Thursday 17 November 2016

(108) Homo naledi: The sticks and lianas theory

Basic Dimension

http://sexualreligion.blogspot.com/ 

Number Archive





Sticks theory replaced with grass-cable theory

I'm sorry, but the sticks theory has been replaced with the grass-cable theory. With good arguments, this is the only sufficient condition on which Homo naledi could safely reach Dinaledi Chamber:

(253) Homo naledi: grass-cables are the sufficient condition 

- In our explanatory model of the transport of bodies through the Rising Star Cave are grass-cables the sufficient condition. For, if the route was laid with grass-cables nothing else was needed to reach Dinaledi Chamber.

- If perfect, the same would apply to echolocation and grass-cables were not really needed. Then echolocation would also be a sufficient condition for navigation to Dinaledi Chamber. But because of expected technical imperfection, echolocation can only be used as a complementary tool to grass-cables.

- Fire is neither necessary nor sufficient for navigation in the Rising Star Cave. Neither necessary: In principle, having no light and by feel Homo naledi might have found his way to Dinaledi Chamber, while laying down the grass-cables in the meantime. Without cables he would get lost on his return. Nor sufficient: Keeping the fire on is difficult and fire is not really transportable through Superman's Crawl and the Chute. So, just like echolocation, fire is but a complementary tool to grass-cables.

-  Homo naledi thought that the God of Darkness resided in the deepest part of the cave. To discover the route to Dinaledi Chamber - or whatever - he probably used fire on both sides of Superman's Crawl. The transportation of fire through Superman's Crawl is possible but very unlikely. 

- Fire scared the God of Darkness and they ran out of oxygen quickly. So, Homo naledi did not use fire after the grass-cables were laid. Fire is just a complementary tool to grass-cables, because it is unreliable and difficult transportable. With fire alone they would get lost at a certain moment.

- After laid grass-cables, they simply counted the number of cables (standard length) for orientation. Chimps can count too. But the challenging hypothesis is that they discovered elementary echolocation in the meantime, what would make distinction between large and small spaces possible. Then, echolocation would be an additional tool to grass-cables for navigation.

- Fire was not necessary if Homo naledi was practiced in echolocation before finding his route to the deepest point of the cave. And after grass-cables were laid, fire was not needed any longer. So, only for laying grass-cables, fire was desirable but not really necessary, it is a complementary tool to grass-cables.

- Grass-cables are needed because fire and echolocation are not perfect. Grass-cables are the only sufficient condition for navigation in the Rising Star Cave.


- In concluding, Homo naledi did not use fire on a regular basis, but instead used grass-cables for navigation and possibly echolocation for overview.

- Connecting the dots, Homo naledi must have been a very intelligent and warm feeling creature. He was not randomly exploring all caves in the area, but was looking for the steepest descent to the center of the Earth. Connecting the dead with the God of Darkness was their guarantee for rebirth.

- Searching for the steepest descent they laid out standard lengths of grass-cables through all corridors of the caves. But on encountering a dead end, they further ignored that passage. Then, they pulled back all grass-cables except the first one, so they always knew they had already explored that corridor.

- When they finally left the Rising Star Cave, they pulled back all grass-cables.

- Somewhere they must have buried a big flagstone on which all routes are engraved.

End of   (253) Homo naledi: grass cables are the sufficient condition 



Hansel and Gretel and their trail to Dinaledi chamber:






https://www.evolutionnews.org/2017/04/disappointment-it-looks-like-homo-naledi-is-younger-than-previously-thought/


(190) Australopithecus interbred with Homo sapiens?
 

