Tag Archives: hominids

The first hominids might have evolved in Europe, fossil jaw suggests

A new paper examines whether Europe and not Africa was the cradle of hominids some 7 million years ago.

Greece Jaw.

This jaw and teeth were found in Greece and belonged to what might have been the oldest hominid.
Image credits W. Gerber / University or Tübingen.

The teeth of a chimp-sized primate known as Graecopithecus, which lived in southeastern Europe some 7 million years ago, suggests that the species is actually an early hominid and not an ape as we previously believed, a team led by geoscientist Jochen Fuss of the University of Tübingen, Germany, reports. They cite partial fusion of the second premolar root as a particular similarity between Graecopithecus and early hominids.

What makes a man

Graecopithecus could be the first hominid to pop up, the researchers write. One lower jaw, found in Athens with most teeth still in their sockets, was dated to about 7,175 million years ago, and a single upper second premolar found in Bulgaria, to approximately 7.24 million years ago. Still, with only these bits on hand, it’s hard to make an airtight case for Graecopithecus as a hominid. Although the dates match, it’s still a mystery if this creature walked upright — a hallmark of hominids.

So it’s still unclear whether Graecopithecus was an ape with hominid-like features or a hominid with some apelike characteristics. At the same time, however, the team notes that fossil evidence of humanoids in Africa around this time is also pretty sketchy, in some cases even controversial, and revolves around two hominid lines dating to between about 7 million and 6 million years ago, Sahelanthropus and Orrorin.

“Europe is as likely a place of [hominid] origins, and even of the last common ancestor of chimpanzees and humans, as Africa,” says University of Toronto paleoanthropologist and study co-author David Begun.

The team used a CT scanning device to view Graecopithecus’s teeth in full 3D, including the roots hidden by jawbone. Using this model to compare to other early hominids, they discovered the partial fusion of the second premolar root as a striking similarity. Previous research has found that the number of these roots is tightly controlled genetically and doesn’t change due to environmental factors — so the root fusion in Graecopithecus, similar to those seen in later hominids, would suggest a direct evolutionary link.

Model Teeth.

Image credits Jochen Fuss et al, PLOS ONE (2017).

The findings are not without their own criticisms. First of all, some say that the number of premolar roots varies enough even among early hominids to make the fused roots a less conclusive piece of evidence. But, when working with so few fossils from so long ago, it’s hard to prove anything conclusively — for example, the team which discovered one East African hominid, Ardipithecus kadabba, later argued that Sahelanthropus and Orrorin aren’t distinct lineages but can be folded into Ar. kadabba — and that’s not an isolated case.

A lack of hominid precursor (our chimp and gorilla ancestors) fossil, in particular, makes it difficult to establish if creatures such as Graecopithecus or Ar. kadabba are truly hominids since there’s nothing to compare them against. Finally, there was quite a bit of back-and-fro going on between Africa and Europe’s eastern Mediterranean region between 9 million and 7 million years ago, with apes, giraffes, antelopes, hippos, and a host of other critters living and transiting through the region or between the continents, Begun adds, making it hard to pinpoint where everyone came from. So Graecopithecus could have evolved in either Europe or Africa.

But if evidence mounts that Graecopithecus was a hominid and evolved in Europe, the out of Africa theory could find itself into even rougher waters.

The full paper “Potential hominin affinities of Graecopithecus from the Late Miocene of Europe” has been published in the journal PLOS One.

Seaweed might have helped determine who we are today

Millions of years ago, the Homo sapiens branch started diverging from other primitive hominids. Many things started changing, but the key aspects were in the brain. In almost every way, the brain is what separates us from our ancestors. A new study claims that seaweed provided us with many of the nutrients necessary for that development.

Your brain on seaweed

Seaweeds may have been on the menu for ancient humans. Image via Pixabay.

Pretty much every quality that defines our humanity is connected to the brain. This incredibly performant, energy-hungry organ makes us who we are, and we’re still not even close to unraveling all its secrets. But to perform properly, the brain also needs a lot of resources. Our ancestors needed a lot of resources just to get by, and when their brains started getting larger and more powerful, they needed an extra bit of resources. But it’s not just like they needed some extra food, they needed an extra type of food. Among others, the brain needs significant quantities of magnesium and zinc to function, and new research suggests we may have gotten those nutrients from algae.

