New BioLogos Post on Stone Tool Discovery in China

My BioLogos post on the stone tool discovery at the Chinese site of Shangchen is up.  Comments welcome here and there.

New Chinese Material Pushes the Exit From Africa to 2.1 mya

Nature is reporting research on new Chinese material that strongly suggests that the Georgian site of Dmanisi is not the earliest location to which migration out of Africa went.  Here is the abstract:

Considerable attention has been paid to dating the earliest appearance of hominins outside Africa. The earliest skeletal and artefactual evidence for the genus Homo in Asia currently comes from Dmanisi, Georgia, and is dated to approximately 1.77–1.85 million years ago (Ma)1. Two incisors that may belong to Homo erectus come from Yuanmou, south China, and are dated to 1.7 Ma2; the next-oldest evidence is an H. erectus cranium from Lantian (Gongwangling)—which has recently been dated to 1.63 Ma3—and the earliest hominin fossils from the Sangiran dome in Java, which are dated to about 1.5–1.6 Ma4. Artefacts from Majuangou III5 and Shangshazui6 in the Nihewan basin, north China, have also been dated to 1.6–1.7 Ma. Here we report an Early Pleistocene and largely continuous artefact sequence from Shangchen, which is a newly discovered Palaeolithic locality of the southern Chinese Loess Plateau, near Gongwangling in Lantian county. The site contains 17 artefact layers that extend from palaeosol S15—dated to approximately 1.26 Ma—to loess L28, which we date to about 2.12 Ma. This discovery implies that hominins left Africa earlier than indicated by the evidence from Dmanisi.

For the new site sequence data, we don't have any hominin remains so we don't know exactly what these folks looked like but the tools are very primitive.  A section from a companion piece reads thus:

The identity of their makers is, for now, unclear: no hominin bones have been recovered at Shangchen. “We would all love to find a hominin — preferably one with a tool in its hand,” says Dennell. Homo erectus is one possibility, because some of the earliest members of this species were found at Dmanisi. But Dennell thinks that the Shangchen toolmakers belonged to an earlier species in the genus Homo.

Petraglia and Rezek both say that the age of the tools — not to mention the possibility that hominins arrived in China even earlier than the 2.12-million-year mark — suggests that the toolmaker was a species such as Homo habilis. This relatively small-brained hominin is thought to have been confined to Africa between around 2.4 million to 1.4 million years ago.

Jungers holds open the possibility that the Shangchen toolmaker was a species of Australopithecus, a group of more ape-like hominins to which the iconic fossil Lucy belongs. So far, all Australopithecus fossils have been discovered in Africa.

Before his death, Grover Krantz argued for the presence of Australopithecus in East Asia but could never get anyone to come on board with him. Everyone was pretty content to label what was coming out of the ground as Homo erectus.I think it would be a stretch if the hominins from Shangchen were australopithecines since we don't see any advanced species of Australopithecus in East or North Africa between 2 and 2.5 mya.  In fact, Au. boisei drops out around 2.1, likely out-competed by early Homo.

Nonetheless, something was making stone tools in China at 2.1 mya and that is “Yuuuuge” news. 

Acts and Fiction: The ICR Does A Hatchet Job on Dmanisi Skull 5

The ICR has, bluntly, called the description of the new Dmanisi skull 5 a fraud.   Lets find out why.  The conclusion, based on the descriptors of the morphology of skull 5 is that it has a mix of early Homo and Homo erectus traits.  Brian Thomas of the ICR thinks it is nothing more than an ape.  In support of this, he puts together seven points, which I will take one at a time.  The analysis is somewhat repetitive at times because Mr. Thomas' points, themselves, are.

Point No. 1

It is anatomically quite different from known human skulls. The Science authors wrote, "The morphology of skull 5 stands apart from that of any other known fossil Homo specimen through its combination of a small braincase with a large prognathic face." Maybe it "stands apart from" man because it was not a man. Could it actually be an ape's skull?

