We received correspondence from Professor Roberto Macchiarelli (University of Poitiers) possibly shedding new light on Sahelanthropus tchadensis. a six million year old cranium and said to be the earliest known hominin. At the same time as the finding of the fragmented cranium in 2003, there were adjacent bone fragments including a femur. The femoral shaft is all that remains of the original bone; the distal condyles and proximal trochanter have disappeared. Absence of trochanter and condyles mean the case for bipedality cannot be made on the evidence of the femur alone.
The foramen magnum on the reconstructed cranium has the proper orientation for bipedality however. Lacking each end of the femoral shaft, scientists cannot determine whether this individual had erect posture in trees or was a dedicated biped on the ground.
See the discussion of S. tchadensis on our Timeline.
Red the commentary in the journal Nature.