, Heterodon, Pachytherium, and Chlamydotherium, the latter as large as a rhinoceros. Eutatus, allied to Tolypeutes, is from the Pliocene deposits of La Plata.
The Aard-vark, or Cape ant-eater (Orycteropus capensis) is a curious form of Edentate animal, with the general form of an ant-eater, but with the bristly skin and long obtuse snout of a pig. A second species inhabits the interior of North-East Africa and Senegal, that of the latter country perhaps forming a third species (Plate IV. vol. i. p. 261).
Eactinct Orycteropodidae.—The genus Macrotherium, remains of which occur in the Miocene deposits of France, Germany, and Greece, is allied to this group, though perhaps forming a separate family. The same may be said of the Ancylotherium, a huge animal found only in the Miocene deposits of Greece.
The true ant-eaters are strictly confined to the wooded portions of the Neotropical region, ranging from Honduras to Paraguay on the East side of the Andes. The three genera now generally admitted are : Myrmecophaga (1 sp.), the great ant-eater, Northern Brazil to Paraguay; Tamandua (2 sp.), 4-toed anteaters, Guatemala, Ecuador to Paraguay (Plate XTV. vol. ii. p. 24); Cyclothurus (2 sp.), 2-toed ant-eaters, Honduras and Costa Rica to Brazil.
Eactinct Ant-eaters.—The only extinct form of this family seems to be the Glossotherium, found in the caves of Brazil, and the Tertiary deposits of Uruguay. It is said to be allied to Myrmecophaga and Manis.
General Remarks on the Distribution of the Edentata.
These singular animals are almost confined to South America, where they constitute an important part of the fauna. In Africa, two family types are scantily represented, and one of these extends over all the Oriental region. In Pliocene and PostPliocene times the Edentata were wonderfully developed in South America, many of them being huge animals, rivalling in bulk, the rhinoceros and hippopotamus. As none of these forms resemble those of Africa, while the only European fossil Edentata are of African type, it seems probable that South Africa, like South America, was a centre of development for this group of mammalia; and it is in the highest degree probable that, should extensive fluviatile deposits of Pliocene or Miocene age be discovered in the former country, an extinct fauna, not less strange and grotesque than that of South America, will be brought to
light. From the fact that so few remains of this order occur i. Europe, and those of one family type, and in Miocene eposits only, it seems a fair conclusion, that this represents an incursion of an ancient Ethiopian form into Europe analogous to that which invaded North America from the south during the Post-Pliocene epoch. The extension of the Manididae, or scaly ant-eaters, over tropical Asia may have occurred at the same, or a somewhat later epoch. For a summary of the Numerous Edentata of North and South America which belong to extinct families, see vol. i. p. 147.
The Didelphyidae, or true opossums, range throughout all the wooded districts of the Neotropical region from the southern boundary of Texas to the River La Plata, and on the west coast to 42° S. Lat., where a species of Didelphys was obtained by Professor Cunningham. One species only is found in the Nearctic region, extending from Florida to the Hudson River, and west to the Missouri. The species named Didelphys californica inhabits Mexico, and only extends into the southern extremity of California. The species are most numerous in the great forest region of Brazil, and they have been recently found to the west of the Andes near Guayaquil, as well as in Chili. The exact number of species is very doubtful, owing to the difficulty of determining them from dried skins. All but two belong to the genus Didelphys, which has the range above given for the family (Plate XIV, vol. ii. p. 24) ; Chironectes (1 sp.), the yapock or water opossum, inhabits Guiana and Brazil; Hyracodon (1 sp.), is a small