Sahelanthropus tchadensis dating techniques
In addition, computed tomography (CT, an imaging technique, similar to x-ray, that permits researchers to observe the internal structures of bones) scans of the proximal femur show that the cortical bone (outer layer of bone) has differential thickness along the top and bottom surfaces; it is thickened inferiorly and thinner superiorly.
This morphology has been argued to indicate that s was bipedal is unresolved.
This species lived sometime between 7 and 6 million years ago in West-Central Africa (Chad).
Walking upright may have helped this species survive in diverse habitats, including forests and grasslands.
Drawing connections between is bipedal, these environmental reconstructions would suggest that the earliest species practicing this form of locomotion evolved in more forested habitats, contrary to the once widely held belief that bipedality was an adaptation to life on the savanna.
While some researchers are convinced by the features in this species that seem to indicate that it practiced bipedalism, others remain skeptical.
Specimens include teeth and lower jaw fragments, pieces of the humerus (the bone of the upper arm), pieces of the femur (thigh bone), and a phalanx (finger bone).
The molar teeth of femur has led some researchers to suggest that it practiced bipedal locomotion.
However, an Australopithecus bahrelghazali mandible was found in Chad by Mamelbaye Tomalta, Najia and Alain Beauvilain, Michel Brunet and Aladji H. The original placement of this species as a human ancestor but not a chimpanzee ancestor would complicate the picture of human phylogeny.
In particular, if Toumaï is indeed a direct human ancestor, then its facial features bring into doubt the status of Australopithecus whose thickened brow ridges were reported to be similar to those of some later fossil hominins (notably Homo erectus), and where the brow ridge morphology of Sahelanthropus differs from that observed in all australopithecines, most fossil hominins and extant humans.