1.8M-year-old skull gives glimpse of our evolution

[Buster's Uncle]

1.8M-year-old skull gives glimpse of our evolution
Associated Press
By SETH BORENSTEIN and SOPHIKO MEGRELIDZE 2 hours ago



In this photo taken Oct. 2, 2013, in Tbilisi, Georgia, David Lordkipanidze, director of the Georgia National Museum, holds a pre-human skull found in 2005 in the ground at the medieval village Dmanisi, Georgia. The discovery of a 1.8 million-year-old human ancestor, the most complete ancient hominid skull found to date, captures early human evolution on the move in a vivid snapshot and indicates our family tree may have fewer branches than originally thought, scientists say. (AP Photo/Shakh Aivazov)


     
DMANISI, Georgia (AP) — The discovery of a 1.8-million-year-old skull of a human ancestor buried under a medieval Georgian village provides a vivid picture of early evolution and indicates our family tree may have fewer branches than some believe, scientists say.

The fossil is the most complete pre-human skull uncovered. With other partial remains previously found at the rural site, it gives researchers the earliest evidence of human ancestors moving out of Africa and spreading north to the rest of the world, according to a study published Thursday in the journal Science.

The skull and other remains offer a glimpse of a population of pre-humans of various sizes living at the same time — something that scientists had not seen before for such an ancient era. This diversity bolsters one of two competing theories about the way our early ancestors evolved, spreading out more like a tree than a bush.

Nearly all of the previous pre-human discoveries have been fragmented bones, scattered over time and locations — like a smattering of random tweets of our evolutionary history. The findings at Dmanisi are more complete, weaving more of a short story. Before the site was found, the movement from Africa was put at about 1 million years ago.

When examined with the earlier Georgian finds, the skull "shows that this special immigration out of Africa happened much earlier than we thought and a much more primitive group did it," said study lead author David Lordkipanidze, director of the Georgia National Museum. "This is important to understanding human evolution."



This photo taken Oct. 2, 2013, in Tbilisi, Georgia, shows a pre-human skull, that was found in 2005


For years, some scientists have said humans evolved from only one or two species, much like a tree branches out from a trunk, while others say the process was more like a bush with several offshoots that went nowhere.

Even bush-favoring scientists say these findings show one single species nearly 2 million years ago at the former Soviet republic site. But they disagree that the same conclusion can be said for bones found elsewhere, such as Africa. However, Lordkipanidze and colleagues point out that the skulls found in Georgia are different sizes but are considered to be the same species. So, they reason, it's likely the various skulls found in different places and times in Africa may not be different species, but variations in one species.

To see how a species can vary, just look in the mirror, they said.

"Danny DeVito, Michael Jordan and Shaquille O'Neal are the same species," Lordkipanidze said.

The adult male skull found wasn't from our species, Homo sapiens. It was from an ancestral species — in the same genus or class called Homo — that led to modern humans. Scientists say the Dmanisi population is likely an early part of our long-lived primary ancestral species, Homo erectus.





Tim White of the University of California, Berkeley, wasn't part of the study but praised it as "the first good evidence of what these expanding hominids looked like and what they were doing."

Fred Spoor at the Max Planck Institute in Germany, a competitor and proponent of a busy family tree with many species disagreed with the study's overall conclusion, but he lauded the Georgia skull discovery as critical and even beautiful.

"It really shows the process of evolution in action," he said.

Spoor said it seems to have captured a crucial point in the evolutionary process where our ancestors transitioned from Homo habilis to Homo erectus — although the study authors said that depiction is going a bit too far.

The researchers found the first part of the skull, a large jaw, below a medieval fortress in 2000. Five years later — on Lordkipanidze's 42nd birthday — they unearthed the well-preserved skull, gingerly extracted it, putting it into a cloth-lined case and popped champagne. It matched the jaw perfectly. They were probably separated when our ancestor lost a fight with a hungry carnivore, which pulled apart his skull and jaw bones, Lordkipanidze said.





The skull was from an adult male just shy of 5 feet (1.5 meters) with a massive jaw and big teeth, but a small brain, implying limited thinking capability, said study co-author Marcia Ponce de Leon of the University of Zurich. It also seems to be the point where legs are getting longer, for walking upright, and smaller hips, she said.