[Anyway, they definitely are half Australopithecus, which dates from 2.5 - 7 million years ago. This means half their genes are old and half are young. So, they still might have been evolved in the developmental stage of Rebirth. They likely survived for millions of years. Just learned Hominin subspecies do not change much in evolution after they are established.]


https://lens.elifesciences.org/09561/index.html#toc

An exhaustive search by a professional caving team and researchers has failed to find any other plausible access points into the Dinaledi Chamber, and there is no evidence to suggest that an older, now sealed, entrance to the chamber ever existed. Furthermore, detailed surface mapping of the landscape overlying the Rising Star cave system (Figure 2A) illustrates that no large flowstone-filled fractures occur in the region above the Dinaledi Chamber.


https://www.youtube.com/watch?v=qeBeszy6a14

The Lunate Sulcus by Ralph Holloway

Ralph Holloway is an endocast specialist who studies the inside skull to determine brain development of hominins. He also investigated the skull of Salam (3.3 Ma; 400cc; Ethiopia) and discovered the three years old child's brain was already rewired and different from chimps. The lunate sulcus marking vision structures had moved back on the skull making place for a larger neo cortex. So Salam was already more intelligent than chimps with 400cc brains:





So remember, it is not just brainsize but also wiring. So don't be depressed ðŸ˜‰.


Homo naledi, the game changer

The Rising Star Cave is well known for about 60 years and has been extensively investigated with modern means as artificial light. Only then, at last, we found Dinaledi chamber. The cave is part of a much larger complex. So, Homo naledi likely has been everywhere.

But how is it possible primitive creatures found Dinaledi chamber without any light? Compared to us Homo naledi must have been in the Rising Star Cave for at least 60 years. In the dark they would have needed an enormous period to find all entrances. But that's not the case for then we would have found a tremendous amount of waste. But the Rising Star Cave is clean and empty. Why we see no garbage? That's because we think that Homo naledi was like us. That's our error of thinking.

If Homo naledi investigated the cave, he must have plotted a 3D-map into his mind instantaneously. What we miss is a game changer, a paradigm shift. Like great apes Homo naledi must have had hidden qualities lost in the evolution.

http://video.nationalgeographic.com/video/news/150910-homo-naledi-analysis-workshop-vin?source=relatedvideo







Don't miss the following very impressive trail:
https://www.youtube.com/watch?v=vI-JF28T44U


                           

          

A strategy to Dinaledi chamber


Are we smarter than chimps or bonobos? It depends. Have you ever seen a chimp straight into the eyes? Then you know to have met a very intelligent creature. 

What is smart? Most things we share with them fit into an orange. Even mice understand our feelings and emotions rather well. No, Panini definitely are highly intelligent creatures but they are missing something. Quadrupeds miss the systematic and constructive creativity which is responsible for our frontal lobe, that's the difference with bipeds. Therefore they never grasped the enormous possibilities of bipedality. So bipedalism must have been a mutation of the first homininae:





Just like building the Sexual Model of Religion we must now build the Homo naledi strategy to enter Dinaledi chamber in little rational steps. We know oxygen will disappear quickly in caves and that's why homo erectus used fire only at the entrance for fresh air and to keep predators out. Would they have used fire from torches, then charcoal would have been reported all over the place, what is not the case. So, they did not use any form of light. That's the condition to start with:


1: Homo naledi used no light in the Rising Star Cave.

Anyway the path to Dinaledi chamber must be investigated thoroughly for traces.










   

Surroundings of the Rising Star Cave


Inside the Rising Star Cave



Published September 10, 2015
Cite as eLife 2015;4:e09561


Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa



       https://elife-publishing-cdn.s3.amazonaws.com/09561/elife-09561-fig2-v1.jpg





3D Laser mapping

https://www.linkedin.com/pulse/rising-star-mobile-3d-laser-scanning-homo-naledis-cave-henno-morkel

3D Laser Mapping - a world leader in providing innovative bespoke 3D laser scanning solutions to various industries, were privileged to do some 3D laser scanning with our hand-held mobile laser scanner the ZEB1 at the Rising Star Cave.  


In total it took us 3-4 hours to scan 80% of the Rising Star Cave, the total length of the cave measured from the scanned data was approximately +- 1.2 km, and we descended vertically about 30m underground.











Fig. 4 – Right side view of the point cloud data from the Rising Star cave; the points are coloured by elevation height, meaning red is the highest elevation and blue is the lowest elevation.


The Oldest Human Ancestor





And Australopithecus Africanus





It is easy to understand why primates never wandered over large distances without any form of defense. Bipeds roamed around the forests but climbed into the trees in case of danger. This transition period lasted for several million years. Homo naledi still climbed into the trees as is seen from its skeleton. 

