South African hominin younger than thought


Where Homo naledi was found

From Science News:

A narrow, sometimes treacherous path took Rising Star cave explorers from the surface to the Lesedi Chamber in South Africa. Homo naledi fossils excavated there come from at least three individuals, including an adult male that the investigators named Neo. An adjacent, belowground passageway connects to the Dinaledi Chamber, where H. naledi fossils were first unearthed.

Homo naledi may have lived at around same time as early humans

New dating puts famed hominid in South Africa as recently as 236,000 years ago

By Bruce Bower

4:00am, May 9, 2017

Fossils of a humanlike species with some puzzlingly ancient skeletal quirks are surprisingly young, its discoverers say. It now appears that this hominid, dubbed Homo naledi, inhabited southern Africa close to 300,000 years ago, around the dawn of Homo sapiens.

H. naledi achieved worldwide acclaim in 2015 as a possibly pivotal player in the evolution of the human genus, Homo. Retrieved from an underground chamber in South Africa, fossils of this species were thought to be anywhere from 900,000 to at least 1.8 million years old (SN: 8/6/16, p. 12). A younger age for H. naledi resolves one mystery about these cave fossils. It doesn’t, however, answer questions about how long ago the species first appeared and when it died out.

What is now known is that H. naledi bodies somehow ended up in Dinaledi Chamber, part of South Africa’s Rising Star cave system, between 236,000 and 335,000 years ago, an international team reports in one of three papers published May 9 in eLife. Paleoanthropologist Lee Berger of the University of the Witwatersrand in Johannesburg headed the team. Geoscientist Paul Dirks of James Cook University in Townsville, Australia, directed the dating effort.

In the first paper, two methods of measuring the concentration of natural uranium and other radioactive elements, and damage caused by those elements over time, provided key age estimates for three H. naledi teeth. A thin sheet of rock deposited by flowing water just above the fossils was also dated.

In a second new paper, Berger’s group — led by paleoanthropologist John Hawks of the University of Wisconsin–Madison — describes 131 newly discovered H. naledi fossils from a second underground cave, dubbed Lesedi Chamber, within the Rising Star cave system. The finds come from at least three individuals and include an adult male’s partial skeleton comparable in completeness to Lucy’s famous, 3.2-million-year-old remains from East Africa. Both of these specimens consist of about 40 percent of the skeleton. The researchers named the Lesedi partial skeleton “Neo,” which means gift in Sesotho, a language spoken in South Africa.

Berger and his colleagues say the Lesedi discoveries support their controversial suggestion that H. naledi deliberately put bodies of the dead in Rising Star’s underground chambers (SN: 5/14/16, p. 12). The team says there are no signs that either predatory animals or streams carried H. naledi corpses into the caves.

Individuals from both underground chambers display the same distinctive pattern of skeletal features, signs that they all belong to H. naledi, not to Homo erectus or any other previously identified Homo species, the investigators contend. These features include relatively small, orange-sized brains and curved fingers like those of Homo species that lived around 2 million years ago, as well as wrists, hands, legs, feet and body sizes comparable to those of Neandertals and humans.

Although the Dinaledi finds are unexpectedly young, H. naledi’s ancient-looking characteristics suggest that the hominid originated near the root of the Homo genus, 2 million years ago or more, Berger and colleagues propose in the third new paper. That would make the South African species a possible ancestor or close relative of H. erectus, which dates to around that time. The oldest Homo fossils date to 2.8 million years ago in East Africa (SN: 4/4/15, p. 8).

Another possibility, Berger’s group says, is that H. naledi originated a few hundred thousand years ago and is most closely related to early H. sapiens or other Homo species that may have inhabited southern Africa at that time. A relatively late origin for H. naledi would suggest it evolved from larger-brained ancestors, the researchers say. That would be unusual: Scientists have long held that the brain only became larger as Homo species evolved.

But that proposed scenario has some parallels to Indonesia’s Homo floresiensis, better known as the hobbit. These hominids, whose remains date to between about 100,000 and 60,000 years ago (SN: 4/30/16, p. 7), had chimp-sized brains, short statures and, like H. naledi, some skull features resembling early Homo species. Hobbits either evolved smaller brains or retained small brains after splitting from a much older Homo species in Africa.

Unlike H. naledi, hobbits lived on an island where a lack of competition with other Homo species may have assisted their survival. It’s unclear how H. naledi survived in Africa alongside larger-brained Homo species, perhaps even H. sapiens. Occasional interbreeding in southern Africa — similar to what occurred later among H. sapiens, Neandertals and Denisovans in Eurasia (SN: 10/15/16, p. 22) — may have benefited H. naledi, Berger’s team suspects.

