Exclusive: Building the Face of a Newly Found Ancestor | National Geographic

We've all seen crime investigation shows where they find a skull in the woods, and they take it to a forensic artist who builds the soft tissue of the face back on, and it becomes a recognizable entity. The crime is sometimes solved, but how do you do that for an extinct species?

This is a reconstruction of Homo naledi. It's based on fossils that were found in the fall of 2013, deep inside of a cave in South Africa. It's a very interesting species; it's not very much like anything we've found before, so I doubt if there's going to be much argument that this represents a new species.

Basically, what I do is study the evidence that exists in the fossil record, and I use that evidence to predict what a face might look like. The key to all that is comparative anatomy. So, I have to do a lot of facial dissection of great apes, African apes, orangutans, and humans.

From the very beginning, this was such a fascinating ancestor to work on because it's such a weird combination of primitive and more humanlike traits. You start with a skull, and certain measurements on that skull tell you some things about the soft tissue of the face.

The ears are a boondoggle, really, for people like me who reconstruct heads because there's not much information a skull can tell you about the form of the ears. It's not true with noses. Homo naledi had a spine right at the base of the nasal opening that projects out of the nasal cavity, and that tells you that there is at least somewhat of a projecting nose. That's a human characteristic.

Skin color is a problem I obviously have to deal with when I'm thinking about the skin color that should be appropriate for a specific prehistoric hominid. I look to the populations that are living there today. In this case, I'm dealing with a form that lived in South Africa, so the San people were a good model for me to base the idea of skin color on.

The actual pattern of the hair — we simply don't have that kind of information in the fossil record, so I'm making a guess there. I'm using commonalities in the hair pattern in faces that you see in great apes and humans.

It's a wonderful thing to be in the position of being the guy who figures out what some ancient species that's never been found before looked like. So, the final form of a reconstruction of a face is often a surprise to me.

It's the cumulative result of all these individual anatomical decisions, but it has this big "Eureka" moment at the end of the reconstruction, which is almost like the end of a mystery story where an identity is revealed. That's an exciting moment for me — to have that often surprising moment of seeing the face as an entirety for the first time.