Climbing up and down the chute to Dinaledi chamber was not the slightest effort, since he was very small and thin. He had small shoulders but long and strong arms. He was made for the Rising Star Cave in all respects as we will argue below.

Before Australopithecines definitely left the forests they must already have invented some kind of weapons against predators. Now we know today's chimps can throw stones and sometimes beat with branches to potential attackers. That will be our starting point.

But throwing stones can be done only in the neighbourhood of the place to live because stones are too heavy to transport through the savannas. That leaves branches as the first and only weapon for Australopithecines. Just like chimps they would have beaten their attackers with very heavy branches. But heavy sticks cannot be transported over large distances. 

Wandering around the forests they experienced entrained branches automatically worn on rocky soil. They themselves invented nothing. So, they came up with the idea of a sharpened point. They also noticed sharp points could be made easily against sharp rocks. They needed not to invent the stone hand axe, because the encounter with sharp rock walls precedes this invention and this was sufficient to tighten branches. So, the first Australopithecines invented nothing by themselves
and if necessary they escaped into the trees. 

First Australopithecines must have roamed through the savannas with light and very sharp sticks made of wooden branchesThey must have carried their defense against predators with their hands, another opportunity was not there. They tied ropes made of grasses to the sticks and dragged them along the ground easily, as a pencil in a sharpener.

Now realize Hominini (7 mya; 400cc) had about 5 million years behind of roaming through the savannas with wild animals before they likely entered the Rising Star Cave as Homo naledi (2,3 mya (?); 550 cc):




We definitely can be sure they used all kinds of wooden sticks to work with and of course as former apes they have found lianas and other rope like materials. They were not as mad as we are. They were very rational thinking creatures otherwise they would not have survived. Have you ever slept a night in the African wilderness? I did, but I did not like it.

Those Australopithecines were amazing 'people'. It is only when humans developed their brains they became insane and started magical thinking (religion). First homininae must have been very intelligent creatures like chimps but then with some logical thinking and planning already.

So, 5 million years before entering the Rising Star Cave humanlike creatures definitely were acquainted with wooden sticks and kinds of rope. This means we are allowed to let them use sticks and ropes upon entering the Rising Star Cave:


1: Homo naledi used no light in the Rising Star Cave.
2: Homo naledi used sticks and ropes entering Dinaledi chamber.


We know a knot in a rope occurs naturally. So. if they had ropes like lianas or long grasses they were known with knots. The trick was to get them out again. But clever chimps can get simple knots out of ropes. 
And much more clever Australopithecines had 5 million years time to tie and untie ropes, so maybe they needed no sticks at all in the Rising Star Cave.

In concluding, Homo naledi was able to tie all kinds of grasses together. And remember, grasses are much easier transported into a cave than wooden sticks.

Next postulate is that monkeys and great apes have a three-dimensional compass at night not to fall off the trees and to find their sleeping place again. This set of premises allows us to let make Homo naledi a map of the cave without any form of light. This could be explored with chimps and bonobos:


1: Homo naledi used no light in the Rising Star Cave.
2: Homo naledi used sticks and ropes entering Dinaledi chamber.
3: Homo naledi inherited a three-dimensional compass in the dark.



Hidden qualities of Homo naledi

The Rising Star Cave is well known for about 60 years and has been extensively investigated with modern means as artificial light. Only then, at last, we found Dinaledi chamber. The cave is part of a much larger complex. So, Homo naledi likely has been everywhere.

But how is it possible primitive creatures found Dinaledi chamber without any light? Compared to us Homo naledi must have been in the Rising Star Cave for at least 60 years. In the dark they would have needed an enormous period to find all entrances. But that's not the case for then we would have found a tremendous amount of waste. But the Rising Star Cave is clean and empty. Why we see no garbage? That's because we think that Homo naledi was like us. That's our error of thinking.

