Sahelanthropus
Sahelanthropus tchadensis is an extinct species of the Homininae (African apes) dated to about 7 million years ago, during the Miocene epoch. The species, and its genus Sahelanthropus, was announced in 2002, based mainly on a partial cranium, nicknamed Toumaï, discovered in northern Chad.
Sahelanthropus tchadensis lived close to the time of the chimpanzee–human divergence, possibly related to Orrorin, a species of Homininae that lived about one million years later. It may have been ancestral to both humans and chimpanzees (which would place it in the tribe Hominini), or alternatively an early member of the tribe Gorillini. In 2020, the femur was analyzed, and it was found that Sahelanthropus was not bipedal,[2] casting doubt on its position as a human ancestor.
Funded by the Mission Paléoanthropologique Franco–Tchadienne, Ahounta Djimdoumalbaye, Fanoné Gongdibé, Mahamat Adoum, and Alain Beauvilain identified the first remains in the Toros-Menalla area (TM 266 locality) in the Djurab Desert of northern Chad. By the time Michel Brunet and colleagues formally described the remains in 2002, a total of six specimens had been recovered: a nearly complete but heavily deformed skull, a fragment of the midline of the jaw with the tooth sockets for an incisor and canine, a right third molar, a right first incisor, a right jawbone with the last premolar to last molar, and a right canine. With the skull as the holotype specimen, they were grouped into a new genus and species as Sahelanthropus tchadensis, the genus name referring to the Sahel, and the species name to Chad. These, along with Australopithecus bahrelghazali, were the first discoveries of any fossil African great ape (outside the genus Homo) made beyond eastern and southern Africa.[1] By 2005, a third premolar was recovered from the TM 266 locality, a lower jaw missing the region behind the second molar from the TM 292 locality, and a lower left jaw preserving the sockets for premolars and molars from the TM 247 locality.[3]
The skull was nicknamed "Toumaï", a name from the local Daza language meaning "hope of life", given to infants born just before the dry season. The nickname was suggested by the then-president of Chad, Idriss Déby, in honour of one of his comrades-in-arms who had been killed in the coup d'état against his predecessor, Hissène Habré. Toumaï also became a source of national pride, and Brunet announced the discovery before the Ministry of Foreign Affairs and a television audience in the capital of N'Djamena, "l'ancêtre de l'humanité est Tchadien...Le berceau de l'humanité se trouve au Tchad. Toumaï est votre ancêtre" ("The ancestor of humanity is Chadian...The cradle of humanity is in Chad. Toumaï is your ancestor.")[4]
Toumaï had been found with a femur, but this was stored with animal bones and shipped to the University of Poitiers in 2003, where it was stumbled upon by graduate student Aude Bergeret the next year. She took the bone to the head of the Department of Geosciences, Roberto Macchiarelli, who considered it to be inconsistent with bipedalism contra what Brunet et al. had earlier stated in their description analysing only the distorted skull. This was conspicuous because Brunet and his team had already explicitly stated Toumaï was associated with no limb bones, which could have proven or disproven their conclusions of locomotion. Because Brunet had declined to comment on the subject, Macchiarelli and Bergeret petitioned to present their preliminary findings during an annual conference organised by the Anthropological Society of Paris, which would be held at Poitiers that year. This was rejected as they had not formally published their findings yet.[5][6] They were able to publish a full description in 2020, and concluded Sahelanthropus was not bipedal.[2]
All Sahelanthropus specimens, representing six to nine different adults, have been recovered within the 0.73 km2 (0.28 sq mi) area.[2]
