EarthSky: Twenty years of discoveries changing story of human evolution

EarthSky has an interesting article that summarizes twenty years of human evolution discoveries.  They write:

Perspectives on our own species have also changed. Archaeologists previously thought Homo sapiens evolved in Africa around 200,000 years ago, but the story has become more complicated. Fossils discovered in Morocco have pushed that date back to 300,000 years ago, consistent with ancient DNA evidence. This raises doubts that our species emerged in any single place.

This century has also brought unexpected discoveries from Europe and Asia. From enigmatic “hobbits” on the Indonesian island of Flores to the Denisovans in Siberia, our ancestors may have encountered a variety of other hominins when they spread out of Africa. Just this year, researchers reported a new species from the Philippines.

All of these discoveries point to the idea that there was considerable population mixing throughout the Middle to Late Pleistocene not just in Africa but throughout the Old World. We know that it took place in China around 120,000 years ago by the evidence from Linjing.  These particular hominins have characteristics found in modern humans, Neandertals and Homo erectus.

Interestingly, the idea that our species did not originate in any single place was an idea pursued by Rachel Caspari almost two decades ago, at a paper given at one of the American Association of Physical Anthropologists conventions.  At the time, it was still thought that the “Out of Africa” replacement model was still the best explanation for modern human origins.We now know that it is not.

Earliest Art Made By Humans?

Artnet News has a post on a discovery in Henan Province, China that purports to be the oldest indications of consciously-created art.  From Sarah Gascone:

Abstract patterns carved on bone fragments discovered in China could be the oldest art ever made, dating back to between 105,000 and 125,000 years ago.

The marks on two bones were found at a site in Henan Province thought to be populated by Denisovans, an extinct species or subspecies of ancient humans, according to a new study in the Cambridge University Press journal Antiquity. The markings on the weathered rib bones contain traces of ochre on one specimen, the earliest evidence of pigment’s use for decorative purposes.

The newly discovered artworks pre-date even the 73,000-year-old markings—thought by some to be abstract drawings—found last year on a rock excavated from a South African cave, and previously thought to be the earliest-known example of human artistic activity.

Here is an image of the markings:

Photo Credit: Francesco d’Errico and Luc Doyon.

There seems to be a persistent thought that people of this age simply could not make art of this kind. I think it more stems from the fact that this kind of representation rarely survives in the fossil record. We know that as far back as 300k, there was division of labor and that there was quite a bit of population mixing this far back.  There is also a record of Neandertal cave paintings at 65k.  It is nice to find this kind of artistic expression but it ought not to surprise us. 

Bat-Winged Dinosaurs in the Jurassic

“From there to here, from here to there, funny things are everywhere.” —Dr. Seuss

A new discovery in China (natch) indicates that, during the Jurassic, there were flying dinosaurs that, effectively, used the same sort of propulsion system used by modern bats.  From Science Magazine:

A number of tiny, bat-winged dinosaurs flew the Jurassic skies, according to the strongest evidence yet for such creatures—a well-preserved fossil of a starling-size fluffball that may have looked a little like a flying squirrel. The find, recovered near a farming village in northeastern China, suggests dinosaurs were experimenting with several methods of flight during this period, but many were an evolutionary dead end.

“This fossil seals the deal—there really were bat-winged dinosaurs,” says Stephen Brusatte, a paleontologist at the University of Edinburgh who was not involved with the study.

Scientists were already confident that a number of dinosaurs could fly. There are birds, of course, which are technically dinosaurs and appeared during the Jurassic period, at least 150 million years ago. Other dinosaurs sported feathers on their hind- and forelimbs, effectively giving them four birdlike wings.

Evidently, most of these creatures were very small, some the size of a starling.  It seems that the idea of flight was much more common during this period than was originally thought.  Here is an artist's reconstruction.

The more we discover, the stranger it gets.

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.

'Swiss Army knife of prehistoric tools' Found in China

Science Daily is on a roll.  This came out a bit back during the late semester crunch and I didn't get a chance to post about it.  Stone tools have been found in south China that appear to be made using the Levallois technology, which originated during the Middle Stone Age, in Africa.  They write:

A study by an international team of researchers, including from the University of Washington, determines that carved stone tools, also known as Levallois cores, were used in Asia 80,000 to 170,000 years ago. Developed in Africa and Western Europe as far back as 300,000 years ago, the cores are a sign of more-advanced toolmaking -- the "multi-tool" of the prehistoric world -- but, until now, were not believed to have emerged in East Asia until 30,000 to 40,000 years ago.

