Researchers react to critics of work on oldest human relative
Almost every important fossil hominid seems to spawn controversy. Now Toumaï, man's oldest known ancestor, has his.
The integrity of the 7-million-year-old specimen (Sahelanthropus tchadensis) came under attack in April, when the South African Journal of Science published an article claiming that Toumaï's jaw had a molar glued in the wrong place to round out his set of teeth (A. Beauvilain and Y. Le Guellec S. Afr. J. Sci. 100, 142–145; 2004).
The article was written by Alain Beauvilain, a geographer from the University of Paris X and an author on the original paper, with Yves Le Guellec, a dentist acquaintance of his. Palaeoanthropologists say there is nothing wrong with the published description of Toumaï (M. Brunet et al. Nature 418, 145; 2002), which puts pressure on the South African journal to clarify matters.
The backlash against the pair, who attracted much attention in the French media when their article was published, began in June. Martin Pickford, chairman of palaeoanthropology and prehistory at the Collège de France in Paris and the reviewer of the article, wrote to the South African Journal of Science offering his “humble apologies” to the journal and to the leader of the Toumaï discovery team, Michel Brunet, a palaeoanthropologist at the University of Poitiers. Pickford admits that he “paid insufficient attention” to details in the article.
Protests continued last month, when more than two dozen of the world's leading palaeoanthropologists wrote to the journal saying that the third molar on the right of Toumaï's jaw is indeed a right molar — not a left one as the critics claim. Brunet says his analysis shows that Toumaï's right molar matches breaks in the tooth's roots, apparently settling the argument.
Beauvilain has helped Brunet organize many trips to bandit-infested areas of the Sahara, but he acknowledges that he was not involved in writing the manuscript and is not a trained palaeoanthropologist.
The South African journal is trying to resolve the dispute, although it has not been able to contact Le Guellec, and Beauvilain is sticking to his guns. “The tooth is clearly from the left side, even if a number of palaeoanthropologists maintain it is from the right,” he told Nature last week.
Additional reporting by Sabine Louët.