---

Recently discovered 800,000 year old bones may lead to a change in scientists' concepts of the human family tree. Elizabeth Farnsworth reports.

---

JIM LEHRER: Now, the new old bones story and to Elizabeth Farnsworth.

ELIZABETH FARNSWORTH: A boy who lived in Spain almost 800,000 years ago offers clues to how we humans came to be. That's the conclusion of a new study by Spanish paleontologists who have been analyzing fossils from a cave near Burgos in Northern Spain. The findings were published today in the American journal "Science." The fossils are the remains of the earliest known Europeans, and the Spanish scientists say the boy is a missing piece in the human evolutionary puzzle. To tell us more we're joined by Rick Potts, director of the human origins program at the Smithsonian Institution. Thanks for being with us.

RICK POTTS, Smithsonian Institution: Thanks for inviting me.

ELIZABETH FARNSWORTH: What's the most important thing about this find?

RICK POTTS: Well, it shows a combination of features of modern features, that is, those features seen in modern humans, and also features found in earlier fossils. So this is a mixture of traits that one would expect in an evolutionary sequence. And indeed--

ELIZABETH FARNSWORTH: So you're talking about the pieces of the boy's skull.

RICK POTTS: The pieces of the boy's skull. Exactly. And the other point is that the Spanish researchers have given it a new name, a new species name, and believe it is the link between modern humans, on the one hand, and the famed group of early humans known as the neanderthals on the other.

ELIZABETH FARNSWORTH: And what's the name they've given it?

RICK POTTS: They've given the name homo antecessor, and that means the human that came before.

ELIZABETH FARNSWORTH: Okay. You've brought some skulls to help us understand this. Show them to us.

RICK POTTS: Well, what we have here is a modern human. This is what you and I and everyone on the face of the planet today looks like. And the middle part of the face is the part that is of interest. The part around the nose, as you can see in a modern human, has a depression on the side, and where the cheekbone--you follow your own cheekbone, in fact, where it joins the front of the face, it comes in at a fairly flat angle. In archaic humans, such as we see here with this neanderthal--and this is a replica--an exact replica of a neanderthal--you see that the middle part of the face is very swollen and that the angle where the cheekbone joins the front of the face is much more angled and almost vertical. What we see in the modern--in the new find from Spain is--

ELIZABETH FARNSWORTH: Which we don't have a replica of because they just have little pieces of it, right?

RICK POTTS: They just have little pieces of it, but they've put it together, and they haven't allowed casts or replicas of it out yet, but we're very much looking forward to getting them. But the new find--the boy--shows a modern-looking mid face, in that area, a long width, very archaic or primitive-looking features like a brow ridge, a heavy jaw, and primitive teeth.

ELIZABETH FARNSWORTH: So what does that add up to? What does that lead them to conclude about--about our origins?

RICK POTTS: Well, what's so interesting about this is that in Western Europe at the site in Spain they suggest that they have the root of the two lines, the two branches leading to modern humans and neanderthals, and it opens up a lot of interesting questions. For example, it's certainly--the neanderthals are known in Europe, but modern humans are thought by many scientists to have originated in Africa. And so what's going on in Africa at this same time range--around 800,000 years ago--there are very few fossils--fossil humans from that time range in Africa, and we need to find more.

ELIZABETH FARNSWORTH: But the idea would be that this homo antecessor is the common link out of which one line became neanderthal and the other line became us.

RICK POTTS: That's correct.

ELIZABETH FARNSWORTH: And then neanderthal became extinct.

RICK POTTS: Then neanderthal became extinct, and they became extinct about 30,000 years ago. It seems like a long time ago, but it's a relatively short period of time.

ELIZABETH FARNSWORTH: So what does this change? Why is this revolutionary, or why is this new?

RICK POTTS: Well, for one thing, it adds another species to our family tree. And that is a process--a scientific process--that has been going on, especially over the last 10 years. Most of the new branches, the new species to our human family tree have been added in the early time frame millions of years ago, and this particular one that deals directly with us and our ancestor.

ELIZABETH FARNSWORTH: Now, some questions have been raised about this, that it's, indeed, these are the remains of the oldest known Europeans but not a new species, is that right?

RICK POTTS: That's right. A number of scientists believe that it's part of the range of variation of other species that are known, such as the neanderthals or even species earlier than the neanderthals.

ELIZABETH FARNSWORTH: And would it make any difference that it's a boy's skull, that perhaps it wasn't fully developed?

RICK POTTS: Yeah. It's an immature individual. We all know that the bones of the face grow as you go to adulthood, and so it would be very interesting to have a more complete set of adult remains. They have part of six different skeletons but the pieces are pretty fragmentary of the adults, and so I think scientists will wait to see what else they find from this cave in Spain.

ELIZABETH FARNSWORTH: How did they find the cave in the first place? How did they find this layer of remnants, of people that lived 780,000 years ago?

RICK POTTS: As I understand the story, that there was someone looking for cave bear fossils, bear fossils, and found, in fact, these humans, and so the Spanish authorities and scientists went into the cave, and they have found actually over 80 fossil humans. But most of them have to do with a time range slightly later than what the new finds deal with.

ELIZABETH FARNSWORTH: What else do they know about the boy? What can they say about that period? This is the ice age, right?

RICK POTTS: This is the ice age, and, of course, the ice age is not a single time of cold but, rather, was a time of great fluctuation. And so one of the great questions is: How were these early humans behaving? How were they acting and interacting with their environments, especially times when they were warm, when the environment was warm and very cold? And this is one of the key questions in human origins.

ELIZABETH FARNSWORTH: You said that we'd need to find--or you all would need to find these kinds of people in Africa to be able to learn more. Is that what you're looking for?

RICK POTTS: Yes, yes, indeed. In fact, a few weeks from now I'm leading a Smithsonian expedition to East Africa to a site there in the Rift Valley of Kenya that falls right in the same time range, from about one million years ago to six hundred thousand years ago. And the place is absolutely littered with stone tools, the business cards, if you will, of the early humans. But we haven't yet found any fossil humans. I think I have an idea why that's the case, but they were beginning to live--the early humans were beginning to live up in the highlands, and so we're going to be looking at new sites this time.

ELIZABETH FARNSWORTH: And just briefly, what else has to happen to sort of nail down this--let's say you--for the Spanish paleontologists, what do they have to do to make this more acceptable?

RICK POTTS: Sure. Well, they need to find I think more in the same time range, around this 800,000 year layer, and the more that they find, the more we'll be able to understand what the population was like, the range of variation in the face, for example, extend into the range of neanderthals, and so this population may actually be like the neanderthal, or do they range separate and, thus, a new species of early human?

ELIZABETH FARNSWORTH: Well, Rick Potts, thanks for being with us.

RICK POTTS: My pleasure.

REGIONS TOPICS RECENT PROGRAMS ABOUT US FEEDBACK SUBSCRIPTIONS / FEEDS:

Support the kind of journalism done by the NewsHour...Become a member of your local PBS station.
PBS Online Privacy Policy Copyright ©1996- MacNeil/Lehrer Productions. All Rights Reserved.