"This is a strange combination of features that we didn't know before in early Homo," Ponce de Leon said.

___



This 2005 photo provided by the journal Science shows a pre-human skull found in the ground








http://news.yahoo.com/1-8m-old-skull-gives-glimpse-evolution-181117272.html

[Unorthodox]

Ooo, much better pics than the article I saw earlier. 

[Buster's Uncle]

   Yeah; best set I've seen, and I stuck in a few extras at the bottom that weren't included in the article.

[Unorthodox]

Wait, in the one pic, what's the one on the right? 

And what's that next to the skull in the ground?!

[Buster's Uncle]

That is a rodent tooth.

Dunno whether the rat was huge or the skull a lot tinier than I assumed.  You can go to the article at the link to see the captions I didn't type in...

[Buster's Uncle]

Skull Suggests Single Human Species Emerged From Africa, Not Several
Well-Preserved Find 1.8 Million Years Old Drastically Simplifies Evolutionary Picture
By Robert Lee Hotz
   






The discovery of a 1.8 million-year-old skull has offered evidence that humanity's early ancestors emerged from Africa as a single adventurous species, not several species as believed, drastically simplifying the story of human evolution, an international research team said Thursday.

A newly discovered 1.8 million-year-old skull offers evidence that humanity's early ancestors emerged from Africa as a single adventurous species, not several, as believed. Robert Lee Hotz reports on the News Hub. Photo: Georgian National Museum.

The skull—the most complete of its kind ever discovered—is "a really extraordinary find," said paleoanthropologist Marcia Ponce de Leon at the University of Zurich's Anthropological Institute and Museum, who helped analyze it. "It is in a perfectly preserved state."

A 1.8-million-year-old hominid skull -- the most complete of its kind ever found – was unearthed at Dmanisi in Georgia. Georgian National Museum

Unearthed at Dmanisi in Georgia, an ancient route in the Caucasus for the first human migrations out of Africa, the skull was found at a spot where partial fossils of four other similar individuals and a scattering of crude stone tools had been found several years ago. They all date from a time when the area was a humid forest where saber-tooth tigers and giant cheetahs prowled. Preserved in siltstone beneath the hilltop ruins of a medieval fortress, the remains are the earliest known human fossils outside Africa, experts said.

David Lordkipanidze, director of the Georgian National Museum, who led the team, reported the discovery in Science. The primitive skull was first uncovered on Aug. 5, 2005—his birthday. "It was a very nice present," he said.

Taken together, the finds at Dmanisi are especially important because experts in evolution could analyze the physical differences between individuals living in the same place at the same time almost 2 million years ago, when humankind first emerged from Africa to people the world, according to Yale University anthropologist Andrew Hill.

"It gives you a chance to look at variation for the first time," said Dr. Hill, who was not involved in the discovery.

By comparing these five extinct creatures at Dmanisi to each other, and to other specimens from the same era in Africa, the researchers concluded that all of the primordial peoples of the Homo genus—the root-stock of the modern human family tree—likely belonged to just one species spreading out across the continents, not three or more as many experts have argued.

Their conclusion breaks with recent practice in the scholarly search for human origins. Typically, researchers have highlighted the differences between various human fossils, often assigning each new discovery to a separate species, and not grouping them by physical traits they had in common.

In this analysis, researchers concluded that the fossil remains most likely belonged to a tool-using species called Homo erectus, which existed from about 2 million years ago to about 143,000 years ago. Its fossilized remains have been found in Africa, Spain, Indonesia, India, China and Java. The earliest Homo sapiens, modern humans, emerged about 195,000 years ago.

"They nailed it," said paleoanthropologist Tim D. White at the University of California at Berkeley, who was not involved in the project. "This will cut a lot of dead wood that has accumulated in the family tree that paleontologists love to draw."

Known simply as Skull #5, the fossilized head bones likely belonged to a male, whose brain was about one-third the size of a modern human brain. The skull has a "strange combination of features," Dr. Ponce de Leon said. The face was relatively flat and long, with massive brows, a projecting jaw and big teeth.

