The video recounts the discovery of Sahelanthropus tchadensis, nicknamed Toumaï, focusing on the controversy surrounding additional postcranial fossils found alongside the skull.
Initial Discovery and Secrecy #
- Sahelanthropus tchadensis skull (Toumaï) discovered in 2000 in Chad.
- Initial report in Nature in 2002 described the skull as a new hominin genus and species.
- The skull was dated to approximately 7 million years ago, making it one of the earliest known hominins.
- Controversy arose almost immediately regarding Toumaï's bipedalism and its placement on the human lineage.
- Researcher Aude Chaline reportedly found a femur and two ulnae at the Toumaï site shortly after the skull.
- These postcranial bones were transferred to Poitiers, France, for study by Michel Brunet's team, the lead paleontologist of the Toumaï discovery.
- The existence of these bones was kept secret from the wider scientific community for nearly two decades.
Evelyne Crégut-Bonnoure's Involvement #
- In 2004, Evelyne Crégut-Bonnoure, an expert in fossil animal locomotion, was invited to study fossil animal remains from the Toros-Menalla site.
- She discovered a box containing the previously unreported hominin femur, along with other hominin fragments and more than 6,000 other fossils from the Sahelanthropus site.
- Crégut-Bonnoure was asked by Roberto Macchiarelli, a paleoanthropologist also working with the Poitiers team, to analyze the femur.
- Her findings indicated that the femur belonged to a bipedal primate, potentially strengthening the case for Toumaï's hominin status.
- The researchers involved were explicitly told to keep the existence and the study of the femur secret, with threats of career repercussions if they disclosed it.
Reasons for Secrecy and Delayed Publication #
- The main reason cited for secrecy was the political unrest in Chad, making it difficult to return to the site and conduct further research.
- Some believe the secrecy was due to the ongoing debate about Toumaï's bipedalism. If the femur did not support bipedalism, it could undermine the significance of the skull.
- Another theory suggests that the researchers wanted to publish a comprehensive study of the postcranial remains in one go, rather than piecemeal publications.
- The lead researchers (Brunet et al.) were reportedly uncomfortable with Macchiarelli's or Crégut-Bonnoure's involvement in the publication of the postcranial remains.
Leak and Publication #
- In 2009, a document detailing the femur's potential hominin bipedalism circulated amongst a small group of researchers.
- In 2018, Roberto Macchiarelli anonymously leaked information about the femur, fearing it would never be published.
- This leak prompted French journalists to investigate, leading to an article in Le Monde in 2019, revealing the existence of the femur.
- Michel Brunet initially dismissed the femur as belonging to an animal.
- In 2020, Macchiarelli and Crégut-Bonnoure published their independent analysis of the femur in the Journal of Human Evolution, arguing for Toumaï's bipedalism.
- This publication was widely criticized by other researchers for ethical reasons.
- In 2022, Brunet's team published their own analysis of the femur and ulnae in Nature, also concluding that Toumaï was bipedal.
- The discrepancies in the two analyses (e.g., specific measurements, interpretation of bipedalism) remain a subject of active debate.
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