What are your thoughts on the evolutionary line leading to H. naledi? And why there hasn't been found any predecessor fossils? If they were more arboreal than other humans, perhaps they evolved in more forested environments where fossils might be much more difficult to find.
In regard to the cognitive question, I note studies showing cognitive function mapping more closely to number of neurons than cranial size. Neurons can be packed more or less densely in different parts of the brain and in different species. Perhaps they had a more comparable amount of neutrons to H. sapiens, especially in the frontal areas of brain, than might be thought if we simply compared cranial capacity.
Thanks for asking this great question! I have a lot of thoughts about this obviously, some that we're working to test. You point to an interesting idea, that habitat for H. naledi might have been different from other contemporary hominins. There are actually a number of skulls and other postcranial fossils that have been attributed to H. erectus based on smallish brain size or other traits, that actually may be ancestors of H. naledi. Examples include the frontal bone from Olorgesailie, Kenya, around a million years old, the OH 12 skull from Olduvai Gorge around 800,000 years old, and the DAN5 skull dating as far back as 1.5 million years.
One thing to keep in mind is that our sample of H. naledi is limited to a single place and possibly a very narrow time. The sample may not be characteristic of the overall variation of the species. I think we'll find a lot more examples of H. naledi-like groups from the Middle Pleistocene and earlier.
What are your thoughts on the evolutionary line leading to H. naledi? And why there hasn't been found any predecessor fossils? If they were more arboreal than other humans, perhaps they evolved in more forested environments where fossils might be much more difficult to find.
In regard to the cognitive question, I note studies showing cognitive function mapping more closely to number of neurons than cranial size. Neurons can be packed more or less densely in different parts of the brain and in different species. Perhaps they had a more comparable amount of neutrons to H. sapiens, especially in the frontal areas of brain, than might be thought if we simply compared cranial capacity.
Thanks for asking this great question! I have a lot of thoughts about this obviously, some that we're working to test. You point to an interesting idea, that habitat for H. naledi might have been different from other contemporary hominins. There are actually a number of skulls and other postcranial fossils that have been attributed to H. erectus based on smallish brain size or other traits, that actually may be ancestors of H. naledi. Examples include the frontal bone from Olorgesailie, Kenya, around a million years old, the OH 12 skull from Olduvai Gorge around 800,000 years old, and the DAN5 skull dating as far back as 1.5 million years.
One thing to keep in mind is that our sample of H. naledi is limited to a single place and possibly a very narrow time. The sample may not be characteristic of the overall variation of the species. I think we'll find a lot more examples of H. naledi-like groups from the Middle Pleistocene and earlier.