352 ORIGIN OF LIFE IN AMEEICA 



Among living bears the nearest relation of the Andean species 

 seems to be the Malayan bear (Ursus malayanus) inhabiting 

 the Malay peninsula and neighbouring countries. But the 

 European Miocene Ursus boeckhi and the Pliocene Ursus 

 etruscus are members of the same group, and it appears to me 

 possible that the South American Tremarctos and the Ursus 

 malayanus groups may have had a common ancestor which 

 passed from southern Europe to South America by way of the 

 mid-Atlantic land bridge and the Antilles in Oligocene times. 

 Although tapirs have a much wider range in South America 

 than bears, their American distribution also suggests that, 

 like the bears, they are immigrants either from Europe or 

 Asia. Their general range is in so far comparable to the 

 distribution just cited as the only living tapirs are confined 

 to South America and southern Asia. Tapirs are often alluded 

 to as among the most striking and familar instances of what 

 is called " discontinuous distribution." But we know a good 

 deal more of the geological history of tapirs than of bears. Of 

 the two South American tapirs the smaller one is confined to 

 the Andes between Colombia and Peru, while the other 

 (Tapirus americanus) has probably spread eastward from a 

 western centre of dispersal, for it occurs from eastern Peru to 

 Brazil, Venezuela, Guiana and to northern Argentina. Two 

 other tapirs live in Central America. The genus is only known 

 fossil from Pleistocene South American deposits, and it might 

 appear as if it were a recent immigrant from North America. 

 But in the latter continent only a single fossil species 

 (Tapirus haysi) has been discovered, and that likewise in 

 Pleistocene beds. Professor Osborn asserts that a tapir, un- 

 distinguishable from the living South American species 

 (Tapirus americanus), invaded North America together with 

 Mylodon and Megatherium in Pleistocene times. I am not 

 aware of any reliable osteological characters distinguishing the 

 living South and Central American species. If there are such, 

 Professor Osborn's * statement may possibly refer to one of 

 the latter. Still, it is quite evident that the genus Tapirus 

 could not have come across any Bering Strait land connection 

 in Pleistocene times and have travelled to Argentina before 



* Osborn, H. F., "Age of Mammals," p. 472. 



