Homo sapiens afarensis vs. Homo sapiens sapiens afarensis ?

[Jacques Cinq-Mars]

Anyone lucky enough to have rapid access to Nature should make sure to look at tomorrow’s issue and then, hopefully, provide the Forum with his/her views on what is reported below by the Globe & Mail.

Jacques Cinq-Mars

GLOBE & MAIL BREAKING NEWS

Breaking News INTERNATIONAL - POSTED AT 4:44 AM EDT
Wednesday, Jun. 11, 2003

Skulls of oldest nearly modern humans unearthed
Associated Press.

Scientists have unearthed three 160,000-year-old human skulls in Ethiopia that are the oldest known and best-preserved fossils of modern humans' immediate predecessors.

The nearly complete skulls of an adult male and a child and the partial skull of a second adult appear to represent a crucial stage of human evolution when the facial features of modern humans arose.

Discovered in Ethiopia's fossil-rich Afar region, the skulls have clearly modern features - a prominent forehead, flattened face and reduced brow - that contrast with older humans' projecting, heavy-browed skulls.

"They're not quite completely modern, but they're well on their way. They're close enough to call Homo sapiens," said Tim White, a University of California, Berkeley paleontologist who was co-leader of the international team that excavated and analyzed the skulls.

Previously, the earliest fossils of Homo sapiens found in Africa had been dated to about 130,000 to 100,000 years, although they were less complete and sometimes poorly dated, Mr. White said.

The new skulls, which were dated at between 160,000 and 154,000 years old, are described in two papers that appear in Thursday's issue of Nature.

Mr. White and his colleagues assigned the new creatures to a subspecies of Homo sapiens they named Homo sapiens idaltu - idaltu meaning "elder" in the Afar language.

Two other scientists not involved with the research said the skulls are an important find that fill a big gap in the African human fossil record, the period between about 100,000 and 300,000 years ago.

They agreed with Mr. White that the skulls' age and appearance strongly support genetic evidence that modern humans arose in Africa between 100,000 and 200,000 years ago - and not at multiple locations in Europe, Africa and Asia as some researchers suggest.

Rick Potts, director of the Human Origins Program at the Smithsonian Institution, said the skulls, while still large and thick-boned, are undeniably modern.

Unlike the heavy brows and projecting facial features of earlier humans, in the news skulls those features have retracted dramatically under the braincase and there is a prominent forehead.

Mr. Potts said that while Mr. White and his colleagues conclude that the fossil skulls are likely those of ancestral subspecies of Homo sapiens, he believes they represent modern Homo sapiens.

"My view of it is that these fossils have enough modern traits to be considered the earliest well-dated fossils of our species of modern Homo sapiens," he said.

Mr. Potts said he would not be surprised if additional excavations in Africa push back the origins of modern humans to about 200,000 years - humans who would have then spread to Europe and Asia.

G. Philip Rightmire, a paleoanthropologist at State University of New York at Binghamton, called the skulls a "spectacular'' find.

He said they provide the clearest fossil evidence to date for an African origin of modern humans, and strike another blow against the idea that modern humans had a "multiregional" origin both within and outside the African continent.

"I think this pretty much serves as another nail in the coffin of multiregionalism," Mr. Rightmire said.

A proponent of the multiregional theory disputed that conclusion, saying the paper ignores fossils of about the same age of nearly modern humans found in Europe, China and Indonesia.

Milford Wolpoff, a professor of biological anthropology at the University of Michigan in Ann Arbor, also said the skulls, while significant, shed little light on the origins of modern humans.

"It tells us something about dates, it tells us something about features but it doesn't resolve the issue of where modern humans came from," he said.

The skulls were found in a desolate area about 140 miles northeast of Ethiopia's capital, Addis Ababa, near the village of Herto.

Skull fragments from a total of 10 individuals were unearthed, but conspicuously lacking were their jaws and any bones below the neck.

Mr. White said two of the skulls appear to have been scraped clean of flesh, suggesting an ancient mortuary practice, or possibly cannibalism.

Scattered across the same area were thousands of stone tools, including hand axes, along with the butchered bones of hippopotamus and antelope.

Mr. White said the site, once the lush shoreline of a large lake, was probably a seasonal foraging ground for the humans.

[colin]

The quote in the article, apparently from Wolpoff, that points out that the paper ignores other "nearly modern" finds from elsewhere, is telling. It will be interesting to see how "modern" the new finds are compared with something like Dali. It has long seemed to me that had Dali been found in Africa, it would have attracted the same sort of claims that are now being made for these new skulls. As Dali is on the "wrong" continent to fit the story, it is rather quietly left to one side by the ooa people.
Very exciting though. Cant wait to see some pictures.
Cheers
Colin  

[Scott MacEachern]

There's a free link to a commentary by Chris Stringer here

I have PDFs of the two relevant articles from _Nature_. Probably not a good idea to post them, but I would be happy to e-mail them to anyone who wants a look. Just send me a message at smaceach@bowdoin.edu. (One of the articles, on the behavioural contexts of the finds, lists Desmond Clark as first author, which will very unfortunately likely be one of the last times we will see that.)

