Fossil may refute theory

25 March 2005 | 07:23 Code : 4841 Geoscience events
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The long-held scientific theory that many mammals, along with other animal groups, originated in Africa may have a few loopholes in it, according to a new study by scientists from UF and Johns Hopkins University.

The long-held scientific theory that many mammals, along with other animal groups, originated in Africa may have a few loopholes in it, according to a new study by scientists from UF and Johns Hopkins University.

In the Wyoming badlands, an area of severe erosion, researchers have found fossils of an elephant shrew, which is in the same family as elephants, aardvarks and sea cows, said Jonathan Bloch, a paleontologist with UF’s Florida Museum of Natural History.

“We found a very primitive, very old fossil” dated at 54 million years old, Bloch said.

He said the bones are evidence that this mammal originated in North America and then migrated to Africa.

This contradicts the popular Afrotheria idea — that many species are native to Africa and traveled to other continents.

Elephant shrews are “tiny little hopping mammals,” Bloch said, and were once thought to have originated in Africa. But his team’s evidence points to the shrews migrating there instead.

There, in relative isolation, the mammalian species could have evolved into the huge, modern elephants in Africa.

Millions of years ago, Gondwana, a large part of the giant supercontinent Pangea, began to split apart into the continents of modern day, Bloch said.

As Gondwana split, land bridges existed for years, allowing animals to migrate to different continents.

“This is significant because it shows there was more interchange upon the breakage of Gondwana than we previously thought,” Bloch said.

Findings were published in this month’s issue of the journal Nature.


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