“Nutrients needed for this transition from a primitive ancestor to modern Homo sapiens were (and still are) available in seaweeds. Seaweeds could be found and harvested in abundance on shores, and for a foraging lifestyle, a rich coastal environment would be a significant source of a consistent supply of these nutrients,” says Professor Ole G. Mouritsen, University of Southern Denmark.

Professor Mouritsen has dedicated much of his life to studying food science and molecular biophysics. It’s not the first time he’s suggested something like this — he’s been a long time advocate of seaweeds, highlighting their nutritional value, importance as food as well as medicinal and industrial uses. There’s still little evidence to suggest that ancient humans feasted on seaweeds, but Mouritsen backs up his claim:

“However, the changing patterns of resource distribution associated with the extensive drying and expansion of the African savannahs between 2.5 and 2 million years ago have been the impetus for a shift in foraging behavior among early members of the genus Homo. Foraging over longer distances for food would have contributed to bipedalism and a different body stature as increasingly larger ranges had to be traversed, and in the case of our primitive ancestors, this would undoubtedly lead to significant changes in diet,” the authors write.

Delicious? Debatable. Nutritious? You betcha! Image via Wikipedia.

This is still a lot of indirect evidence, but we do know that coastal areas attracted early hominoids in search for food. They likely didn’t know how tides worked, which would have prevented them from being effective fishermen, but seaweeds would have been much easier to get hold of. Basically, the study doesn’t show that they did eat seaweeds, it shows that they very well might have.

“Our ancestors would find foods like fish, crustaceans, snails, seaweeds, bird eggs and perhaps occasional dead marine vertebrates. But they probably did not have the necessary rudimental understanding of seasonal tidal cycles and their influence on shellfish availability. Seaweeds of different types, on the other hands, can be found all across the intertidal zone from the high water mark to the subtidal regions and they could be readily and repeatedly harvested for food by all family members, including women and children,” the authors state.

Nutrients for the brain

The team zoomed in on several nutrients found in seaweeds which are crucial for proper brain development — both then and now:

  • Vitamin B12. The bane of vegans worldwide, B12 is only found in animal products such as meat, eggs, fish, and milk — with one exception: it is also confirmed in Pyropia species of seaweeds. There’s a good chance it can be found in other seaweeds as well, it’s just that we haven’t analyzed them yet. B12 is crucial for blood flow in the brain which supports cognitive functions such as speech.
  • Taurine. It’s found in large amounts in the central nervous system and in the retina, especially in developing bodies. Newborns have three times more taurine than the brain of adults. Taurine can be found in red algae, marine fish, shellfish and mammal meat.
  • Magnesium. This is one of the more readily available nutrients, easily found in a variety of vegetables and nuts. Still, there’s a chance that early humans got some of their magnesium from seaweeds, which are an excellent source. Magnesium is key for storing new bits of information in the neural networks of the brain.
  • Zinc. Like magnesium, zinc is found in several foods but meat (and especially the liver) is a great source of zinc. It’s also extremely abundant in oysters, crustaceans, and seaweeds. Also like magnesium, zinc is important in memory development.
  • Poly-unsaturated fatty acids (PUFAs). Certainly one of the most interesting nutrients on this list, PUFAs were thought to be obtained by early humans from fish and shellfish, but this study proposes seaweeds as an alternative source.
  • Iodine. Today, we get a lot of iodine from salt artificially enriched in the element — and that’s a good thing because iodine is crucial for the proper functioning of the thyroid hormones. But seaweeds also contain great amounts of iodine.

At the end of the day, it’s hard to prove whether or not our ancestors ate seaweeds or not — though this study makes a convincing case that they very well might have — but perhaps the more important takeaway is for the present, not for the past. Seaweeds are an excellent source of nutrients, especially if you don’t want to consume meat. With an ever-growing population and a struggling agriculture, they might pop up more and more on our plates.

Journal Reference: M. Lynn Cornish, Alan T. Critchley, Ole G. Mouritsen. Consumption of seaweeds and the human brain. Journal of Applied Phycology, 2017; DOI: 10.1007/s10811-016-1049-3

 

(A) KJS 7472, a small bovid metatarsal from KS-2 bearing cut marks; (B) KJS 7379, a medium-sized bovid humerus from KS3 bearing pair of hammerstone notches, the specimen is also cut-marked (not figured); (C) KJS 5447, a mammal limb bone shaft fragment from KS-2 with percussion pit and striae, the specimen is also cut-marked (not figured); (D) KJS 2565, a small bovid femur from KS-2 with numerous cut marks. Scale is 1 cm in panels (A-D); 1 mm in the panel (D) close-up. Specimen numbers are field designations, not KNM accession numbers.

