New Jebel Irhoud Date Causes Rethink of Chinese Dali Skull

Newsweek (Yes, that Newsweek) has a story on the reexamination of the Chinese Dali cranium, in light of the revised dates for the Jebel Irhoud skulls.  Kastalia Medrano writes:

Known as the Dali skull, it was discovered nearly 40 years ago in China’s Shaanxi province. It belonged to a member of the early hominin species Homo erectus. Its facial structure and brain case are intact, despite being dated to around 260,000 years ago. The Dali skull is so old that archaeologists initially didn’t believe it could share features with the modern Homo sapiens.

But Xinzhi Wu of the Chinese Academy of Sciences in Beijing believed that due to the overwhelming physical similarities, Homo erectus must have shared DNA with Homo sapiens. After decades of this idea being dismissed by mainstream academia, Wu and a colleague, Sheela Athreya of Texas A&M University, recently reanalyzed the Dali skull and found it may force us to rewrite our evolutionary history after all. It’s incredibly similar to two separate Homo sapiens skulls previously found in Morocco. “I really wasn’t expecting that,” Athreya told New Scientist.

If we’d found only the Moroccan skulls, and not the Dali skull, it would make sense to keep believing all modern humans evolved in Africa. But the similarities show that early modern humans may not have been genetically isolated from other parts of the world, like what we know today as China.

“I think gene flow could have been multidirectional, so some of the traits seen in Europe or Africa could have originated in Asia,” Athreya told New Scientist.

Okay, now the nuts and bolts.Dali has always been thought to occupy that rarified space between Homo erectus  and early modern Homo sapiens.  It was always thought to be between 200 and 250 kya, and optically-stimulated luminescence dating (a variant of thermoluminescence) places it between 258 and 267 kya.  My analyses of the skull suggested that it was, in no way, shape or form, a modern human but it did not tend to cluster with the Neandertals in terms of head shape.  Athreya and Wu have done an extensive multivariate analysis and conclude (from the article, likely behind a paywall:

When just the facial skeleton is considered, Dali aligns with Middle Paleolithic H. sapiens and is clearly more derived than African or Eurasian Middle Pleistocene Homo. When just the neurocranium is considered, Dali is most similar to African and Eastern Eurasian but not Western European Middle Pleistocene Homo. When both sets of variables are considered together, Dali exhibits a unique morphology that is most closely aligned with the earliest H. sapiens from North Africa and the Levant.

These results add perspective to our previous view of as Dali a “transitional” form between Chinese H. erectus and H. sapiens. Athough no taxonomic allocation is appropriate at this time for Dali, it appears to represent a population that played a more central role in the origin of Chinese H. sapiens. Dali's affinities can be understood in the context of Wu's Continuity with Hybridization scenario and a braided-stream network model of gene flow. Specifically, we propose that Pleistocene populations in China were shaped by periods of isolated evolutionary change within local lineages at certain times, and gene flow between local lineages or between Eastern and Western Eurasia, and Africa at other times, resulting in contributions being made in different capacities to different regions at different times.

In combination with the Xuchang remains, the reanalysis of this skull suggests that, indeed, there is a long and complex interrelationship between different hominin groups that dates back some 400 thousand years. From the paper:

In the braided-stream network model, evolutionary change in China was the result of a shifting network of gene flow among distinct regional Chinese populations, as well as between Chinese and Western Eurasian populations. These were not isolated evolutionary lineages; gene flow both within China and between Eastern Eurasia, Western Eurasia and Africa was intermittent and could explain the similarities in aspects of the neurocranium found here between Dali and Western Eurasian Middle Pleistocene humans. Gene flow would best be described as a braided stream network with periods of isolated evolutionary change within a local lineage at times, and periods of gene flow between local lineages or paleo-demes at other times, resulting in contributions being made in different capacities to different regions at different times.

It is pretty clear that our simplistic models of Recent African Replacement and Multiregional Evolution need to be reworked. It is becoming more apparent that what we are looking at either a polytypic species with a huge geographical range or a syngamion of related species that intermixed regularly. The Xuchang skulls were, apparently, not unique.

Scientifice American: "Creationism Invades Europe"

Scientific American is sounding an alarm that creationism is gaining support in Europe. Stefaan Blancke and Peter C. Kjærgaard write:

We are used to thinking about creationism as an exclusively North American phenomenon. It is not. Although it originated in the U.S., organized creationism has gone global. But in Europe creationism does not represent a united community; it varies strongly from one country to the next. In some countries creationism provides an identity to smaller local religious communities, and has little impact. This is the case in Scandinavia. In other places creationism is tied to substantial and well-organized subcultures. We find this in the Netherlands. And in some places creationism exists among religious elites that have considerable political power. Russia is a notable example.