Well, no.  It has no ape characteristics at all.  They are clearly hominin in nature.   For example:

1. The foramen magnum (the hole for the spinal column) is at the base of the skull, rather than the back, as is the case for apes.  It is how we know that it was bipedal.  There is not a single ape, fossil or otherwise that has this characteristic. 
2. On observation of the skull, there is clearly an angular torus (a ridge of bone extending from the ear to the back of the head), a trait not found in early African Homo but found in the rest of the Dmanisi skulls and all East Asian Homo erectus specimens, suggesting that this population represented a point at which there was radiation out of Africa in two directions, toward Europe and Asia. This is not a trait found in any ape. 
3. When scaled for brain weight/body size, the brain case is too large to be an ape.  It is clearly a hominin.  Further, other skulls in the Dmanisi sample range from 601 to 730 cubic centimeters in size, a quarter more to double the size of any extant or fossil ape. 
4. The teeth are clearly hominin in morphology (see images below).  While there is considerable procombency of the incisors (they angle forward from the face), there is no expansion of the canines beyond the tooth row, the premolars are not rotated to sharpen the canines and there is no diastema (space) between the canines and incisors to make room for an expanded canine in the opposite tooth row.  This is clearly a hominin mouth, not an ape one.

Point No. 2

It is too loosely linked with human postcranial material. The study author's phrase "probably associated" cannot substitute for solid scientific evidence.

So?   Say it isn't linked with any of the post cranial material.  That doesn't change the morphology of the skull in any way.

Point No. 3

It has a very ape-like brain volume—far smaller than that of a human. It was estimated at 546cc, similar to that of gorillas and Australopiths, but only about half the average size of a human

As Mr. Thomas so correctly notes, the cranial size is not necessarily an indication of intelligence or of hominin status.  He also doesn't define what he means by "human."  Conventional anthropologists define "human" as being bipedal (and not the weird Oreopithecus-style gait).  No other primate does this and it dates to around 4.4 million years ago.  Further, given that size is not a reliable indicator, point 3 above still stands.

Point No. 4

It has a heavily built, ape-like jaw. Skull 5 "has the largest face, the most massively built jaw and teeth and the smallest brain within the Dmanisi group," according to a news release from the University of Zurich where three of the Science authors work.⁴ But where is the evidence proving that all five Dmanisi skulls even belong to the human group?

There is variability in all fossil samples. For example, the Mladeč sample from central Europe that dates to between 34 and 37 thousand years ago is quite variable, with some crania resembling Neandertals and others resembling modern humans. Further, as Lordkipanidze et al. point out, the range of variation present in the Dmanisi sample is not greater than what one would find in a sample of chimpanzees or the world-wide sample of modern humans (although intra-populational differences in the modern human sample, I am quite sure, are less).

Point No. 5

It links to other material that is not clearly identified or dated. The Science authors reported, "Furthermore, the remarkably large and robust dentognathic remains of early H. erectus from Java (Trinil/ Sangiran) exhibit close affinities with skull 5." But the abstract describing the Java remains reads, "Temporal changes, within-group variation, and phylogenetic positions of the Early Pleistocene Javanese hominids remain unclear."
Additionally, experts in human evolution have a long history of assigning human and ape remains to the Homo erectus human category. By tying skull 5 to past category confusion, the Science authors muddied their own identification of skull 5 as human.

The fact that some temporal changes in Homo erectus remain unclear does not diminish the importance or morphology of the East Asian Homo erectus fossils, themselves, many of which are nicely dated to between 1.5 and 1.8 million years ago.  From the paper that Thomas cites:

Further, it is absolutely clear that there are differences between these hominins and later populations:   The Bapang-AG H. erectus population is advanced, showing a similar degree of dentognathic reduction as the Middle Pleistocene Chinese H. erectus represented by the Zhoukoudian and Lantian remains. In this respect, this population is significantly derived relative to African early H. erectus and the oldest hominids of Java (Grenzbank/Sangiran group). However, it remains unclear whether these apparent similarities reflect affinities or homoplasy between the Bapang-AG and Chinese H. erectus.

