HOMO NALEDI: DISCOVERIES, CHARACTERISTICS, SKULL - CULTURE VOCABULARY - 2025

The Homo Naledi is an extinct species of hominid that lived in South Africa is estimated about 2 million years (± 0.5 million), estimate based on his skull resembles those of other species: H. rudolfensis, H. erectus and H. habilis.

In the eternal search for its origins, the human being has striven to locate remains that draw the evolutionary trace that gave rise to Homo sapiens. For many years paleontological research and findings in different latitudes of the planet have shed light and formed a common thread in scientific conclusions related to this topic.

Facial reconstruction of Homo naledi. By Cicero Moraes (Arc-Team) et alii, via Wikimedia Commons

However, just in mid-2013 an expedition led by archaeologists Lee Berger and John Hawks, along with a group of specialists from the University of the Witwatersrand in Johannesburg in South Africa, found the remains of what turned out to be a new species of hominin.

This specimen is destroying what was considered true until now, as a result of the evidence previously found.

Discovery

In an intricate chamber of the cave system known as the Rising Star, located about 50 miles north of Johannesburg, these scientists stumbled upon what may be the largest find of hominid remains ever to be found.

Almost 1,600 pieces make up the group of skeletal remains found in the Naledi cave - whose name gave rise to the species - that correspond according to studies to about 15 individuals of various age groups.

Holotypo of Homo naledi, Dinaledi Hominin 1 (DH1). A, B: skull. C, D, E, F: maxilla. G: skull, mandible and maxilla in anatomical alignment. H, I, J, K: jaw. Scale = 10 cm.

Such a number of remains allowed a practically total reconstruction of the skeleton of this new ancestor, which shows morphological characteristics that contradict what until now was the universally accepted human evolutionary pattern.

The peculiarities of Homo naledi combine characteristics that until then were never expected to be found in a single individual.

The development of the rounded shape of the skull that houses a very small brain and the presence of a thumb confronting the rest of the fingers (which nevertheless continued to have long and curved phalanges), present a kind of puzzle that threatens the hypotheses known evolutionary

Fossil recovery

The odyssey that the recovery of the remains meant is framed in the difficulties of access to the chamber where they were found.

This required that the thinnest-built cavers were the ones to open the way to a route, which travels at several levels a route of more than 80 m, since during the same they had to overcome cracks of up to only 25 cm. The cavern in question is located about 30 meters from the surface.

The scenes, which were recorded by the team of archaeologists who were in charge of the project, are faithful testimony of the difficulties they faced in collecting the material and the danger of the descent.

Curiously, everything indicates that the bodies did not arrive there as a result of some cataclysm or natural disaster, so it is presumed that they were corpses - even of several generations - that were piled up on site for hygiene reasons.

Until now, this practice was attributed only to Homo sapiens, which was supposed to be the first species to initiate some kind of mortuary rites.

characteristics

At first glance, the skeleton of Homo naledi resembles a puzzle made with pieces of modern man and chimpanzee. The most relevant characteristics are manifested in their height, which has been determined to reach an average of 1.50 m, and their weight of approximately 45 kg.

On the one hand, the shape of the skull is quite rounded as in Homo sapiens, but paradoxically it is of a reduced size that in some cases is half the current average skull.

This contradicts the belief that the more flattened shape found in older species evolved into roundness as the brain grew.

Teeth

Another important factor that dismantles arguments accepted so far has to do with the teeth.

Of course, the size of the teeth is preconfigured to some extent by the size of the skull, so they are much smaller than other hominid species, but additionally their shapes indicate eating habits considered advanced.

Torso

Regarding the torso, we see the most marked retrograde feature, with a narrow rib cage at the top and widening at the bottom, showing a strong link with older species.

This helps to make her look somewhat incongruous with her lower extremities, which could practically be mistaken for a current human.

Hands and feet

Details

Right hand of Homo naledi. By Lee Roger Berger research team (http://elifesciences.org/content/4/e09560), via Wikimedia Commons

In the hands there are also characteristics considered antagonistic. The thumb opposite to the rest of the other fingers contrasts with their curved shape.

Until now the development of the thumb was attributed to a point in evolution where the use of tools predominated and the habit of climbing, which justifies long, curved fingers, had been almost completely abandoned.

Foot of Homo naledi.

Age of the remains

In 2017, it was determined that the remains are between 230 thousand and 330 thousand years old, which surprisingly means that Homo naledi has overlapped at some point in history with Homo sapiens; that is, the human being as we know him today.

This fact astonished the scientific world since, despite having certain current characteristics, it was not to be expected that a hominid of that relatively recent date would still have such marked differences in other aspects, especially with regard to the size of the skull and, therefore, of the brain.