And now the, somewhat, startling conclusion:

With the find -- and absent human fossils linking the tools to migrating populations -- researchers believe people in Asia developed the technology independently, evidence of similar sets of skills evolving throughout different parts of the ancient world.

This particular conclusion seems somewhat ignorant of the fossil record, which clearly has hominins in the area that have distinct Neandertal traits.  The authors, in fact, even mention the possibility that the appearance of the tools might be tied to these earlier migrations, then seem to dismiss this for reasons that are, in my mind, not clear. 

The site, itself, Guanyindong Cave in Guizhou Province, is not new, having been excavated in the 1960s and 1970s.What is new is the date of 80-170 kya.  Levallois tools were thought to have arrived in the area around 30-40 kya and are seen as the artifacts of a late migration.  This re-dating of the sediments of Guanyindong Cave means that these kinds of tools were in the area some 100 ky earlier than was originally thought.  I do, however, think their evidence for independent origin is sparse. 

Another Human Species in China?

The Christian Science Monitor and other outlets are reporting on a new find from Xuchang, China, that seems to possess intermediate traits between archaic and modern Homo sapiens:

In an article published Friday in the journal Science, the researchers note that the skull fragments date to the Late Pleistocene epoch, a time marked by the expansion of H. sapiens and the extinction of other species in the genus Homo. During the early part of that epoch, Neanderthals roamed Europe and western Asia while humans began to journey out of Africa. But fossil records of human species in Eastern Asia from that time period are thin, muddying the picture of that era for a substantial region of the planet.

The skulls found in China were found to bear very close resemblances to those of Neanderthals, including a very similar inner ear bone and a prominent brow ridge. But the brow ridge was much less pronounced than one would expect from Neanderthals, with a considerably less dense cranium, as one might expect in an early H. sapiens. Researchers also found that the skulls were large by both modern and Neanderthal standards, with a whopping 1800 cubic centimeters of brain capacity.

So where do they fit in the grand scheme of things?

"The overall cranial shape, especially the wide cranial base, and low neurocranial vault, indicate a pattern of continuity with the earlier, Middle Pleistocene eastern Eurasian humans. Yet the presence of two distinctive Neanderthal features ... argue for populational interactions across Eurasia during the late Middle and early Late Pleistocene," said Dr. Trinkaus in a statement.

This kind of population mixing makes sense. We already know that modern humans and Neandertals interbred in Europe and that the geographic range of Neandertals stretched from Portugal to Teshik Tash, in Russia and Shanidar Cave, in Iraq.

The remains are dated to Marine Oxygen Isotope Stage 5d or 5e, making them between 105 and 125 ky in age.  Here is a description of the neurocranium from the paper:

The large Xuchang 1 neurocranium closely approximates the shapes of those of Middle Pleistocene humans, especially eastern Eurasians (Fig. 2 and fig. S17). The vault height is low, similar to those of the Neandertals and the higher Middle Pleistocene vaults, and the low vault height is reflected in a low temporal squamous portion (figs. S27 and S28). It is also produced by the very flat midsagittal parietal arc. In contrast, the maximum cranial breadth is the largest known in the later Pleistocene (fig. S15), and it is securely based on an undistorted posterior cranium. Moreover, the widest point is low, on the temporal bones (fig. S17), as in most earlier crania, rather than on the parietal bones, as among Neandertals and most modern humans. In addition, the one complete mastoid process is short and slopes inward (fig. S17), rather than being longer and more vertical, as in modern humans and some Neandertals. These features combine to provide the cranium with an occipital profile similar to those of earlier human crania, contrasting with the rounded profiles of Neandertals and the laterally vertical ones of modern humans.

There are a few things that are immediately interesting about this. First, this skull is YUGE.  1800 cc is monstrous.  The average cranial capacity of modern humans is around 1450 cc and that of Neandertals, around 1550 cc.  Second, the low, flat cranium with the widest point on the temporal bones (just above your ears) are traits of Homo erectus, not modern humans or Neandertals, suggesting strongly that there was some sort of continuity from this group through to modern humans in this region.  Neandertals simply don't have those traits.  Nonetheless, the cranium clearly shows some Neandertal traits in the ear and rear of the vault.  This continuity is characterized by the authors thus: "This morphological combination, and particularly the presence of a mosaic not known among early Late Pleistocene humans in the western Old World, suggests a complex interaction of directional paleobiological changes and intra- and interregional population dynamics."  As more information becomes available, we will have a better idea of how this find fits in the east Asian evolutionary picture.  This is exciting.  Up until this point, we have had very few finds in China that fall within this general time frame, most notably the Dali and Mapa remains.  I will have to rework my section on human origins for the BioLogos site for this region. 

