Meet our new cousin: Homo naledi

Something very exciting happened this year. We heard the announcement of a new species – quite ancient but closely related to our very own species: the Homo naledi.

In October 2013, two recreational covers (Rick Hunter and Steven Tucher) happened upon some fossil bones within a cave, known as the Dinaledi chamber, located within the Gauteng province of South Africa.

Having heard about scientists in nearby areas searching for fossils, they took some photos and shared them with geologists and a palaeontologist named Lee Berger. This led to the development of the Rising Star Expedition, an international team of 47 individuals led by Lee Berger. In November 2013, the National Geographic Society along with The University of Witwatersrand funded excavation of the cave to examine and analyse the fossils found upon the bed surface of the cave. A second excavation soon followed in March 2014, lasting 4 weeks. What they discovered was astonishing. Overall, approximately 1550 fossil bones were unearthed, nearly completing skeletons of at least 15 individuals. They proposed the bones were of a new species – the Homo naledi.

Now, you may think that being part of the genus Homo, that must make this new species a past, extinct relation of ourselves. Well, this may be true.

Many of the features of the fossil bones are very similar to our bones. For example, they are thought to have had a similar body mass and stature of a shorter human, weighing around 4kg and standing (yes, standing) at 5ft tall. Analysis of the legs, feet and ankles has led to the belief that the Homo naledi were able to walk on two rear limbs, dissimilar to related sub-tribes of the Homininae, such as the Panina – otherwise known as chimpanzees. The skeletal structure, the volume of the base of the skull and the skull shape are similar to that of the early Homo sapien, just of a smaller size. Strikingly, the structure and formation of the eye sockets resemble those of early humans also. Furthermore, some of the hand bones, including the thumb, wrist and palm, are similar to our early ancestors, the Neanderthals, and ours. This gives a sense that they could hold and grasp objects, or even tools, for their own benefit. Nature published a paper describing these similarities. Their teeth are also small, suggesting that their diet did not involve eating food that required heavy chewing, differing from many other primates such as monkeys.

Homo naledi hands_976

Credit: Peter Schmid, SPL and BBC.

Credit: Peter Schmid, Thinkstock and BBC.

Credit: Peter Schmid, Thinkstock and BBC.

However, the Homo naledi has some features similar to that of another extinct sub-tribe of the Homininae, the Australopithecina. Their finger bones were long and slightly curved, suggesting they were adapted to climbing, swinging and suspending from trees. This may have been an important feature of their lives. Their torso and upper body reflected that of a more primitive being, with some suggesting it might have been quite ‘ape-like’. Nevertheless, the similarities of the Homo naledi to the Homo sapien outweigh similarities to the Australopithecina, suggesting that their origin did began in the Homo genus. However, the similarities to the Australopithecina cannot be ignored. Therefore, it is possible that they may have been a hybrid, with different species of Homo naledi evolving across different parts of South Africa, possibly leading to our own evolution. But this is a question that may never be answered, and certainly requires more analysis…

The evolutionary tree of the Homininae. Credit: Wikipedia.

The evolutionary tree of the Homininae. Credit: Wikipedia.

The specie name for Homo naledi is in reference to the Dinaledi chamber in which they were discovered. The Dinaledi chamber translates to the ‘chamber of stars’, and in the Sotho language of South Africa, ‘naledi’ means star. Quite adept don’t you think?

Although this is a fascinating and capturing discovery that may lead to a deeper understanding of our origins, some have a theory that the bones were positioned and purposely placed in the cave, and that they may not be real at all. What do you think about this theory? If you would like to comment, please do so below.

A breath-taking reconstruction of the Homo naledi. Credit: Mark Theissen, National Geographic.

A breath-taking reconstruction of the Homo naledi. Credit: Mark Theissen, National Geographic.

Devon Smith                                                                                                                           The University of Sheffield                                                                                         @DevonCaira

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