Oldest evidence of hunting by human ancestors is two million years old

A great evolutionary leap forward in our lineage occurred once our hominid ancestors first began to hunt game to acquire meat, which once part of their diet greatly helped them to develop larger brains – especially cooked meat. When exactly this first occurred is controversial to answer. A team of archaeologists, however, have come across the oldest evidence of hunting, scavenging and meat eating by human ancestors.

Some two million years ago, early human ancestors known as the Oldowan hominin began to exhibit certain adaptions  that required greater daily energy expenditures, including an increase in brain and body size, heavier investment in their offspring and significant home-range expansion. How these early hominids had access to the necessary resources to acquire such expensive evolutionary traits has been the subject of debate among scientists for some time. The leading theory is that they began to consume meat, acquiring it by means of hunting or scavenging game put down by specialized hunting animals like lions. Demonstrating this proved to be challenging, however.

[RELATED] Human tool use pushed back 800,000 years by new discovery

Recently though, a team of researchers, led by Prof Joseph Ferraro from Baylor University in Waco, Texas, has finally found tangible evidence of this behavior. The researchers collected a slew of archaeological evidence from a two million-year-old site of Kanjera South, located on the shores of Lake Victoria in Kenya. Among the vestiges collected there, the scientists found an abundance of nutritious animal remains acquired through a combination of both hunting and scavenging behaviors.

“This study provides important early archaeological evidence for meat eating, hunting and scavenging behaviors – cornerstone adaptations that likely facilitated brain expansion in human evolution, movement of hominins out of Africa and into Eurasia, as well as important shifts in our social behavior, anatomy and physiology,” Prof Ferraro explained.

(A) KJS 7472, a small bovid metatarsal from KS-2 bearing cut marks; (B) KJS 7379, a medium-sized bovid humerus from KS3 bearing pair of hammerstone notches, the specimen is also cut-marked (not figured); (C) KJS 5447, a mammal limb bone shaft fragment from KS-2 with percussion pit and striae, the specimen is also cut-marked (not figured); (D) KJS 2565, a small bovid femur from KS-2 with numerous cut marks. Scale is 1 cm in panels (A-D); 1 mm in the panel (D) close-up. Specimen numbers are field designations, not KNM accession numbers.

(A) KJS 7472, a small bovid metatarsal from KS-2 bearing cut marks; (B) KJS 7379, a medium-sized bovid humerus from KS3 bearing pair of hammerstone notches, the specimen is also cut-marked (not figured); (C) KJS 5447, a mammal limb bone shaft fragment from KS-2 with percussion pit and striae, the specimen is also cut-marked (not figured); (D) KJS 2565, a small bovid femur from KS-2 with numerous cut marks. Scale is 1 cm in panels (A-D); 1 mm in the panel (D) close-up. Specimen numbers are field designations, not KNM accession numbers. (c) PLoS One

Numerous antelope carcasses exhibit cut marks made when Oldowan hominins used simple stone tools to remove animal flesh. Some bones also bear evidence that hominids used fist-sized stones to break them open to acquire bone marrow. Also at the site, a large number of isolated heads of wildebeest-sized antelopes were found. These animals are a lot larger than antelopes and could be consumed for days after being collected, suggesting they could be scavenged as even the largest African predators like lions and hyenas were unable to break them open to access their nutrient-rich brains.

“Tool-wielding hominins at Kanjera South, on the other hand, could access this tissue and likely did so by scavenging these heads after the initial non-human hunters had consumed the rest of the carcass,” Prof Ferraro explained.

“Kanjera South hominins not only scavenged these head remains, they also transported them some distance to the archaeological site before breaking them open and consuming the brains. This is important because it provides the earliest archaeological evidence of this type of resource transport behavior in the human lineage.”

Findings were detailed in the journal PLoS One.

Neanderthal and modern man

High-quality Neanderthal genome published for open access

Neanderthal and modern manGerman scientists at the Max Planck Institute for Evolutionary Anthropology in Leipzig have completed the first high-quality draft Neanderthal genome sequence, marking another leap forward in understanding our fellow hominids and how our species interacted, if there was such thing, with other hominid species. Moreover, the whole Neanderthal genome has been made freely available to the scientific community to accelerate research.