New BioLogos Post on the Daoxian Modern Human Teeth

My BioLogos post on the new anatomically modern human fossil remains from the South China Daoxian Cave is up.  As always, comments welcome here and there.

New Hominin Finds in China

In somewhat hyperbolic terms, Discovery News reports on “Mysterious Dark-Skinned Stone Age People Found.” Jennifer Viegas writes:

A newly found Stone Age people featured darker skin, an unusual mix of primitive and modern features and had a strong taste for venison.

Remains of possibly four individuals of the so-called "Red Deer Cave People" were unearthed in southwest China and may represent a new species of human.

The fossils from two caves, date to just 14,500 to 11,500 years ago. Until now, no hominid remains younger than 100,000 years old have been found in mainland East Asia resembling any other species than our own. "We have discovered a new population of prehistoric humans whose skulls are an unusual mosaic of primitive, modern and unique features -- like nothing we've seen before," said Darren Curnoe, associate professor in the School of Biological, Earth & Environmental Sciences at the University of New South Wales and lead author of a study about the find in the journal PLoS One.

Curnoe wrote about the finds in 2009:

While the material falls within the range for modern human variation, the individuals show some archaic features and are robust. Only a handful of potential stone tools have been recovered from the site; many are hammer stones.

It would be quite peculiar if this were another species of human, although the evolutionary picture is getting muddy in Europe, so it stands to reason that it should be muddy in Asia, especially given that we have the Denisova evidence. In the PLoS article (http://dx.doi.org/10.1371/journal.pone.0031918) the authors remark that it is possible that they represent a late-surviving archaic group or that the Homo sapiens populations that were coming out of Africa were remarkably diverse morphologically and that these individuals represent a more primitive population of those migrants. There is reasonably good evidence that there were different groups that migrated to East Asia over the course of the last million or so years and this group may simply reflect one.

It is an odd mix of traits to be sure. The brain case is somewhat low (http://dx.doi.org/10.1371/journal.pone.0031918.g005), and yet the mandibles have chins, a late-arriving characteristic, only present in modern humans. Additionally, the face is flat(http://dx.doi.org/10.1371/journal.pone.0031918.g003) and there is no space behind the last molar, indicating modernity. Either way, it is fascinating find but the headlines are unnecessarily over-the-top. Read the whole article.

Aside: Curnoe is a splitter with the best of them and in the mould of Bernard Wood. He was responsible for a new species of Homo, in South Africa, Homo gautengensis, because he felt that the remains differed from other specimens of early Homo enough to give them their own species designation. This name has not had traction in the palaeoanthropological community.

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What Gigantopithecus Ate

A story in PhysOrg reports on research done on the diet of Gigantopithecus blacki, the immense primate that lived during the late Miocene in southern China and Vietnam. They write:

Drs. ZHAO LingXia, ZHANG LiZhao and WU XinZhi, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Achttp://www.blogger.com/img/blank.gifademy of Sciences, and ZHANG FuSong from Institute of Geology and Geophysics, Chinese Academy of Sciences, analyze enamel stable carbon isotope values of G. blacki and the associated mammalian megafauna from two sites in South China, and find that this giant ape and other large mammals solely fed on C3 biomass, and lived in forest habitats, as reported in the journal of Chinese Science Bulletin, 2011(56), No.33:3590-3595.

C3 biomass sources are more primitive than C4, which include the canes and more open-field grains. This is not a surprise, just confirmation of what we suspected.

This was a truly unusual and majestic ape, standing some eight to ten feet tall. There were two species, G. bilasporensis and G. blacki, the latter of which lasted until around 300 k years ago. It is this form that is likely the impetus behind the Sasquatch and abominable snowman stories. Here is an artist' sketch, based on accumulated jaws and teeth.





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Palaeontology Ramping Up in China

Randy Boswell of the Ottawa Citizen has an article on work that is going on in China involving the transition from Dinosaurs to birds and the work of a Canadian palaeontologist:

But a Canadian scientist working in China has scored a paleontological hat trick in the past month alone, co-authoring three papers that detail the discovery of two new species of the extinct reptiles -- including one with a striking resemblance to the roadrunner -- and reveal a previously unknown feature of "feathered arms" in a birdlike dinosaur with the posture of a penguin.

