11

It was mid-January, just after our Christmas break in early 2009, and it was a beautiful summer morning. Back at the lab, the technicians were returning to work, and preparation of the fossils would start up again soon. I had, by then, finished the first high-resolution digital map of the site, and we were ready to begin excavations to recover more material. We needed to start to understand how the blocks containing the skeletons actually went together before the miners had blasted the site.

Soon Peter, Steve, and Darryl would arrive in South Africa to begin work together on the fossils. We needed to compare the Malapa bones systematically with those from other fossil sites, and we booked the fossil vault for several weeks to carry out those comparisons. Together with Job, we would look at the way forward for publication, collaboration with other scientists, and access to the material. I would also look to strengthen these scientists’ associations with Wits, building a long-term commitment to support work in South Africa.

As I became increasingly excited about the scientific potential, I returned to the site myself. I stepped down into the pit, going over to the spot where the humerus and scapula had been. Paul Dirks’s team of geologists had been out to the site in November 2008, assessing the deposits and removing small samples to attempt to figure out the age of that white line of flowstone—it might be the key to understanding the age of the fossils. I wondered about their results as I looked at the large, empty space where we had removed the big block containing the skeleton. I used my fingers to trace a line above that empty space, which seemed to demarcate some sort of boundary in the rock.

A loose block caught my eye. It was just sitting on the edge of the pit, 20 centimeters or so above where the adult skeleton’s arm had been. That rock had somehow gone unnoticed when we collected the big block. I lifted it from the spot where it rested and turned it over in my hands, looking for any fossils. No more than 30 centimeters long, and half again as wide, it probably didn’t contain much, I thought.

A small patch of yellow bone caught my attention. I knew its cross section, shaped like a bowling pin. One of the bones prepared last year had been the elbow end of the right humerus of Matthew’s child, and I was certain this piece had the same cross section. This broken part would connect to the other, allowing us to refit two parts of the humerus together. Maybe it was all there in the block. That would be a coup.

I took the chunk of breccia back to the lab, but only months later would I find out what secrets that small block actually held.

IN THE HOMININ LAB at Wits, I watched Darryl, Steve, Peter, and Job work on the fossils. They sat with Kris Carlson, whom we had recently added to the team, coming on to play a critical role in the application of technology to the study of the Malapa fossils.

The table was draped in green velvet where the team had arrayed the Malapa skeletons alongside dozens of casts of fossils from other sites across Africa. Two weeks of work together had brought us all toward one key question: What were they?

“So, is everyone leaning toward this being Homo?” I asked. Everyone paused their work and looked at me.

“Tobias seemed to think so,” Darryl said. “And if he’s convinced, that would go a long way toward convincing others.”

Phillip Tobias had dropped in to the lab a few days earlier. Showing emotion as he handled the fossils, he noted how small the teeth and mandible seemed to be in comparison to Australopithecus. He declared it “Homo habilis–like.” He would know, we all thought, because he had, after all, been one of the authors of the original description of habilis with Louis Leakey and John Napier back in 1964. His was not an opinion to be taken lightly.

We had easily eliminated the fossils’ being robustus. That species was easily recognized from its teeth—the very large molars; the tiny incisors and canines; the premolar teeth that, in humans, are small, two-cusped affairs but are nearly the size of molars in robustus. There would be no mistaking the teeth in front of us: They did not come from a robust australopith.

The question really came down to this: Were these remains better placed in the genus Homo or in the genus Australopithecus?

It was a timeless question. Tobias had asked it with Louis Leakey in 1964 when they defined Homo habilis. For many months after the habilis fossils were discovered, Phillip had resisted calling them Homo, noting their similarities with the South African Australopithecus africanus. Phillip faced the question again in 1976, when Alun Hughes and his workers uncovered a skull at Sterkfontein known as Stw 53. This skull shared several features with the habilis skulls from East Africa, and came from some of the latest Sterkfontein deposits, which contained rudimentary stone tools like those from Olduvai Gorge, but scientists have argued over the skull ever since. Homo or Australopithecus? Richard Leakey had faced the question with his discovery of the KNM-ER 1470 skull in 1972, the skull that he saw as a complete skull of Homo habilis but that a later scientist would put into a species of its own, Homo rudolfensis. Don Johanson faced the question in 1974 with his teeth from Hadar, in which he saw similarities with Homo, and the Lucy skeleton: In the end he placed both together into Australopithecus. Meave Leakey, too, had faced the question in 1999 with a fossil skull from the Lomekwi site, west of Lake Turkana. That skull had similarities to some Homo specimens, especially the 1470 skull—yet it was different, sharing more features with primitive species like afarensis. Her team placed the enigmatic skull into a genus all its own, Kenyanthropus platyops.

Now, it was our turn to face this question. The answer would not come easy. We first had to compare the new Malapa fossils with the fossils that had been unearthed at Sterkfontein over the years. Since the early days of Robert Broom’s discoveries at the site, Sterkfontein had become a key problem for understanding human evolution. paleo​anthropo​logists recognized nearly all the Sterkfontein fossils as representing just one species, Australopithecus africanus.

But the Sterkfontein fossils represented a lot of diversity. If you went to excavate a cemetery full of the bones of modern humans, you would almost never find such large differences among individuals as we could see among the Sterkfontein fossils. They must have accumulated at this site for many thousands of years, probably from many populations. Maybe there was even more than one species there—certainly others had suggested as such—but the jury was still out.

Looking at our Malapa jaw, we could not easily lump it with any of the others. But it was hard to be sure.

We had Homo fossils in the vault to compare it with. Tobias had called the Stw 53 skull Homo habilis, although other scientists disagreed. As Tobias saw it, its brain was a bit bigger than that of the australopiths, and its face a bit shorter, squared off a bit at the front just below its nose. But we hadn’t found those parts of the Malapa skeletons yet.

We were looking at a treasure trove of new fossils—two partial skeletons. But they were nearly all postcranial bones. For the entire history of paleoanthropology in Africa, scientists had focused their attention primarily on the skulls and teeth. Mostly, that was what they had found. So far our skeletons were missing these parts, except for the two isolated teeth and the mandible. Those pieces were Homo-like, as Tobias had confirmed. But how could we test that hypothesis with the rest of the skeletons when there were hardly any other fossils of early Homo to compare them against?

“We need a skull,” Darryl lamented.

I nodded. A skull would help.

“And we need to go look at all of the Homo material in East Africa,” Job added.