0
$\begingroup$

The jaguar is a close relative of the Asiatic leopard and must have had a common ancestor within the last 5 million years. The South American tapir is obviously closely related to the Malayan tapir and must also have had a common ancestor within he last 5 million years. How did the leopard and tapir, typically tropical species, get from Asia to South America?

An obvious route would be the land route via the Bering Straits and the southern shore of Alaska which was used by humans about 15,000 years ago when the Ice Age had lowered sea level, but both animals are tropical and it is hard to believe they would have chosen such an icy route. The jaguar and tapir have in any case been separated from their Asiatic relatives for a lot longer than 15,000 years. I am wondering whether they could have arrived via a different route from the one chosen by the earliest human inhabitants of the Americas. Can anyone throw any light on this?

Continental drift played a part in isolating Old World monkeys from South American monkeys and setting Australia adrift carrying only marsupials, so is there a possibility that when Africa and Amazonia were closer together, immigration from Africa could have taken place, bearing in mind that there were times when sea levels were much lower?

$\endgroup$
  • 4
    $\begingroup$ this question have been asked on our sister site biology.stackexchange.com/questions/57703/… before. $\endgroup$ – trond hansen Nov 21 '19 at 5:46
  • $\begingroup$ some animals do move from one continent to another over the ice too theguardian.com/world/2019/jul/02/… $\endgroup$ – trond hansen Nov 21 '19 at 6:04
  • $\begingroup$ There have been other ice ages, too. $\endgroup$ – Erik Nov 21 '19 at 8:40
  • 5
    $\begingroup$ I'm voting to close this question as off-topic because this question have been asked before on our biology site biology.stackexchange.com/questions/57703/… $\endgroup$ – arkaia Nov 21 '19 at 17:29
  • 1
    $\begingroup$ @MichaelWalsby - You are reading that wikipedia article incorrectly, and it doesn't help that that wikipedia article is dubious. Whether tapirs originated in North America, Europe, or Asia is highly debated. What is not debated is that the South American tapirs did not originate in South American, nor did the Southeast Asia tapir originate in Southeast Asia. And they didn't originate in Africa, either. $\endgroup$ – David Hammen Nov 22 '19 at 1:53
2
$\begingroup$

The jaguar is a close relative of the Asiatic leopard and must have had a common ancestor within the last 5 million years. The South American tapir is obviously closely related to the Malayan tapir and must also have had a common ancestor within he last 5 million years.

While the first statement is more or less correct, the latter is not. The Asian and American branches of the tapirs split about 25 million years ago.

Regarding migration routes, felines have migrated back and forth between Asia and North America many times in the last eight million years or so. The ancestors of Tapirs apparently migrated back and forth between North America and Europe before 25 million years ago, when the climate was much warmer and the continents had slightly different shapes.

... is there a possibility that when Africa and Amazonia were closer together, immigration from Africa could have taken place?

Regarding South America, there were very few placental mammals in South America until about 3 million years ago, when the Isthmus of Panama formed. The age of the Isthmus is debated. The sudden appearance of placental mammal fossils about 2.7 million years ago in South America, including jaguars and tapirs, is not. South America's jaguars and tapirs migrated to South America via North America rather than Africa.

$\endgroup$
  • $\begingroup$ I don't dispute your separation date of 25 myr for Malayan and Amazonian tapirs, but to look at them one wouldn't think it was that far back. There should be tapir fossils leading from Alaska to Amazonia. Maybe one day they'll be found. But going back 25 myr, Africa and S. America must have been very close. That was about the date Old World monkeys separated from New World monkeys. It's difficult to believe they chose the Alaskan route and then took another 22 myr to reach Amazonia. I don't believe the experts have got these migration routes properly figured out. $\endgroup$ – Michael Walsby Nov 21 '19 at 19:28
  • $\begingroup$ @ David Hamman Wikipedia gives a date of 40 myr BP for separation of old World and New World monkeys, and says they crossed from Africa to Amazonia via the Atlantic, not via N. America. Another source says the separation date was 35 myr ago, and also says the route was via the Atlantic. If monkeys can do it, why not tapirs? This confusion verifies my assertion that the experts haven't got it properly figured out. $\endgroup$ – Michael Walsby Nov 21 '19 at 20:23
  • 1
    $\begingroup$ @MichaelWalsby - (1) There are lots of tapir / tapir-like fossils from all over North America, (including as far north as Ellesmere Island!), Europe, and Asia dating back to 30 plus million years ago. (2) There are no tapir fossils in South America from before the Isthmus of Panama formed ~3 million years ago. (3) There are no tapir fossils from Africa, period. South America's tapirs came from North America as a part of the Great American Biotic Interchange. $\endgroup$ – David Hammen Nov 21 '19 at 20:53
  • $\begingroup$ @ David Hammen You may well be right. All I am saying is that if monkeys can do it, why not tapirs or leopards? I think you will agree that the Wikipedia article blows the theory that S. America had only marsupials till 3 million years ago right out of the water. Remember that tapirs are rainforest animals and fossils don't preserve well in rainforest conditions. Another thing is that being closely related, tapir fossils and footprints are difficult to distinguish from rhino. I'm still not sure which spoor I saw in Malaya. Tapir-like fossils from N.America could be rhinos. $\endgroup$ – Michael Walsby Nov 21 '19 at 21:27

Not the answer you're looking for? Browse other questions tagged or ask your own question.