Corwin Sullivan, an evolution expert raised in Ontario and B.C. and educated at the University of Toronto and University of Victoria, says the flurry of published studies is "mostly a coincidence of timing," but also reflects how China has emerged as the world's richest fossil hotbed, particularly when it comes to tracing links between dinosaurs and birds.

The amount of material that is coming out of this area is staggering and there is much more to come.

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And Not Just Chinasaurs...

Foxnews has a report on some amazingly preserved spiders found in China. It states, in part:

The creepy crawlies were unearthed by Paul Seldon, a paleontologist from Kansas, who discovered them in China's Daohugou region. This area is rich with fossils because, during the Jurassic era, the fossil bed here was part of a lake in a volcanic region.

Spider fossils from this period are rare, because the arachnids' soft bodies don't preserve well. But Mr Seldon was delighted to discover these specimens had been almost perfectly preserved because they had became trapped in volcanic ash.

They are thought to be around 165 million years ago. Here is the accompanying picture from the Foxnews Story.



Neat!
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Dinosaur Footprints in East China City

Zhucheng City has been found to be the home of a series of Dinosaur footprints that represent more than six different dinosaurs. The story in Xinhaunet reports:

The footprints in at least three layers are rare in the world in terms of both their number and total size, they said.

The footprints, which range from 10 cm to 80 cm in length, revealed more than six kinds of dinosaurs, including Tyrannosaurus, Coelurosaurs and Hadrosaurs.

The footprints were in the same direction. Wang said this might be a result of migration or panic escape by plant-eating dinosaurs when facing a surprise raid from meat-eating counterparts.

Now, how again do you get fossil footprint in a world-wide flood? In different layers?

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Another Bird-Dinosaur Link

Yahoo news is reporting an incredible fossil find in China:

A young dinosaur that fatefully wandered into a mudpool around 155 million years could help explain the mysterious evolution of birds, says the world's most famous fossil-hunter.

A team led Xing Xu, a Chinese dino expert with scores of astonishing finds to his name, uncovered the fossilised remains of a small, exceptional dinosaur in the Shishugou Formation in western China's Junggar Basin.

The creature is the only known beaked herbivorous therapod -- the family of two-legged dinosaurs that were notorious meat-eaters -- from the Jurassic era, they report in Nature, the London scientific journal.

But that is apparently not what is getting everybody's attention. It is the feet:

A widely-accepted theory is that birds emerged from small therapod dinosaurs, developing wings from reptilian forelimbs. The earliest known bird, Archaeopteryx, lived around 150 million years ago.

But in the late 1990s, evidence came forward that appeared to punch a hole in the bird-dino idea. Therapods have digits corresponding to the first, second and third digits -- the thumb, index and middle finger -- on a human hand.

But scientists discovered that in bird embryos, all five digits start to emerge, yet only the second, third and fourth digits survive to develop into the wing structure. The first and outer digits disappear.

In other words, the 1-2-3 of dino digital orthodoxy ran into the 2-3-4 of avian digital reality. There was no way that bird's wings could have developed this way, said critics. They claimed either theropods were not the forerunners of birds -- or else theropods and birds shared some pre-dino common ancestor.

But the new study shows that Limusaurus, startlingly, has a greatly-reduced first digit, while its second, third and fourth digits are far more fully developed. This could be a sign of a process by which digit use shifted, with ceratosaurs as a sort of halfway house, argues Xu.

It could be that this was just one of many different variants of late non-avian, early avian theropods. Another piece of the puzzle.

Extinction in the Oceans

A news article that appeared on Yahoo News has implicated a huge volcanic eruption 260 million years ago in the devastation of life in the oceans:

The researchers were able to pinpoint the exact timing of the massive eruption thanks to a layer of fossilized rock which showed mass extinction of different life forms -- clearly linking the volcanic blasts to a major environmental catastrophe.

"The abrupt extinction of marine life we can clearly see in the fossil record firmly links giant volcanic eruptions with global environmental catastrophe," said Paul Wignall, a professor and palaeontologist at the University of Leeds, who was the lead author of the research paper in the May 29 edition of Science.

The eruption in southwest China unleashed about a half million cubic kilometers of lava, covering an area five times the size of Wales, according to the research by scientists at the British university.

Although the news of the extinction is new, the existence of this volcano is not. Geologic maps dating from the 1960s clearly showed the existence of a massive cone in central-west China. I remember looking at them and thinking "dang, that's a huge volcano."