On a late-summer day in 2001, at the University of Poitiers in west-central France, the palaeontologist Michel Brunet summoned his colleagues into a classroom to examine an unusual skull. Brunet had just returned from Chad, and brought with him an extremely ancient cranium. It had been distorted by the aeons spent beneath what is now the Djurab desert; a crust of black mineral deposits left it looking charred and slightly malevolent. It sat on a table. “What is this thing?” Brunet wondered aloud. He was behaving a bit theatrically, the professor Roberto Macchiarelli recalled not long ago. Brunet was a devoted teacher and scientist, then 61, but his competitive impulses were also known to be immoderate, and he seemed to take a ruthless pleasure in the jealousy of his peers. “Michel is a dominant male,” Macchiarelli told me. “He’s a silverback gorilla.”
Inspecting the skull, one could make out a mosaic of features at once distinctly apelike and distinctly human: a small braincase and prominent brow ridge, but also what seemed to be a rather unprotruding jaw, smallish canines and a foramen magnum – the hole at the base of the skull through which the spinal cord connects to the brain – that suggested the possibility of an upright bearing, a two-legged gait. Macchiarelli told Brunet he did not know what to make of it. “Right answer!” Brunet said.
The discovery was announced to the world the following year on the cover of Nature, the leading scientific journal, and in a televised ceremony in the Chadian capital, N’Djamena. “A new hominid is born,” Brunet declared. “By virtue of his age, he is the ancestor of all Chadians. But also the ancestor of the whole of humankind!”
The skull, which Brunet called “Toumaï” – a name from the Djurab, meaning “hope of life” – belonged to a two-legged animal of the Upper Miocene epoch, between 6 and 7m years old. Assuming it was indeed our distant forebear, it was the most ancient ever found, by a margin of as much as 1m years. The location of its discovery furthermore suggested that the human lineage might not have evolved in the savannas of the Great Rift valley of east Africa, as long understood, but rather about 1,500 miles west, in what were once the gallery forests of the greater Sahara. Toumaï stood to upend our very notions of how and why we came to be, to “fundamentally change the way we reconstruct the tree of life”, one prominent palaeontologist wrote. Brunet, to whom the honour of naming the new species fell, called it Sahelanthropus tchadensis: “Sahel Man of Chad.”
But immediately questions were raised about whether the species was correctly assigned to the human lineage. The authors of a sneering letter in Nature suggested renaming it “Sahelpithecus” (“Sahel Ape”), most notably because it did not, according to their counter-analysis of the skull, walk on two feet – bipedalism being one of the very few available criteria for identifying ancient members of our evolutionary branch. Yet it escaped the notice of no one in the field that some of the letter-writers were affiliated with another hominid species, which had, until the arrival of Sahelanthropus, held the record for the oldest known. And while the question of Sahelanthropus’s gait was acknowledged to be a crucial one, the skull alone was not going to provide a definitive answer. For that, “postcrania” would be required: remains from the neck down, especially the lower body – a pelvis, a femur. Unfortunately, Brunet reported in Nature, none had been recovered.
Brunet became a celebrity scientist. In France, he shared caviar with President Jacques Chirac. In Chad, where he ran a programme of field research, he befriended the dictator Idriss Déby; the Chadian national airline was soon renamed after Toumaï. In 2003, Brunet received a $1m Dan David award for discoveries that “cast a new light on the history of human origins”. In Poitiers, grant money poured in.
Fame made Brunet grandiose and, in the opinion of some colleagues, slightly paranoid. He seemed to assume that everyone everywhere was consumed with the idea of studying Toumaï, “as if it were the most precious thing on Earth”, said Olga Otero, a researcher who worked with him for years. Brunet’s relations with Macchiarelli, in particular, deteriorated. He had recruited Macchiarelli, who was 15 years his junior, from Rome, and he seemed to expect a certain deference. The palaeontology group in Poitiers was organised to an unusual degree around Brunet, its director; he had a tendency to treat the other scientists as if they were his vassals, as mere “service providers”, Otero said, expecting them to conduct research that furthered his own work, and refusing to sign off on projects that did not. Many members, especially the graduate students, put up with it in exchange for the resources and visibility he afforded them, I was told. But Macchiarelli had no interest in pledging loyalty. “Doubts, additional questions, argument and criticism contribute to the strength, not the weakness, of scientific thought,” he told Nature in 2003. Brunet referred to him derisively as “the Italian”, Macchiarelli told me.
In early 2004, Brunet and much of his group were in the Chadian desert with a film crew, making a documentary about Toumaï. In Poitiers, however, a master’s student named Aude Bergeret was undertaking a study of numerous Chadian fossils, including some from the zone where Toumaï itself had been recovered. One of these fossils, listed as an “undetermined long bone”, was scheduled to be cut in half for examination of the sediments inside. Bergeret wanted to be sure to extract as much information as possible from it beforehand. “There came a point where I was making observations, but I frankly wasn’t sure what I was looking at,” she told me. She needed guidance. The adviser who could have provided it was in the desert with Brunet. Macchiarelli, however, who had been one of her instructors, was on hand.
Initially, Macchiarelli declined to examine the bone. He did not want to get between Bergeret and her advisers, he told me, and he was cognisant of the ethical norms of the field, which dictate that one does not study fossils unearthed by someone else without their express authorisation. His relations with Brunet were already tense. And he also knew that Brunet had a special sensitivity about Chadian remains, the most important of which had been recovered under circumstances that were, from Brunet’s perspective, far from ideal.
Brunet had not in fact been in Chad for the discovery of the cranium that made him famous, and had not even authorised, much less directed, the small expedition that found it in 2001. Rather, a geographer named Alain Beauvilain, who handled the logistics of the Chadian operations, had, with three Chadian colleagues, set out from N’Djamena on an impromptu prospecting mission in the desert. Beauvilain, who had already been feuding with Brunet in the years before the discovery, was not shy about sharing these details with the world. As director of the research programme, Brunet was, by convention, the ultimate discoverer, but as soon as the description of Toumaï was published in Nature, he had Beauvilain recalled to France. And since then he had tried, in essence, to write him out of the story.
... continue reading