Antropoid primates– the forerunners of modern apes, monkeys and humans – first appeared in Asia, but what happened to them when climate change rendered much of the region too cold to be hospitable? A study published this week in the journal Science may have the answer.
“At the Eocene-Oligocene boundary, because of the rearrangement of Earth’s major tectonic plates, you had a rapid drop in temperature and humidity,” K. Christopher Beard, senior curator at the University of Kansas Biodiversity Institute and co-author of the new study, explained in a statement. “Primates like it warm and wet, so they faced hard times around the world.”
In North America and Europe, the creatures died out when this cooling began approximately 34 million years ago, but managed to survive in Africa and Southern Asia. Now, the discovery of a half-dozen new fossil primate species in southern China had revealed that the transitional period nearly wiped out these creatures, forcing them to migrate to Africa to survive and evolve.
Beard and his colleagues spent more than a decade working at a site in the Yunnan Province of southern China, where they managed to unearthed jaw and tooth fragments belonging to six new species of primates that help explained what happened to our forerunners during this period.
Courtesy IVPP, Chinese Academy of Sciences
Had temperatures not cooled significantly, humans may have evolved in Asia
The fossils managed to survive thanks to their tough enamel surfaces, the study authors noted, and analysis revealed that the creatures were primarily tropical tree-dwellers that fled to this part of China because it was warm enough for them to avoid extinction. One of the creatures, known as the Oligotarsius rarus, was remarkably similar to the modern-day tarsier.
“If you look back at the fossil record, we know that tarsiers once lived on mainland Asia, as far north as central China,” said Beard. “The fossil teeth described in this paper are nearly identical to those of modern tarsiers. Research shows that modern tarsiers are pretty much living fossils – those things have been doing what they do ever since time immemorial, as far as we can tell.”
Had climate change not occurred during the Eocene-Oligocene transition, causing temperatures around the world to plummet, the main phases of primate evolution may have continued to take place in Asia, as the creatures would have had little reason to migrate to Africa, he and his fellow researchers said. More to the point, the study sheds new light on the vulnerability of primates to climate change.
“This is the flip side of what people are worried about now,” Beard concluded. “The Eocene-Oligocene transition was the opposite of global warming – the whole world was already warm, then it cooled off. It’s kind of a mirror image. The point is that primates then, just like primates today, are more sensitive to a changing climate than other mammals.”
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Image credit: Thinkstock
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