Description

Sahelanthropus tchadensis lived ~ 7 to 6 million years ago in what is now Chad, central Africa. The fossils come predominantly from the Toros-Menalla region in the Djurab Desert.
The best known specimen is a crushed but reconstructable cranium nicknamed “Toumaï” (TM 266-01-060-
Its brain size is small (on the order of ~ 320–380 cc) — in the chimpanzee range rather than near later hominins.
Morphologically, S. tchadensis shows a mosaic of traits:
Reduced canine size (compared to many apes)
Thick enamel on postcanine teeth (intermediate between apes and later hominins)
A relatively forward-placed foramen magnum (i.e. skull base feature suggestive of upright posture)

Because of that skull-base trait, the original describers argued S. tchadensis was adapted for at least some bipedal posture. However, the paucity of postcranial material (bones of the arms, legs, torso) means this interpretation is debated. Some fragmentary limb bones (including a femur) possibly associated with S. tchadensis have been discussed, but whether they indeed belong to this species—and whether they confirm habitual bipedality—is contested.

The paleoenvironment around Toros-Menalla is inferred to have been a mosaic: gallery forest, wooded savanna, and more open patches near water sources (ponds, floodplains) in a semi-Sahel setting.