If Homo naledi investigated the cave, he must have plotted a 3D-map into his mind instantaneously:




What we miss is a game changer, a paradigm shift. Like great apes Homo naledi must have had hidden qualities lost in the evolution.


https://www.youtube.com/watch?v=YFR4a9vcri4&feature=youtu.be



https://www.newscientist.com/article/2128583-mystery-human-species-homo-naledi-had-tiny-but-advanced-brain/

It’s not the size of your brain, it’s how you organise it. The most recently discovered species of early human had a skull only slightly larger than a chimpanzee’s, but its brain looked surprisingly like our own – particularly in an area of the frontal lobe with links to language.
This could back suggestions that these mysterious early humans showed advanced behaviours, such as teamwork and burial, even though we still don’t know exactly when they lived.

Burial rites

It had a peculiar mix of anatomical features, which is part of what makes it hard to tell when the species lived. But what really set tongues wagging was the suggestion by Berger and his colleagues that H. naledi had deliberately disposed of its dead in this deep, dark, difficult-to-reach cave chamber full of remains.

Such an endeavour probably required emotional sophistication, not to mention teamwork, to carry out the task, but H. naledi’s skull was less than half the size of our own. Could its tiny brain have powered such advanced behaviour?


Tiny human

What excites the team most is a region on the side of H. naledi’s frontal lobe called Brodmann area 45, part of Broca’s area, which in modern humans has links to speech production. In this part of our brains, the pattern of gyri and sulci is very different from that seen in chimpanzees. H. naledi seems to have had our pattern, even though as an adult its BA45 was not much larger than that of a chimpanzee.
“You look at the naledi cast and you think – holy crap this is just a tiny human,” says Hawks.

Team member Shawn Hurst of Indiana University in Bloomington discussed the findings at a meeting of the American Association of Physical Anthropologists in New Orleans last week. “I would think the implication is that [H. naledi] was moving strongly towards enhanced communication,” he says.






Chimp cognitive research

We know chimpanzees have some remarkable ways to remember the numbers 1-9 randomly placed on a computer screen and to identify them in the correct order. They can replace them exactly on an empty screen. Varying random numbers on the screen has no influence on this ability. Also they fill in missing numbers. It is shocking.

Chimps are better with facts and bonobos with feelings. Hence let's see if chimps can orientate in a dark three dimensional labyrinth.

We conclude chimps need the ability to map 3D information instantaneously to survive in trees in nature. Now notice this computer screen contained only two dimensional 2D-information. Would apes have more hidden qualities to find their way in the trees at dark nights?

Are quadrupeds better than bipeds in 3D mapping of information. 
Could bipedal Australopithecines still find their way in the trees at night. Could Homo naledi instantaneously make a map of the Rising Star Cave? Did Homo naledi need no light in caves? At least he was half ape, half human.

In a labyrinth bipeds like Homo sapiens have a kind of two-dimensional orientation. Humans simply do not need 3D-orientation. But if you were an ape sleeping at night in the trees, you would have advantage of 3D-orientation. Then you might need a map of the tree to find your nest in the dark. The same 3D representation could have been used for routes in caves. Then Australopithecines would not have needed light at all in The Rising Star Cave.


1: Homo naledi used no light in the Rising Star Cave.
2: Homo naledi used sticks and ropes entering Dinaledi chamber.
3: Homo naledi inherited a three-dimensional compass in the dark.
4: Homo naledi had a fabulous mental representation of 3D-impressions.


 Update from art. 252:


Two diagrams contain the whole theory: 




Assumption 376Tribal rebirth means the conservation of group identity if reborn are former ancestors. This emphasizes group identity from inbred cultures. Otherwise it would concern hybrids. In the case of outbreeding cultures the identity of reborn is not important and hybrids from other tribes are welcomed. This means outbreeding cultures will bury their dead in the ground only. And because Homo naledi protected the bodies of the deceased fanatically, we decide them to be an inbred culture.


 Update from art. 252:




Update from art. 252:




The hand of Homo naledi

Berger, L. R. et al. 2015. Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa. eLife: 2015;4:e09560, DOI http://dx.doi.org/10.7554/eLife.09560. 



Our comparative analyses reveal that the wrist and palm are generally most similar to those of Neandertals and modern humans, while the fingers are more curved than some australopiths. This distinctive mosaic of morphology has yet to be observed in any other hominin taxon and suggests the use of the hand for arboreal locomotion in combination with forceful precision manipulation typically used during tool-related behaviours.