Svante Paabo and his colleagues at the Max Planck Institute first made world headlines when they presented the first Neanderthal genome draft in 2008, after they sequenced DNA samples taken from three bones found in a cave in Croatia. Now, for their most recent work, the German scientists sequenced a Neanderthal genome from  a toe bone excavated in 2010 in Denisova Cave in southern Siberia.

“The genome of a Neanderthal is now there in a form as accurate as that of any person walking the streets today,” Svante Paabo, a geneticist who led the research

The team of researchers have already been able to determine which genes the Neanderthal specimen had inherited from its mother, and which from its father – something that wasn’t deemed possible a mere ten, even five years ago. At the moment, analysis is underway to determine how the Neanderthal relates to modern humans and Denisovans — another extinct human species whose genome was previously extracted from remains found in the same Siberian cave. Previously, it was established that Neanderthals share %99.7 of their genes with modern day humans, and some studies claim that 4% of our genes are Neanderthal, although inactive.

“We will gain insights into many aspects of the history of both Neanderthals and Denisovans, and refine our knowledge about the genetic changes that occurred in the genomes of modern humans after they parted ways with the ancestors of Neanderthals and Denisovans,” Paabo said.

What’s of greater importance, maybe, is that this extremely high quality genome sequence will be openly available to the scientific community for further studying.

UPDATE: Some websites have used headlines for this announcement that reference the sequence as “COMPLETE”. It’s worth noting that we have yet to sequence the Neanderthal genome in its entirety, and as such titles as these are misleading. What this high-quality draft released by the German researchers represents is the best we have at the moment, though, and still marks an important achievement.

Aus­tra­lo­pith­e­cus sed­iba skull

Early ancestor is only hominid that ate bark

Aus­tra­lo­pith­e­cus sed­iba skull

Aus­tra­lo­pith­e­cus sed­iba skull

That’s right. Scientists have found that one of our early ancestors, the Aus­tra­lo­pith­e­cus sed­iba, South Af­ri­can spe­cies from two mil­lion years ago, used to have an unique diet of forest fruits and other woodland plants. Basically, all the other hominids, we currently know of, fo­cused more on grasses and sedges. This makes A. sediba a truly unique relative in the evolutionary human tree.

The first fossils of Australopithecus sediba, discovered in South Africa in 2008, were hailed as a remarkable discovery. The hominid was pretty short, even by early human species standards, had long arms, could walk on two legs, despite most likely it still preferred climbing trees and had a very small brain. What’s the position of the Australopithecus sediba in the human lineage, though?

“The question is, is this a great great grandad or grandma or is it a cousin?

“They were eating bark and woody substances, which is quite a unique dietary mechanism; it hasn’t been reported for any other human relative before,” said Dr Louise Humphrey of the palaeontology department at London’s Natural History Museum.

Half-ape/half-human, the Australopithecus sediba was hailed as the missing link, but even now researchers are analyzing its fossils and genetic markup.

These findings were made after scientists an­a­lyzed the A. sed­iba di­et by zap­ping fos­sil­ized teeth, from two individuals, with a la­ser. This allowed the researchers to sample car­bon from the enam­el of teeth, so re­search­ers can pin­point which types of plants the car­bon comes from. Results showed that the A. sediba consumed two groups of plants: so-called “C3” plants like trees, shrubs and bushes, which were preferred by the South African hominid and “C4” plants like grasses and sedges con­sumed by many oth­er early ho­minids.

Australopithecus Sediba illustration “It is an im­por­tant find­ing be­cause di­et is one of the fun­da­men­tal as­pects of an an­i­mal, one that drives its be­hav­ior and ec­o­log­i­cal niche. As en­vi­ron­ments change over time be­cause of shift­ing clima­tes, an­i­mals are gen­er­ally forced to ei­ther move or to adapt to their new sur­round­ings,” said Paul Sand­berg of the Uni­vers­ity of Col­o­rad­o Boul­der, a co-author of the new stu­dy.

Hey buddy, you got some bark between your teeth.

Remarkably, the researchers also found fos­sil­ized par­t­i­cles of plant tis­sue known as phy­toliths trapped in an­cient tooth tarter.  A un­ique as­pect of the proj­ect was the anal­y­sis of mi­cro­scop­ic, fos­sil­ized par­t­i­cles of plant tis­sue known as phy­toliths trapped in an­cient tooth tarter.