Thomas' second point on tying this skull to category confusion is a terminological inexactitude.  Experts in human evolution do no such thing.  In fact, there has been a raging dispute about how expansive the Homo erectus taxon actually is, with splitters, like Ian Tattersall on one side arguing that the human fossil record between 2 million and 500,000 years B.P. is taxonomically more diverse than we think and Milford Wolpoff, who argues that we need to lump everything into Homo and dispense completely with the taxon Homo erectus.  The only person I know of who is assigning too many fossils to Homo erectus is Marvin Lubenow who, in his execrable book Bones of Contention was unable, as nearly as I could tell, to distinguish Homo erectus from anything else and who made numerous errors because of this.  Further, Lordkipanidze and colleagues did not tie the skull to category confusion, they attempted to place it taxonomically within the entire range of Homo.

But even if it were case that they were tying skull 5 to Homo erectus, that is still nothing like saying it is an ape, since no Homo erectus fossils are ape-like in any way, shape or form.  Case in point:

The top image is an African Homo erectus specimen (KNM-ER 3883) while the bottom one is a chimpanzee.  The differences are striking.

Point No. 6

The researchers' approach to skull 5 may be similar to other fraudulent or dubious finds. Dutch physician Eugene Dubois, anxious to find proof of human evolution, uncovered the famous Java "man" fossils in 1891. It was not until 30 years later that Dubois revealed the truth behind the find and admitted he had been hiding fully human skulls from the same Javan site. Some later suggested that his Java man skull cap was actually that of a gibbon. Could today's scientists be subject to the same eagerness to prove evolution, leading to skewed analyses? Because human origins research can be so subjective, one researcher of the history of paleoanthropology voiced a relevant caution: "We have only to recall the Piltdown adventure to see how easily susceptible researchers can be manipulated into believing that they have actually found just what they had been looking for."

The Science authors also wrote that skull 5 looks like the famous KNM-ER 1470 found in Africa. But skull 1470 was pieced together from so many separated fragments that it may not constitute a real, single individual. Understandably, its identification has long been difficult. Who knows which pieces were from humans and which were from apes?

Even so, the part of skull 1470 showing a forehead and human-like brow ridges differs from the apish appearance of skull 5. Did the Science authors link skull 5 to Africa's KNM-ER 1470 for evolutionary rather than anatomical reasons?

Okay, this one made me really mad because it accuses the researchers of not being competent or careful about what they have described.  The remains that DuBois uncovered were manifestly Homo erectus.  They weren't fully human and they sure as heck weren't a gibbon.   The research community refused to accept DuBois' claims because they thought he was working in the wrong part of the world, and they were susceptible to eurocentrism, a problem which dogged the discipline for decades.

Human origins research isn't any more or less subjective than any other scientific enterprise.   It grows and changes in relation to new data that is unearthed.  You might say the same thing about cosmology or cell theory or microbiology, fields that are always attempting to understand how things work.  Researchers are human and they make mistakes.  But they also try to fix them.  What is conveniently left out of Thomas' paragraph is that the Piltdown hoax was uncovered by scientists, working with scientific methods.  Science, as a self-correcting enterprise, works very well, and palaeoanthropology is no different. 

Regarding ER 1470, his reference is another young-earth creationist, Duane Gish, who has been shown repeatedly to have a severely limited knowledge of the fossil record (See Don Prothero's book Evolution: What the Fossils Say and Why it Matters for examples)  The idea that it represented pieces of humans and apes is unsupported.  The skull has many, many contiguous pieces—enough to reliably construct the cranium and the face.  Further, the pieces that were found are manifestly not from fossilized apes, none of which have ever been found in East Africa.  The primary dispute was not what it looked like, the primary dispute was how old it was. Richard Leakey said that it was 2.9 my old and everyone else said "Well, no, Richard, that can't be right."  Eventually, when stratigraphic and radiometric analysis was done, it was discovered to be around 1.9 million years old.