In comparison with the generally modern human/Neandertal-like morphology of the H. naledi wrist, thumb and palm, the fingers of Hand 1 are long and remarkably curved, similar to those of extant apes and early hominins 

The mean curvature of H. naledi proximal phalanges (PPs, n=11) is almost identical to that of A. afarensis [Lucy, BD] and OH7, and is not statistically distinct from African apes. The mean curvature of the IPs (n=14) is higher than that of any other hominin and not statistically distinct from Asian apes (Fig. 7).

Thus, the strong degree of phalangeal curvature in H. naledi is a clear functional indication that its fingers experienced high loads during grasping required for climbing or suspensory locomotion






Discussion

Over the course of human evolution, the hand was freed from the constraints of locomotion and has evolved primarily for manipulation. However, reconstructing the hands’ transition to bipedality and to tool use has been the source of much debate5,6,33,35,45. Furthermore, the few hand bones attributed to H. erectus s.l.22,25,34 are not an adequate sample from which to confidently test hypotheses about the evolution of the hominin wrist and hand during this transitional period. Australopiths and H. habilis are characterized by derived, human-like morphologies, primarily of the lower limb, which clearly indicate habitual bipedalism, but also varying suites of primitive, great ape-like features, primarily of the upper limb, which have elicited different functional interpretations. Some view the primitive features of early hominins as retentions from an arboreal ancestor that were either being lost or were selectively neutral and, as such, considered largely non-functional and adaptively insignificant46. Others, who aim to reconstruct early hominin behaviour as a whole, consider the primitive features as functionally useful with adaptive value retained under stabilizing selection47,48. Resolution of this debate requires morphological features that are ontogenetically sensitive to loading during life and, as such, can demonstrate how a bone was used during an individual’s lifetime49.

The strongly curved phalanges of H. naledi in association with an otherwise modern human/Neandertal-like hand, provide key evidence, consistent with primitive morphologies of the upper limb and thorax1for the retention of a significant frequency of climbing in a fossil hominin biped1,50 that was also apparently adapted to the demands of intensified manipulative behavioursThe curvature of other early hominin (that is, australopiths and OH7) phalanges is intermediate between that of extant apes and modern humans, and it has been argued that these curved digits indicate frequent use of arboreal substrates in these hominins47,48In contrast to the phalangeal morphology, the full suite of derived thumb and wrist features in Hand 1 is found only in committed, habitual tool users (for example, Neandertals and modern humans), suggesting that much of the hand anatomy in H. naledi may be the result of selection for precision handling and better distribution of compressive loads during forceful manipulative behaviours such as tool making and tool use (although tools have not been recovered in the Dinaledi Chamber itself2). Nevertheless, long and curved phalanges clearly suggest the use of the hand during life for powerful locomotor grasping and the functional importance of climbing in H. naledi. Therefore, as a whole, Hand 1 demonstrates that the ability for forceful precision manipulation is compatible with the use of the hand for arboreal locomotion. Whether or not this dual role required functional trade-offs that compromised the performance of these behaviours to some degree is currently unclear. When further considered within the context of the human-like foot50 and long lower limb1 in H. naledi, the hand morphology is consistent with the hypothesis that early hominins retained primitive use of the upper limb, even while fine-tuning specific aspects of the postcranial anatomy to facilitate novel behaviours such as efficient terrestrial locomotion and tool use.


In the history of paleontology species have been rated as toolmakers for less. This is of fundamental importance: This climbing ape also must have been an experienced toolmaker. He definitely must have had a lot of experience in tying ropes of all kinds of grasses. But now we found a formidable theoretical possibility to lay a cord made of tied grasses from the entrance of the cave to Dinaledi chamber. These lianas had to be removed after a certain time not to lead intruders to Dinaledi chamber.