H. naledi DNA would help clarify the species’ evolutionary status. But attempts to extract DNA from Dinaledi fossils have so far failed. Researchers have yet to test Lesedi fossils for DNA or to try to generate age estimates for the new finds.

“My intuition is that Homo naledi points to a diversity of African Homo species that once lived south of the equator” in Africa, Hawks says. It’s unlikely Homo evolution proceeded in a straight line, from one species to the next, in a specific part of subequatorial Africa, he proposes.

Paleoanthropologists familiar with the new reports interpret the findings differently.

An “astonishingly young” age for a Homo species with several ancient-looking features suggests H. naledi was the sole survivor of an array of much older, closely related species, proposes Chris Stringer of the Natural History Museum in London. H. naledi probably made some of the many stone tools found at southern African sites dating to around 300,000 years ago that have not yielded hominid fossils, he adds. But despite Berger’s claims, Stringer doubts a creature with a brain size close to that of a gorilla disposed of its dead deep within a pitch-black, hard-to-navigate cave system, especially since the controlled use of fire for torches was probably also needed.

Berger’s team plans to excavate near openings to the Rising Star cave system where stone tools and signs of fire use may turn up.

However complex H. naledi’s behavior may have been, ancient aspects of its anatomy rule it out as an ancestor of H. sapiens, says Donald Johanson of Arizona State University in Tempe. Johanson, codiscoverer of Lucy, argues that H. sapiens originated in East Africa. Researchers generally place that evolutionary turning point, wherever it occurred, at between 200,000 and 300,000 years ago. “The Rising Star Cave hominids, much like the hobbits, evolved in isolation and have no relevance to the origins of humankind,” Johanson says.

Still, even a largely isolated H. naledi population may have occasionally interbred with other Homo species in southern Africa, says Fred Smith of Illinois State University in Normal. Later Homo evolution “is far more complex than has generally been thought,” he says.

Berger and his colleagues second that point.

Newly obtained dating of the fossil hominin species Homo naledi, which was first discovered in 2015, significantly alters its position in the overall pattern of human evolution. Furthermore, it raises significant questions regarding the pattern of human evolution more generally: here.

Neandertal DNA discovery on cave floor


This 2016 video from the USA is called CARTA: DNA–Neandertal and Denisovan Genomes; Neandertal Genes in Humans; Neandertal Interbreeding.

From Science magazine:

DNA from cave soil reveals ancient human occupants

Lizzie Wade

28 Apr 2017

Summary

Fifty thousand years ago, a Neandertal relieved himself in a cave in present-day Belgium, depositing, among other things, a sample of his DNA. The urine clung to minerals in the soil and the feces eventually decomposed. But traces of the DNA remained, embedded in the cave floor.

Now, researchers have shown they can find and identify such genetic traces of both Neandertals and Denisovans, another type of archaic human, enabling them to test for the presence of ancient humans even in sites where no bones have been found.

Scientists say ancient DNA from sediments will help them complete the map of ancient human occupations and allow them to see where species may have overlapped and interacted. Many believe it will become a standard tool in paleoarchaeology, much like radiocarbon dating is today.

Water tubing accidents, table run-ins cause Neandertal-like injuries. Analysis shows that comparing ancient and modern bone breaks yields little insight into hominids’ everyday dangers. By Bruce Bower, 1:57pm, May 1, 2017: here.

Megatherium giant sloth was vegetarian


This February 2017 video is called 10 Interesting Facts About Sloths.

From the Senckenberg Research Institute and Natural History Museum in Germany:

Giant sloth was vegetarian: Diet of fossil Megatherium decoded

April 18, 2017

Summary: Scientists have examined the diet of the extinct Giant Sloth Megatherium. Based on analyses of the collagen in the fossil bones, the researchers concluded in their study that Megatherium subsisted on an exclusively vegetarian diet. Until recently, there had been much speculation about the food habits of these elephant-sized, ground-dwelling animals.

Together with an international team, Senckenberg scientists examined the diet of the extinct Giant Sloth Megatherium. Based on analyses of the collagen in the fossil bones, the researchers concluded in their study, which was recently published in the scientific journal Gondwana Research that Megatherium subsisted on an exclusively vegetarian diet. Until recently, there had been much speculation about the food habits of these elephant-sized, ground-dwelling animals.

Sloths may well rank among the world’s most peculiar animals: With their backs pointing downward, they hang in trees and move in slow motion from branch to branch with the aid of their sickle-shaped claws. “Sloths already occurred 10,000 years ago, for example the species Megatherium,” explains Professor Dr. Hervé Bocherens of the Senckenberg Center for Human Evolution and Palaeoenvironment at the University of Tübingen.