“The fact that these phy­toliths are pre­served in the teeth of two-mil­lion-year-old ho­minids is re­mark­a­ble and speaks to the amaz­ing pre­serva­t­ion at the site,” said Sand­berg. “The phy­tolith da­ta sug­gest the A. sed­iba in­di­vid­u­als were avoid­ing the grasses grow­ing in open grass­lands that were abun­dant in the re­gion at the time.”

The findings were reported in the journal Nature.

The Burtele partial foot after cleaning and preparation. (c) Yohannes Haile-Selassie/The Cleveland Museum of Natural History

New hominid species that lived alongside the famous Lucy was mostly a climber, not a walker

Africa proves yet again that it’s the cradle of the hominid family, and in consequence the human species. Scientists have found foot fossils in Ethiopia that don’t match those of any kind of hominid discovered thus far, dating from 3.4 million years ago, making the specimen contemporary with Lucy, an Australopithecus afarensis specimen, of vast significance during its initial discovery as it presented evidence that it was adapted for upright walking. The new fossils, although very limited in number, proves one very interesting fact – the new discovered hominid didn’t use bipedal locomotion, but instead was more suited to climbing trees.

The Burtele partial foot after cleaning and preparation. (c) Yohannes Haile-Selassie/The Cleveland Museum of Natural History

The Burtele partial foot after cleaning and preparation. (c) Yohannes Haile-Selassie/The Cleveland Museum of Natural History

The discovery is of great importance, showing, among other highly fascinating facts, that the Australopithecus a. didn’t represent a single line of hominids during three to four million years ago, a period from which no other remains from a different species had been uncovered until now.

Australopithecus a. was well adapted to bipedal movement, as attested by Laetoli footprints in Tanzania from as early as 3.7 million years ago, and more evidently by its feet bone structure – a strong arch and the big toe lined up with the other four digits (are you looking at your feet yet? Lucy had similar feet to ours), a feature indispensable to bipedal locomotion. The new species, however, presents a divergent opposable toe, long digits as well as other bones that didn’t match the afarensis feet, closely resembling modern chimpanzees.

In fact, Yohannes Haile-Selassie, a paleoanthropologist at the Cleveland Museum of Natural History in Ohio, suggest that the newly found foot fossils bear a striking resemblance to the earlier hominin Ardipithecus ramidus, nicknamed Ardi, which lived 4.4 million years ago, in the same region known today as Ethiopia. The new fossils, comprised of only  eight bones out of the usual 24, were unearthed in 2009 by  Stephanie Melillo

[RELATED] Human ancestors started walking on two legs to carry more scarce resources, study suggests

The find proves that there was a more diverse locomotion among hominids than previously thought. Thus, one group decided to abandon their tree climbing way and settle for bipedality, while another maintained a climbing foot and stayed at least part time in the trees. As time passed, evolution showed that bipedal movement was more efficient, as all our post-Lucy ancestors retained their upward locomotion.

It’s clear that more fossils are needed to determine if this is indeed a new species, although it most likely is, and for at least sketching the individual which had these kind of feet attached to it. The site where the fossils were found was just recently excavated, so there might be a solid chance for finding even more remains.

“Human evolution is often portrayed as a triumph of bipedalism, but who among us has not occasionally regretted our species’ comparative clumsiness in trees?” wrote Daniel E. Lieberman, a human evolutionary biologist at Harvard who was not involved in the research. “I, for one, am pleased to know that some hominins retained feet well adapted for arboreality millions of years after we started to walk on two feet.

The findings were reported in the journal Nature.

[source]

(A) An adult male chimpanzee seen holding tools (anvil in left hand, hammer in left foot) and Coula edulis nuts (mouth and right hand) part of a nut-cracking session. (B) Adult male chimpanzee seen carrying three papayas (one in each hand and one in mouth) during crop-raiding. (c) W C M McGrew

Human ancestors started walking on two legs to carry more scarce resources, study suggests

One of the biggest anthropological mysteries scientists have been trying to unravel is the long put question of  how did humans develop bipedal movement. There have been many theories formulated hypothesizing why our ancestors eventually switched from four limbs walking to two – some appealing, some a bit too far the edge. A recent study performed by a joint team of biological anthropologists at University of Cambridge and Kyoto University claims, with experimental data to back-up as evidence, that our human forefathers might have switched to two legs because it made carrying valuable, scarce resources easier in one go.

The researchers sought to understand how our hominid ancestors developed bipedal movement by studying the chimpanzee’s walking behavior, our closest relative. The researchers found that chimpanzees tend to switch their movement on two limbs instead of the usual four in situations when they want to monopolize a resource and want to carry as much of it as possible in one go.