Scott

[lagarvelho]

Jacques:

You will be interested to know that a kind soul on another forum put up a pdf of the article(s) and comments.  Oh well.  Another bunch of stuff to read as soon as I get a moment and print it.  Suppose I could read it off the computer, but I find it easier to read paper.  

However, judging by the pictures, it seems to me that what they've got doesn't look very "modern" to me.  At best it may resemble the later Qafzeh and Shkul people.  But I'll have to examine them more closely.
Anne G

[Jacques Cinq-Mars]

. . .  and here is Nature’s own short piece on the article in question.

* People who are not lucky enough to have access to Nature should surf the Web very carefully; they could well, by chance, hit upon the three Nature articles/reports that deal with these new Ethiopian finds!

Jacques Cinq-Mars

color=Red]NATURE – Science Update

Skulls reveal dawn of mankind
Ethiopian fossils confirm our African roots.
11 June 2003

MICHAEL HOPKIN[/color]

Homo sapiens idàltu: our 160,000 year old relatives.

Skulls found in Ethiopia are the oldest modern human fossils yet. The 160,000-year-old bones open a valuable window on the birth of Homo sapiens.

The fossils boost the theory that our species arose in Africa, says Tim White of the University of California, Berkeley, whose team made the discovery1. Many experts have argued that Africa was the cradle of humankind, opposing the view that we arose in several regions throughout the globe.

"It's a nice example of the fossil record confirming what we have believed," says Daniel Lieberman, who studies human evolution at Harvard University in Cambridge, Massachusetts.

Head start

White and his colleagues came across the specimens in Herto, the scorching desert of Ethiopia's Middle Awash region. The haul comprises two complete crania - one adult, one child - and large fragments of skull from another adult.

The bones "have all the features of modern humans - there's nothing lacking", says Lieberman. For example, the adult cranium has a large, globular braincase and a flat face.

The crania also show some slightly more primitive characteristics, such as widely spaced eyes. This indicates the fossils' position at the root of the H. sapiens family tree. White's team has assigned the specimens to a new subspecies, H. sapiens idaltu.

The fossils were nestling amid a profusion of hippopotamus and antelope bones and a range of blades and other tools. This suggests that our ancestors were proficient butchers2.

The child's skull has a sheen which suggests it may have been handled after death.
source: Nature

The tools themselves show a mixture of fairly advanced Stone Age technology - in which sharp blades of the desired shape were struck from a prepared rock - and more primitive sharp stones. It seems that cultural innovation mirrored the development of modern humans' anatomy.

The human skulls themselves also sport blade marks - perhaps indicating that they were stripped of their flesh after death for preservation. The child's skull has a distinctive sheen, suggesting, says White, that it was repeatedly handled and could even have been used as an ornament or drinking vessel. "This could be the first glimmering of emotion surrounding death," he argues.

It's a plausible idea, agrees anthropologist Alison Brooks of George Washington University in Washington, DC. She points out that many tribal cultures in the modern world preserve the bones of the dead. But she warns that evidence of flesh removal is not necessarily evidence that bones were used in post-mortem rituals - it is often difficult to tell whether the bones were buried or kept.

Early signs

Having pinned our ancestors down in Africa, the question now is how did we evolve within that huge continent. Did modern humans, for example, start in East Africa and spread from there? Or did our various anatomical and cultural hallmarks arise in different regions?

I doubt we will find one single place where everything happened
Chris Stringer

"I doubt we will find one single place where everything happened," says Chris Stringer, who studies human origins at London's Natural History Museum. He suggests, for example, that desert conditions could have isolated early populations from one another. Such populations could have reintegrated sometime later, if the climate became more favourable, and shared the advanced traits they each had developed.

Questions like this will not be answered without more fossils of a similar vintage. "African fossil finds are very scattered," White says. "But maybe this [find] will focus people's attention on this period."
References

White, T. D. et al. 2003. Pleistocene Homo sapiens from Middle Awash, Ethiopia. Nature, 423, 742 – 747.

Clark, J. D et al. 2003. Stratigraphic, chronological and behavioural contexts of Pleistocene Homo sapiens from Middle Awash, Ethiopia. Nature, 423, 747 – 751.

© Nature News Service / Macmillan Magazines Ltd 2003.