The extinct relatives of the sloths could reach the size of an elephant and were much too heavy to spend a significant amount of time in the trees. Instead, they lived on the ground, where they excavated large burrows. For many years, their dietary habits were an enigma; the long claws on their hands and feet, in particular, gave rise to various speculations. Did the sloths use their claws to dig up subterranean insect colonies? Did the long claws serve as hunting tools, and were the giant animals carnivores? Or did the fossil representatives live on a strictly vegetarian diet, like the recent sloths? “These questions were at the center of our new study,” adds Bocherens.

Normally it is possible to deduce the feeding habits of fossil animals on the basis of the shape and wear of their teeth – however, the teeth of the Giant Sloth are not comparable to those of modern animals. “We therefore had to use a different method, so we measured the composition of carbon isotopes – the ratio of protein and mineral content – in the fossilized sloth bones,” explains Bocherens, and he continues, “Our measurements show that Megatherium lived on an exclusively vegetarian diet.”

In carnivores, the proportion of proteins is significantly higher than in herbivores, which primarily eat food high in carbohydrates. These differences can be documented in the isotopes. In order to reinforce their results, the scientists compared their data with more than 200 bones from modern mammals, whose diet is known, as well as with fossil specimens from both carnivores and herbivores. “Our results show that by using this method, it is possible to reconstruct the feeding habits of animals even several thousand years after their death,” adds the biogeologist from Tübingen.

Knowledge of the sloths’ feeding habits is important in order to understand their role in past ecosystems. “Moreover, the results can help us understand the interactions between Megatherium and the first human inhabitants of America – their habitats overlapped for several thousand years, before the Giant Sloth became extinct,” offers Bocherens as a preview.

Ancient saber-toothed cat skull discovery in Germany


This video says about itself:

12 August 2015

“Homotherium” is an extinct genus of machairodontine saber-toothed cats, often termed “scimitar-toothed cats”, that ranged from North America, South America, Eurasia, and Africa during the Pliocene and Pleistocene epochs.

It first became extinct in Africa some 1.5 million years ago. In Eurasia it survived until about 30,000 years ago. In South America it is only known from a few remains in the northern region, from the mid-Pleistocene. The most recent remains of Homotherium date to 28,000 years BP.

Homotherium” reached 1.1 m at the shoulder and weighed an estimated 150 [kilogram] – and was therefore about the size of a male African lion. Compared to some other machairodonts, like “Smilodon” or “Megantereon”, “Homotherium” had shorter upper canines, but they were flat, serrated and longer than those of any living cat. Incisors and lower canines formed a powerful puncturing and gripping device. Among living cats, only the tiger has such large incisors, which aid in lifting and carrying prey. The molars of “Homotherium” were rather weak and not adapted for bone crushing. The skull was longer than in “Smilodon” and had a well-developed crest, where muscles were attached to power the lower jaw. This jaw had down-turned forward flanges to protect the scimitars. Its large canine teeth were crenulated and designed for slashing rather than purely stabbing.

It had the general appearance of a cat, but some of its physical characteristics are rather unusual for a large cat. The limb proportions of “Homotherium” gave it a hyena-like appearance. The forelegs were elongated, while the hind quarters were rather squat with feet perhaps partially plantigrade, causing the back to slope towards the short tail. Features of the hind limbs indicate that this cat was moderately capable of leaping. The pelvic region, including the sacral vertebrae, was bear-like, as was the short tail composed of 13 vertebrae—about half the number of long-tailed cats.

From the Senckenberg Research Institute and Natural History Museum in Germany:

Skull of saber-toothed cat found almost complete

Third individual saber-toothed cat was discovered in Schöningen

April 12, 2017

Summary: An excavation team found the remains of a saber-toothed cat at the archeological site in Schöningen. An examination of the skull fragments revealed the animal to be a representative of the European saber-toothed cat, Homotherium latidens. The recent discovery constitutes the third example of this large predatory cat from Schöningen.

Led by scientists of the Senckenberg Research Institute and the University of Tübingen, the excavation team found the remains of a saber-toothed cat at the archeological site in Schöningen. An examination of the skull fragments at the Dutch University of Leiden revealed the animal to be a representative of the European saber-toothed cat, Homotherium latidens. The recent discovery constitutes the third example of this large predatory cat from Schöningen.

