Ancient Primate Skeleton Hints at Monkey and Human Origins

[Buster's Uncle]

Ancient Primate Skeleton Hints at Monkey and Human Origins
By Tanya Lewis, LiveScience Staff Writer  | LiveScience.com – 2 hrs 59 mins ago..

The skeleton of Archicebus achilles, shown in this artist's sketch, is among the best-preserved examples of early primates.

 
The oldest well-preserved skeleton of a primate, a 55-million-year-old specimen found in China, has been discovered, researchers report.

The primate appears to be the most primitive known relative of the group that contains tarsiers, small primates found only in Southeast Asia. The finding suggests this group diverged from anthropoids, the group that contains monkeys, apes and humans, during the Eocene epoch (55.8 million to 33.9 million years ago), a time of widespread warming.

It's not the oldest primate fossil, researchers say, but it is one of the oldest most-complete skeletons of the group known as tarsiiformes.

"This discovery is really exciting," vertebrate paleontologist Jonathan Bloch of the University of Florida's museum of natural history told LiveScience, "because it shows us the first really [well-articulated] skeleton of one branch of the crown primate tree," (the group including all primates alive today and their common ancestor). Bloch was not involved in the study.

The fossil confirms speculation that the earliest primates probably lived in trees, ate insects and were active during the daytime.

The primate, now named Archicebus achilles (roughly translated as "ancient monkey"), would have weighed about 1 ounce (20-30 grams), suggesting the earliest primates were very small. The skeleton shares some features of tarsiers and some of anthropoids. For instance, the specimen's heel bone strongly resembles those of anthropoids, hence the species name, "achilles."
 

According to the researchers, this fossil and other evidence suggest the first steps of primate evolution took place in Asia, rather than Africa. But Bloch and others disagree with this interpretation.

"Crown primates appeared simultaneously in North America, Europe and Asia 56 million years ago," Bloch said. "I don't think this specimen tells us much about where primates themselves evolved," he added.

The fossil was dug up from an old lake bed in central China's Hubei Province, close to where the Yangtze River now flows.

The fossil was scanned with X-rays at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France, to produce a 3D digital reconstruction without damaging the specimen.

The Archicebus skeleton is roughly 7 million years older than the previously known oldest fossil primate skeletons, which include Darwinius from Messel, Germany, and Notharctus from the Bridger Basin, Wyoming.

Archicebus is not the oldest primate, anthropologist Mary Silcox of the University of Toronto Scarborough, Canada, told LiveScience. Nevertheless, "this new species will significantly impact our understanding of what is primitive for the common ancestor of living primates," Wilcox said.

The findings were reported online today (June 5) in the journal Nature.

http://news.yahoo.com/ancient-primate-skeleton-hints-monkey-human-origins-170918762.html

[Buster's Uncle]

Meet your distant cousin: Tiny hyperactive primate
By SETH BORENSTEIN | Associated Press – 3 hrs ago..

 
WASHINGTON (AP) — New fossil evidence of the earliest complete skeleton of an ancient primate suggests it was a hyperactive, wide-eyed creature so small you could hold a couple of them in your hand — if only they would stay still long enough.

The 55 million-year-old fossil dug up in central China is one of our first primate relatives and it gives scientists a better understanding of the complex evolution that eventually led to us. This tiny monkey-like creature weighed an ounce or less and wasn't a direct ancestor. Because it's so far back on the family tree it offers the best clues yet of what our earliest direct relatives would have been like at that time, according to a study published Wednesday in the journal Nature.

"It's a close cousin in fact," said study author Christopher Beard, curator at the Carnegie Museum of Natural History in Pittsburgh. He said it is "the closest thing we have to an ancestor of humans" so long ago.

Primate is the order of life that includes humans along with apes, monkeys, and lemurs. Humans are set apart from other mammals because of our grasping five fingers and toes, nails, and forward-facing eyes. And this new species called Archicebus achilles fits right in, Beard said.

Among primates there are three suborders: anthropoids which include apes, monkeys and us; and two other suborders that include lemurs and the lesser known tarsiers. This new species is in the same grouping as tarsiers, but close to the offshoot branch in the family tree where humans come from. The fossil includes anthropoid-like features.

"It's a cute little thing; it's ridiculously little," Beard said. "That's one of the more important scientific aspects of the whole story."

With a trunk only 2.8 inches long, the furry creature was about as small as you can get and still be a mammal, Beard said. Just like elephants and horses, the farther back in time you get for some of today's bigger mammals, the smaller they get, Beard said.

Because it was so small and warm-blooded it had to eat bugs and move constantly to keep from losing internal heat, Beard said.

That means, Beard said, our earliest primate relatives were "very frenetic creatures, anxious, highly caffeinated animals running around looking for their next meal." They lived in a tree-lined area near a Chinese lake, swinging around trees in a hotter climate, Beard said.

Outside experts praised the study as significant, confirming what some thought about our primate ancestors. Rick Potts, director of the human origins program at the Smithsonian Institution, said this fossil's mix of different features illustrate the fascinating and crucial changes that occur around major evolutionary branch points in our family tree.

The study also bolstered another theory that early primates first developed in Asia, even though humans evolved nearly 50 million years later in Africa, Beard said.

http://news.yahoo.com/meet-distant-cousin-tiny-hyperactive-primate-171835703.html