“Bipedality as the key human adaptation may be an evolutionary product of this strategy persisting over time. Ultimately, it set our ancestors on a separate evolutionary path,” said Professor William McGrew, from the Department of Archaeology and Anthropology, University of Cambridge.

To test their theory which simply states that bipedal movement resulted from the need to transport resources with maximum efficiency, the researchers performed two surveys. One was in a natural clearing in Bossou Forest, Guinea, where anthropologists exposed chimpanzees to three situations in which certain nuts were available in limited or abundant supply. The oil palm nut, is naturally widely available and the chimpanzees are fully aware of this, while the other resource used in the study, the coula nut, is considered to be a scarce or “unpredictable” resource, so the latter made for a perfect control factor.

A possible explanation as to how our early ancestors came to walk on two legs

Behavior was monitored in three separate instances:

  • when only oil palm nuts were available
  • when a small number of coula nuts was available
  • when coula nuts were the majority available resource

In the first situation, no significant alternation in their movement behavior occurred. In the second instance, however, the chimpanzes procedeed in transporting more coula nuts in one go. They proceeded much in the same why in the third instance as well, only this time they ignored the oil palm nuts altogether, since they saw the coula nuts as a much more valuable resource, deeming the current situation as a one time opportunity, unpredictable, from which they had to profit at maximum efficiency.

(A) An adult male chimpanzee seen holding tools (anvil in left hand, hammer in left foot) and Coula edulis nuts (mouth and right hand) part of a nut-cracking session. (B) Adult male chimpanzee seen carrying three papayas (one in each hand and one in mouth) during crop-raiding. (c) W C M McGrew

(A) An adult male chimpanzee seen holding tools (anvil in left hand, hammer in left foot) and Coula edulis nuts (mouth and right hand) part of a nut-cracking session. (B) Adult male chimpanzee seen carrying three papayas (one in each hand and one in mouth) during crop-raiding. (c) W C M McGrew

During the last two instances, the frequency with which the chimps switched from four to two limbs increased by a factor of four. Bipedal movement allowed the chimpanzees to carry much more resources (~around twice as much), but even so that didn’t seem enough as some were seen carrying nuts even in their mouths. It’s important to note that most transport overall was quadrupedal.

The second leg of the study was concentrated around a 14-month long survey of Bossou chimpanzees and crop-raiding, where again high-value resources are obtained with unpredictable frequency. The researchers observed that 35% of their activity involved some sort of bipedal movement, and once again, this behavior appeared to be linked to a clear attempt to carry as much as possible in one go. When correlated with the first survey, these findings lead reseachers to claim that when faced with situations where scarced resources are available at an unpredictable frequency, most often chimpanzees will switch to bipedal movement so they might carry as much as possible.

Our former hominid ancestors were subjected to more or less similar situations, faced with both unpredictable resource frequency and changing climates. With this in mind, the researchers suggest that selection pressure towards the economically favorable bipedal movement might have lead our ancestors on a separate evolutionary path where bipedal movement became the dominant form of locomotion.

The findings were reported in the journal Current Biology.

A skull from a specimen, recovered from Longlin cave in China, belonging to the Red Deer Cave people - possibly a new species of human. (c) Darren Curnoe

Mysterious hominid fossils found in China hint towards a new human species

A skull from a specimen, recovered from Longlin cave in China, belonging to the Red Deer Cave people - possibly a new species of human. (c) Darren Curnoe

A skull from a specimen, recovered from Longlin cave in China, belonging to the Red Deer Cave people - possibly a new species of human. (c) Darren Curnoe

An incredible find was publicized just earlier  – fossils remains from stone age people were unearthed from two caves in China. Upon further inspection it was found that the bone features, particularly skulls, were unlike any other human or early ancestor remains ever found, suggesting that the researchers may have actually found a new species of human.

Bones, including partial skulls, have been unearthed from at least four individuals, which were estimated to have lived some 14,300 to 11,500 years ago. Presenting anatomical features which mix both archaic and modern human complexion, the Red Deer Cave people, as they’ve been called after the name of the location they’ve been found in, have simply stunned researchers.

“They could be a new evolutionary line or a previously unknown modern human population that arrived early from Africa and failed to contribute genetically to living east Asians,” said Darren Curnoe, who led the research team at the University of New South Wales in Australia.