Long claws, razor-sharp, curved canine teeth and the size of a fully grown lion: the saber-toothed cat (Homotherium latidens) was a competitor as well as a dangerous predator that even posed a risk to the humans of its time. “In the course of our excavation in May 2015, we came across conspicuous bone fragments,” explains Dr. Jordi Serangeli, a scientist at the University of Tübingen and the excavation leader at the approximately 300,000-year-old archeological site, and he continues, “In total, there are three individuals of Homotherium present in these relatively young sediment layers.

Until the first discovery of a saber-toothed cat in 2012 at the Schöningen excavation site in Lower Saxony it had been assumed that the large cats were already extinct about 200,000 years earlier, i.e., around 500,000 years ago. “Our findings show that 300,000 years ago, the saber-toothed cats were not as rare as previously thought,” adds Serangeli.

During a restoration in 2016, André Ramcharan and Ivo Verheijen at the University of Leiden were able to reassemble the eleven bone fragments into an almost complete neurocranium. “We then compared the reconstructed skull with recent and already extinct species of large carnivores and were thus able to demonstrate that the remains represented the head of a European saber-toothed cat,” explains Professor Dr. Thijs van Kolfschoten of the University of Leiden.

The third saber-toothed cat specimen that was discovered offers a great potential: thanks to the excellent level of preservation at the Schöningen dig, the interior of the skull reflects the shape and structure of the Homotherium brain. By examining the detailed brain structures, the team of scientists hopes to gain insights into the visual and hearing abilities as well as the feeding habits of the large cats. “The third Homotherium from Schöningen is invaluable for our understanding of the European saber-toothed cat,” summarizes Professor Nicholas Conard of the Senckenberg Centre for Human Evolution and Palaeoenvironment and head of the Institute for Early Prehistory and Quaternary Ecology at the University of Tübingen.

In the near future the international team from the Schöningen project intends to publish the results of its interdisciplinary studies regarding the three saber-toothed cats discovered to date. “Moreover, we expect that future digs will produce additional Homotherium finds,” offers Serangeli as a preview.

The dig in Schöningen keeps a team of ten members employed full-time — and during the main excavation season, the team is joined by five to ten students, who support the scientific excavation. Worldwide, about 50 scientists from 30 institutions and a wide variety of disciplines are involved in researching the discoveries from Schöningen. The dig is financed by the State of Lower Saxony.

The spectacular new discovery is put on display for the public at the palaeon in Schöningen as part of the special exhibition “The Ice Age Huntress.” Thanks to the close cooperation between Senckenberg, the international partners and the der palaeon GmbH, it is possible to make spectacular scientific findings available to the public in a timely manner.

Neanderthals and raven bones


CUTS ABOVE Notches carved into a raven’s wing bone by Neandertals include two that were added to create a consistent, possibly symbolic pattern, scientists say. Added notches are second from bottom and second from top in the side view of the bone. Photo: Francesco d’Errico

From Science News:

Neandertals had an eye for patterns

Notches on a raven bone suggests human relatives intentionally created even spacing

by Bruce Bower

2:00pm, March 29, 2017

Neandertals knew how to kick it up a couple of notches. Between 38,000 and 43,000 years ago, these close evolutionary relatives of humans added two notches to five previous incisions on a raven bone to produce an evenly spaced sequence, researchers say.

This visually consistent pattern suggests Neandertals either had an eye for pleasing-looking displays or saw some deeper symbolic meaning in the notch sequence, archaeologist Ana Majkić of the University of Bordeaux, France, and her colleagues report March 29 in PLOS ONE.

Notches added to the bone, unearthed in 2005 at a Crimean rock shelter that previously yielded Neandertal bones, were shallower and more quickly dashed off than the original five notches. But additions were carefully placed, resulting in relatively equal spacing of all notches.

Although bone notches may have had a practical use, such as fixing thread on an eyeless needle, the even spacing suggests Neandertals had a deeper meaning in mind — or at least knew what looked good.

Previous discoveries suggest Neandertals made eagle-claw necklaces and other personal ornaments, possibly for use in rituals (SN: 4/18/15, p. 7).

New research suggests that advances in the production of Early Stone Age tools had less to do with the evolution of language and more to do with the brain networks involved in modern piano playing. The findings are a major step forward in understanding the evolution of human intelligence: here.

Ancient Stone Age aurochs depiction discovery


A 38,000-year-old engraved stone (left), depicting an aurochs, or wild cow, covered with dots, was unearthed at a French rock-shelter. Symbolic elements of Europe’s earliest human culture appear in the engraving, its discoverers say. Drawings of the find (center) and of the aurochs separated from the dots show the scene more clearly. P. Jugie/Musée National de Préhistoire (photo), R. Bourrillon et al/Quaternary International 2017

From Science News:

Cow carved in stone paints picture of Europe’s early human culture

Symbolic dots, style link 38,000-year-old engraving to other famous cave art finds

By Bruce Bower

7:00am, February 3, 2017

This stone engraving of an aurochs, or wild cow, found in a French rock-shelter in 2012, provides glimpses of an ancient human culture’s spread across Central and Western Europe, researchers say.

