A Previously unknown species of hominins, Homo Naledi was discovered as recently as 2013, in the Dinaledi Chamber of the Rising Star cave system. Researchers found an extensive collection of fossils, belonging to 15 individuals of the same species. When examined, researchers found that the individuals belonged to a previously unknown species, because their morphology was different than that of other known species of primates. In their description, Berger et al. found that the hominin has unique cranial morphology, although closely related to other species of hominins, human-like adaptations of the hand and wrist, and humanlike foot and limb structure. This hominin species was of the size of a small current man, reaching 1.5 m in height. The authors chose to describe to describe the individuals based on multiple components, due to the availability of rich material that they disposed of. The Homo Naledi fossils represent the largest collection of hominins ever discovered in Africa
The discovery of a new species must always be carefully announced, after extensive analysis and consideration. This is particularly important in view of the historical habit of Eurpean researchers, who have assigned this label indiscriminately for many years, thus creating confusion in regards to the origin of human beings. As Stringer explains, “Within fifty years, the new European finds were being assigned to dozens of new human species in an unfortunate tumult of typology, where trivial differences were elevated to assume real biological significance”(20). In this context, careful examination and dating of the biological material is paramount because it helps to place the fossils within the right historical context and to illuminate one more aspect of human evolution. As Stringer (74) further shows, the methods of examination have evolved to a great extent, and it is now much easier to determine the exact measurements of a fossil, thus also making it more easier for researchers to establish the place of Homo Naledi in the origin of humans.
Homo Naledi has features which place it in the Homo genus, and yet, it also presents older features that are characteristic of the Australopithecines. In this regard, Berger at al. explain that, “In light of this evidence from complete skeletal samples, we must abandon the expectation that any small fragment of the anatomy can provide singular insight about the evolutionary relationships of fossil hominins” (23). The researchers found different characteristics of the Australopithecus genus, such as the primitive dental proportions and australopith hip mechanics. However, the small teeth of the samples place the species much later in human evolution. Moreover, the the peroneal trachea of the specimens is small enough to be associated with that of much more recent species, and even Homo sapiens.
The brain size is also extremely important in determining the age and evolutionary stage of primates. The small endocrinal volume of this species places it more within the range of Australopithecus than Homo, at only 465-560 cc. Despite this volume, the cranial size is similar to that of early homo populations (Berger et al. 18). The species therefore challenges the trajectory of human evolution, because the researchers cannot find a place for Homo Naledi in history. The researchers found that the Homo Naledi is a transitional stage between Astralopithecines and Homo Habilis, thus establishing that the age of this species is at least 2 million years, perhaps up to 2 million and half. However, dating is still uncertain. The authors show that, “If the fossils prove to be substantially older than 2 million years, H. naledi would be the earliest example of our genus that is more than a single isolated fragment (Berger et al. 24). However, if the species is much younger it would create the possibility that several homo species existed in African until later in human evolution, including a small- brained species (Berger et al. 24). Therefore, Homo Naledi also challenges researchers because it highlights the ignorance of science in regards to the history of human evolution. Scientists believe that human evolution remains an incomplete picture.
The act that the species may be a transitional stage between Australopithecus and Homo adds to the trajectory of human evolution as discussed by Stringer (39-41), because also features different combinations of features, which could be found in other transitional stages, such as the Homo Heidelbergensis, which presents a combination of features found in more primitive fossils of Erectus, and modern humans. While Homo Heidelbergensis lived 500, 000 years ago, and represents a linking piece in human evolution between Homo Erectus and Homo Sapiens, due to the fact that it has a combination of features from both species, Homo Naledi represent a transitional stage as well, being an example of the earliest Homo species. Regardless of whether Homo Naledi is a transitional stage in human evolution, or a separate species which coexisted with Homo species later in human evolution, but had a small brain size usually found in apes, this finding is nevertheless extremely important for scientists, and can reveal yet unknown facts about the origin of humans.
Further studies should determine the age of the fossils. As Stringer (60) shows, carbon dating is not a reliable dating method for Homo Naledi fossils because they are too old to be dated in this way. A more potent way of dating the fossils could be the use of DNA samples, if such samples can be extracted from the fossils. This would show in what way the Homo Naledi is related to later human samples, and would thus provide a more reliable way of dating the samples. This would also allow the researchers to understand how humans evolved in this early period, or whether Homo Naledi is a direct human ancestor, or a separate species which coexisted with other more evolved types of hominins, such as the Homo Floresiensis described by Stringer (100). This hominid species coexisted with other species until as recently as 18, 000 years ago, and also had an ape-like brain.
Apart from performing DNA tests on the samples, further research could also study the behavior particularities of this species which represents a quintessential aspect of human evolution. Discovering how the group of Homo Naledi got in the cage system, and why they were found in such a large number, is an interesting and intriguing quest, because the large number of fossils suggests deliberate actions, that might had have a purpose. As Stringer (136) shows, chimps in the wild have shared tradition such as gathering. However, certain behaviors, like burying the death in ritualistic ways are specific to Homo Sapiens alone. Therefore, studying whether this was a burial place for the Homo Naledi might challenge many of the existing theories regarding human evolution. This is particularly true since as shown above, Homo Naledi had a small brain size, more similar to that of apes than to that of modern humans. Consequently, it is rather improbable that they had burial rituals of any kind. By studying the geology of the area and how the cave system looked like in the past may explain how the individuals may have reached this place, even though it may not give clues as to why this happened.
Therefore, after examining the physical characteristics of the Homo Naledi, the researchers found that this may represent a transitional stage in human development, and may be the earliest form of the Homo genus that was found in Africa. In line with Stringer’s account of the development of the human species, the discovery of this new species shows that there are intermediate stages in human development. However, this is still uncertain in lack of accurate dating, and in fact, this species may represent a form of primitive hominis which coexisted with more developed Homo species, until fairly recently. Either way, this species challenges what we know regarding human evolution, and forces scientists to look further for new information regarding human origin.
Works Cited
Berger, Lee et al. “Homo Naledi, A New Species of the Genus Homo from the Dinaledi Chamber, South Africa”. Genomic and Evolutionary Biology 4 (2015): 1-35.
Stringer, Chris. Lone Survivors: How We Came to Be the Only Humans on Earth. New York: Henry Holt and Company. 2012. Print.