Cranial capacity

Homo naledi skull

The center of the controversy caused by the discovery of Homo naledi is limited to its cranial capacity. Until now, this characteristic was associated with the degree of evolution of the species and, as a consequence, with its antiquity.

However, in this case the cranial capacity rejects this premise as other characteristics previously reserved for species of more recent date are present.

The cranial capacity of this new predecessor of Homo sapiens is close to 610 cc (465 cc in females) which, compared to the current one that is around 1300 cc, gives it such a great disadvantage that it makes it difficult to apply traditional criteria to justify the presence of other genetic advances in its configuration.

Evolution

What was handled in the international scientific media was that the evolution of the brain -in terms of its dimensions- would have triggered behaviors that, in turn, originated the other changes that finally resulted in Homo sapiens. All of this is now being reviewed.

The fact that with a brain of such small dimensions this new species of hominid has achieved stylizations in hands, wrists, teeth and feet so close to those we have today, is an enigma for the modern paleontological community.

Handling of corpses

It can be seen as minor that this group of primitive men were specifically concerned with disposing of their corpses, but that suggests a certain human consciousness that had not been detected in other species.

This also shows what may be the emergence of the first funeral rites, or at least the determination to preserve the hygiene of the environment where they were developed.

All these considerations are a matter of controversy at present and reason for revision of paradigms assumed by the entire global scientific community.

Tools

Although no work tools or some utensils were found at the excavation site -which gives strength to the thesis of being chambers to deliberately deposit corpses-, the constitution of the hand and wrists denotes a fairly precise handling of tools.

The size of the fingers and their relationship to the size of the thumb indicates that this species was able to grip tools firmly and safely. As the thumb is confronted with the rest of the fingers, the possibility of manipulating tools with some dexterity can be inferred.

Another issue to which this still unconfirmed possibility is also associated is that, by the time Homo naledi existed, rudimentary tools made of stone already existed, so it would not be unreasonable to think that they passed through his hands.

Feeding

The shape and size of the collected dentures also shed some light on the diet of this new human ancestor.

The teeth are unexpectedly small and its molars have up to five cusps, indicating that Homo naledi may have eaten food harder than its predecessors.

The height of the teeth and their hardness suggests that they were capable of feeding on elements that other hominids did not consider.

The wear present in the studied dentures, corresponding to the remains of older individuals, shows that it is probable that Homo naledi did not have problems in consuming certain foods coated with minerals or remains of sediments.

The dental arch should also be mentioned as another distinguishing characteristic, since it has the parabola shape present in modern humans, in contrast to the first hominids whose dentitions are accommodated in mandibles and maxillae rather in a "U" shape, suggesting shape snout.

Habitat

As in the case of eating habits, the finding of Homo naledi does not make clear the issue of the possible habitat where this not-so-ancient human relative developed.

What is clear after anthropological and paleontological studies of these controversial remains is that this species was able to combine its mobility between bipodal walks and movements through vegetation and trees, just as chimpanzees still do.

Because this scientific event of global importance is so recent, there are still many unknowns to solve and that scientists are currently analyzing. In fact, there are other chambers in the same cave system that contain fossils that are sure to provide more clues.

References

1. Greshko, Michael (2017). "Did This Mysterious Ape-Human Once Live Alongside Our Ancestors?" in National Geographic. Retrieved on August 30 from National Geographic: news.nationalgeographic.com
2. "Resistant molars of Homo Naledi point to a harsh diet" (2018) in Europa Press. Retrieved on August 30 in Europa Press: europapress.es
3. Wong, Kate (2016). "Debate breaks out about a strange new human species" in Scientific America. Retrieved on August 30, 2018 from Scientific America: scientificamerican.com
4. Berger, Lee & team (2015). "Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa" ​​in eLife Sciences. Retrieved on August 30 from eLife Sciences: elifesciences.org
5. Keep, Stephanie (2017). "Is there anything truly surprising about Homo naledi?" in Berkeley. Retrieved August 30, Berkeley: evolution.berkeley.edu
6. "Homo Naledi" in Wikipedia. Retrieved on August 30 from Wikipedia wikipedia.org
7. EFE Agency (2018). "Homo naledi, the mysterious link in human evolution" in El Nuevo Herald. Retrieved on August 25 from El Nuevo Herald: elnuevoherald.com
8. Brophy, Juliet (2018). "What homo naledi teaches us about being human" at TEDxLSU. Retrieved on August 30 from Youtube: youtube.com
9. De Ruiter, Darryl J (2017). "Did Homo Naledi Deliberately Dispose of Their Dead?" in TEDxTAMU. Retrieved on August 30 from YouTube: youtube.com