Rows of dots partly cover the aurochs. A circular depression cut into the center of the animal’s body may have caused the limestone to split in two, says Stone Age art specialist Raphaëlle Bourrillon of the University of Toulouse-Jean Jaurès in France. Radiocarbon dating of animal bones unearthed near the discovery at Abri Blanchard rock-shelter put the engraving’s age at roughly 38,000 years, Bourrillon and colleagues report online January 24 in Quaternary International.

The rock art is similar to some engravings and drawings found at other French and German sites, including the famous Chauvet Cave (SN: 6/30/12, p. 12), and attributed to the Aurignacian culture, which dates to between 43,000 and 33,000 years ago. Like the new find, that art includes rows of dots, depictions of aurochs and various animals shown in profile with a single horn and a long, thin muzzle.

Within a few thousand years of arriving in Europe from Africa, Aurignacian groups developed regional styles of artwork based on images that had deep meaning for all of them, proposes anthropologist and study coauthor Randall White of New York University, who directed the excavation.

European Ice Age hunter-gatherers destroyed forests


This video says about itself:

1 March 2011

Join a small group of ancient Europeans as they teeter on the brink of annihilation, struggling with the most extreme living conditions anyone has ever faced, from encroaching sheets of ice that swallowed every bit of fertile land to a climate that was, on average, 70 degrees colder than it is today.

For these humans, survival meant more than simply keeping warm; it meant abandoning their hunting and gathering lifestyle and finding a whole new way of living – a way of living that endures to this day. Go back in time 24,000 years to the last Ice Age and watch in awe as Ice World brings this amazing stuggle to life. Through computer graphics and reconstructions, you’ll see how the earth’s climate shifted over time, eventually covering much of North America and Europe with two-mile-thick ice sheets.

From Leiden University in the Netherlands:

Ice Age hunters destroyed forests throughout Europe

28 November 2016

Large-scale forest fires started by prehistoric hunter-gatherers are probably the reason why Europe is not more densely forested. This is the finding of an international team, including climate researcher Professor Jed Kaplan of the University of Lausanne and archaeologist Professor Jan Kolen of Leiden University. Publication on 30 November in PLOS ONE.

Deliberate or negligent

This research has generated new insights on the role of hunters in the formation of the landscape. It may be that during the coldest phase of the last Ice Age, some 20,000 years ago, hunter-gatherers deliberately lit forest fires in an attempt to create grasslands and park-like forests. They probably did this to attract wild animals and to make it easier to gather vegetable food and raw materials; it also facilitated movement. Another possibility is that the large-scale forests and steppe fires may have been the result of the hunters’ negligent use of fire in these semi-open landscapes.

Large-scale impact of humans on landscape

The researchers combined analyses of Ice Age accumulations of silt and computer simulations with new interpretations of archaeological data. They show that hunters throughout Europe, from Spain to Russia, were capable of altering the landscape. This first large-scale impact of humans on landscape and vegetation would have taken place more than 20,000 years before the industrial revolution. The Ice Age is often presented as an era of extreme cold and snow that was ruled by mammoths, bison and giant bears. But the researchers show that humans were also capable of having a significant impact on the landscape.

Layers of ash

Searching for evidence of this human impact explains why there are conflicting reconstructions for this period. Reconstructions of the vegetation based on pollen and plant remains from lakes and marshland suggest that Europe had an open steppe vegetation. But computer simulations based on eight possible climate scenarios show that under natural conditions the landscape in large areas of Europe would have been far more densely forested. The researchers conclude that humans must have been responsible for the difference. Further evidence has been found in the traces of the use of fire in hunting settlements from this period and in the layers of ash in the soil.

Previous Leiden research already suggested human intervention

The team from Lausanne was made up of climate researchers and ecologists Jed Kaplan, Mirjam Pfeiffer and Basil Davis. Archaeologists Jan Kolen and Alexander Verpoorte from Leiden University also worked on the research. An earlier publication by Leiden’s Human Origins research group, that was published in Current Anthropology, had already suggested that hunter-gatherers from the Stone Age may well have modified the natural environment considerably through their use of fire. The new publication in PLOS ONE confirms this hypothesis and may be one of the earliest examples of large-scale human impact on the landscape throughout the whole of Europe.