Four employees of the Centre National d'Appui à la Recherche (CNAR, National Research Support Center) of the Ministry of Higher Education of the Republic of Chad, three Chadians (Ahounta Djimdoumalbaye,[2] Fanoné Gongdibé and Mahamat Adoum) and one French (Alain Beauvilain[3]) collected and identified the first remains in the Toros-Menalla area (TM 266 locality) in the Djurab Desert of northern Chad, July 19, 2001.

[4] The skull was nicknamed Toumaï by the then-president of the Republic of Chad, Idriss Déby, not only because it designates in the local Daza language meaning "hope of life", given to infants born just before the dry season and who, therefore, have fairly limited chances of survival, but also to celebrate the memory of one of his comrades-in-arms, living in the north of the country where the fossil was discovered, and killed fighting to overthrow President Hissène Habré supported by France.

[6][7] 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.

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.

[10] Upon description, Brunet and colleagues were able to constrain the TM 266 locality to 7 or 6 million years ago (near the end of the Late Miocene) based on the animal assemblage, which made Sahelanthropus the earliest African ape at the time.

[1] In 2008, Anne-Elisabeth Lebatard and colleagues (which includes Brunet) attempted to radiometrically date using the 10Be/9Be ratio the sediments Toumaï was found near (dubbed the "anthracotheriid unit" after the commonplace Libycosaurus petrochii).

[13] Their methods were soon challenged by Beauvilain, who clarified that Toumaï was found on loose sediments at the surface rather than being "unearthed", and had probably been exposed to the harsh sun and wind for some time considering it was encrusted in an iron shell and desert varnish.

All these genera were anatomically too derived to represent a basal hominin (the group containing chimps and humans), so molecular data would only permit their classification into more ancient and now-extinct lineages.

Cranial features show a flatter face, U-shaped tooth rows, small canines, an anterior foramen magnum, and heavy brow ridges.

[11] In 2023, however, Meyer and colleagues examined its ulna shaft and argued that Sahelanthropus is not an obligate biped based on the mathematical analysis of its locomotor behavior which indicated that its forelimbs had different functions compared to modern humans and hominins, and that it probably walked on its knuckles like modern gorillas and chimpanzees, so more examination is required to truly identify its locomotor behavior (i.e. whether it exhibited facultative bipedalism) and its phylogenetic position as a hominin in the evolution of humans.