Point No. 7:

It is replete with ape features. Skull 5 has a U-shape dental arch, not the more parabolic shape humans present. Its chin slopes back like an ape without the forward-jutting bottom point of a human chin. There is no human nose bridge, and it has prominent attachment points for enormous jaw and neck muscles.

It most certainly does have a human-shaped dental arch.  Turn any human skull on its head and you will find dental anatomy exactly like what you find in Skull 5. Lets take a look.  On the left is a modern human from an inferior view.  On the right is Dmanisi Skull 5.  The tooth rows are very similar in shape, with similarly-proportioned teeth.

 

Now lets compare both of these skulls to that of a chimpanzee to see exactly what the differences are.

Well, for one, you can clearly see the diastema between the canine and the incisors.  You can also see that the maxillary tooth rows in the chimpanzee are parallel, instead of a gentle U that you see in the other two skulls.  The canine on the chimpanzee is very expansive, sharp and extends beyond the tooth row.  Further, you can see that, in Skull 5, the foramen magnum is underneath the skull, not toward the back as in the chimpanzee.   Skull 5 looks nothing like the chimpanzee skull and, in fact, shares most (if not all) of its similarities with the modern human from this anatomical position.

The lack of a chin is absolutely expected at this point in human evolutionary history and is related entirely to tooth size.  As the front teeth have shrunk in size, the bone has resorbed in the front of the jaw, creating the chin.  In fact, tooth size has continued to shrink even since the advent of modern humans, with an 11% drop since the Neolithic.  What Mr. Thomas does not seem to realize is that the chin has only appeared in the last 100 thousand years and is absent not just on early Homo but Homo erectus and archaic Homo sapiens.  The lack of a chin, in no way impairs its status as a hominin, unless you don't consider Neandertals hominins.  There is no human nose bridge on the skull because that didn't appear until archaic Homo sapiens, some 400 thousand years ago.

Thomas ends his article with this: 

Biblical creationists are not restricted to interpreting skull 5 according to evolution. Instead, they are free to exercise a healthy scientific skepticism of current interpretations. If Dmanisi skull 5 ends up not being human at all, then its titillating implications for human evolution fizzle. It would then simply become an extinct ape kind's skull found in a long-collapsed animal den into which saber-toothed cats may have dragged both human and other prey.

This is only true if the information is being treated honestly. Unfortunately, because Mr. Thomas does not possess the necessary education in either comparative primate or fossil human anatomy, he cannot do this. That he has seemingly failed to educate himself on even the basic anatomy necessary to understand these errors further compounds the problem.  His analysis is riddled with inaccuracies and unwarranted conclusions and, as such, constitutes no evidence against evolution or that the Dmanisi fossils are anything other than what the investigators say they are.

This is yet another hatchet job by the ICR.

Hat tip to Todd Wood.

"Single Evolving Lineage of Early Homo"

This was reported a month or so back.  A new fossil has been described from the site of Dmanisi, the 1.8 million year-old site in the Russian republic of Georgia.  The skull is almost totally complete and, with associated jaw, is one of the best examples of early Homo in existence.  From the abstract of the Lordkipanidze et al¹ article:

The Dmanisi sample, which now comprises five crania, provides direct evidence for wide morphological variation within and among early Homo paleodemes. This implies the existence of a single evolving lineage of early Homo, with phylogeographic continuity across continents.

The idea of a single, evolving lineage is the closest you will get to someone admitting that there might be anagenetic speciation going on here. It also suggests a wide range for early Homo that extended from eastern Africa, across the upper coast, and across the strait of Gibraltar. There is evidence of early Homo at Orce, in Spain and Pirro Nord, in Italy from around 1.6 to 1.3 million years ago. No actual hominin remains exist at these sites but the stone tools that have been found found match, generally, those found at Dmanisi. Not a smoking gun but close.