Did they use it? I doubt, but they definitely could. So, theoretically they could find their way into the dark. And well very easily in combination with the following: 

I think chimps - but possibly also Homo naledi - have the savant syndrome to be blessed with an astonishing memory for maps, as  proven for Panini earlier in psychological cognitive research. If they ever formed a cognitive representation of a map they will remember it, but I don't know for how long. So, theoretically we must combine tied ropes with the astonishing 3D memory for jumping from branch to branch at dark nights.









Rebirth without soul

From our religious chapters we inferred already the first bipedal Homininae - being no quadrupedal chimps - must have buried their dead. Otherwise their dead would have been torn apart by wild animals and then they would be really dead. For 'sleeping forever' they must have been buried what was no problem because Australopiths drew their food from the soil. Below the development of human religion from animal religion:





3. Rebirth in caves without splitting body and soul.

(Australopithecus, 3-2 mya; 450 cc).
(Homo naledi, 1.97 mya (?); 500 cc): possibly a hybrid between (Australopithecus, 4.3-2 mya; 400 cc) and (Homo erectus, 2 mya; 900 cc).

As mentioned earlier, in addition to genetic immortality deceased tribal members were gathered in caves for eternal tribal identity.

Homo naledi wanted to prevent decay of bodies by worms and insects in the soil. Perhaps, he found the first noticed primitive way of mummifying the sleeping deceased (who remained in their bodies) in the refrigerator of the Rising Star Cave. Then it would not be reincarnation, but only tribal immortality of gathered bones in addition to genetic immortality into descendants for eternal tribal identity.

But think about it. Then there was no reason to throw them into the chute since there were plenty other and easier caves without all this trouble. No, we miss something in this scenario.

- We also know the underworld in Greek mythology. Homo naledi knew a lot from caves and possibly got the idea a complete underworld existed in the underground connected by all caves he knew. He also knew all life finally started from the soil. So, he knew it was the underworld which was life giving

Homo naledi possibly assumed the giant Rising Star Cave somehow was the holy entrance to new life far beneath the surface of the earth. And the harrowing shark-mouth chute, the 12 meter deep funnel to Dinaledi chamber was the actual access to that world. This was the big mouth to the underworld and so they threw their deceased right into their next life. Just like Hindus throw their dead into the Ganges. It was the first form of rebirth without splitting body and soul.

Rebirth is possible only if dead bodies are relatively unharmed and after rebirth there must be no remains found. That happened with the body of Jesus and with the bodies of Dinaledi chamber. Homo naledi didn't expect bodies to stay there forever. He was so sure of his belief that he didn't even bother to inspect Dinaledi chamber, maybe this was just considered sacrilege. The Rising Star Cave might be the only very special case to study rebirth of Australopiths.



In conclusion:

So, we may conclude the discovery of the Rising Star Cave is serendipity, a matter of good luck in science (as the discovery of penicillin). The Rising Star Cave must be seen as an extremely rare field experiment that satisfies scientific requirements for research into rebirth. And guess what, it is quite possible this is the only cave in the world suitable for rebirth research. 

All other facilities might need reincarnation. Homo naledi will likely change our opinion about animal religion completely. And from human reincarnation back to animal rebirth is going through the sound barrier of animal religion. Homo naledi will give humankind a fantastic insight in the development of animal religion.






Addendum

http://meeting.physanth.org/program/2016/session39/kivell-2016-functional-interpretation-of-the-homo-naledi-hand.html

The 85th Annual Meeting of the American Association of Physical Anthropologists (2016)


Functional interpretation of the Homo naledi hand

TRACY L. KIVELL1,2,3, ANDREW S. DEANE3,4, MATTHEW W. TOCHERI5,6, CALEY M. ORR7, PETER SCHMID3,8, JOHN HAWKS3,9, LEE R. BERGER3 and STEVEN E. CHURCHILL10,3.
1School of Anthropology and Conservation, University of Kent, 2Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, 3Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, 4Department of Anatomy and Neurobiology, College of Medicine, University of Kentucky, 5Department of Anthropology, Lakehead University, 6Human Origins Program, Department of Anthropology, National Museum of Natural History, Smithsonian Institution, 7Department of Cell and Developmental Biology, University of Colorado School of Medicine, 8Anthropological Institute and Museum, University of Zuerich, 9Department of Anthropology, University of Wisconsin-Madison, 10Department of Evolutionary Anthropology, Duke University
April 16, 2016 9:15, Imperial Ballroom A Add to calendar