“While finely balanced, I think the evidence is slightly weighted towards the Red Deer Cave people representing a new evolutionary line. First, their skulls are anatomically unique. They look very different to all modern humans, whether alive today or in Africa 150,000 years ago,” Curnoe told the Guardian.

“Second, the very fact they persisted until almost 11,000 years ago, when we know that very modern looking people lived at the same time immediately to the east and south, suggests they must have been isolated from them. We might infer from this isolation that they either didn’t interbreed or did so in a limited way.”

The fossils were retrieved from two cave sites in China, Maludong, or Red Deer Cave, near the city of Mengzi in Yunnan province, and Longlin cave,  in southwest China. Curiously enough, the fossils were initially found encased in blocks of rock, which hid their features and thus lead them to be ignored. The Red Deer Cave remains were found 1989, while the Longlin cave remains were found in 1979, however they remained unstudied until 2008. Were it not for the inherent curiosity of the researchers involved in the project to study these fossils, they simply would’ve remained to this day in some warehouse, gathering dust as they did for millennias.

“In 2009, when I was in China working with co-author Professor Ji Xueping, he showed me the block of rock that contained the skull,” Curnoe recalled. “After picking my own jaw up from the floor, we decided we had to make the remains a priority of our research.”

Quite possibly a new species of human. How were they different?

Artist impression of what the Red Cave People might have looked like between 11,500 and 14,500 years ago. (c) Peter Schouten

Artist impression of what the Red Cave People might have looked like between 11,500 and 14,500 years ago. (c) Peter Schouten

The individuals have, in some respects, unique features to humans. For instance, strongly curved forehead bone, a very broad nose and eye sockets, large molar teeth, prominent brows, thick skulls and flat faces, which flare widely on the side making wide for very strong chewing muscles. Their brains were average sized by ice age standards, and they used to cook their meals, judging from the number of mammal skeletons found nearby the remains, all of them species still around today, with the exception of the giant red deer.

The Red Deer People are the earliest population found so far, which does not adhere to modern human anatomical conformity. In fact, they’re unique in respect to any other species in the human evolutionary tree. Fact most curious, when considering that their location was surrounded by modern human populations, as attested by fossil evidence from the same period. The researchers suggest that they either stayed extremely isolated or kept interbreeding off-grounds.

This is the latest, although not yet confirmed as a new species, of a wave of new identified human species found only in these recent past years. Homo floresiensis or the “hobbit”, which lived on the island of Flores, Indonesia, until as recently as 17,000 years ago, was first discovered in 2007. The Denisovans lived around 30,000 years ago and the first and only trace of them so far was found in the Denisovan Caves of Siberia in 2010. All of them found in Asia, along with past Neanderthal sites and this latest one in China.

Curnoe and colleagues have a couple of possible scenarios concerning the existence of these Red Deer Cave people. One is that they’re part of very early migration of a primitive-looking Homo sapiens that lived separately from other forms in Asia before dying out, while another assumes that they were indeed a distinct hominid species, which evolved in Asia and lived near modern human populace. The last hypothesis is the most interesting, as well – they were hybrids.

“It’s possible these were modern humans who inter-mixed or bred with archaic humans that were around at the time,” explained Dr Isabelle De Groote, a palaeoanthropologist from London’s Natural History Museum.

“The other option is that they evolved these more primitive features independently because of genetic drift or isolation, or in a response to an environmental pressure such as climate

The findings were reported on March 14 in the journal PLoS ONE.

Visitors of the Museum for Prehistory in Eyzies-de-Tayac, France observe a Neanderthal man ancestor's reconstruction (AFP/File, Patrick Bernard)

Human mating with Neanderthals made our immune system stronger

The mating between Neanderthals and modern homo sapiens has been a highly controversial matter between scientists in the anthropology scene for decades now. That was until last year, however, when anthropologists convened that the two related species did indeed mate, but the genes passed down from Neanderthals were inactive.

Recently, there’s been another reason for contradiction, once with the publishing of a new study this Thursday by Stanford scientists in which they outline how DNA inherited from Neanderthals and newly discovered hominids, dubbed the Denisovans, has contributed to the immune system of modern day man among populations in Europe, Asia and Oceania. Just so you can get an idea of how volatile studies and discoveries in the scientific world can be.

Prehistoric interbreeding is considered responsible for 4% of the homo sapiens genome; the Standford research, lead by Peter Parham from Stanford University School of Medicine in California, identifies stretches of DNA derived from our distant relatives.