What is intriguing about this is that it is not a huge intellectual leap that is making these hominins move.  The newly-described Dmanisi skull has a cranial capacity of 546 cubic centimeters, barely 100 more than the late australopithecines.  The morphological diversity also has people interested.  From the Science Daily story:

According to [Christophe] Zollikofer, the reason why Skull 5 is so important is that it unites features that have been used previously as an argument for defining different African "species." In other words: "Had the braincase and the face of the Dmanisi sample been found as separate fossils, they very probably would have been attributed to two different species." Ponce de León adds: "It is also decisive that we have five well-preserved individuals in Dmanisi whom we know to have lived in the same place and at the same time." These unique circumstances of the find make it possible to compare variation in Dmanisi with variation in modern human and chimpanzee populations. Zollikofer summarizes the result of the statistical analyses as follows: "Firstly, the Dmanisi individuals all belong to a population of a single early Homo species. Secondly, the five Dmanisi individuals are conspicuously different from each other, but not more different than any five modern human individuals, or five chimpanzee individuals from a given population."

the differences between the East African and Eurasian fossils then could be just regional variation in an evolving polytypic species. This kind of explanation certainly gives the "lumpers" a leg up and, if this explanation is the best one going, calls into our question the splitting that we have applied to other species. Is it, instead, appropriate to sink such taxonomic forms such as Homo heidelbergensis, Homo ergaster, Homo rudolfensis and Homo habilis, all of which exhibit considerable size and shape dimorphism, into one species: Homo erectus which now has taxonomic precedence?

¹A Complete Skull from Dmanisi, Georgia, and the Evolutionary Biology of Early Homo David Lordkipanidze, Marcia S. Ponce de León, Ann Margvelashvili, Yoel Rak, G. Philip Rightmire, Abesalom Vekua, and Christoph P. E. Zollikofer Science 18 October 2013: 342 (6156), 326-331.

The Evolution of Modern Clothing

A University of Florida study has determined that modern humans first developed clothing around 170,000 years ago and that this enabled them to migrate out of Africa. Danielle Torrent writes:

Principal investigator David Reed, associate curator of mammals at the Florida Museum of Natural History on the UF campus, studies lice in modern humans to better understand human evolution and migration patterns. His latest five-year study used DNA sequencing to calculate when clothing lice first began to diverge genetically from human head lice.

Funded by the National Science Foundation, the study is available online and appears in this month’s print edition of Molecular Biology and Evolution.

“We wanted to find another method for pinpointing when humans might have first started wearing clothing,” Reed said. “Because they are so well adapted to clothing, we know that body lice or clothing lice almost certainly didn’t exist until clothing came about in humans.”

The data shows modern humans started wearing clothes about 70,000 years before migrating into colder climates and higher latitudes, which began about 100,000 years ago. This date would be virtually impossible to determine using archaeological data because early clothing would not survive in archaeological sites.

Oh? Okay, lets parse this. Modern humans invented clothing so they could move into colder climates. News flash: hominids were knocking on the gates of Europe 1.8 million years ago. This we know from the Caucasus site of Dmanisi. Furthermore, there are Chinese Homo erectus sites that date to between 250 and 550 thousand years ago. These locales were not temperate. The site of Zhoukoudian is near Beijing, which can experience temperatures as low a -4 degrees Fahrenheit. It is with this hominid that we see the first control of fire. The story continues:

“The new result from this lice study is an unexpectedly early date for clothing, much older than the earliest solid archaeological evidence, but it makes sense,” said Ian Gilligan, lecturer in the School of Archaeology and Anthropology at The Australian National University. “It means modern humans probably started wearing clothes on a regular basis to keep warm when they were first exposed to Ice Age conditions.”

Again, the hominids in China lived during the East Asian equivalent of the Mindel glaciation, during which it would have been colder than it is now.The story continues:

The study also shows humans started wearing clothes well after they lost body hair, which genetic skin-coloration research pinpoints at about 1 million years ago, meaning humans spent a considerable amount of time without body hair and without clothing, Reed said.

Not sure I buy this either. You can't survive in those locales during glacial periods without one or the other. You can't pick fire up and move it around with you. During the mid- to late Pleistocene, you had hominids in southern Europe, northern China, the Caucasus and other places. During the Würm glaciation, the tundra line was at Vienna.

I would like to see a follow-up story.

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