It’s only been a few weeks since the announcement of the discovery of bones of Homo naledi, a new species related to modern humans. Found in a cave called Rising Star, about 50 km north-west of Johannesburg, South Africa, the bones have immediately been studied and two articles just published in the journal “Nature Communications” describes studies on the these hominids’ hands and feet.
Paleoanthropologist Tracey Kivell is the lead author of the study on the hands of Homo naledi, based on nearly 150 bones that include the almost complete right hand of an adult. The hands of these hominids revealed a unique anatomical combination which is different from that of other known species related to humans.
Homo naledi had wrist and thumb bones with anatomical features in common with modern humans and Neanderthals. They suggest that they had a strong grip and the ability to use stone tools. However, the finger bones are more curved than those of most of the early human species such as Australopithecus afarensis, the species the famous Lucy belonged to. This suggests that Homo naledi used their hands to climb trees.
From this mix of modern human and more primitive characteristics, the researchers concluded that Homo naledi had hands that were specialized for the use of tools but at the same time were still being used for locomotion. An interesting feature is that these hands indicate an ability to use tools by hominids with a small brain.
William Harcourt-Smith is the lead author of the study on the feet of Homo naledi. Theyìre the most similar part to that of modern humans but this research leads to believe that they used them differently. In fact, an analysis of 107 bones of the foot indicates that these hominids were well adapted to walking on two feet but probably could easily climb trees.
Being bipedal is a key feature in the evolution of humans and feet reveal a lot about how a hominid walks. Those of Homo naledi are much more similar to those of modern humans than to those of chimpanzees except for two important characteristics: the toes of Homo naledi are more curved and their feet are generally flatter than those of the average modern human.
Putting together these two studies, we get a portrait of a hominid with a bipedal walking like a human being modern but that at the same time could move easily among the trees. The bones found were thrown into the cave where they were found so there was no way to date them leaving us for the moment with a lot of doubts about Homo naledi’s position in the human family tree.
An attempt of dating via radioisotopes will be made only after completion of all other analyzes of the bones because it requires the destruction of some samples, although small. The hope is that Homo naledi’s bones are not too old and is therefore possible to try to recover pieces of DNA using the latest genetic techniques to better understand these interesting hominids.