Sex with Neanderthals made modern day humans stronger

The researchers focuses their attention  on a small set of genes on chromosome six, known as the human leukocyte antigen (HLA) class I genes, which help the immune system adapt to fight off new pathogens that could cause various infections, viruses and diseases. HLA-B*73, one of the types, was traced down to the newly discovered hominids called Denisovans, who likely  mated with humans arriving in West Asia on their way out of Africa. The variant is rare in modern African populations but is common in people in west Asia.

“The HLA genes that the Neanderthals and Denisovans had, had been adapted to life in Europe and Asia for several hundred thousand years, whereas the recent migrants from Africa wouldn’t have had these genes,” said Dr. Peter Parham.

“So getting these genes by mating would have given an advantage to populations that acquired them.”

A similar scenario was found with HLA gene types in the Neanderthal genome.

“We are finding frequencies in Asia and Europe that are far greater than the whole genome estimates of archaic DNA in modern humans, which is 1-6%,” said Professor Parham.

From the analysis, the scientists estimated that more than half of the genetic variants in one HLA gene in Europeans could be traced back to Neanderthal or Denisovan DNA. Asians owe up to 80%, and Papua New Guineans up to 95%.

Skepticism among other scientists

While this is a remarkable, ground-breaking study by all means, some scientists are still reluctant to accept its impact on the immune system and, consequently, passing on off active genes.

“I’m cautious about the conclusions because the HLA system is so variable in living people,” commented John Hawks, assistant professor of anthropology at the University of Wisconsin-Madison, US.
Denisovan tooth DNA from a tooth (pictured) and a finger bone show the Denisovans were a distinct group

“It is difficult to align ancient genes in this part of the genome.

“Also, we don’t know what the value of these genes really was, although we can hypothesise that they are related to the disease environment in some way.”

The study was published in the latest edition of the journal Science.

Two bones bearing the scars of tool use, discovered in Dikika, Ethiopia. Credit: Dikika Research Project.

Human tool use pushed back 800,000 years by new discovery

Two bones bearing the scars of tool use, discovered in Dikika, Ethiopia. Credit: Dikika Research Project.

Two bones bearing the scars of tool use, discovered in Dikika, Ethiopia. Credit: Dikika Research Project.

Although the oldest sexual toy may have dated from the stone age, a newly published discovery of two fossils bearing the mark of tool used to scrub off the meat  dating back  3.39 million years could be enough to make anthropologists revise their current text books. What makes this study potentially monumental is the fact that it could prove tool use among our ancestors was used far earlier than specialists believed, dethroning the Homo habilis as the first hominid to use tools and making way for the Australopithecus afarensis (around Lucy‘s time)- this pushes back human tool use by approximately 800,000 years.

The dug was made in Dikika, Ethiopia by Shannon McPherron, an archaeologist at the Max Planck Institute for Evolutionary, who states “It’s never been shown before that Lucy used stone tools, and it’s never been shown before that Lucy ate meat.”

Scientists have long believed that use of tools and meat consumption is linked with larger brains as a consequence of the protein influx, but this latest study published in Nature suggests that this isn’t at all the case, seeing how Australopithecus afarensis has a very undeveloped genus.

“By pushing the date for tool use and meat eating in our lineage back by around 1 million years, our finds show that tool use and meat eating was not unique to (the genus) Homo, a widely accepted notion in our field,” co-author Zeresenay Alemseged states.

“Also, by showing that A. afarensis was involved in these activities, we showed that you do not need a large brain to do this,” added Alemseged, director of the Department of Anthropology at the California Academy of Sciences.

“This is a kind of find that will force us to revise our human evolution and anthropology textbooks.”

With all this mind, a hint of a problem still arises – no actual tools were found, only tool marks. Did the Australopithecus build their own tools or did they just used flint shaped rocks? Whatever’s the case an amount of planning is required and that may be evidence enough, unless of course this just an isolated incident.

“It potentially opens up a new period in human evolution where our ancestors were experimenting with stone tools, laying the foundation for the development we see at around 2.5 million years ago,” McPherron said.

UPDATE: Though the find still remains the earliest attested hominid tool use, a study that came only a year after the presently discussed one reports one a 600,000 old tool-mill made by a Homo Erectus community.  The discovery was dated using pedostratigraphic analysis, optically stimulated luminescence, and magnetostratigraphic analysis which authenticated the aforementioned period.