Over 150 hand bones of Homo naledi, including a complete hand – missing only the pisiform – found in semi-articulation, have been uncovered from the Dinaledi Chamber of the Rising Star cave system, South Africa. These remains are from at least six adult and two juvenile individuals and offer a rare opportunity to investigate overall hand function in a fossil hominin. We conducted linear and 3D morphometric analyses of the wrist bones, metacarpals and phalanges in comparison to extant apes and fossil hominins. The morphology of the H. naledi thumb bones indicates powerful grasping combined with a distinctly small trapezium-first metacarpal joint that differs from other fossil hominins. The radial carpal bones demonstrate changes in shape and orientation that are known only in Neandertals and modern humans and have been interpreted as adaptations to tool-related behaviours. In contrast to the derived wrist morphology, the phalanges are remarkably curved, more so than most australopiths, indicating H. naledi used its hands for climbing. This combination of later Homo-like and australopith-like features in H. naledi suggests that the hominin hand could be both specialised for complex manipulative tasks but also be functionally proficient for locomotion. Within the context of the remainder of the skeleton, including an australopith-like shoulder and pelvis, but Homo-like foot, H. naledi was an efficient biped that still spent a significant amount of time in the trees.

Research supported by the National Geographic Society, National Research Foundation, European Research Council #336301 (TLK), Max Planck Society (TLK) Smithsonian Scholarly Studies Program (MWT) and Canada Research Chairs Program (MWT).






The age of Homo naledi and associated sediments in the Rising Star Cave, South Africa



Abstract


New ages for flowstone, sediments and fossil bones from the Dinaledi Chamber are presented. We combined optically stimulated luminescence dating of sediments with U-Th and palaeomagnetic analyses of flowstones to establish that all sediments containing Homo naledi fossils can be allocated to a single stratigraphic entity (sub-unit 3b), interpreted to be deposited between 236 ka and 414 ka. This result has been confirmed independently by dating three H. naledi teeth with combined U-series and electron spin resonance (US-ESR) dating. Two dating scenarios for the fossils were tested by varying the assumed levels of 222Rn loss in the encasing sediments: a maximum age scenario provides an average age for the two least altered fossil teeth of 253 +82/–70 ka, whilst a minimum age scenario yields an average age of 200 +70/–61 ka. We consider the maximum age scenario to more closely reflect conditions in the cave, and therefore, the true age of the fossils. By combining the US-ESR maximum age estimate obtained from the teeth, with the U-Th age for the oldest flowstone overlying Homo naledi fossils, we have constrained the depositional age of Homo naledi to a period between 236 ka and 335 ka. These age results demonstrate that a morphologically primitive hominin, Homo naledi, survived into the later parts of the Pleistocene in Africa, and indicate a much younger age for the Homo naledi fossils than have previously been hypothesized based on their morphology.
DOI: http://dx.doi.org/10.7554/eLife.24231.001



How do you figure out a fossil’s age? (By John Hawks)

We applied six different methods. The most valuable of these were electron spin resonance (ESR) dating, and uranium-thorium (U-Th) dating. ESR relies on the fact that teeth contain tiny crystals, and the electron energy in these crystals is affected by natural radiation in the ground over long periods of time after fossils are buried. U-Th relies on the fact that water drips into caves and forms layers of calcite, which contain traces of uranium. The radioactive fraction of uranium decays into thorium slowly over time. So the proportion of thorium compared to uranium gives an estimate of the time since the calcite layers formed. One of these calcite deposits, called a flowstone, formed above the H. naledi fossils in the Dinaledi Chamber. That flowstone helps to establish the minimum age: the fossils must be older than the flowstone above them.


https://www.theguardian.com/science/2017/may/09/new-haul-of-homo-naledi-bones-sheds-surprising-light-on-human-evolution















cc-by-nc-sa




This work is licenced under a Creative Commons Attibution-Non Commercial-ShareAlike 4.0 International Licence.



No comments:

Post a Comment