The creature had a healed cheek fracture, a touch of arthritis and, by the evidence of wear, used his teeth for gripping things. He stood upright, with relatively modern arms and legs, the researchers said.

The other four fossilized individuals unearthed earlier at Dmanisi included skull fragments belonging to an elderly toothless male, a young female, a second adult male and an adolescent whose gender wasn't known. Although they shared common ground, they died separately, perhaps decades apart.

Using Skull #5 as a benchmark, the researchers compared the five specimens. They examined the variations in skull bones, jaws and teeth traditionally used to sort such fossils into different species.

Through a computer analysis, the researchers determined that the variations among these five early humans were no greater than the differences normally found between members of any single primate species, including chimpanzees, bonobos or modern humankind.

If their analysis proves true, experts will have to reconsider the pattern of early human evolution.

"There are these jaw-dropping moments in the life of a scientist," said neurobiologist Christoph Zollikofer at the University of Zurich, who analyzed the skull and the other Dmanisi fossils. "You can feel in your brain how all these preconceived ideas you had start falling to pieces."


http://online.wsj.com/news/articles/SB10001424052702304384104579141600675336982

[Buster's Uncle]

Georgia shows off skull thought to rewrite human evolution
AFP
By Kerry Sheridan 1 hour ago



The well-preserved skull from 1.8 million years ago was found in the remains of a medieval hilltop Georgian city of Dmanisi


     
Tbilisi (AFP) - Georgian scientists on Friday presented a 1.8 million-year-old skull discovered in the Caucasus nation that researchers say could force a re-evaluation of current theories of human evolution.

The skull -- unearthed in the medieval town of Dmanisi some 100 kilometres (62 miles) southwest of the capital Tbilisi -- is the first completely preserved skull found from that period.

Along with four other skull samples uncovered at the site, it appears to show that early man was a single species with a wide range of looks rather than several distinct species.

"Today in this skull -- and the other Dmanisi samples -- we see all the features lumped together in one group that we previously thought identified different groups," David Lordkipanidze, Georgia's national museum director, told AFP after a presentation in Tbilisi on Friday.

"This is the most important thing -- we are touching the earliest stages of genus homo and its lineage," Lordkipanidze said.

The collection -- which is housed in the vault of Georgia's national museum -- is "the richest collection of hominids in the world from that time", according to Lordkipanidze, the lead researcher on the project.

"We wanted to share with the Georgian public here what we had found," he said before allowing a small number of journalists into the vault to see the original skull.

The stunningly well-preserved find -- known as Skull 5 -- has an almost-complete set of teeth and seems more elongated than a normal human skull.

The fossil —- which is about a third the size of a modern human head —- is normally kept in a special padded box in the vault.

Wearing white gloves to avoid contaminating the sample, a beaming Lordkipanidze held up both the jaw and main section of the skull as photographers took pictures.



David Lordkipanidze -- the director of the Georgian National Museum -- holds the skull


A replica of the skull was unveiled for display to visitors in the museum.

The conclusions -- published in the US journal Science on Thursday -- are the result of some eight years of research carried out by Georgian and international scientists since the discovery of the skull in 2005.

The skull was found lying a few metres from where its jawbone had been discovered earlier in 2000.

The scientists behind the discovery claim the different lineages some experts have described in Africa -- such as Homo habilis and Homo rudolfensis -- were all just ancient people of the species Homo erectus who looked different from each other.

They also suggest that early members of the modern man's genus Homo, first found in Africa, soon expanded into Asia despite their small brain size.

But not all experts agree.

"I think that the conclusions that they draw are misguided," said Bernard Wood, director of the hominid paleobiology doctoral program at George Washington University.

"What they have is a creature that we have not seen evidence of before," he said, noting its small head but human-sized body.

"It could be something new and I don't understand why they are reluctant to think it might be."

Researchers did give the skull's owner a new name, Homo erectus ergaster georgicus, in a nod to the skull as an early but novel form of Homo erectus found in Georgia.

The site of the discovery -- thought to have been close to an important water source -- also contained rudimentary stone tools hinting at early butchery techniques and the bones of large, sabre-toothed cats.


http://news.yahoo.com/skull-discovery-suggests-early-man-single-species-180440066.html

...

I strongly suspect a bunch of science writers are being credulous.