For years, although creationists were growing in number in European countries and gradually developing an influence in schools and local communities, they mostly kept under the radar and were not a major concern. Not until, at least, about a decade ago, when the Council of Europe issued a warning against the growth of creationism and the potential threat to the educational system it posed. At that point, creationism became a matter of public and political debate. Polls were taken all over Europe to determine public opinion. Some online polls were hijacked by creationists in Turkey to alter the outcome. Books, pamphlets and Web sites were launched and circulated. And the media loved it.

While one does tend to think of young earth creationism as a uniquely American phenomenon (after all, it sprang from the Seventh Day Adventists in the early 1900s), it is important to note that the currently reigning king of creatonism, Ken Ham, is Australian by birth and upbringing.

The authors remark that the scientific community got caught flat-footed and now are scrambling to catch up to the wave of web sites, pamphlets, magazines and TV programs that are being sponsored by the young earth creation groups.  This is similar to what happened here in the United States.  It was only dimly understood that creationism was making inroads in society, despite the high-profile cases involving the public schools.  The home school community is almost lock-step creationist, a situation that has caused no small amount of grief in our household.  The post below this one is but one example of this. 

The Origins of Modern Humans, The Fossil Evidence, Part II

The second of my BioLogos posts on the fossil evidence concerning the origins of modern humans is up. 

Geologically Recent Ape in Europe

Deutsche Welle world has an interesting story about dental remains that have been discovered in Europe that put Miocene apes in the region as recently as 7 million years ago. According to the story:

"The latest data have shown that contrary to the hominids in Western and Central Europe (with the exception of the insular Oreopithecus), hominids from the Eastern Mediterranean may have lived up to 8 to 7.5 [million years ago], preadapted to the more open biotopes of the Balkan-Iranian zoographic province," the team wrote.

What is important to note about this story (and it threw me for a minute) is that the author is using the newer phylogenetic systematics-driven definition of “hominid.” In this scheme, “hominids” are now at the family level and include us and all of the great apes and “hominins” (us and our ancestors) are at the sub-family level.

A problem, voiced by one of the excavators, is, of course, that it is just one tooth, so we cannot say too much about it. Still, it is interesting if it bears up.

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European Hand Axes Almost a Million Years Old

New dating has revealed that hand axes from two sites in Spain are close to a million years old. Yahoo UK reports:

Gary Scott and Luis Gibert of the Berkeley Geochronology Center in Berkeley, California applied a technique called magnetostratigraphy to determine that the hatchets were in fact crafted between 760,000 and 900,000 years ago.

Magnetostratigraphy is based on the periodic reversal of Earth's magnetic field.

Acting like tiny compasses, fine-grained magnetic minerals in the tools contain a record of the polarity at the time they were used. Once buried in sediment, the polarity is preserved.

"The age (of the axes) must be Early Pleistocene, the most recent period dominated by reverse polarity, 1.78-to-0.78 million years ago," the researchers concluded.

Magnetostratigraphy is also known as palaeomagnetism. It was always suspected that the hand axe use was there, it is just that there has been no concrete evidence. This changes that. There is a tool assemblage called the "Mousterian of Acheulean Tradition," that is practiced by Neandertals in southern Europe and Gibraltar but it is more advanced than the typical hand axes you find associated with Homo erectus. The transition likely took place much after this, in southern Europe.

Out of Europe????

Bob Holmes of the New Scientist is reporting on a spectacular find in Spain of a 12 million year old primate that seems to show characteristics of both African and European Miocene apes. While the hype level is not as high as it was with Ida, the find raises some questions about where the later hominoids came from. He writes:

The fossil, named Anoiapithecus brevirostris by Salvador Moyà-Solà of the Catalan Institute of Palaeontology in Barcelona, Spain, and his colleagues, dates from a period of human evolution for which the record is very thin. While only the animal's face, jaw and teeth survive, their shape places it within the African hominid lineage that gave rise to gorillas, chimps and humans. However, it also has features of a related group called kenyapithecins.

Moyà-Solà says that A. brevirostris and some similar-looking kenyapithecins lived in Europe shortly after the afrohominid and kenyapithecin lineages split, and so that the divergence itself may have happened there. If he is right, our hominid ancestors lived in Europe and only later migrated to Africa, where modern humans evolved.

Methinks this is a tad premature, since we have Miocene apes on all continents and the remains are not as certainly diagnostic.



It will certainly get people thinking about primate origins in a new way.